Yuan Maodan, Dai Anbang, Liao Lin, Chen Yan, Ji Xuanrong
State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Materials (Basel). 2021 Aug 26;14(17):4855. doi: 10.3390/ma14174855.
Ultrasonic is one of the well-known methods for surface roughness measurement, but small roughness will only lead to a subtle variation of transmission or reflection. To explore sensitive techniques for surfaces with small roughness, nonlinear ultrasonic measurement in through-transmission and pulse-echo modes was proposed and studied based on an effective unit-cell finite element (FE) model. Higher harmonic generation in solids was realized by applying the Murnaghan hyperelastic material model. This FE model was verified by comparing the absolute value of the nonlinearity parameter with the analytical solution. Then, random surfaces with different roughness values ranging from 0 μm to 200 μm were repeatedly generated and studied in the two modes. The through-transmission mode is very suitable to measure the surfaces with roughness as small as 3% of the wavelength. The pulse-echo mode is sensitive and effective to measure the surface roughness ranging from 0.78% to 5.47% of the wavelength. This study offers a potential nondestructive testing and monitoring method for the interfaces or inner surfaces of the in-service structures.
超声是一种广为人知的表面粗糙度测量方法,但小粗糙度只会导致透射或反射的细微变化。为了探索针对小粗糙度表面的敏感技术,基于有效的单胞有限元(FE)模型,提出并研究了穿透传输和脉冲回波模式下的非线性超声测量。通过应用穆尔纳根超弹性材料模型实现了固体中的高次谐波产生。通过将非线性参数的绝对值与解析解进行比较,验证了该有限元模型。然后,在这两种模式下反复生成并研究了粗糙度值从0μm到200μm不等的随机表面。穿透传输模式非常适合测量粗糙度低至波长3%的表面。脉冲回波模式对于测量波长0.78%至5.47%范围内的表面粗糙度敏感且有效。本研究为现役结构的界面或内表面提供了一种潜在的无损检测和监测方法。