三维编织CMC的弯曲断裂研究

从界面断裂的角度出发，对三维编织CMC的断裂作了理论研究和数值分析，对于三点弯曲试件，通过数值拟合修正了能量释放率G的理论表达式中的自由常数A，同时也研究了材料的各个参变量对于断裂韧性的影响，由此得出了一个基本完善的三点弯曲试件断裂韧性G的理论公式，该能量释放率方法可以应用于单试件的试验计算，与断裂韧性的柔度标定方法相比，该方法一方面可以减少试验件数量；另一方面，试验结果显示出在试件切口尺雨处于0．4≤a/W≤0.5时，可以获得比较稳定的断裂韧性值。

A STUDY ON FRACTURE TOUGHNESS AND TEST OF CERAMIC MATRIX COMPOSITES

The works of theoretic studies and numerical simulation are done on the base of interfacial fracture theory in this paper. To TPB, The free constant A in the theoretic expression of energy release rate G is revised by numerical simulation, and the influence of material parameters on energy release rate also is investigated. Hence, a basically integrated theoretic formulation of the fracture toughness is deduced for the TPB test, and is available to tests of single specimen. In one hand, comparing with the test method of marking compliance, this theoretic formulation of the fracture toughness needs lesser specimens of TPB; and in the other hand, the results of tests show that a more steady value of fracture toughness can be obtained by the formulation when rates of specimens notch length a to specimens height W are interval of 0.4 and 0.5.