A Comparison of the Crack Plane Equilibrium Model for Elastic-Plastic Fracture Analysis with the Irwin's Plastic Zone Corrected LEFM

탄소성 파괴해석을 위한 크랙 평면 평형모형과 항복 선형 파괴역학과의 비교에 관한 연구

  • Lee, Kyu-Yong (National Fisheries University of Pusan) ;
  • Smith, F.W. (Dept. of Mechanical Engineering, Colorado State University)
  • 이규용 (부산수산대학) ;
  • Published : 1984.03.01

Abstract

It is well known that the application of linear elastic fracture mechanics is inadequate to solve the large deformation fracture failures which occurr in ductile manner because of the large scale yielding due to the severe stress concentration in the region adjacent to the crack tip. The authors have been evolved a fracture model, the crack plane equilibrium model, for this kinds of elastic-plastic fracture problems in the previous report. In this report, the crack plane equilibrium model was compared with the Irwin's plastic zone corrected linear elastic fracture mechanics through theoretical comparisons and experimental results to examine the validity of the crack plane equilibrium model as an available tool for nonlinear fracture analysis. Through this study, the main results were reached as follows; Irwin's plastic zone corrected linear elastic fracture mechanics could be applicable only for small scale yielding problems as expected while the crack plane equilibrium model valid as a fracture model for large deformation fracture failure. However, the followings should be considered for the more precise evaluations of CPE model; 1) It is necessary to test more specimens which contain small cracks in the range of 2a/W<0.1. 2) It is important to detect the crack initiation point during the fracture test for determining an accurate fracture load. 3) Effects of specimen thickness in the fracture process zone should be examined.

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