1. |
Golasiński K.♦, Maj M., Tasaki W.♦, Pieczyska E.A., Kim H.♦, Full-Field Deformation Study of Ti–25Nb, Ti–25Nb–0.3O and Ti–25Nb–0.7O Shape Memory Alloys During Tension Using Digital Image Correlation,
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-024-07414-8, pp.1-10, 2024Abstract: A Ti–25Nb shape memory alloy (SMA) exhibits shape memory effect associated with stress-induced martensitic transformation from β to α″ phase. Addition of oxygen stabilizes the β phase and changes stress–strain response. Oxygen-added Ti–25Nb SMAs show a more distinct superelastic behavior. In this work, digital image correlation (DIC) was applied to investigate for the first time full-field deformation of Ti–25Nb, Ti–25Nb–0.3O and Ti–25Nb–0.7O (at. pct) SMAs. The specimens were subjected to loading–unloading tensile tests to study local and global mechanical characteristics related to activity of particular deformation mechanisms of the SMAs. Strain and strain rate fields were quantitatively compared at selected stages of each SMA’s deformation. It was found that the Ti–25Nb SMA exhibits a macroscopically localized Lüders-type deformation associated with the stress-induced phase transformation, whereas Ti–25Nb–0.3O and Ti–25Nb–0.7O SMAs show more discrete types of deformation related to activity of interstitial oxygen atoms. As a consequence, at particular stages of deformation, local values of strain rate of Ti–25Nb SMA were significantly higher than those of average strain rate. The results obtained in this paper provide a better understanding of the deformation mechanism in the oxygen-added Ti–25Nb based SMAs. Affiliations:
Golasiński K. | - | other affiliation | Maj M. | - | IPPT PAN | Tasaki W. | - | other affiliation | Pieczyska E.A. | - | IPPT PAN | Kim H. | - | other affiliation |
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2. |
Nowak M., Szeptyński P.♦, Musiał S., Maj M., Sub‑global equilibrium method for identifcation of elastic parameters based on digital image correlation results,
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-024-00979-6, Vol.24, pp.169-190, 2024Abstract: In this work, a new, simple method is presented, which enables identifcation of material properties of solids basing on the digital image correlation (DIC) measurements. It may be considered as a simplifed alternative of low computational complexity for the well-known fnite element model updating (FEMU) method and virtual felds method (VFM). The idea of the introduced sub-global equilibrium (SGE) method is to utilize the fundamental concept and defnition of internal forces and its equilibrium with appropriate set of external forces. This makes the method universal for the use in the description of a great variety of continua. The objective function is the measure of imbalance, namely the sum of squares of residua of equilibrium equations of external forces and internal forces determined for fnite-sized part of the sample. It is then minimized with the use of the Nelder–Mead downhill simplex algorithm. The efciency of the proposed SGE method is shown for two types of materials: 310 S austenitic steel and carbon-fber-reinforced polymer (CFRP). The proposed method was also verifed based on FE analysis showing error estimation. Keywords: Identifcation of material constant,Digital image correlation,Nelder–Mead downhill simplex algorithm,Finite element analysis,Optimization,Linear elasticity Affiliations:
Nowak M. | - | IPPT PAN | Szeptyński P. | - | other affiliation | Musiał S. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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3. |
Kucharski S. J., Maj M., Ryś M., Petryk H. M., Size effects in spherical indentation of single crystal copper,
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, ISSN: 0020-7403, DOI: 10.1016/j.ijmecsci.2024.109138, Vol.272, pp.1-15, 2024Keywords: Hardness, Lattice rotation, Plasticity, Strain Gradient Affiliations:
Kucharski S. J. | - | IPPT PAN | Maj M. | - | IPPT PAN | Ryś M. | - | IPPT PAN | Petryk H. M. | - | IPPT PAN |
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4. |
Kowalczyk-Gajewska K., Maj M., Bieniek K., Majewski M., Opiela K.C., Zieliński T.G., Cubic elasticity of porous materials produced by additive manufacturing: experimental analyses, numerical and mean-field modelling,
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-023-00843-z, Vol.24, pp.34-1-34-22, 2024Abstract: Although the elastic properties of porous materials depend mainly on the volume fraction of pores, the details of pore distribution within the material representative volume are also important and may be the subject of optimisation. To study their effect, experimental analyses were performed on samples made of a polymer material with a predefined distribution of spherical voids, but with various porosities due to different pore sizes. Three types of pore distribution with cubic symmetry were considered and the results of experimental analyses were confronted with mean-field estimates and numerical calculations. The mean-field ‘cluster’ model is used in which the mutual interactions between each of the two pores in the predefined volume are considered. As a result, the geometry of pore distribution is reflected in the anisotropic effective properties. The samples were produced using a 3D printing technique and tested in the regime of small strain to assess the elastic stiffness. The digital image correlation method was used to measure material response under compression. As a reference, the solid samples were also 3D printed and tested to evaluate the polymer matrix stiffness. The anisotropy of the elastic response of porous samples related to the arrangement of voids was assessed. Young’s moduli measured for the additively manufactured samples complied satisfactorily with modelling predictions for low and moderate pore sizes, while only qualitatively for larger porosities. Thus, the low-cost additive manufacturing techniques may be considered rather as preliminary tools to prototype porous materials and test mean-field approaches, while for the quantitative and detailed model validation, more accurate additive printing techniques should be considered. Research paves the way for using these computationally efficient models in optimising the microstructure of heterogeneous materials and composites. Keywords: Pore configuration, Anisotropy, Elasticity, Micro-mechanics, Additive manufacturing Affiliations:
Kowalczyk-Gajewska K. | - | IPPT PAN | Maj M. | - | IPPT PAN | Bieniek K. | - | IPPT PAN | Majewski M. | - | IPPT PAN | Opiela K.C. | - | IPPT PAN | Zieliński T.G. | - | IPPT PAN |
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5. |
Golasiński K., Maj M., Urbański L., Staszczak M., Gradys A.D., Pieczyska E.A., Experimental study of thermomechanical behaviour of Gum Metal during cyclic tensile loadings: the quantitative contribution of IRT and DIC,
Quantitative InfraRed Thermography Journal, ISSN: 1768-6733, DOI: 10.1080/17686733.2023.2205762, pp.1-18, 2023Abstract: Thermomechanical behaviour of Gum Metal (Ti–23Nb–0.7Ta–2.0Zr–1.2O, at.%) under cyclic tension was experimentally investigated using infrared thermography and digital image correlation. The thermomechanical characteristics of particular stages of the subsequent loading-unloading cycles of Gum Metal were identified, i.e. (I) the linear, elastic loading accompanied by the temperature drop, (II) the nonlinear super-elastic loading related to the temperature growth, (III) the transient stage (at which both the superelastic-like behaviour and the plastic one are present simultaneously) and the temperature starts growing fast, (IV) the plastic deformation with a significant growth of temperature, (V) the superelastic-like unloading accompanied by a fast drop in temperature, (VI) the transient unloading with a slower decrease in temperature and (VII) the elastic unloading, with a slight increase in temperature. Thermoelastic effect in Gum Metal during both loading and unloading was analysed in each tensile cycle. Finally, the evolution of strain and temperature fields just before unloading in each cycle was discussed and a comparison of the fields at selected stages of cycles 12 and 24 was presented. The results of this work enabled us to identify the non-dissipative processes of elastic and superelastic-like deformations as well as the dissipative process of plastic deformation. Keywords: Gum Metal,β-Ti alloy,cyclic tension,superelasticity,thermoelastic effect,infrared thermography,digital image correlation Affiliations:
