Model-reduction techniques for reliability-based design problems of complex structural systems

• The use of component mode synthesis for reliability-based design is explored.
• The reduction technique produces highly accurate models with few component modes.
• The reduction is achieved without compromising the accuracy of final designs.
• Computational efforts are reduced by more than one order of magnitude.
• The approach is applicable for the design of a class of medium/large finite element models.

This work presents a strategy for dealing with reliability-based design problems of a class of linear and nonlinear finite element models under stochastic excitation. In general, the solution of this class of problems is computationally very demanding due to the large number of finite element model analyses required during the design process. A model reduction technique combined with an appropriate optimization scheme is proposed to carry out the design process efficiently in a reduced space of generalized coordinates. In particular, a method based on component mode synthesis is implemented to define a reduced-order model for the structural system. The re-analyses of the component or substructure modes as well as the re-assembling of the reduced-order system matrices due to changes in the values of the design variables are avoided. The effectiveness of the proposed model reduction technique in the context of reliability-based design problems is demonstrated by two numerical examples.