金属材料拉伸应力非线性超声特性研究  

Research on Nonlinear Ultrasonic Properties of Tension Stress in Metal Materials

作　　者：阎红娟[1,2] 徐春广[2] 肖定国[2] 蔡海潮[2] 

机构地区：[1]北方工业大学机械与材料工程学院,北京100144 [2]北京理工大学机械与车辆学院,北京100081

出　　处：《机械工程学报》2016年第6期22-29,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51275042);国家重大科技工程专项(2011ZX04014-081);科技部国际合作专项(S2012ZR0084)资助项目

摘　　要：使用摄动法求解小应变情况下一维非线性波动方程,研究超声波在固体介质中传播时非线性波动规律,分析二阶非线性系数β、三阶非线性系数δ与基波和各次谐波关系。据此研究金属材料在拉伸应力变化时,高阶非线性系数β、δ等参数随拉伸应力变化规律。构建非线性超声检测系统,测量2024铝合金和45钢在拉伸试验过程中非线性系数β、δ的变化趋势。试验结果表明:非线性系数与拉伸应力σ呈单调上升关系。对于2024铝合金,当拉伸应力σ小于屈服极限的84.6%时,二阶非线性系数β与拉伸应力σ近似成线性关系;当拉伸应力σ大于屈服极限84.6%时,二阶非线性系数β随拉伸应力σ的增加变化很小。对于45钢,当拉伸应力σ小于屈服极限的84.5%,二阶非线性系数β与拉伸应力σ近似成线性关系;当拉伸应力大于屈服极限的84.5%时,二阶非线性系数β急剧增加。对于三阶非线性系数δ,2024铝合金和45钢转变点分别出现在屈服极限的76.9%和78.9%处。二阶与三阶非线性系数对于拉应力具有不同的灵敏度,三阶非线性系数δ比二阶非线性系数β对应力的变化更为敏感。Assuming small strain condition, perturbation method is used to resolve one dimensional wave equation. The nonlinear wave rule is studied when ultrasonic wave propagates in solid medium. When tension stresses change in metal materials, the variation trends of the nonlinear coefficients β and δ are studied. The nonlinear ultrasonic testing system is set up to detect the harmonic wave amplitudes. The variation trends of the nonlinear coefficients with stresses are acquired. The results show that the nonlinear coefficients increase with the tension stress. For 2024 aluminum alloy, the second order nonlinear coefficient β is approximately linear with the tension stress when the tension stress is smaller than 84.6% of the yield strength, and it increases slowly with tension stress when the tension stress is bigger than 84.6% of the yield strength. For 45 steel, the second order nonlinear coefficient β increases linearly with the stress when the tress is smaller than 84.5% of strength stress, and it increases quickly with stress when the stress is bigger than 84.5% of the yield strength. The third nonlinear coefficients δ have change points in 76.9% and 78.9% of yield strength for 2024 aluminum alloy and 45 steel, respectively. The second nonlinear coefficients β and the third nonlinear coefficients have different sensitivities to the stress. The third nonlinear coefficients δ have higher sensitivity than the second nonlinear coefficients β.

关 键 词：非线性超声 拉伸应力 高阶非线性系数 

分 类 号：TB551[理学—物理]