Golasiński K. | - | IPPT PAN | Maj M. | - | IPPT PAN | Urbański L. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Gradys A.D. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN |
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6. |
Krajewski M., Witowski A.♦, Liou S.♦, Maj M., Tokarczyk M.♦, Wasik D.♦, Poly(vinylidene fluoride-co-hexafluoropropylene) films filled in iron nanoparticles for infrared shielding applications,
Macromolecular Rapid Communications, ISSN: 1022-1336, DOI: 10.1002/marc.202300038, No.2300038, pp.1-7, 2023Abstract: In order to use the infrared (IR) radiation shielding materials, they should take a form of thin film coatings deposited on glass/polymer substrates or be used as fillers of glass/polymer. The first approach usually suffers from several
technological problems. Therefore, the second strategy gains more and more attention. Taking into account this trend, this work presents the usage of iron nanoparticles (Fe NPs) embedded into the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) films as the shielding material in near-infrared (NIR) and mid-infrared (MIR) region. The performed
investigations show that the transmittance of copolymer films decreases with
increasing content of the Fe NPs inside them. It is found that the average fade of IR transmittance for 1, 2.5, 5, 10, and 50 mg of Fe NPs is about 13%, 24%, 31%, 77%, and 98%, respectively. Moreover, it is observed that the PVDF-HFP films filled in the Fe NPs almost does not reflect the NIR and MIR radiation. Hence, the IR shielding properties of the PVDF-HFP films can be effectively tuned by the addition of proper amount of the Fe NPs. This, in turn, shows that the PVDF-HFP films filled in the Fe NPs constitute a great option for IR antireflective and shielding applications. Keywords: antireflective materials, copolymer films, infrared radiation shielding materials, iron nanoparticles, nanofillers Affiliations:
Krajewski M. | - | IPPT PAN | Witowski A. | - | other affiliation | Liou S. | - | University of Maryland (US) | Maj M. | - | IPPT PAN | Tokarczyk M. | - | University of Warsaw (PL) | Wasik D. | - | University of Warsaw (PL) |
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7. |
Musiał S., Maj M., Urbański L., Nowak M., Field analysis of energy conversion during plastic deformation of 310S stainless steel,
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, ISSN: 0020-7683, DOI: 10.1016/j.ijsolstr.2021.111411, Vol.238, pp.111411-1-20, 2022Abstract: The paper concerns the experimental analysis of the energy conversion process during uniaxial tension of 310S austenitic steel. The plastic work distributions were obtained taking into account the influence of strain rate and plastic anisotropy based on the displacement gradient determined experimentally using Digital Image Correlation (DIC) method. On the other hand, the energy dissipated as heat was obtained by the calculation of heat sources from the transient heat conduction equation basing on both the evolution of the temperature field determined by Infrared Thermography and mechanical field provided by DIC. It was shown that the proportions between the terms of the heat conduction equation and between the particular components of the energy dissipated as heat are significantly different for various process durations. As a measure of energy conversion the energy storage rate was used. At the beginning of the plastic deformation, the values are in the range from 0.4 to 0.6 depending on the strain rate and then decrease monotonically up to the level of around 0.15 with the increasing strain. Moreover, just before the end of the process the values decrease significantly and become close to 0 or even negative, which means that the material loses its ability to store the energy. Keywords: digital image correlation, infrared thermography, energy conversion, transient heatconduction equation, heat sources, energy storage rate Affiliations:
Musiał S. | - | IPPT PAN | Maj M. | - | IPPT PAN | Urbański L. | - | IPPT PAN | Nowak M. | - | IPPT PAN |
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8. |
Frydrych K., Libura T., Kowalewski Z., Maj M., Kowalczyk-Gajewska K., On the role of slip, twinning and detwinning in magnesium alloy AZ31B sheet,
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2021.141152, Vol.813, pp.141151-1-14, 2021Abstract: The paper reports experimental and numerical study of different deformation mechanisms activated in the AZ31B mag nesium alloy sheet subjected to cyclic in-plane tensile – compressive deformation. The influence ofslip, twinning and detwinning upon the mechanical response and texture evolution of the material is thoroughly investigated. The regime of twinning and detwinning activity is assessed based on the variation of hardening modulus in the course of the process. Velocity-based large strain crystal plasticity model accounting for twinning and detwinning is formulated. The crystal plasticity model parameters are identified using the implementation of the evolutionary algorithm. Predicted activity of deformation mechanisms is discussed with respect to the experimental data. Keywords: twinning, detwinning, crystal plasticity, magnesium alloys, AZ31B, evolutionary algorithm Affiliations:
Frydrych K. | - | IPPT PAN | Libura T. | - | IPPT PAN | Kowalewski Z. | - | IPPT PAN | Maj M. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN |
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9. |
Maj M., Nowak M., Musiał S., Płociński T.♦, Experimental analysis of material, lattice and plastic rotation during deformation of aluminium multicrystal,
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2020.139725, Vol.790, pp.139725-1-5, 2020Abstract: This paper focuses on the experimental determination of the distribution of material, lattice and plastic rotation during deformation of crystalline aggregate. The proposed methodology uses standard electron backscattering diffraction technique combined with 3D digital image correlation data. The presented approach is used for analysis of rotations during deformation of aluminium multicrystal. Keywords: image analysis, electron backscattering diffraction, plastic deformation, misorientation, plastic rotation Affiliations:
Maj M. | - | IPPT PAN | Nowak M. | - | IPPT PAN | Musiał S. | - | IPPT PAN | Płociński T. | - | Warsaw University of Technology (PL) |
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10. |
Bochenek K., Węglewski W., Morgiel J.♦, Maj M., Basista M., Enhancement of fracture toughness of hot-pressed NiAl-Re material by aluminum oxide addition,
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2020.139670, Vol.790, pp.139670-1-6, 2020Abstract: In the search for a remedy to increase the fracture toughness of NiAl, the effect of rhenium and aluminum oxide addition is explored. Using a powder metallurgy processing route an optimum composition of NiAl-Re-Al2O3 material is found which manifests KIC over two times higher than as-received NiAl sintered under the same conditions. Keywords: fracture behavior, stress/strain measurements, intermetallics, composites, powder metallurgy, grains and interfaces Affiliations:
Bochenek K. | - | IPPT PAN | Węglewski W. | - | IPPT PAN | Morgiel J. | - | Institute of Metallurgy and Materials Science, Polish Academy of Sciences (PL) | Maj M. | - | IPPT PAN | Basista M. | - | IPPT PAN |
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11. |
Golasiński K.M., Pieczyska E.A., Maj M., Staszczak M., Świec P.♦, Furuta T.♦, Kuramoto S.♦, Investigation of strain rate sensitivity of gum metal under tension using digital image correlation,
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-020-00055-9, Vol.20, No.2, pp.53-1-14, 2020Abstract: Mechanical behavior of a multifunctional titanium alloy Gum Metal was investigated by conducting tensile tests at various strain rates and applying digital image correlation (DIC) technique. Stress–strain curves confirmed low Young's modulus and high strength of the alloy. The determined values of yield strength had a tendency to increase, whereas the elongation to the specimen rupture tended to decrease with increasing strain rate. True stress versus strain curves were analyzed using selected lengths of virtual extensometer (VE) placed in the strain localization area. When the initial length of the VE was the same as the gauge length, work hardening was observed macroscopically at lower strain rates, and a softening was seen at higher strain rates. However, the softening effect was not observed at the shorter VE lengths. Evolution of the Hencky strain and rate of deformation tensor component fields were analyzed for various strain rates at selected stages of Gum Metal loading. The DIC analysis demonstrated that for lower strain rates the deformation is macroscopically uniform up to the higher average Hencky strains, whereas for higher strain rates the strain localization occurs at the lower average Hencky strains of the deformation process and takes place in the smaller area. It was also found that for all strain rates applied, the maximal values of Hencky strain immediately before rupture of Gum Metal samples were similar for each of the applied strain rates, and the maximal local values of deformation rate were two orders higher when compared to applied average strain rate values. Keywords: titanium alloy, gum metal, strain rate sensitivity, strain localization, digital image correlation, full-field deformation analysis Affiliations:
