References of "Duysinx, Pierre"
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See detailEnhanced Approximation Schemes for Classical Optimization Algorithm
Bruyneel, Michaël ULg; Vermaut, O.; Duysinx, Pierre ULg et al

Report (1998)

The report assesses the capabilities of the algorithms CONLIN, MDQA, an GCM available in Boss Quattro to solve composite structure optimization. The algorithms are evaluated with respect to the ... [more ▼]

The report assesses the capabilities of the algorithms CONLIN, MDQA, an GCM available in Boss Quattro to solve composite structure optimization. The algorithms are evaluated with respect to the optimization of sandwich panel parameters (ply thickness and orientation, and foam core thicknesss). [less ▲]

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See detailTopology Optimization of Continuum Structures with Local Stress Constraints
Duysinx, Pierre ULg; Bendsoe, Martin Philip

in International Journal for Numerical Methods in Engineering (1998), 43

We introduce an extension of current technologies for topology optimization of continuum structures which allows for treating local stress criteria. We rst consider relevant stress criteria for porous ... [more ▼]

We introduce an extension of current technologies for topology optimization of continuum structures which allows for treating local stress criteria. We rst consider relevant stress criteria for porous composite materials, initially by studying the stress states of the so-called rank 2 layered materials. Then, on the basis of the theoretical study of the rank 2 microstructures, we propose an empirical model which extends the power penalized sti ness model (also called SIMP for Solid Isotropic Microstructure with Penalization for intermediate densities). In a second part, solution aspects of topology problems are considered. To deal with the so-called 'singularity' phenomenon of stress constraints in topology design, an -constraint relaxation of the stress constraints is used. We describe the mathematical programming approach that is used to solve the numerical optimization problems, and show results for a number of example applications. [less ▲]

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See detailNew Developments in Handling Stress Constraints in Optimal Material Distributions
Duysinx, Pierre ULg; Sigmund, Ole

in Proceedings of 7th AIAA/USAF/NASA/ISSMO symposium on Multidisciplinary Design Optimization (1998)

There is a general interest to consider stress constraints in topology optimization of continuum structures. By their very nature stress constraints are local constraints which result in large scale ... [more ▼]

There is a general interest to consider stress constraints in topology optimization of continuum structures. By their very nature stress constraints are local constraints which result in large scale optimization problems that are often expensive to solve. Here in order to reduce the computing the effort we explore an alternative technique based on equivalent global (that is integrated) constraints. We define two global stress constraints based on the p-norm and p-mean of the epsilon-relaxed overall stress criteria in the finite elements. We present a new formulation of the epsilon-relaxation technique which is better suited to topology optimization of continuum structures and which makes the relaxation process automatic. The "p-mean" and "p-norm" functions bound by lower and upper value the maximum value of the epsilon-relaxed overall stress criterion. Based on numerical experiments this study compares the global and the local constraint formulations. Even if the use of integrated constraints leads a reduction of the computing time by one or two orders of magnitude, they definitely give a weaker control of local stress level. This sometimes can lead to solutions that are a bit different. [less ▲]

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See detailTopology Optimization of Continuum Structures with Stress Constraints
Duysinx, Pierre ULg; Bendsoe, Martin Philip

in Gutkowski, W.; Mroz, Z. (Eds.) Proceedings of the Second World Congress of Structural and Multidisciplinary Optimization (WCSMO2) (1997, May)

We introduce an extension of topology optimization of continuum structures to deal with local stress criteria. We first consider relevant stress criteria for porous composite materials, initially by ... [more ▼]

We introduce an extension of topology optimization of continuum structures to deal with local stress criteria. We first consider relevant stress criteria for porous composite materials, initially by studying the stress states of the so-called rank 2 layered materials. Then, an empirical model is proposed for the power law materials (also called SIMP materials). In a second part, solution aspects of topology problems are considered. To deal with the so-called 'singularity' phenomenon of stress constraints in topology design, an $\epsilon$ constraint relaxation of the stress constraints is used. We describe the mathematical programming approach that is used to solve the numerical optimization problems. The proposed strategy is applied to illustrative applications. [less ▲]

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See detailLayout Optimization : A Mathematical Programming Approach
Duysinx, Pierre ULg

Report (1997)

This paper presents applications of specially tailored methods of the mathematical programming approach for solving topology design problems formulated as an optimal material distribution, providing a way ... [more ▼]

This paper presents applications of specially tailored methods of the mathematical programming approach for solving topology design problems formulated as an optimal material distribution, providing a way to enlarge the scope of potential applications of topology optimization. The first feature of the methodology is to resort to dual maximization to solve optimization problems with a huge number of design variables, using the concept of Sequential Convex Programming (SCP). Here a central theme is the choice of convex approximations suited to the problems. First order approximations are firstly considered and compared. However, to increase the performances of the procedures (for example, to reduce the number of steps to arrive to a stationary design), a new approach to build un-expensive second approximation schemes, especially relevant for large scale problems, have been developed and validated. To illustrate the efficiency of the mathematical programming approach, the final part of the paper deals with an efficient treatment of perimeter constraints. Such constraints are essential to regularize material distribution with non optimal microstructures, but perimeter constraints are very difficult to handle in a numerical procedure for practical designs. The paper presents a solution to this problem that has been implemented and validated on a wide range of applications. [less ▲]

