Optimization of imperfection-sensitive symmetric systems for specified maximum load factor Original Research Article

A method is presented for optimum design of a symmetric structure which reaches an unstable bifurcation point as the load factor is increased. Reduction of the maximum load level due to the antisymmetric imperfection is considered, and a straightforward algorithm is proposed for calculating the magnitude of reduction of the load factor corresponding to the most critical mode of antisymmetric imperfection. The sensitivity coefficients of the bifurcation load factor are calculated by using the interpolation method developed by the authors, and an approximate formulation is presented for sensitivity analysis of the maximum load factor. It is shown in the examples that the errors in the sensitivity coefficients do not lead to any significant difference in the optimum design.