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Tauzowski P., Błachowski B., Lógó J.♦, Computational framework for a family of methods based on stress-constrained topology optimization,
COMPUTERS AND STRUCTURES, ISSN: 0045-7949, DOI: 10.1016/j.compstruc.2024.107493, Vol.303, pp.1-14, 2024Abstract: This study presents a general computational framework for topology optimization under constraints related to various engineering design problems, including: reliability analysis, low-cycle fatigue assessment, and stress limited analysis. Such a framework aims to facilitate comprehensive engineering design considerations by incorporating traditional constraints such as displacement and stress alongside probabilistic assessments of fatigue failure and the complex behaviors exhibited by structures made of elastoplastic material. The framework's amalgamation of diverse analytical components offers engineers a versatile toolkit to address intricate design challenges. Notably, the inclusion of reliability analysis introduces a probabilistic perspective, transforming conventional design constraints into random parameters, thereby enhancing the robustness of the design process.
Key to the framework's efficacy is its implementation using MATLAB mathematical computing software, leveraging the platform's efficient code execution and object-oriented programming paradigm. This choice ensures an intuitive and potent environment for designers and researchers, facilitating seamless adaptation across various engineering applications. Additionally, the proposed previously by the Authors algorithm for the topology optimization is extended by adaptive strategy allowing for efficient adjustment of an amount of material removed at individual optimization step.
The presented framework is offering a comprehensive and integrated approach to address multifaceted design challenges while enhancing design robustness and efficiency. Keywords: Topology optimization, Stress constraints, First order reliability analysis, Low-cycle fatigue, Plasticity Affiliations:
Tauzowski P. | - | IPPT PAN | Błachowski B. | - | IPPT PAN | Lógó J. | - | University of Technology and Economics (HU) |
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Tauzowski P., Błachowski B., Lógó J.♦, Optimal topologies considering fatigue with reliability constraint,
Advances in Engineering Software, ISSN: 0965-9978, DOI: 10.1016/j.advengsoft.2023.103590, Vol.189, pp.1-12, 2024Abstract: This paper addresses a challenging engineering problem that combines stress-limited topology optimization, reliability analysis, and plasticity-based low-cycle fatigue. Each of these issues represents a complex problem on its own, necessitating significant computational effort. In this study, we propose a novel approach that integrates safety assessment into the topology optimization process while considering the number of cycles for low-cycle fatigue. Our method employs a linear approximation of the performance function for safety control, incorporating the number of failure cycles within a complex, multi-level load program. The methodology is validated through real experiments, using a finite element model with cubic shape functions that yield nearly identical results between numerical and experimental outcomes in the case of fatigue-resistant design for a bi-axially tensioned structural joint. Keywords: Topology optimization, stress constraints, Reliability analysis, low-cycle fatigue, fatigueplasticity Affiliations:
Tauzowski P. | - | IPPT PAN | Błachowski B. | - | IPPT PAN | Lógó J. | - | University of Technology and Economics (HU) |
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Tauzowski P., Błachowski B., Lógó J.♦, Topology optimization of elasto-plastic structures under reliability constraints: a first order approach,
COMPUTERS AND STRUCTURES, ISSN: 0045-7949, DOI: 10.1016/j.compstruc.2020.106406, Vol.243, pp.106406-1-15, 2021Abstract: The objective of this study is to propose a relatively simple and efficient method for reliability based topology optimization for structures made of elasto-plastic material. The process of determining the optimal topology of elasto-perfectly plastic structures is associated with the removal of material from the structure. Such a process leads to weakening of structural strength and stiffness causing at the same time increase the likelihood of structural failure. An important aspect of engineering design is to track this probability during the optimization process and not allow the structure safety to exceed a certain level specified by the designer. The purpose of this work is to combine the previously developed yield-limited topology optimization method with reliability analysis using first order approach. Effectiveness of the proposed methodology is demonstrated on benchmark problems proposed by Rozvany and Maute, and the elasto-plastic topology design of L-shape structure which is frequently used in different approaches for stress constrained topology optimization. Keywords: topology optimization, reliability analysis, elasto-plastic analysis Affiliations:
Tauzowski P. | - | IPPT PAN | Błachowski B. | - | IPPT PAN | Lógó J. | - | University of Technology and Economics (HU) |
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Błachowski B.D.♦, Tauzowski P.♦, Lógó J.♦, Yield limited optimal topology design of elastoplastic structures,
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, ISSN: 1615-147X, DOI: 10.1007/s00158-019-02447-9, Vol.61, pp.1-24, 2020Abstract: This study is devoted to a novel method for topology optimization of elastoplastic structures subjected to stress constraints. It should be noted that in spite of the classical solutions of the different type of elastoplastic topology problems are more than 70 years old, the integration of the Prandtl-Reuss constitutive equations into the topology optimization process is not very often investigated in the last three decades. In the presented methodology where the classical variational principles of plasticity and the functor-oriented programming technique are applied in topology design, the aim is to find a minimum weight structure which is able to carry a given load, fulfills the allowable stress limit, and is made of a linearly elastic, perfectly plastic material. The optimal structure is found in an iterative way using only a stress intensity distribution and a return mapping algorithm. The method determines representative stresses at every Gaussian point, averages them inside every finite element using the von Mises yield criterion, and removes material proportionally to the stress intensities in individual finite elements. The procedure is repeated until the limit load capacity is exceeded under a given loading. The effectiveness of the methodology is illustrated with three numerical examples. Additionally, different topologies are presented for a purely elastic and an elastoplastic material, respectively. It is also demonstrated that the proposed method is able to find the optimal elastoplastic topology for a problem with a computational mesh of the order of tens of thousands of finite elements. Keywords: topology optimization,elastoplastic structures,minimum-weight design,stress constraints Affiliations:
