き裂エネルギー密度による安定成長き裂の破壊低抗評価 : 第6報、平面ひずみ形破壊への適用

抄録

The objective of the present study is to propose a practical method to evaluate the fracture resistance of a stably growing crack by crack energy density and to verify its applicability. The 1st report proposed the method, and the 2nd to 5th reports showed its applicability to the ductile crack in the thin plate. The present report shows the applicability to a plane-strain fracture in a thick board by inspecting the correspondence of the evaluated fracture resistance to the fracture mode change and to the J-integral. Based on a stable growing crack test with 25% side-groove CT specimens, we get the expected results : (1) The evaluated fracture resistance by the crack energy density becomes constant, corresponding to the stable crack growth with a uniform plane-strain fracture mode observed by SEM (2) The additional rate of the crack energy density agrees with the variable rate of the J-integral to the crack growth.