Browse ORBi by ORBi project

- Background
- Content
- Benefits and challenges
- Legal aspects
- Functions and services
- Team
- Help and tutorials

A mesh-shape sensitivity synthesis for boundary-formulated shape optimal design ; Fleury, Claude in The 34th AIAA/ASME/ASCE/AHS/ASC structures, structural dynamics, and materials conference AIAA/ASME, adaptive structures forum : April 19-22, 1993/La Jolla, CA (1993) This paper presents a sequential mesh-shape sensitivity synthesis with which only the structural boundary information is required during the shape optimization process. Large structural shape reformation ... [more ▼] This paper presents a sequential mesh-shape sensitivity synthesis with which only the structural boundary information is required during the shape optimization process. Large structural shape reformation as well as the minimum mesh distortion can be obtained. This method avoids the repetitive remeshing procedure by employing an optimization driven mesh smoothing algorithm proposed by Hwang and Fleury. It eliminates the need to explicitly define the grid point peturbations for the shape sensitivity by extracting the mesh sensitivity from the optimized mesh. Since only the structural boundary is involved in the shape optimization scheme, the method used to create the finite element mesh is not important as long as the element topology for the model is valid. Examples are provided to show the effectiveness of this approach. [less ▲] Detailed reference viewed: 14 (1 ULg)Mathematical Programming Methods for Constrained Optimization: Dual Methods Fleury, Claude in Progress in Astronautics and Aeronautics (1993), 150 Detailed reference viewed: 45 (0 ULg)CAD/FEM Coupling in Shape Optimization ; Duysinx, Pierre ; Fleury, Claude Conference (1992, November) Detailed reference viewed: 37 (4 ULg)Finite element grid optimization with geometric approach ; Fleury, Claude in The 33rd Aiaa/Asme/Asce/Ahs/Asc Structures, Structural Dynamics and Materials Conference: April 13-15, 1992/Dallas, Tx (1992) Detailed reference viewed: 4 (1 ULg)Discrete Valued Optimal Design Problems Fleury, Claude in Bendsoe, Martin P.; Mota Soares, Carlos A. (Eds.) Topology design of structures: Proceedings of the NATO Advanced Workshop, Sesimbra, Portugal, June 20-26, 1992 (1992) Detailed reference viewed: 6 (0 ULg)Optimization software : View from Europe Duysinx, Pierre ; Fleury, Claude in KAMAT, M. P. (Ed.) Structural Optimization Status and Promise (1992) Detailed reference viewed: 24 (5 ULg)Shape and mesh optimization using geometric modeling methods Fleury, Claude ; in AIAA/ASME/ASCE/AHS/ASC 31st Structures, Structural Dynamics and Materials Conference : April 2-4, 1990 (1990) Detailed reference viewed: 12 (0 ULg)Sensitivity and optimization of composite structures in MSC/NASTRAN ; Fleury, Claude in Finite Elements in Analysis & Design (1989), 5(3), 223-235 The main purpose of this paper is to present the considerations and the resultant approach used to implement design sensitivity capability for composites into a large-scale, general-purpose finite element ... [more ▼] The main purpose of this paper is to present the considerations and the resultant approach used to implement design sensitivity capability for composites into a large-scale, general-purpose finite element system (msc/nastran). The design variables for composites can be lamina thicknesses, orientation angles, material properties, or a combination of all three. As a secondary goal, the sensitivity analysis has been coupled with a general-purpose optimizer to validate sensitivity analysis results and also demonstrate how easy it is couple to an optimizer once a general senssitivity capability is available. This preliminary version of the optimizer is capable of dealing with minimum weight structural design with a rather general design variable linking capability at the element level or the system level. Only sizing type of design variables (i.e., lamina thicknesses) can be handled by the optimizer. Test cases have been run and validated by comparison witj independent finite element packages. The linking of a design sensitivity capability for composites in msc/nastran with an optimizer would give designsrs a powerful, automated tool to carry out practical optimization design of real-life, complicated composite structures. [less ▲] Detailed reference viewed: 118 (0 ULg)First and second order convex approximation strategies in structural optimization Fleury, Claude in Structural and Multidisciplinary Optimization (1989), 1(1), 3-10 In this paper, various methods based on convex approximation schemes are discussed, that have demonstrated strong potential for efficient solution of structural optimization problems. First, the convex ... [more ▼] In this paper, various methods based on convex approximation schemes are discussed, that have demonstrated strong potential for efficient solution of structural optimization problems. First, the convex linearization method (CONLIN) is briefly described, as well as one of its recent generalizations, the method of moving asymptotes (MMA). Both CONLIN and MMA can be interpreted as first order convex approximation methods, that attempt to estimate the curvature of the problem functions on the basis of semi-empirical rules. Attention is next directed toward methods that use diagonal second derivatives in order to provide a sound basis for building up high quality explicit approximations of the behaviour constraints. In particular, it is shown how second order information can be effectively used without demanding a prohibitive computational cost. Various first and second order approaches