基于高次体波谐振的弹性板厚度测量方法研究

Study on thickness measurement of elastic plates by high-overtone bulk acoustic resonances

利用压电片在弹性板中激发出的高次体波谐振,提出一种评估弹性板厚度变化的测量方法。根据该层状结构的高次谐振的频率随弹性板厚度变化的关系,给出测量方法的理论分析和数值计算。计算结果表明,并联谐振频率和并联谐振频率间隔与弹性板厚度的偏差量相关。其中,并联谐振频率随厚度偏差量呈线性变化,并具有周期性跳变规律。研究这种跳变规律,能提升高次谐振模式测量板厚的精度。此外,通过对数值仿真算例和实验测量比较,验证了本测量方法的可行性。

Using a high-overtone bulk acoustic resonance of multi-layered elastic structure excited by a piezoelectric patch,a method for evaluating the elastic plate thickness is presented.According to the relations between the frequencies of high-overtone resonances and the thickness changes of the elastic plates,the theory and numerical calculations of the method are given.The calculated results demonstrate the parallel resonance frequencies and the spacing of the parallel resonance frequencies（SPRF） are relative to thickness deviations of the elastic plates.The parallel resonance frequencies linearly vary with the thickness deviations,and there is a periodical jumping phenomenon as the deviations increase. By investigating the tendency of the jumping,one can improve the measurement accuracy of the thickness of the elastic plates.Additionally,the feasibility of the measurement method has been verified by comparing a numerical calculation example and an experimental measurement.