提高碳纤维增强树脂基复合材料弹性常数超声表征精度的方法

为提高碳纤维增强树脂基复合材料(Carbon Fiber Reinforced Plastic,CFRP)单向板弹性常数的超声表征精度,基于超声液浸背反射法开展了实验测量和数值模拟。首先,搭建了角度旋转测试装置,并结合信号互相关处理技术实现了不同方向上的延时测量和声速计算;然后,通过模拟退火优化算法反演声速数据,得到了5个独立弹性常数;最后,利用理论计算和CIVA软件模拟仿真对实验测量结果进行了验证。结果表明:1-3平面内准纵波和准横波声速随入射角度而变化,与1-2平面内的表现出明显差异,由此显示材料为横观各向同性的;独立弹性常数分别为12.88、6.39、126.83、4.85、2.97GPa;理论计算、CIVA软件模拟仿真及实验测量结果的声速偏差小于6.4m/s,实验数据波动范围小于0.33%,对应的弹性常数误差均小于0.47%。相关方法同样适用于其他正交各向异性介质的弹性常数测试。

Improve methods for elastic constants ultrasonic characterization accuracy of carbon fiber reinforced plastic

In order to improve elastic constants ultrasonic characterization accuracy for unidirectional carbon fiber reinforced plastic (CFRP) plates, experimental measurement and numerical simulation were conducted based on back reflection ultrasonic immersion technique. A single-axis rotation testing setup was developed firstly, and the delay time measurements and ultrasonic velocity calculations at different angles were realized by combining cross-correlation signal processing method. Then, the five independent elastic constants were obtained by the inversion of ultrasonic velocity data using simulated annealing optimization algorithm. Finally, the experimental measurement results were verified by theoretical calculation and CIVA software simulation. The results indicate that the ultrasonic velocities of quasi-longitudinal wave and quasi-transverse wave varied with incident angle in 1-3 plane, which is observably distinct from that of 1-2 plane, thus shows that the material is transversely isotropic. The independent elastic constants are 12.88, 6.39, 126.83, 4.85, 2.97 GPa, respectively. The deviations for ultrasonic velocities of theoretical calculation, CIVA software simulation and experimental measurement results are below 6.4 m/s, the fluctuation of experimental measurement data is below 0.33%, and the corresponding errors of elastic constants are below 0.47%. The methods concerned are also valid for the testing of elastic constants for other orthotropic media.