Author(s)

A.F.M. Azevedo, A. Adao da Fonseca

Abstract

Computer Aided Optimum Design of Structures 67 Second-order shape optimization of a steel bridge A.F.M. Azevedo, A. Adao da Fonseca Faculty of Engineering, University of Porto, Porto, Portugal Email: alvaro@fe.up.pt, adaodafonseca@civilfe.up.pt Abstract A comparison is made between the cost minimization of a truss with variable cross-sectional dimensions and fixed geometry (sizing) and the same problem with variable nodal coordinates (shape optimization). Both problems can be formulated as a mathematical program that comprises both structural analysis and design. When this integrated formulation is used, the number of variables in the mathematical program is usually large and an efficient algorithm is required. In this paper the shape optimization problem is solved by a second-order algorithm called NEWTOP that is based on the Lagrange-Newton method. The expressions that define the mathematical program are parsed and their first and second deriv

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