矩形槽尺寸对于兰姆波散射场的调制特征分析

The amplitude modulation of notch size on Lamb wave scattering

基于模式展开法推导了兰姆波在板面上矩形槽处的散射场求解方案,通过算例研究了低频时首阶对称模与非对称模的反射系数,分析了反射幅度的分布特性.研究发现:槽长变化时各散射系数变化均受矩形槽处薄板内各兰姆波传播模耦合调制,调制频率符合各模式半波长谐振特征,各调制函数初始相位主要受槽深影响,给出了a0模调制函数中初始相位受槽深的影响曲线.研究结果明确了散射系数谐振特性与敞口结构振动特征的关系,验证了求解方案的可行性.

A scattering solution based on modal decomposition method is proposed to study Lamb wave scattering near a rectangular notch on a plate. The resonant characteristics of the reflection coefficients of the first symmetric and antisymmetric Lamb mode are investigated at low frequency. It＇s found that the resonances are subjected to a coupled modulation of the traveling Lamb modes in the remnant thinner plate. The decoupled modulation functions respecting to a varying notch width are subjected to the half-wavelength of a particular Lamb mode, while the original phases in the functions are mainly affected by the notch depth, which regarding to a0 mode at different notch depth are illustrated. The relations between scattering coefficients at outside of the notch region and the resonant characteristics in the open--end plate region are confirmed by our research and the feasibility of the proposed solution is also proved.