中文摘要：

针对压力容器和管道安全运行需要,发展了一种非线性超声谐振结垢检测方法。从理论上分析非线性细观弹性材料因迟滞效应引起的非线性弹性本构关系。研究发现,随着超声波激励幅值的增加,迟滞导致的非线性效应主要表现为超声波谐振频率向低频偏移和谐振频谱品质因数的变化。对涂有不同厚度模拟结垢的板试件进行非线性超声谐振检测试验,研究了激励电压水平对基波及二次谐波谐振频谱的影响规律,提出基于二次谐波弹性迟滞非线性系数和耗散迟滞非线性系数的结垢层厚度表征方法。在此基础上,将非线性超声谐振检测方法应用于实际工程中炉管结垢层检测,结果表明,利用二次谐波的弹性迟滞非线性系数和耗散迟滞非线性系数能较好反映炉管结垢状况。研究工作为实际工程中炉管结垢层检测提供了新的思路和方法。

英文摘要：

According to requirement of safe operation of pressure vessels and pipelines, a nonlinear ultrasonic resonance technique is proposed. The nonlinearly elastic constitutive relation induced by hysteresis effect in nonlinear mesoscopic elastic materials is analyzed theoretically. Research shows that with the increase of amplitude of ultrasound, the nonlinear effects mainly presented as shift of resonant frequency and variation of quality factor. Nonlinear ultrasonic resonance experiments are conducted on plates with simulant scales. Research focused on the influence of amplitude of excitation on the resonant frequencies of fundamental wave and harmonics, and the hysteretic elastic nonlinearity and hysteretic dissipative nonlinearity in second harmonics are used to characterize the scaling thick. The proposed nonlinear ultrasonic resonance technique is applied for scale detection in industrial pipelines. The results show that the hysteretic elastic nonlinearity and hysteretic dissipative nonlinearity in second harmonic could be used for thick measurement of scale in pipelines. The research provides a novel method for scaling detection in industrial pipeline.