摘要
Ⅰ. INTRODUCTIONIn general, a cleavage crack will unstably propagate in high speed to catastrophic failure<sup>[1]</sup>. In the view of fracture mechanics, the crack growth resistance or R curve under plane strain configuration should be saturated at 2%, and the crack propagates rapidly after that<sup>[1]</sup>. K<sub>IC</sub>=ER<sub>c</sub>/（1-v<sup>2</sup>）, where R<sub>c</sub> is the saturate resistance value. Chu and Thompson,
基金
Project supported by the National Natural Science Foundation of China.
