基于准静态拉伸试验的临界CTOA测量

为了寻求更为简单、准确的临界裂纹尖端张开角（CTOA_c）测量方法以推广CTOA准则的应用，本文对材料CTOA_c的测量方法进行了研究。根据CTOA的性质及Göteborgs Kungliga Segel Sällskap（GKSS）提出的CTOA_c估算方法导出了两种不同裂纹尖端张开位移（CTOD）定义之间的关系，并进一步得到一种基于准静态拉伸试验的CTOA_c测量方法，该方法与GKSS提出的估算方法相等效但更加简单。为了验证准静态拉伸试验法的准确性，对7B04 M（T）试样进行了静态拉伸试验，并使用上述两种方法估算7B04的CTOA_c，结果表明两种方法估算出的CTOA_c仅相差1%。同时分别采用平面应变核模型、平面应力模型对试样进行了弹塑性有限元模拟，模拟结果与试验结果相吻合。

Critical CTOA measurement based on quasi-static tensile test

In order to find a more simple and accurate measurement critical crack tip opening angle (CTOA_c) method and promote CTOA criterion's application, measurement methods of material CTOA_c were studied. The relationship between two different crack tip opening displacement (CTOD) definitions has been derived from CTOA's properties and CTOA_c estimation method proposed by Göteborgs Kungliga Segel Sällskap (GKSS). Upon the relationship, a CTOA_c measurement method based on quasi-static tensile test was proposed, which is equivalent to but simpler than GKSS estimation method. In order to verify the validity of the proposed method, static tensile tests on 7B04 M(T) specimens were performed, and the 7B04's CTOA_c values were estimated by the two methods above. The results show that only 1% discrepancies have been observed between the two CTOA_c values. In addition, plane strain core model and plane stress model on specimens were generated in elastic plastic finite element, and the simulation results have coincided with test results.