PLASTIC BEHAVIOUR AND STABILITY CONSTRAINTS IN THE RELIABILITY BASED SHAKEDOWN ANALYSIS AND OPTIMAL DESIGN OF SKELETAL STRUCTURES

This paper includes description of reliability based design optimization of elasto-plastic skeletal structures under multi-parameter static loading. Presented approach is based on the assumption that the complementary strain energy of the residual forces is considered as an overall measure of the plastic performance for plastic shakedown analysis and optimal design of the structure, and this measure is an uncertain quantity responsible for resistance of the structure by assuming Gaussian distribution. The problems yield to nonlinear mathematical programming which are solved by the use of bi-level sequential quadratic algorithm. Simple portal frames are optimized to illustrate the proposed approaches.