Golasiński K.M. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Świec P. | - | other affiliation | Furuta T. | - | Toyota Central Research & Development Laboratories (JP) | Kuramoto S. | - | Ibaraki University Japan (JP) |
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12. |
Frydrych K., Maj M., Urbański L., Kowalczyk-Gajewska K., Twinning-induced anisotropy of mechanical response of AZ31B extruded rods,
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2019.138610, Vol.771, pp.138610-1-14, 2020Abstract: Texture and twinning-induced anisotropy of the yield stress and hardening of AZ31B extruded rods is investigated. The multidirectional compression tests involving strain path changes are performed in order to: i. assess which slip and twinning systems are active in the polycrystalline sample with a strong texture, ii. analyze the influence of the preliminary deformation upon twin formation, iii. observe the resulting change of the mechanical response. In order to fulfil these goals mechanical testing is supplemented by microstructure analysis. Experimental observations are used to validate the proposed crystal plasticity framework when it is combined with the viscoplastic self-consistent scheme. On the other hand, the results of numerical simulations are used to confirm an advocated interpretation of experimental findings. Finally, the experimental and numerical results are discussed with respect to the theoretical study of slip and twinning activity on the basis of the generalized Schmid criterion. It is concluded that twinning activity influences the mechanical response predominantly by the texture change and to lesser extent by modification of strain hardening due to slip-twin interactions. Keywords: crystal plasticity, anisotropy, plastic deformation, twinning, hcp Affiliations:
Frydrych K. | - | IPPT PAN | Maj M. | - | IPPT PAN | Urbański L. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN |
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13. |
Golasiński K.M., Pieczyska E.A., Maj M., Mackiewicz S., Staszczak M., Kowalewski Z.L., Urbański L., Zubko M.♦, Takesue N.♦, Anisotropy of gum metal analysed by ultrasonic measurement and digital image correlation,
MATERIALS SCIENCE AND TECHNOLOGY, ISSN: 0267-0836, DOI: 10.1080/02670836.2019.1629539, Vol.36, No.9, pp.996-1002, 2020Abstract: The mechanical anisotropy of a multifunctional titanium alloy, Gum Metal, is investigated in this paper. The structural characterisation showed a strong <110> texture for Gum Metal, that is a result of the cold-swaging process applied during its manufacture. Gum Metal was treated as a transversally isotropic solid because of this texture. A significant difference from Young's moduli of the alloy was detected from the ultrasonic measurement of parallel and perpendicular directions to the alloy swaging direction. Samples of Gum Metal cubes were compressed in two different orientations. During the deformation process, two perpendicular walls of each sample were monitored by two visible range cameras for further two-dimensional digital image correlation analysis, this confirmed a strong plastic anisotropy in Gum Metal. Keywords: gum metal, compression, mechanical anisotropy, digital image correlation, ultrasonic measurement, texture, titanium alloy, full-field deformation measurement Affiliations:
Golasiński K.M. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Mackiewicz S. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Kowalewski Z.L. | - | IPPT PAN | Urbański L. | - | IPPT PAN | Zubko M. | - | other affiliation | Takesue N. | - | Fukuoka University (JP) |
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14. |
Kowalczyk-Gajewska K., Pieczyska E.A., Golasiński K.M., Maj M., Kuramoto S.♦, Furuta T.♦, A finite strain elastic-viscoplastic model of gum metal,
International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2019.02.017, Vol.119, pp.85-101, 2019Abstract: A hyperelastic-viscoplastic model of Gum Metal is presented. The model is formulated in the large strain framework. The free energy function is postulated consisting of the hyperelastic and viscoplastic components. Original extension of the Neo-Hooke model with a power law component is proposed for hyperelasticity, which enables to describe a relatively large non-linear elastic regime observed for the alloy. Viscoplastic strain follows the Perzyna-type law with an overstress function. The model is implemented into the finite element method and used to simulate the Gum Metal response in multiple tension loading-unloading cycles. The results are compared with experimental outcomes. Good accordance of the simulation results and the available experimental data is obtained. Keywords: large strain, hyperelasto-viscoplasticity, gum metal, cyclic deformation Affiliations:
Kowalczyk-Gajewska K. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN | Golasiński K.M. | - | IPPT PAN | Maj M. | - | IPPT PAN | Kuramoto S. | - | Ibaraki University Japan (JP) | Furuta T. | - | Toyota Central Research & Development Laboratories (JP) |
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15. |
Musiał S., Nowak M., Maj M., Stress field determination based on digital image correlation results,
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1016/j.acme.2019.06.007, Vol.19, No.4, pp.1183-1193, 2019Abstract: The aim of this work was to determine the stress distribution during plastic deformation, based on the displacement field obtained using the digital image correlation (DIC) method. To achieve stress distribution, the experimentally measured displacement gradient and the elastoplastic material model with isotropic hardening were used. The proposed approach was implemented in the ThermoCorr program. The developed procedure was used to determine stress fields for uniaxial tension and simple shear processes, carried out on samples made of austenitic steel 304L. Both material parameters, such as the Young's modulus, Poisson's ratio, yield stress, and parameters of the hardening curve, were acquired experimentally. The macroscopic force obtained from the DIC-based stresses and its finite element analysis (FEA) equivalent were compared with that measured during the experiment. It was shown that the DIC-based approach gives more accurate results with respect to FEA, especially for a simple shear test, where FEA significantly overestimates the value of experimentally obtained macroscopic force. Keywords: stress field determination, digital image correlation (DIC), finite element analysis (FEA), elastoplastic constitutive model, plastic work Affiliations:
Musiał S. | - | IPPT PAN | Nowak M. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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16. |
Pieczyska E.A., Golasiński K.M., Maj M., Furuta T.♦, Kuramoto S.♦, Development of strain localization in a beta-titanium alloy gum metal analyzed by infrared camera and digital image correlation for various strain rates,
Proceedings — Open Access Journal, ISSN: 2504-3900, DOI: 10.3390/proceedings2019027051, Vol.27, No.1, pp.51-1-4, 2019Abstract: Effects of thermomechanical couplings were studied in a new beta Ti alloy by IR and DIC techniques. The obtained stress-strain curves confirmed low Young’s modulus and high strength of the alloy. The determined values of yield strength increases and values of elongation till rupture decreases with increasing strain rate. It was found, by using fast and sensitive infrared camera, that the large limit of the Gum Metal reversible nonlinear deformation originates from mechanisms of dissipative nature, probably exothermic stress-induced transition of α" nanodomains. Keywords: titanium alloy, gum metal, strain rate, infrared camera, temperature change, DIC Affiliations:
Pieczyska E.A. | - | IPPT PAN | Golasiński K.M. | - | IPPT PAN | Maj M. | - | IPPT PAN | Furuta T. | - | Toyota Central Research & Development Laboratories (JP) | Kuramoto S. | - | Ibaraki University Japan (JP) |
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17. |
Pieczyska E.A., Golasiński K.M., Maj M., Staszczak M., Kowalewski Z.L., Furuta T.♦, Kuramoto S.♦, Yielding and strain localization effects in gum metal - a unique Ti alloy - investigated by digital image correlation and infrared thermography,
Materials Today: Proceedings, ISSN: 2214-7853, DOI: 10.1016/j.matpr.2019.03.119, Vol.12, pp.235-238, 2019Abstract: The research concerns investigation of yielding and developing of the strain localization in new β-Ti alloy characterized by unique elastic-plastic properties, named Gum Metal. The alloy was subjected to tension on testing machine at three various strain rates up to rupture. Digital image correlation and infrared thermography were applied to analyze the experimental results. Strain distributions were determined on the basis of digital image correlation algorithm. The related temperature variations were found in contactless manner using infrared thermography. Mechanical and the corresponding thermal data were used to study the Gum Metal large nonlinear reversible deformation and localization effects. Keywords: gum metal, tension, large nonlinear elastic deformation, thermomechanical couplings, temperature change, digital image correlation Affiliations:
Pieczyska E.A. | - | IPPT PAN | Golasiński K.M. | - | IPPT PAN | Maj M. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Kowalewski Z.L. | - | IPPT PAN | Furuta T. | - | Toyota Central Research & Development Laboratories (JP) | Kuramoto S. | - | Ibaraki University Japan (JP) |
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18. |
Pieczyska E.A., Maj M., Golasiński K.M., Staszczak M., Furuta T.♦, Kuramoto S.♦, Thermomechanical Studies of Yielding and Strain Localization Phenomena of Gum Metal under Tension,
Materials, ISSN: 1996-1944, DOI: 10.3390/ma11040567, Vol.11, No.567, pp.1-13, 2018Abstract: This paper presents results of investigation of multifunctional beta-Ti alloy Gum Metal subjected to tension at various strain rates. Digital image correlation was used to determine strain distributions and stress-strain curves, while infrared camera allowed for us to obtain the related temperature characteristics of the specimen during deformation. The mechanical curves completed by the temperature changes were applied to analyze the subsequent stages of the alloy loading. Elastic limit, recoverable strain, and development of the strain localization were studied. It was found that the maximal drop in temperature, which corresponds to the yield limit of solid materials, was referred to a significantly lower strain value in the case of Gum Metal in contrast to its large recoverable strain. The temperature increase proves a dissipative character of the process and is related to presence of w and a” phases induced during the alloy fabrication and their exothermic phase transformations activated under loading. During plastic deformation, both the strain and temperature distributions demonstrate that strain localization for higher strain rates starts nucleating just after the yield limit leading to specimen necking and rupture. Macroscopically, it is exhibited as softening of the stress-strain curve in contrast to the strain hardening observed at lower strain rates. Keywords: gum metal, yield limit, thermomechanical coupling, infrared thermography, digital image correlation, strain localization Affiliations:
Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Golasiński K.M. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Furuta T. | - | Toyota Central Research & Development Laboratories (JP) | Kuramoto S. | - | Ibaraki University Japan (JP) |
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19. |
Nowak M., Maj M., Determination of coupled mechanical and thermal fields using 2D digital image correlation and infrared thermography: Numerical procedures and results,
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1016/j.acme.2017.10.005, Vol.18, pp.630-644, 2018Abstract: The objective of the work is to develop numerical method for determining coupled thermo-mechanical fields based on experimental data obtained from two cameras working in the visible and infrared mode. The sequence of images recorded by the first camera is used to determine the displacement field on the sample surface using the 2D digital image correlation (DIC) method. The resulting field from DIC analysis in a form of a set of discrete points with the corresponding in-plane displacement vector is used as the input for the next step of analysis, where the coupled temperature field is computed. This paper provides a detailed description of the numerical procedures, that allow, to obtain coupled thermal and mechanical fields together with the specification of experimental data needed for calculations. The presented approach was tested on an experimental data obtained during uniaxial tension of the multicrystalline aluminum. The developed numerical routine has been implemented in dedicated software, which can be used for the testing of materials on both a macro and micro scales Keywords: Digital image correlation (DIC), Infrared thermography (IRT), Coupled thermo-mechanical fields, Aluminum multicrysta Affiliations:
Nowak M. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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20. |
Pieczyska E.A., Staszczak M., Kowalczyk-Gajewska K., Maj M., Golasiński K.M., Golba S.♦, Tobushi H.♦, Hayashi S.♦, Experimental and numerical investigation of yielding phenomena in a shape memory polymer subjected to cyclic tension at various strain rates,
POLYMER TESTING, ISSN: 0142-9418, DOI: 10.1016/j.polymertesting.2017.04.014, Vol.60, pp.333-342, 2017Abstract: This paper presents experimental and numerical results of a polyurethane shape memory polymer (SMP) subjected to cyclic tensile loading. The goal was to investigate the polymer yielding phenomena based on the effects of thermomechanical coupling. Mechanical characteristics were obtained with a testing machine, whereas the SMP temperature accompanying its deformation process was simultaneously measured in a contactless manner with an infrared camera. The SMP glass transition temperature was approximately 45oC; therefore, when tested at room temperature, the polymer is rigid and behaves as solid material. The stress and related temperature changes at various strain rates showed how the SMP yield limit evolved in subsequent loading-unloading cycles under various strain rates. A two-phase model of the SMP was applied to describe its mechanical response in cyclic tension. The 3D Finite Element model of a tested specimen was used in simulations. Good agreement between the model predictions and experimental results was observed for the first tension cycle. Keywords: Shape memory polymer, Tension cyclic loading, Thermomechanical coupling, Yield limit, Thermoelastic effect, Constitutive model Affiliations:
Pieczyska E.A. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN | Maj M. | - | IPPT PAN | Golasiński K.M. | - | IPPT PAN | Golba S. | - | University of Silesia (PL) | Tobushi H. | - | Aichi Institute of Technology (JP) | Hayashi S. | - | SMP Technologies Inc. (JP) |
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21. |
Golasiński K.M., Pieczyska E.A., Staszczak M., Maj M., Furuta T.♦, Kuramoto S.♦, Infrared thermography applied for experimental investigation of thermomechanical couplings in Gum Metal,
Quantitative InfraRed Thermography Journal, ISSN: 1768-6733, DOI: 10.1080/17686733.2017.1284295, Vol.14, No.2, pp.1-8, 2017Abstract: Results of initial investigation of thermomechanical couplings in innovative β-Ti alloy called Gum Metal subjected to tension are presented. The experimental set-up, consisting of testing machine and infrared camera, enabled to obtain stress–strain curves with high accuracy and correlate them to estimated temperature changes of the specimen during the deformation process. Both ultra-low elastic modulus and high strength of Gum Metal were confirmed. The infrared measurements determined average and maximal temperature changes accompanying the alloy deformation process, allowed to estimate thermoelastic effect, which is related to the alloy yield point. The temperature distributions on the specimen surface served to analyse strain localization effects leading to the necking and rupture. Keywords: gum metal, thermomechanical coupling, nonlinear elasticity, yield point, infrared camera Affiliations:
