A mesh-shape sensitivity synthesis for boundary-formulated shape optimal design

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 ▲]

CAD/FEM Coupling in Shape Optimization

Conference (1992, November)

Discrete Valued Optimal Design Problems

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)

Shape and mesh optimization using geometric modeling methods

in AIAA/ASME/ASCE/AHS/ASC 31st Structures, Structural Dynamics and Materials Conference : April 2-4, 1990 (1990)

First and second order convex approximation strategies in structural optimization

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 ▲]

Computer Aided Optimal Design of Elastic Structures

in Mota Soares, Carlos A. (Ed.) Computer Aided Optimal Design: Structural and Mechanical Systems (1987)

Shape Optimal Design - An Approach Matching C.A.D. and Optimization Concepts

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)

ACCESS Computer Program for the Synthesis of Large Structural Problems

in Atrek, E.; Zienkiewicz, O. C.; Ragsdell, K. M. (Eds.) et al New Directions in Optimum Structural Design (1984)

Shape optimal-design using B-splines

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 ▲]

Structural Optimization Involving Discrete Design Variables

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)