Comparison of Various Methods of Measuring K1c on Small Precracked Bend Specimens That Fracture after General Yield.

摘要

An experimental investigation into the measurement of fracture toughness on small precracked bend specimens after general yield is described. Six parameters are compared on the basis of their accuracy and utility in predicting KIc. The parameters are: (1) the on-load crack tip opening displacement,COD, (2) the lateral (notch root,crack tip) contraction,NRC, (3) the angle of bend, (4) the stretch zone, (5) the J integral,and (6) the equivalent energy. The results show that,from the standpoint of accuracy and of ease of measurement,the plane strain COD at fracture initiation, (COD) Ic,is the most useful parameter for measuring KIc on small specimens that fracture after general yield. (Author)