基于声发射技术的陶瓷基复合材料声速特性

Acoustic emission-based sound velocity characteristics of ceramic matrix composites

基于Christoffel方程,运用复合材料刚度矩阵与弹性常数间的关系,将正交各向异性模型运用于2DC/SiC复合材料的声学特性中,得到材料声速的表达式。通过循环加卸载试验测量了2D-C/SiC复合材料整个拉伸过程中不同应力水平处的声速变化,研究了声速对2D-C/SiC复合材料的损伤表征。研究发现,随着应力水平的不断增加,声速逐渐下降,2D-C/SiC复合材料损伤程度对声波在材料中的传播速度有较大影响;引入卸载模量和再加载模量,代替声速理论计算切线模量,理论结果与试验结果吻合良好,误差随载荷增加而增大;声波速度随2D-C/SiC复合材料损伤而发生衰减的关系,根据此衰减关系建立了基于声速的损伤表征量。

Based on the Christoffel equation, using the relationship between the composite stiffness matrix and the elastic constant, the orthotropic model was applied to the acoustic properties of 2 D-C/SiC composites, and the expression of the material sound velocity was obtained. Through the cyclic loading and unloading test, the sound velocity changes at different stress levels during the entire tensile process were measured. The damage characterization of the sound velocity on the 2 D-C/SiC composite was studied. The results show that as the stress level continues to increase, the sound velocity gradually decreases, and the material The degree of damage has a greater impact on the propagation speed of sound waves in the 2 D-C/SiC composite;the unloading modulus and reloading modulus are introduced to replace the sound velocity theory to calculate the tangent modulus. It is found that the theoretical results are in good agreement with the test results, and the error increases with the increase of load;The sound wave velocity decreases with the damage of the 2 D-C/SiC composite, and based on this attenuation relationship, the damage characterization based on the sound velocity was established.