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See detailConvex Approximation Methods for Large Scale Structural Problems
Duysinx, Pierre ULg

in Proceedings of the 9th Nordic Seminar on Computational Mechanics (NSCM IX) (1996, October)

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See detailLayout Optimization : A Mathematical Programming Approach
Duysinx, Pierre ULg

Conference (1996, August)

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See detailIntroduction à l'optimisation topologique
Duysinx, Pierre ULg

Report (1996)

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See detailOPTIMISATION TOPOLOGIQUE : DU MILIEU CONTINU A LA STRUCTURE ELASTIQUE
Duysinx, Pierre ULg

Doctoral thesis (1996)

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See detailA Generalized Method of Moving Asymptotes (GMMA) Including Equality Constraints
Zhang, Weihong; Fleury, Claude ULg; Duysinx, Pierre ULg et al

in Structural Optimization (1996), 12(2/3), 143-146

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See detailA New Separable Approximation Scheme for Topological Problems and Optimization Problems Characterized by a Large Number of Design Variables
Duysinx, Pierre ULg; Zhang, Weihong; Fleury, Claude ULg et al

in Olhoff, Niels; Rozvany, Georges I.N. (Eds.) Proceedings of the First World Congress of Structural and Multidisciplinary Optimization (WCSMO1) (1995, May)

This paper is dedicated to a new convex separable approximation for solving optimization problems characterized by a very large number of design variables as in topology design. For such problems, the ... [more ▼]

This paper is dedicated to a new convex separable approximation for solving optimization problems characterized by a very large number of design variables as in topology design. For such problems, the convergence speed can be accelerated if one uses high quality approximation schemes for structural responses. To achieve this task, we propose, here, a new approximation procedure that belongs to the GMMA family. The originality of this new scheme is to rely on an automatic selection procedure of the asymptotes, using only first and zero order information accumulated during the previous iterations. This is possible owing to a diagonal Quasi-Newton update technique. Firstly, the new approximation procedure is validated on classical "benchmarks" of structural optimization. Then, it is compared to other schemes on a typical topology optimization problem. [less ▲]

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See detailStructural Shape Optimization with Error Control
Duysinx, Pierre ULg; Zhang, Weihong; Zhong, H. G. et al

in Proceedings of 20th ASME Design Automation Conference (1994, September)

A robust and automatic shape optimization procedure is presented in this paper, which incorporates recent developments in the field of computer-aided design (CAD) of mechanical structures, such as ... [more ▼]

A robust and automatic shape optimization procedure is presented in this paper, which incorporates recent developments in the field of computer-aided design (CAD) of mechanical structures, such as geometric modelling, automatic selection of independent design variables, sensitivity analysis using reliable mesh perturbation schemes, error estimation and adaptive mesh refinement. A numerical example is given to show the efficiency of the procedure. [less ▲]

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See detailSensitivity Analysis With Unstructured Free Mesh Generators in 2-D Shape Optimization
Duysinx, Pierre ULg; Zhang, Weihong; Fleury, Claude ULg

in Herskowitz, José (Ed.) Proceedings of Structural Optimization 93, The World Congress on Optimal Design of Structural Systems (1993, August)

Shape optimization has to consider new progress in mesh generators to take full benefits from the use of free unstructured meshes in realistic industrial optimization. The main difficulty relies in the ... [more ▼]

Shape optimization has to consider new progress in mesh generators to take full benefits from the use of free unstructured meshes in realistic industrial optimization. The main difficulty relies in the mesh flow determination during sensitivity analysis. The authors present their experience in applying smoothing techniques to transmit boundary perturbations to the inner mesh. It is explained how smoothing can be used to evaluate velocity fields in a simple and inexpensive way while guarantying reliability, efficiency and precision. A wide range of smoothing procedures are compared and confronted with other velocity field approaches to investigate their advantages and drawback. Finally, applications of smoothing procedures in the commercial optimization package OPTI-SAMCEF are described. [less ▲]

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See detailA Parametric Design Based Approach to Structural Shape Optimization
ZHANG, W. H.; Beckers, Pierre ULg; Duysinx, Pierre ULg et al

Conference given outside the academic context (1993)

Detailed reference viewed: 47 (2 ULg)
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See detailNumercial tools for the design of adhesively bonded composite assemblies
Laschet, Gotfriedt; Duysinx, Pierre ULg

in Actes des 8ièmes Journées Nationales sur les Matériaux Composites (JNC8) (1992, November)

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See detailCAD/FEM Coupling in Shape Optimization
Morelle, P.; Duysinx, Pierre ULg; Fleury, Claude ULg

Conference (1992, November)

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See detailOptimization software : View from Europe
Duysinx, Pierre ULg; Fleury, Claude ULg

in KAMAT, M. P. (Ed.) Structural Optimization Status and Promise (1992)

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