基于局部缺陷共振的纤维金属层板微脱黏缺陷评价方法

Evaluation Method of Micro-Debonding Defects in FMLs Based on Local Defect Resonance

大型飞机上的纤维金属层板因工艺、环境等原因易在黏接界面处产生脱黏,成为影响飞机飞行的安全隐患,因此对纤维金属层板黏接层的早期微脱黏进行有效检测与评价具有重要意义。本文提出了一种基于局部缺陷共振(LDR)的黏接界面微脱黏程度的评价方法。在接触声学非线性机制下,将缺陷作为非线性弹簧振子,推导其LDR频率,并通过数值仿真分析了不同激励条件下的共振。以预置不同尺寸脱黏缺陷的玻璃纤维-铝合金黏接板为实验对象,利用粘贴在表面的压电传动/传感单元,根据LDR频率有选择性地采用不同频率的激励信号作用在黏接板上,并对接收的响应信号进行频谱分析。仿真与实验结果表明,基于LDR效应可以增强微脱黏界面间的非线性,并可以通过LDR频率对微脱黏损伤面积进行估算。

Fiber metal laminates are widely used in large aircrafts.Debonding occurs easily at the bonding interface due to process and environmental factors,affecting its performance.It is essential to effectively detect and evaluate the bonding layer.This study proposes a method for evaluating the micro-debonding degree of adhesive interfaces using local defect resonance(LDR).Under the nonlinear mechanism of contact acoustics,the defect is regarded as a nonlinear spring oscillator,and its LDR frequency is determined.Numerical simulation is used to analyze the resonance under different excitation conditions.The experimental object is a glass fiber aluminum alloy bonding plate with different sizes of debonding defects.Piezoelectric actuator/sensor units are pasted on the surface,excitation signals with different frequencies are applied to the actuator according to the LDR frequency,and the spectral analysis of the response signals is conducted.The simulated and experimental results show that the nonlinear feature of the debonding interface can be improved based on the LDR effect.In addition,LDR frequency can be employed to determine the debonding damaged area.