DIRECT DIFFERENTIATION FORMULATION FOR BOUNDARY-ELEMENT SHAPE SENSITIVITY ANALYSIS OF AXISYMMETRICAL ELASTIC SOLIDS

An efficient direct differentiation method by continuum approach is pr esented for the shape design sensitivity analysis of axisymmetric elas tic solids. The method is purely based on the axisymmetric boundary in tegral equation formulation. A new boundary integral equation for sens itivity analysis is derived by taking material derivative to the same integral identity that was used in the adjoint method. As sensitivitie s in terms of the shape design variables are directly calculated by so lving the new BIE, the singular boundary condition which may arise in the adjoint method is avoided in the present direct method. To validat e the theoretical formulation, numerical implementation is done for th ree examples. For a hollow disk and a thick-walled cylinder problem wi th analytic solution, the sensitivities by present method are compared with analytic sensitivities. For an example of a spherical vessel, be ing rather practical, the sensitivities are compared with those by fin ite differences. Copyright (C) 1996 Elsevier Science Ltd.