Golasiński K.M. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Maj M. | - | IPPT PAN | Furuta T. | - | Toyota Central Research & Development Laboratories (JP) | Kuramoto S. | - | Ibaraki University Japan (JP) |
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22. |
Pieczyska E.A., Staszczak M., Maj M., Kowalczyk-Gajewska K., Golasiński K.M., Cristea M.♦, Tobushi H.♦, Hayashi S.♦, Investigation of thermomechanical couplings, strain localization and shape memory properties in a shape memory polymer subjected to loading at various strain rates,
SMART MATERIALS AND STRUCTURES, ISSN: 0964-1726, DOI: 10.1088/0964-1726/25/8/085002, Vol.25, No.8, pp.085002-1-15, 2016Abstract: This paper presents experimental and modeling results of the effects of thermomechanical couplings occurring in a polyurethane shape memory polymer (SMP) subjected to tension at various strain rates within large strains. The SMP mechanical curves, recorded using a testing machine, and the related temperature changes, measured in a contactless manner using an IR camera, were used to investigate the polymer deformation process at various loading stages. The effects of thermomechanical couplings allowed the determination of the material yield point in the initial loading stage, the investigation of nucleation and development of the strain localization at larger strains and the estimation of the effects of thermoelastic behavior during the unloading process. The obtained stress–strain and thermal characteristics, the results of the dynamic mechanical analysis and estimated values of the shape fixity and shape recovery parameters confirmed that the shape memory polymer (T g = 45°C) is characterized by good mechanical and shape memory properties, as well as high sensitivity to the strain rate. The mechanical response of the SMP subjected to tension was simulated using the finite element method and applying the large strain, two-phase model. Strain localization observed in the experiment was well reproduced in simulations and the temperature spots were correlated with the accumulated viscoplastic deformation of the SMP glassy phase. Keywords: shape memory polymer, thermomechanical coupling, infrared camera, tension test, strain rate, strain localization, constitutive model Affiliations:
Pieczyska E.A. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Maj M. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN | Golasiński K.M. | - | IPPT PAN | Cristea M. | - | Petru Poni Institute of Macromolecular Chemistry (RO) | Tobushi H. | - | Aichi Institute of Technology (JP) | Hayashi S. | - | SMP Technologies Inc. (JP) |
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23. |
Staszczak M., Pieczyska E.A., Maj M., Kukla D., Tobushi H.♦, Infrared thermographic analysis of shape memory polymer during cyclic loading,
MEASUREMENT SCIENCE AND TECHNOLOGY, ISSN: 0957-0233, DOI: 10.1088/0957-0233/27/12/124007, Vol.27, No.12, pp.124007-1-6, 2016Abstract: In this paper we present the effects of thermomechanical couplings occurring in polyurethane shape memory polymer subjected to cyclic tensile loadings conducted at various strain rates. Stress–strain characteristics were elaborated using a quasistatic testing machine, whereas the specimen temperature changes accompanying the deformation process were obtained with an infrared camera. We demonstrate a tight correlation between the mechanical and thermal results within the initial loading stage. The polymer thermomechanical behaviour in four subsequent loading-unloading cycles and the influence of the strain rate on the stress and the related temperature changes were also examined. In the range of elastic deformation the specimen temperature drops below the initial level due to thermoelastic effect whereas at the higher strains the temperature always increased, due to the dissipative deformation mechanisms. The difference in the characteristics of the specimen temperature has been applied to determine a limit of the polymer reversible deformation and analyzed for various strain rates. It was shown that at the higher strain rates higher values of the stress and temperature changes are obtained, which are related to higher values of the polymer yield points. During the cyclic loading a significant difference between the first and the second cycle was observed. The subsequent loading-unloading cycles demonstrated similar sharply shaped stress and temperature profiles and gradually decrease in values. Keywords: thermomechanical couplings, infrared camera, shape memory polymer, tension, strain rate, thermoelastic effect, yield point Affiliations:
Staszczak M. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Kukla D. | - | IPPT PAN | Tobushi H. | - | Aichi Institute of Technology (JP) |
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24. |
Pieczyska E.A., Maj M., Kowalczyk-Gajewska K., Staszczak M., Gradys A., Majewski M., Cristea M.♦, Tobushi H.♦, Hayashi S.♦, Thermomechanical properties of polyurethane shape memory polymer–experiment and modelling,
SMART MATERIALS AND STRUCTURES, ISSN: 0964-1726, DOI: 10.1088/0964-1726/24/4/045043, Vol.24, pp.045043-1-16, 2015Abstract: In this paper extensive research on the polyurethane shape memory polymer (PU-SMP) is reported, including its structure analysis, our experimental investigation of its thermomechanical properties and its modelling. The influence of the effects of thermomechanical couplings on the SMP behaviour during tension at room temperature is studied using a fast and sensitive infrared camera. It is shown that the thermomechanical behaviour of the SMP significantly depends on the strain rate: at a higher strain rate higher stress and temperature values are obtained. This indicates that an increase of the strain rate leads to activation of different deformation mechanisms at the micro-scale, along with reorientation and alignment of the molecular chains. Furthermore, influence of temperature on the SMP's mechanical behaviour is studied. It is observed during the loading in a thermal chamber that at the temperature 20°C below the glass transition temperature (Tg) the PU-SMP strengthens about six times compared to the material above Tg but does not exhibit the shape recovery. A finite-strain constitutive model is formulated, where the SMP is described as a two-phase material composed of a hyperelastic rubbery phase and elastic-viscoplastic glassy phase. The volume content of phases is governed by the current temperature. Finally, model predictions are compared with the experimental results. Keywords: shape memory polyurethane, thermomechanical couplings, infrared camera, temperature change, dynamic mechanical analysis, strain rate, constitutive model Affiliations:
Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Gradys A. | - | IPPT PAN | Majewski M. | - | IPPT PAN | Cristea M. | - | Petru Poni Institute of Macromolecular Chemistry (RO) | Tobushi H. | - | Aichi Institute of Technology (JP) | Hayashi S. | - | SMP Technologies Inc. (JP) |
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25. |
Wysocka-Fotek O., Maj M., Oliferuk W.♦, Use of pulsed IR thermography for determination of size and depth of subsurface defect taking into account the shape of its cross-section area,
ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.1515/amm-2015-0181, Vol.60, No.2, pp.615-620, 2015Abstract: The paper is devoted to reconstruction of size and depth (distance from the tested surface) of artificial defects with square and rectangular cross-section areas using the pulsed IR thermography. Defects in form of flat-bottom holes were made in austenitic steel plate. The defect size was estimated on the basis of surface distribution of the time derivative of the temperature. In order to asses the depth of defects with considered geometries on the basis of calibration relations (i.e. dependence of time of contrast maximum vs. defect depth for given defect diameter) obtained for circular defects, the ‘equivalent diameter’ describing not only the defect cross-section area but also its shape was assigned. It has been shown that presented approach gives satisfactory results. Keywords: pulsed IR thermography, defect size, defect depth, cross-section shape of defect Affiliations:
Wysocka-Fotek O. | - | IPPT PAN | Maj M. | - | IPPT PAN | Oliferuk W. | - | other affiliation |
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26. |
Oliferuk W.♦, Maj M., Zembrzycki K., Determination of the Energy Storage Rate Distribution in the Area of Strain Localization Using Infrared and Visible Imaging,
