연성파단의 예측을 위한 거슨 항복함수의 개선에 관한 연구

Abstract

This paper deals with the modification of Gurson’s yield function in order to predict the yield of material which undergoes void initiation and growth under plastic deformation. The accurate prediction of yield point of the material will be helpful to determine ductile fracture of the material. In order to achieve the purpose, the yields of the single voided materials with the various porosities of 1%, 3%, 5%, 10% are calculated by finite element analysis and compare with the Gurson’s yield function according to the porosities. And the yield function is modified through the correction of the prediction of the yield in pure shear state and the addition of mean stress effect to 2nd order porosity term of yield function. Finally, the yield of the multi-voided material with 8, 27, 64 voids of the identical porosity is used in order to verify the modified yield function.