Form

ホ1ウ2Toyota Technological Insti 血1te. Hisakata2−12−1,Tenpaku−ku, Nagoy嬬 468−8511Japan lnthis paper, wc prescnt a parameter一丘ee optimization method for finding the smooth optimal free −form ofa shell structure . The strength design problem dealt with in this paper involves a minmax problem of von Mises stress . The optimum design problem is fbrmulated as a distributed −parameter shape optimization problem under the assumptions a she11 is varied in the out −of plane direction to the sur 飴ce and the thickness was constant. The Kreisselmeier −Steinhauser 負mction is used to transpose the local ilnctional of maximum stress to global integral fUnctional so as to avoid non −diffヒrentiability 。 The shape gradient function and the optimality conditions are derived using the material derivative