EXPERIMENTAL MECHANICS, ISSN: 0014-4851, DOI: 10.1007/s11340-013-9819-1, Vol.55, pp.753-760, 2015Abstract: The presented work is devoted to a new simple method of determination of the energy storage rate (the ratio of the stored energy increment to the plastic work increment) that allows obtaining distribution of this quantity in the area of strain localization. The method is based on the simultaneous measurements of the temperature and displacement distributions on the specimen surface during a tensile deformation. The experimental procedure involves two complementary techniques: i.e. infrared thermography (IRT) and visible light imaging. It has been experimentally shown that during the evolution of plastic strain localization the energy storage rate in some areas of the deformed specimen drops to zero. It can be treated as the plastic instability criterion. Keywords: Infrared thermography, Energy storage rate distribution, Strain localization, Plastic instability criterion, Texture evolution Affiliations:
Oliferuk W. | - | other affiliation | Maj M. | - | IPPT PAN | Zembrzycki K. | - | IPPT PAN |
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27. |
Pieczyska E.A., Staszczak M., Maj M., Tobushi H.♦, Hayashi S.♦, Investigation of thermal effects accompanying tensile deformation of Shape Memory Polymer PU-SMP,
Measurement Automation Monitoring, ISSN: 0032-4140, Vol.61, No.6, pp.203-205, 2015Abstract: Experimental results of effects of thermomechanical couplings occurring in shape memory polymer subjected to tension are presented. Stress-strain curves were recorded by testing machine, while their related temperature changes were measured with infrared camera. The mechanical and thermal characteristics were used to investigate the polymer properties. Three various stages were distinguished during the deformation process. The first, elastic, is accompanied by a drop in the specimen temperature; the second, plastic, is associated with change of the material structure and the temperature increase; the third stage, related to the specimen rupture and damage mechanisms, is accompanied by the significant increase in temperature. Keywords: shape memory polymer, tension, thermomechanical coupling, temperature change, infrared camera Affiliations:
Pieczyska E.A. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Maj M. | - | IPPT PAN | Tobushi H. | - | Aichi Institute of Technology (JP) | Hayashi S. | - | SMP Technologies Inc. (JP) |
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28. |
Staszczak M., Pieczyska E.A., Maj M., Urbański L., Odriozola I.♦, Martin R.♦, Thermomechanical Properties of Vulcanized Rubber investigated by Testing Machine and Infrared Camera,
Measurement Automation Monitoring, ISSN: 0032-4140, Vol.61, No.6, pp.206-209, 2015Abstract: Experimental results of effects of thermomechanical couplings occurring both in natural vulcanized rubber and rubber with self-healing polyurethane subjected to tension at different strain rates are presented. Mechanical characteristics were recorded by testing machine, while the sample temperature changes accompanying the deformation process was measured by infrared camera. The goal was to investigate influence of self-healing polyurethane on the rubber mechanical and thermomechanical properties. It was found that the introduction of the self-healing polyurethane ensures the higher elasticity and the lower tensile strength of the rubber. It was also confirmed that the material is very sensitive to the strain rate; the higher the strain rate, the higher the values of the stress and temperature increases have been obtained. Keywords: vulcanized rubber, self-healing polyurethane, tension test, thermomechanical couplings, temperature changes, infrared camera Affiliations:
Staszczak M. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Urbański L. | - | IPPT PAN | Odriozola I. | - | IK4-CIDETEC (ES) | Martin R. | - | IK4-CIDETEC (ES) |
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29. |
Pieczyska E.A., Maj M., Kowalczyk-Gajewska K., Staszczak M., Urbański L., Tobushi H.♦, Hayashi S.♦, Cristea M.♦, Mechanical and Infrared Thermography Analysis of Shape Memory Polyurethane,
Journal of Materials Engineering and Performance, ISSN: 1059-9495, DOI: 10.1007/s11665-014-0963-2, Vol.23, No.7, pp.2553-2560, 2014Abstract: Multifunctional new material—polyurethane shape memory polymer (PU-SMP)—was subjected to tension carried out at room temperature at various strain rates. The influence of effects of thermomechanical couplings on the SMP mechanical properties was studied, based on the sample temperature changes, measured by a fast and sensitive infrared camera. It was found that the polymer deformation process strongly depends on the strain rate applied. The initial reversible strain is accompanied by a small drop in temperature, called thermoelastic effect. Its maximal value is related to the SMP yield point and increases upon increase of the strain rate. At higher strains, the stress and temperature significantly increase, caused by reorientation of the polymer molecular chains, followed by the stress drop and its subsequent increase accompanying the sample rupture. The higher strain rate, the higher stress, and temperature changes were obtained, since the deformation process was more dynamic and has occurred in almost adiabatic conditions. The constitutive model of SMP valid in finite strain regime was developed. In the proposed approach, SMP is described as a two-phase material composed of hyperelastic rubbery phase and elastic-viscoplastic glassy phase, while the volume content of phases is specified by the current temperature. Keywords: constitutive model, dynamic mechanical analysis, shape memory polyurethane, strain rate, temperature change, thermomechanical couplings Affiliations:
Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Urbański L. | - | IPPT PAN | Tobushi H. | - | Aichi Institute of Technology (JP) | Hayashi S. | - | SMP Technologies Inc. (JP) | Cristea M. | - | Petru Poni Institute of Macromolecular Chemistry (RO) |
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30. |
Pieczyska E.A., Kowalczyk-Gajewska K., Maj M., Staszczak M., Tobushi H.♦, Thermomechanical investigation of TiNi shape memory alloy and PU shape memory polymer subjected to cyclic loading,
Procedia Engineering, ISSN: 1877-7058, DOI: 10.1016/j.proeng.2014.06.264, Vol.74, pp.287-292, 2014Abstract: In applications to sensors, actuators, guide wires, special grips for handicapped people, a shape memory alloy (SMA) or shape memory polymer (SMP) are used as working elements that perform cyclic motions. In order to evaluate the reliability of the shape memory materials (SMM), cycling and fatigue deformation properties are investigated. Since the SMM are very sensitive to temperature, not only mechanical properties but also their related temperature changes accompanying the deformation process should be taken into account. The presented paper embraces experimental investigation of effects of thermomechanical couplings occurring in shape memory alloy and shape memory polymer subjected to various kinds of cycling loading. The deformation was carried out on MTS 858 Testing machine. The strain was measured by a mechanical extensometer, so the stress-strain characteristics were elaborated with high accuracy. Furthermore, a fast and sensitive FLIR Co Phoenix infrared (IR) measurement system was used in order to record infrared radiation from the sample surface. It enables obtaining temperature distribution of the sample as a function of the deformation parameters. For each strain cycle, an increase in temperature during the loading and the temperature decrease during the unloading processes was observed. It was found that the temperature increment recorded during the cyclic deformation depends on the strain rate, the kind of the material and the test conditions. The higher the strain rate the higher the stress and temperature changes were obtained, since the deformation process was more dynamic and has occurred in almost adiabatic conditions. It was shown that various deformation mechanisms are active during various loading stages. Keywords: shape memory alloy, shape memory polymer, cyclic deformation, thermomechanical coupling, infrared camera Affiliations:
Pieczyska E.A. | - | IPPT PAN | Kowalczyk-Gajewska K. | - | IPPT PAN | Maj M. | - | IPPT PAN | Staszczak M. | - | IPPT PAN | Tobushi H. | - | Aichi Institute of Technology (JP) |
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31. |
Staszczak M., Pieczyska E.A., Maj M., Urbański L., Tobushi H.♦, Hayashi S.♦, Właściwości mechaniczne oraz zmiany temperatury polimeru z pamięcią kształtu w procesie rozciągania,
