镁合金粘接层失效的非线性超声检测研究

Study of a Non-linear Ultrasonic for Detecting the Debonding of the Adhesive Layers of Magnesium Alloys

粘接层脱粘问题直接影响材料或结构的整体性能,需要采用合适的方法尽早检测。针对此问题,提出利用非线性超声无损检测方法对其进行检测,建立了粘结层失效的非线性超声测试系统,对脱粘不同程度的镁合金粘结层试件进行了试验研究,有效测量了表征粘接层失效程度的超声非线性系数β,结果表明超声非线性系数对镁合金粘结层失效非常敏感,且随脱粘程度呈二次函数关系增加;同时,建立了有限元仿真模型,对脱粘不同程度的镁合金粘结层试件进行了有限元数值仿真,仿真结果和实验结果在变化趋势上近似一致,进一步证明非线性超声检测技术可以用于粘接层界面失效的无损评价。

A non-linear ultrasonic system for testing the debonding of the adhesive layers w hich is expected to influence the overall performance of materials or structures w as established. On w hich this non-linear ultrasonic non-destructive testing method w as used to test specimens thereof on magnesium alloys w ith different degrees of debonding. By doing so,the ultrasonic non-linearity parameter β w as measured effectively.The experimental results demonstrated that the ultrasonic non-linearity parameter w as sensitive to the debonding of the adhesive layers of the magnesium alloys,and exhibited a quadratic relationship w ith the degree of debonding as the latter increases. Besides,a finite element simulation model w as established to perform numerical simulation of the specimens of the adhesive layers of magnesium alloys w hich had debonded to different degrees. The simulation and experimental results had a same change tendency,w hich further demonstrated that the proposed non-linear ultrasonic testing technology is applicable to the non-destructive evaluation of the debonding of the adhesive layers.