Torello David, Thiele Sebastian, Matlack Kathryn H, Kim Jin-Yeon, Qu Jianmin, Jacobs Laurence J
GW Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Ultrasonics. 2015 Feb;56:417-26. doi: 10.1016/j.ultras.2014.09.008. Epub 2014 Sep 22.
This research considers the effects of diffraction, attenuation, and the nonlinearity of generating sources on measurements of nonlinear ultrasonic Rayleigh wave propagation. A new theoretical framework for correcting measurements made with air-coupled and contact piezoelectric receivers for the aforementioned effects is provided based on analytical models and experimental considerations. A method for extracting the nonlinearity parameter β11 is proposed based on a nonlinear least squares curve-fitting algorithm that is tailored for Rayleigh wave measurements. Quantitative experiments are conducted to confirm the predictions for the nonlinearity of the piezoelectric source and to demonstrate the effectiveness of the curve-fitting procedure. These experiments are conducted on aluminum 2024 and 7075 specimens and a β11(7075)/β11(2024) measure of 1.363 agrees well with previous literature and earlier work. The proposed work is also applied to a set of 2205 duplex stainless steel specimens that underwent various degrees of heat-treatment over 24h, and the results improve upon conclusions drawn from previous analysis.
本研究考虑了衍射、衰减以及声源非线性对非线性超声瑞利波传播测量的影响。基于解析模型和实验考量，提供了一个新的理论框架，用于校正使用空气耦合和接触式压电接收器进行测量时上述影响。基于为瑞利波测量量身定制的非线性最小二乘曲线拟合算法，提出了一种提取非线性参数β11的方法。进行了定量实验，以确认对压电源非线性的预测，并证明曲线拟合程序的有效性。这些实验在2024铝和7075铝试件上进行，β11(7075)/β11(2024)的测量值为1.363，与先前文献和早期工作吻合良好。所提出的工作还应用于一组在24小时内经历了不同程度热处理的2205双相不锈钢试件，结果改进了先前分析得出的结论。