POMIARY AUTOMATYKA KONTROLA, ISSN: 0032-4140, Vol.59, No.9, pp.1002-1005, 2013Abstract: This paper presents experimental evaluation of a new polyurethane shape memory polymer (PU-SMP) produced by SMP Technologies Inc. It discusses mechanical characteristics and temperature changes of the SMP specimens subjected to tension test performed at room temperature with various strain rates. Basing on the mechanical data and the relevant temperature changes, we have studied the thermomechanical properties of the PU-SMP and influence of the strain rate on the strain localization behavior. Finally, we have identified the material parameters for the one-dimensional rheological model of the SMP. Keywords: shape memory polyurethane, tension test, dynamic mechanical analysis, infrared camera, temperature change, thermomechanical properties, rheological model Affiliations:
Staszczak M. | - | IPPT PAN | Pieczyska E.A. | - | IPPT PAN | Maj M. | - | IPPT PAN | Urbański L. | - | IPPT PAN | Tobushi H. | - | Aichi Institute of Technology (JP) | Hayashi S. | - | SMP Technologies Inc. (JP) |
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32. |
Oliferuk W., Maj M., Litwinko R.♦, Urbański L., Thermomechanical coupling in the elastic regime and elasto-plastic transition during tension of austenitic steel, titanium and aluminium alloy at strain rates from 10-4 to 10-1 s-1,
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, ISSN: 0997-7538, DOI: 10.1016/j.euromechsol.2011.08.007, Vol.35, pp.111-118, 2012Abstract: The temperature variation phenomenon during uniaxial deformation of materials with positive coefficient of linear thermal expansion is studied. The formula for a change in the specimen temperature during non-adiabatic tensile deformation is briefly derived. Thermomechanical behaviour of austenitic stainless steel, titanium and aluminium alloy during initial stage of tension at strain rates from 10−4 to 10−1 s−1 has been investigated. It was confirmed, that with increasing stress the temperature of each tested specimen first decreases linearly, reaches a minimum and then starts to rise. The decrease in the specimen temperature corresponds to elastic deformation whereas the temperature rise is related to the plastic one. Thus, the change in the specimen temperature can be used for study of elasto-plastic transition. From the viewpoint of strict theoretical analysis, the yield point will be defined as the stress corresponding to the lowest temperature, if tensile deformation process is adiabatic. The processes of deformation considered in this work are not adiabatic; there is a heat exchange between the specimen and the surroundings. The influence of this fact on the change in the specimen temperature vs. stress is discussed. The problem of yield point as the value of stress corresponding to minimum temperature of the specimen is considered. The influence of the strain rate on the yield point for tested materials is studied. Comparing of the obtained results with theoretical model, the limit above which the deformation process can be treated as the adiabatic one was determined. The values of the yield points determined on the basis of the thermoelastic effect were compared with the stress corresponding to the 0.2% of plastic strain. Keywords: Thermoelastic effect, Yield point, Non-adiabatic deformation Affiliations:
Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN | Litwinko R. | - | other affiliation | Urbański L. | - | IPPT PAN |
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33. |
Wysocka-Fotek O., Oliferuk W., Maj M., Reconstruction of size and depth of simulated defects in austenitic steel plate using pulsed infrared thermography,
INFRARED PHYSICS AND TECHNOLOGY, ISSN: 1350-4495, DOI: 10.1016/j.infrared.2012.02.004, Vol.55, pp.363-367, 2012Abstract: In this paper the size and depth (distance from the tested surface) of defects in austenitic steel were estimated using pulse infrared thermography. The thermal contrast calculated from the surface distribution of the temperature is dependent on both these parameters. Thus, two independent experimental methods of defect size and depth determination were proposed. The defect size was estimated on the basis of surface distribution of the time derivative of the temperature, whereas the defect depth was assessed from the dependence of surface thermal contrast vs. cooling time. Keywords: pulsed IR thermography, temperature time derivative, defect size, thermal contrast, defect depth Affiliations:
Wysocka-Fotek O. | - | IPPT PAN | Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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34. |
Maj M., Oliferuk W., Analysis of Plastic Strain Localization on The Basis of Strain and Temperature Fields,
ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, DOI: 10.2478/v10172-012-0124-2, Vol.57, No.4, pp.1111-1116, 2012Abstract: In the present paper the onset of plastic strain localization was determined using two independent methods based on strain and temperature field analysis. The strain field was obtained from markers displacement recorded using visible light camera. In the same time, on the other side of the specimen, the temperature field was determined by means of infrared camera. The objective of this work was to specify the conditions when the non-uniform temperature distribution can be properly used as the indicator of plastic strain localization. In order to attain the objective an analysis of strain and temperature fields for different deformation rates were performed. It has been shown, that for given experimental conditions, the displacement rate 2000 mm/min is a threshold, above which the non-uniform temperature distribution can be used as the indicator of plastic strain localization. Keywords: plastic strain localization, strain field, temperature field, infrared thermography, heat transfer Affiliations:
Maj M. | - | IPPT PAN | Oliferuk W. | - | IPPT PAN |
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35. |
Zimnoch M.♦, Oliferuk W., Maj M., Estimation of Defect Depth in Steel Plate Using Lock-in IR Thermography,
ACTA MECHANICA ET AUTOMATICA, ISSN: 1898-4088, Vol.4, No.4, pp.6-9, 2010Abstract: The paper deals with the application of lock-in active infrared thermography as one of the non-contact and non-destructive techniques used for estimating defect depth. Preliminary research was done by testing a specimen made of austenitic steel plate with artificially created defects, i.e. flat-bottom holes. The obtained dependence between defect depth and phase shift was presented for different frequencies of “thermal waves” generated inside the sample. The experiment was carried out to determine the application of the lock-in thermography approach in testing materials with a high thermal diffusivity. Keywords: non-destructive testing, lock-in thermography, defect depth, phase shift, thermal diffusivity Affiliations:
Zimnoch M. | - | other affiliation | Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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36. |
Oliferuk W., Maj M., Stress-strain curve and stored energy during uniaxial deformation of polycrystals,
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, ISSN: 0997-7538, DOI: 10.1016/j.euromechsol.2008.06.003, Vol.28, No.2, pp.266-272, 2009Abstract: The subject of this paper is an attempt to obtain information about the energy stored during plastic deformation from experimentally measured stress–strain curve. Theoretical analysis of the stress–strain curve for elastic-perfectly plastic polycrystalline material has shown that only the part of stored energy can be calculated from the stress–strain curve. This part is the energy stored during non-homogeneous plastic deformation. The results of such calculation have been compared with the total stored energy determined experimentally. It has been shown that part of total stored energy related to non-homogeneous plastic deformation of investigated materials is much lower than that corresponding to homogeneous one. Keywords: stored energy, non-homogeneous plastic deformation, geometrically-necessary dislocations Affiliations:
Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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37. |
Oliferuk W., Maj M., Components of energy storage rate during plastic deformation and their identification,
