복합하중을 받는 평판에 존재하는 반타원 표면균열의 공학적 탄소성 파괴해석법

The present paper provides an engineering J estimation equation for surface cracked plates under combined bending and tension. The proposed equation is based on the reference stress approach, and the most relevant normalising loads to define the reference stress for accurate J estimations are given for surfaee eracked plates under combined bending and tension. Comparisons with J results from extensive 3-D FE analyses, covering a wide range of craek geometry. plate geometry and loading combination, show overall good agreement not only at the deepest point but also at arbitrary points along the crack front. For pure tension, agreement between the estimated J and the FE results is excellent, even at the surface point.^(8) On the other hand, for pure bending and combined bending and tension, the estimated J values become less accurate for locations close to the surfaee point. Thus the results in this paper will be useful to assess short-term fracture or low cycle fatigue of surface defects in plates under combined bending and tension.