考虑层间界面导电行为和电阻损耗的碳纤维增强树脂基复合材料结构电磁场扩散与衰减特性

Diffusion and attenuation of electromagnetic field in carbon fiber reinforced polymer structures considering interlaminar interface conductive behavior and resistive loss

为满足碳纤维增强树脂基复合材料(CFRP)损伤涡流检测的应用需求,采用数值仿真和实验结合的方法对CFRP结构的电磁场扩散与衰减特性进行了研究。根据CFRP的结构特点,建立均质各向异性三维电磁场有限元模型,研究了层间界面的两种不同导电行为对CFRP板中涡流分布的影响,比较了界面不同导电行为下板中电磁场衰减特性及其与激励频率的关系。结果表明:界面电学行为对多向板涡流影响显著,不仅改变电流分布形式,还使电流强度降低,但单向板中涡流几乎不受界面导电行为的影响,其分布形式具有单一性;在界面不同导电行为下,单向板中电磁场衰减特性与频率无关,且电流衰减很快,多向板的电磁场衰减特性则与频率变化成正比,其电流衰减较为缓慢。通过电磁场能量守恒定律,分析了电阻损耗是影响单向板电流衰减的主导因素。最后,采用涡流检测实验半定量地验证了数值仿真结果和物理现象。

To satisfy the requirements of eddy current testing in detecting defects of carbon fiber reinforced polymer(CFRP) composites, the numerical simulation and experiment were employed to study the electromagnetic field(EMF) diffusion and attenuation in CFRP structures. A homogeneous anisotropic 3D EMF model was built to study the influence of the two different conductive behaviors at the interlaminar interface on eddy currents distribution in CFRP, and to compare the EMF attenuation under the different conductive behaviors and its relation to frequency. The results show that the behavior affects the currents in multidirectional CFRP significantly, not only changes the currents distribution, but also reduces the currents intensity, while it has little effect on the currents in unidirectional CFRP, and its distribution form is unitary. Under the two behaviors, the EMF attenuation of unidirectional plate is independent of frequency, and the currents decay quickly, while the attenuation in the other plate is proportional to the frequency variation, and the currents decay slowly. According to the law of energy conservation of EMF, it is found that resistive loss is the dominant factor affecting the currents attenuation of unidirectional plate.Finally, the eddy current experiment was used to semi-quantitatively verify the numerical simulation results and physical phenomena.