RUDY I METALE NIEŻELAZNE, ISSN: 0035-9696, Vol.54, No.11, pp.732-735, 2009Abstract: The subject of the present paper is decomposition of energy storage rate into terms related to different mode of deformation. The stored energy is the change in internal energy due to plastic deformation determined after specimen unloading. Hence, this energy describes the state of the cold-worked material. Whereas, the ratio of the stored energy increament to the appropriate increament of plastic work is the measure of energy conversion process. This ratio is called the energy storage rate. Experimental results show that the energy storage rate is dependent on plastic strain. This dependence is influenced by different microscopic deformation mechanisms. It has been shown that the energy storage rate can be presented as a sum of particular components. Each of them is related to the separate internal microscopic mechanism. Two of the components are identified. One of them is the storage rate of statistically stored dislocation energy related to uniform deformation. Another one is connected with non-uniform deformation at the grain level. It is the storage rate of the long-range stresses energy and geometrically necessary dislocation energy. Keywords: stored energy, non-uniform plastic deformation, geometrically necessary dislocations Affiliations:
Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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38. |
Wysocka-Fotek O., Oliferuk W., Maj M., Use of pulse IR thermography for detection and quantitative description of subsurface defects in austenitic steel,
RUDY I METALE NIEŻELAZNE, ISSN: 0035-9696, Vol.54, No.11, pp.684-687, 2009Abstract: Pulsed IR thermography is a non-destructive testing method that allows detection of subsurface defects in material. In this method the surface of the tested specimen is stimulated by heat pulse and its self-cooling process is analyzed. The temperature decrease rate is different for surface over defect with comparison to that over the sound material. It is caused by difference between values of heat diffusivity of defected zone and sound one. The purpose of this work is to determine the size and depth of the defects in austenitic steel on the basis of thermal contrast analysis. Because the thermal contrast is dependent on both these parameters, two independent experimental methods of defect size and depth determination were proposed. Keywords: pulsed thermography, thermal contrast, defect characterization Affiliations:
Wysocka-Fotek O. | - | IPPT PAN | Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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39. |
Oliferuk W., Maj M., Plastic instability criterion based on energy conversion,
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2006.02.465, Vol.462, No.1-2, pp.363-366, 2007Abstract: The energy conversion in the plastic deformation process is described by the energy storage rate, defined as the ratio of the stored energy increment to the plastic work increment. The experiment was performed on 304L and 316L stainless steels. It has been shown that during straining the material reaches the state at which the energy storage rate is zero and after that it is negative. This means that a part of energy stored during previous deformation begins to release. The point where the energy storage rate is zero turned out to be the point of Considere stability criterion. Therefore, the zero and negative values of the energy storage rate can be used as a plastic instability criterion on the macro-scale and the release of stored energy as an indicator to describe the progressive predominance of damage leading to the fracture of tested materials. Keywords: stored energy, plastic work, plastic instability criterion, non-homogeneous deformation, austenitic steel Affiliations:
Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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40. |
Oliferuk W., Maj M., Energy storage rate and plastic instability,
ARCHIVES OF METALLURGY AND MATERIALS, ISSN: 1733-3490, Vol.52, No.2, pp.250-256, 2007Abstract: The energy storage rate, defined as the ratio of the stored energy increment to the plastic work increment, versus strain was experimentally estimated in the range of homogeneous deformation as well as in the range of non-homogeneous one. The experiment were performed on 304L and 316L stainless steels. It has been shown, that during straining the material reaches the state at which the energy storage rate is zero and after that it is negative. This means that a part of energy stored during previous deformation begins to release.
It has been found that the point where the energy storage rate is zero turned out to be the point of Considere stability criterion. Therefore the release of stored energy could be used as an indicator to describe the progressive predominance of damage leading to the fracture of a material. This confirms Considere construction that specimen will undergo stable deformation up to the point on the stress-strain curve, for which the strain hardening rate is equal to the flow stress. Some attempts to explain the release of stored energy in terms of microstructure phenomena has been made. Keywords: energy storage rate, plastic work, non-homogeneous deformation, Considere stability criterion Affiliations:
Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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41. |
Oliferuk W., Maj M., Identyfikacja składników energii zmagazynowanej podczas jednoosiowego rozciągania,
RUDY I METALE NIEŻELAZNE, ISSN: 0035-9696, Vol.52, No.11, pp.695-702, 2007Abstract: Podjęto próbę wyznaczenia energii zmagazynowanej na podstawie zależności naprężenie-odkształcenie. Przeprowadzona analiza teoretyczna pokazała, że w ten sposób można wyznaczyć jedynie dolną granicę energii zmagazynowanej. Na podstawie uproszczonego modelu materiału polikrystalicznego, podjęto próbę identyfikacji składników energii zmagazynowanej. Wykazano, że dolną granicę tej energii można traktować jako energię zmagazynowaną na skutek deformacji mikroskopowo niejednorodnej. Wyniki analizy teoretycznej porównano z całkowitą energią zmagazynowaną wyznaczoną eksperymentalnie. Keywords: energia zmagazynowana, odkształcenie jednorodne i niejednorodne, rozkład gęstości dyslokacji Affiliations:
Oliferuk W. | - | IPPT PAN | Maj M. | - | IPPT PAN |
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Oliferuk W., Beygelzimer Y.♦, Maj M., Synkov S.♦, Reshetov A.♦, Pakieła Z.♦, Zdolność magazynowania energii podczas rozciągania tytanu po wyciskaniu przez matrycę skrętną,
Polska metalurgia w latach 2002-2006; Wydawnictwo Naukowe Akapit (Kraków), Świątkowski K. (Ed.), pp.495-500, 2006Abstract: The presented work is devoted to experimental studies of the energy storage process in the tensile test of the ultrafine-grained (UFG) titanium in comparison with the coarse-grained one. The UFG titanium was obtained using severe plastic deformation method (SPD) called twist extrusion (TE) that is briefly presented.
The experiments were performed on three groups of titanium specimens. Two of them (T1 and T2) were cut from the materials obtained by TE method. The T1 titanium was processed by 4 passes through the left twist die, whereas for the T2 titanium the twist direction was changed after the first pass. The last group (T0) was prepared from the annealed sheet of coarse-grained titanium. It was noticed that mechanical properties of the material underwent TE differs considerably from properties of te coarsed-grained one. It was observed that yield point obtained for specimens after TE is about 30% higher then that for coarsed-grained material. However, the elongation decrease was observed for both groups of specimens after TE (T1~60%, T2~25%) with respect to T0 ones.
The energy storage investigations show the differences in the energy storage rate for T1 and T2 specimens. In the case of T1 specimens the energy storage rate decreases rapidly with strain whereas for T2 specimens (where twist direction was changed) the energy storage rate remains constant at the homogeneous deformation range. The experimental results show that the change of the twist direction during TE may improve the mechanical properties of the material. The constant rate of energy storage in specimens after twist direction change may be macroscopic manifestation of homogeneous and more stable structure of the material. Keywords: energy storage rate, ultrafine-grained titanium, severe plastic deformation, twist extrusion Affiliations:
Oliferuk W. | - | IPPT PAN | Beygelzimer Y. | - | other affiliation | Maj M. | - | IPPT PAN | Synkov S. | - | other affiliation | Reshetov A. | - | other affiliation | Pakieła Z. | - | Warsaw University of Technology (PL) |
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