are compared by applying them to simple problems that have a closed form solution. [less ▲] Detailed reference viewed: 18 (0 ULg)Convex Approximation Strategies in Structural Optimization Fleury, Claude ; in Eschenauer, Hans; Thierauf, Georg (Eds.) Discretization Methods and Structural Optimization - Procedures and Applications: proceedings of a GAMM seminar, October 5-7, 1988, Siegen, FRG (1987) Detailed reference viewed: 14 (0 ULg)Computer Aided Optimal Design of Elastic Structures Fleury, Claude in Mota Soares, Carlos A. (Ed.) Computer Aided Optimal Design: Structural and Mechanical Systems (1987) Detailed reference viewed: 5 (0 ULg)Shape Optimal Design by the Convex Linearization Method Fleury, Claude in Bennett, A. J.; Botkin, M. (Eds.) The Optimum Shape: Automated Structural Design (1986) Detailed reference viewed: 46 (4 ULg)Shape Optimal Design - An Approach Matching C.A.D. and Optimization Concepts ; Fleury, Claude ; Beckers, Pierre in Gero, John S. (Ed.) Optimization in Computer Aided Design: proceedings of the IFIP WG 5.2 Working Conference on Optimization in Computer-Aided Design, Lyon, France, 24-26 October, 1983 (1985) Detailed reference viewed: 60 (0 ULg)Large Scale Structural Optimization by Finite Elements Fleury, Claude in Atrek, E.; Zienkiewicz, O. C.; Ragsdell, K. M. (Eds.) et al New Directions in Optimum Structural Design (1984) Detailed reference viewed: 15 (0 ULg)ACCESS Computer Program for the Synthesis of Large Structural Problems Fleury, Claude ; ; et al in Atrek, E.; Zienkiewicz, O. C.; Ragsdell, K. M. (Eds.) et al New Directions in Optimum Structural Design (1984) Detailed reference viewed: 15 (0 ULg)Optimization Methods Fleury, Claude ; in Haug, Edward J. (Ed.) Computer Aided Analysis and Optimization of Mechanical System Dynamics: Computer aided analysis and optimization of mechanical system dynamics: proceedings of the NATO advanced study institute on computer aided analysis and optimization of mechanical system dynamics (1984) Detailed reference viewed: 24 (4 ULg)Shape optimal-design using B-splines ; Fleury, Claude in Computer Methods in Applied Mechanics & Engineering (1984), 44(3), 247-267 Shape optimal design of an elastic structure is formulated using a design element technique. It is shown that Bezier and B-spline curves, typical of the CAD philosophy, are well suited to the definition ... [more ▼] Shape optimal design of an elastic structure is formulated using a design element technique. It is shown that Bezier and B-spline curves, typical of the CAD philosophy, are well suited to the definition of design elements. Complex geometries can be described in a very compact way by a small set of design variables and a few design elements. Because of the B-splines flexibility, it is no longer necessary to piece design elements together in order to agree with the shape complexity, nor to restrict the shape variations. Moreover, the additional optimization constraints that are most often needed to avoid unrealistic designs when the shape variables are the nodal coordinates of a finite element mesh, are automatically taken into account in the new formulation. An analytical derivation of the sensitivity analysis will be established, giving rise to numerical efficiency. It will be seen that the resulting optimization problem does not involve highly nonlinear functions with respect to the shape variables, so that simple mathematical programming algorithms can be applied to solve it. Some numerical examples are offered to demonstrate the power and generality of the new approach presented in this paper. [less ▲] Detailed reference viewed: 101 (5 ULg)Dual methods for optimizing finite element flexural systems Fleury, Claude ; in Computer Methods in Applied Mechanics & Engineering (1983), 37(3), 249-275 Modern numerical methods for the optimization of large discretized systems are now well developed and highly efficient in the case of thin walled elastic structures modeled by finite elements. However ... [more ▼] Modern numerical methods for the optimization of large discretized systems are now well developed and highly efficient in the case of thin walled elastic structures modeled by finite elements. However, this is not yet true for structures whose components are subject simultaneously to bending and extension loads. In this paper, the idea of Generalized Optimality Criterion (GOC), set forth in previous papers for bar, membrane, and pure bending elements, is extended to deal with general beam and flat shell elements. The modifications brought to the GOC result in explicit approximations for the behavior constraints that are correct up to the first order, but that exhibit a more complex algebraic form. Indeed these explicit expressions are no longer merely linear in the reciprocal design variables. However, they continue to be additively separable, and therefore dual methods remain fully applicable, just as in the original statement of the GOC approach. Numerical examples will be offered to demonstrate the efficiency of the method presented. [less ▲] Detailed reference viewed: 14 (1 ULg)Structural Optimization Involving Discrete Design Variables Fleury, Claude ; in Eschenauer, Hans; Olhoff, Niels (Eds.) Optimization methods in structural design : proceedings of the Euromech-Colloquium 164, University of Siegen, FR Germany, October 12-14, 1982 (1983) Detailed reference viewed: 11 (3 ULg)Reconciliation of Mathematical Programming and Optimality Criteria Approaches to Structural Optimization Fleury, Claude in Morris, A. J. (Ed.) Foundations of Structural Optimization : A Unified Approach (1982) Detailed reference viewed: 41 (2 ULg) |
||