ALTERNATIVE APPROXIMATION FOR STRESSES IN PLATE STRUCTURES

An accurate nonlinear approximation for stresses caused by membrane an d bending loads in plate structures is presented. Although the approxi mation requires only a first-order sensitivity analysis, it is more ac curate than a simple linear Taylor series expansion of the stresses wi th respect to the design variables, or their reciprocals, and is exact for statically determinate structures. It requires less computation, both in approximate analysis and the corresponding sensitivity analysi s, than other approximations with the same order of accuracy. The use of this alternative approximation for plate stresses in the approximat ion concepts approach to structural optimization results in very rapid design convergence. Examples of the structural optimization of plate structures subject to stress constraints are presented to show the acc uracy of this approximation.