Błachowski B.D. | - | other affiliation | Tauzowski P. | - | other affiliation | Lógó J. | - | University of Technology and Economics (HU) |
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Tauzowski P., Błachowski B., Lógó J.♦, Functor-oriented topology optimization of elasto-plastic structures,
Advances in Engineering Software, ISSN: 0965-9978, DOI: 10.1016/j.advengsoft.2019.102690, Vol.135, pp.102690-1-11, 2019Abstract: The paper deals with a novel approach to development of optimality criteria based finite element code for topology optimization of elasto-plastic structures. The novelty of this work is related to the concept of function object called functor and its application to efficient FE code development. First, the general problem of topology optimization under stress constraints is briefly formulated. Then, the programming aspects of topology optimization using traditional object-oriented and functor based programming are discussed. The advantages of the functor based approach are related to simplicity of designing the FE code architecture and reusability of this code. In particular the metric known as 'Lack of cohesion of methods' is useful in comparing these two different paradigms. Finally, the paper is also illustrated with numerical examples of topology optimization using the proposed methodology. Keywords: topology optimization, function object, functor programming, optimal design, elasto-plastic structures, finite element programming Affiliations:
Tauzowski P. | - | IPPT PAN | Błachowski B. | - | IPPT PAN | Lógó J. | - | University of Technology and Economics (HU) |
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Tauzowski P., Lógó J.♦, Pintér E.♦, Parametric Study on the Element Size Effect for Optimal Topologies,
Periodica Polytechnica Civil Engineering, ISSN: 0553-6626, DOI: 10.3311/PPci.11551, Vol.62, No.1, pp.267-276, 2018 | |
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Błachowski B., Tauzowski P., Lógó J.♦, Modal Approximation Based Optimal Design of Dynamically Loaded Plastic Structures,
Periodica Polytechnica Civil Engineering, ISSN: 0553-6626, DOI: 10.3311/PPci.11016, Vol.61, No.4, pp.987-992, 2017Abstract: The purpose of this study is to present an optimal design procedure for elasto-plastic structures subjected to impact loading. The proposed method is based on mode approximation of the displacement field and assumption of constant acceleration of impacted structure during whole time of deformation process until the plastic displacement limit is reached. Derivation of the method begins with the application of the principle of conservation of linear momentum, followed by determination of inertial forces. The final stage of the method utilizes an optimization technique in order to find a minimum weight structure. Eventually, effectiveness and usefulness of the proposed method is demonstrated on the example of a planar truss structure subjected to dynamic loading caused by a mass impacting the structure with a given initial velocity. Keywords: structural dynamics, optimal design, elasto-plastic structures, short-time dynamic loading Affiliations:
Błachowski B. | - | IPPT PAN | Tauzowski P. | - | IPPT PAN | Lógó J. | - | University of Technology and Economics (HU) |
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Lógó J.♦, Movahedi Rad M.♦, Knabel J., Tauzowski P., Reliability based design of frames with limited residual strain energy capacity,
Periodica Polytechnica Civil Engineering, ISSN: 0553-6626, Vol.55, No.1, pp.13-20, 2011Abstract: The aim of this paper is to create new type of plastic limit design procedures where the influence of the limited load carrying capacity of the beam-to-column connections of elasto-plastic steel (or composite) frames under multi-parameter static loading and probabilistically given conditions are taken into consideration. In addition to the plastic limit design to control the plastic behaviour of the structure, bound on the complementary strain energy of the residual forces is also applied. If the design uncertainties (manufacturing, strength, geometrical) are taken into consideration at the computation of the complementary strain energy of the residual forces the reliability based extended plastic limit design problems can be formed. Two numerical procedures are elaborated. The formulations of the problems yield to nonlinear mathematical programming which are solved by the use of sequential quadratic algorithm. Keywords: reliability analysis, limit analysis, residual strain energy, Monte Carlo simulation, optimal design Affiliations:
Lógó J. | - | University of Technology and Economics (HU) | Movahedi Rad M. | - | University of Technology and Economics (HU) | Knabel J. | - | IPPT PAN | Tauzowski P. | - | IPPT PAN |
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Movahedi Rad M.♦, Lógó J.♦, Knabel J., Tauzowski P., Reliability based limit design of frames with limited residual strain energy capacity,
Proceedings in Applied Mathematics and Mechanics, ISSN: 1617-7061, DOI: 10.1002/pamm.200910323, Vol.9, pp.709-710, 2009Abstract: The aim of this paper is to take into consideration the influence of the limited load carrying capacity of the connections on the plastic limit state of elasto-plastic steel (or composite) framed structures under multi-parameter stochastic loading and probabilistically given conditions. In addition to the plastic limit design to control the plastic behaviour of the structure, bound on the complementary strain energy of the residual forces is also applied. This bound has significant effect for the load parameter. If the design uncertainties (manufacturing, strength, geometrical) are expressed by the calculation of the complementary strain energy of the residual forces a reliability based extended limit design problem is formed. The formulations of the problems yield to nonlinear mathematical programming which are solved by the use of sequential quadratic algorithm. The bi-level optimization procedure governed by the reliability index calculation. Keywords: limit analysis of frames, reliability analysis, optimization Affiliations:
Movahedi Rad M. | - | University of Technology and Economics (HU) | Lógó J. | - | University of Technology and Economics (HU) | Knabel J. | - | IPPT PAN | Tauzowski P. | - | IPPT PAN |
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