摘要
飞机结构裂纹的在线监测是保证飞行器安全的重要举措,针对目前常规的无损检测方法无法实现在线及原位监测的不足,根据裂纹引起的超声非线性,基于振动声调制效应对结构裂纹进行监测是一种可行的方法。采用非线性弹簧模型对裂纹进行模拟,建立了两列一维简谐波在含接触界面的结构中的传播模型,通过公式推导,得到了透射信号的基波、调制边频谐波和高次谐波等信号成分的近似表达式,分析了各谐波成分幅值与激励信号参数间的对应关系,推导了边频调制谐波与两低频基波幅值乘积之比R与刚度系数间的关系。通过板中的振动声调制试验,分析了响应信号的谐波成分及各谐波成分随低频振动幅值的变化关系,探讨了指标R随外力变化情况,试验结果基本符合模型推导的结论,为采用基于振动声调制的方法进行裂纹监测提供了理论指导。
On-line Fatigue Crack Monitoring is an important initiative to ensure the safety of aircrafts. Aiming at the deficiency of the conventional non destructive test method that cannot be achieved on-line and in situ,the vibroacoustic modulation（ VAM） provides an effective method for crack monitoring based on the ultrasonic nonlinearity caused by cracks. A nonlinear spring model was used to simulate the crack and a 1-D harmonic wave propagation model in structures with cracks interfaces was established. Approximate expressions of fundamental waves,modulation side-band harmonics and higher harmonics were obtained,and the corresponding relationship between the amplitude of harmonic components and the excitation signal parameters was analyzed. The relationship between the stiffness coefficent and the ratio R of the amplitude of harmonic components to the multiplication of two fundamental waves amplitudes was derived.Through the VAM test on a plate,the relationship between the harmonic components amplitudes and the low frequency vibration amplitudes was analyzed,and the change of index R along with the change of external force was discussed. The experimental results are in good agreement with the results derived from the model. The theoretical guidance was provided for the crack detection using the method of VAM.
作者
刘学君
杨晓华
马广婷
张玎
LIU Xuejun;YANG Xiaohua;MA Guangting;ZHANG Ding(Department of Aviation Mechanism ,Qingdao Branch,Naval Aeronautical and Astronautical University,Qingdao 266041,China;The 91899^th of Unit of PLA,Huludao 125001)
出处
《振动与冲击》
EI
CSCD
北大核心
2018年第10期233-240,共8页
Journal of Vibration and Shock
基金
总装十二五预研项目(143092015)
关键词
裂纹监测
非线性弹簧模型
振动声调制
调制边频
高次谐波
crack monitoring
nonliear spring model
vibro-acoustic modulation
side-band harmonic
higher harmonic
