飞机用铝合金-CFRP搭接结构的电偶腐蚀预测研究

目的通过有限元仿真,预测飞机复合材料-铝合金搭接试件可能产生的腐蚀部位和腐蚀深度。方法采用动电位极化的方法,测得温度为40℃的5%NaCl溶液中铝合金和复合材料两种材料的极化曲线。以极化曲线及其拟合的电化学动力学参数作为边界条件,建立电偶腐蚀仿真模型。通过模型计算,分别得到两种材料的腐蚀预测结果,将其结果与实验室腐蚀试验结果进行对比。结果电偶试件模型预测得到的电偶电位值与实验测量得到的电偶电位值对比误差为4.2%。搭接试件的腐蚀部位为偶接处3 mm内,其腐蚀分布与搭接件电偶腐蚀模型预测的电位分布规律基本一致,腐蚀深度的预测值和腐蚀实验的实测值对比误差为12.5%。结论该研究的仿真预测结果与试验结果在一定程度上具有一致性,证明了仿真模型的正确性。

Prediction of Galvanic Corrosion of Aluminium Alloy-CFRP Lapped Structure in Aircraft

The paper aims to predict corrosion position and corrosion depth of aluminum alloy-CFRP lapped specimen by finite element simulation. The potentiodynamic polarization method was used to measure the polarization curves of aluminium alloy and composite materials in 5% NaCl solution at 40 ℃. Taking polarization curve and its fitting electrochemical kinetic parameters as boundary conditions, a simulation model of galvanic corrosion was established. The corrosion prediction results of the two materials were obtained by the model calculation, and the results were compared with the corrosion test results in the laboratory. The error of galvanic potential between the predicted and measured values was 4.2%. The corrosion site of the lapped specimen was within 3 mm of the coupling, and its corrosion distribution was basically consistent with the potential distribution law predicted by the electric couple corrosion model of the lapped specimen. The comparison error between the predicted corrosion depth and the measured value of the corrosion experiment was 12.5%. The experimental results are consistent with the simulation results, proving the correctness of the simulation model.