三点弯曲试样幂硬化材料裂纹撕裂扩展的实验研究

EXPERIMENTAL STUDY OF THE TEARING INSTABILITY THEORY

本文应用三点弯曲试样和撕裂模量理论对弹塑性裂纹撕裂扩展的稳定性进行了实验研究,得出了适用于三点弯曲试样的施加撕裂模量T_(app)的计算公式。结果说明了材料硬化和系统柔度等因素对裂纹扩展稳定性的影响。实验中采用多层高柔度组合梁系统,得到了随加载系统柔度增加,裂纹扩展从慢稳定到失稳发展的过程。证明了撕裂模量理论的有效性。实验结果与理论预测相符。

Using three point bend(TPB) specimens in the light of the tearing modulus theory proposed by Paris et al., the behavior of stable-unstable crack growth in ductile fracture was studied. A formula for calculating the applied tearing modulus(Tapp)of TPB specimens was derived. The effects of material hardening and load system compliance were examined. In the experimental study, a high adjustable multi-layer fixture was used. The process about the crack growth from slow stable state to unstable state under increasing load system compliance was observed. The test results proved that the effectiveness of the tearing modulus theory was verified.