A displacement based optimization method for geometrically nonlinear frame structures

S. Missoum, Z. Gürdal, L. T. Watson

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


An extension of the displacement based optimization method to frames with geometrically nonlinear response is presented. This method, when applied to small-scale trusses with linear and nonlinear response, appeared to be efficient providing the same solutions as the classical optimization method. The efficiency of the method is due to the elimination of numerous finite element analyses that are required in using the traditional optimization approach. However, as opposed to trusses, frame problems have typically a larger number of degrees of freedom than cross sectional area design variables. This leads to difficulties in the implementation of the method compared to the truss implementation. A scheme that relaxes the nodal equilibrium equations is introduced, and the method is validated using test examples. The optimal designs obtained by using the displacement based optimization and the classical approaches are compared to validate the application to frame structures. The characteristics and limitations of the optimization in the displacement space for sizing problems, based on the current formulation, are discussed.

Original languageEnglish (US)
Pages (from-to)195-204
Number of pages10
JournalStructural and Multidisciplinary Optimization
Issue number3
StatePublished - Sep 2002


  • Frame design
  • Geometric nonlinearities
  • Lagrange multipliers
  • Two-level optimization

ASJC Scopus subject areas

  • Software
  • Control and Systems Engineering
  • Computer Science Applications
  • Computer Graphics and Computer-Aided Design
  • Control and Optimization


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