An approximation technique for design sensitivity analysis of the criticalload in non-linear structures

A new technique of approximating design sensitivities of the critical load is presented in this paper. The technique results in stable and reliable es timations of design sensitivities at prebuckling points. Since taking deriv atives of an approximated eigenvalue problem gives unstable sensitivities a s the point approaches the critical load, the sensitivities are approximate d directly from the exact sensitivity expressions. The sensitivities are ap proximated by applying two common approaches that are used in the critical load estimation and are called 'one- and two-point approximation'. The reli ability and applicability of the proposed technique are demonstrated throug h several numerical examples of truss and beam structures. Two-point approx imation of design sensitivities gives better results than one-point approxi mation. Copyright (C) 1999 John Wiley & Sons, Ltd.