基于Lamb波高阶模态厚度共振的薄片厚度表征  

Characterization of thin sheet thickness by high-order mode thickness resonance of Lamb wave

作　　者：孙铭 袁玲[1] 孙凯华[2] 沈中华[1] 钟华[2] SUN Ming;YUAN Ling;SUN Kaihua;SHEN Zhonghua;ZHONG Hua(College of science,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China;Institute of Mechanical Manufacturing Technology,China Academy of Engineering Physics,Mianyang 621900,Sichuan,China)

机构地区：[1]南京理工大学理学院,江苏南京210094 [2]中国工程物理研究院机械制造工艺研究所,四川绵阳621900

出　　处：《声学技术》2022年第6期838-845,共8页Technical Acoustics

基　　金：国家自然科学基金资助项目(61975080、61801451)。

摘　　要：爆破片是气路控制系统阀门中的关键元件,其厚度是影响压力开关阈值的关键参数,对其厚度的精确表征具有重要意义。为此,研究了薄片的Lamb波高阶模态的厚度共振响应与薄片厚度之间的关系。对200μm和50μm两种不同厚度的不锈钢薄片的厚度共振模式进行了数值模拟,并通过厚度共振频率和厚度之间关系的理论公式计算其厚度。建立了一个使用超声纵波直探头激发、探测不锈钢薄片共振模式的实验系统,得到两种不锈钢薄片的厚度共振频率,通过理论公式计算厚度并与点探头测厚仪的测量结果对比。利用模拟及实验得到的共振峰频率所计算的厚度与实际的厚度测量结果均吻合较好。利用Lamb波在截止频率处可以产生多模态的厚度共振,这些模态均可用于薄片的高精度厚度表征。The rupture disc is a key element in the valve of the gas circuit control system, and its thickness is a key parameter that affects the pressure switch threshold. Therefore, for the accurate characterization of its thickness, the relationship between the thickness resonance response of the Lamb wave in the thin sheet and the thickness of the thin sheet is studied. Numerical simulations of thickness resonance modes in two stainless steel sheets with different thicknesses of 200 μm and 50 μm are conducted, and their thickness values are calculated by the theoretical formulas that expresses the relationship between the thickness and the corresponding thickness resonance frequency. An experimental system is established to excite and detect the resonance mode of the stainless steel sheet with a straight ultrasonic longitudinal wave probe, and the thickness resonance frequencies of two stainless steel sheets are obtained.The thicknesses are also calculated by the theoretical formula and compared with the measurement values of the point probe thickness gauge. The results show that the thicknesses of the two stainless steel sheets obtained by simulation and experiment are in good agreement with the actual measured values. So, Lamb waves can be used to generate multimode thickness resonance at the cut-off frequency and these modes can be used for high-precision thickness characterization of thin sheet.

关 键 词：LAMB波 厚度共振 数值模拟 超声探头 不锈钢薄片 

分 类 号：O426[理学—声学]