A shape or topology design with the stiffness maximized and the maximum str
ess minimized is usually of practical significance in structural optimizati
on. This paper proposes a thickness based evolutionary procedure for such m
ulticriteria design problems. To make the multicriteria optimization suit t
o more realistic structural situations, multiple maximum stress locations a
nd multiple load cases are taken into account in this paper. To balance the
stiffness and stress criteria, a weighting average scheme is adopted to id
entify the overall effects on the two components of design objective due to
varying an element's thickness. Adopting the proposed optimization procedu
re, a design with maximized static stiffness and minimized peak stress is a
chieved by gradually shifting material from the under-utilized regions onto
the over-utilized ones. The examples show the capabilities of the proposed
method for solving multicriteria size and topology designs for both single
and multiple load cases. Copyright (C) 2001 John Wiley & Sons, Ltd.