高频涡流加载下金属板中超声传播特性分析

发布时间：2018-04-20 08:04

  本文选题：高频涡流加载 + 闭合裂纹　； 参考：《河北工业大学》2015年硕士论文

【摘要】：高频涡流加载下,处于静磁场中的金属板将在洛伦兹力作用下,产生应力波,当金属板中存在不连续界面时,涡流在此集中,进而洛伦兹力的作用将显著增强,并将影响金属板中超声波的传播过程。本文详细研究了高频涡流加载下金属板电磁场、力场和位移场的多场耦合理论,给出了基于洛伦兹力机理的高频涡流加载耦合方程。在此基础上,研究了高频涡流加载下金属微裂纹界面的波动机理,建立了金属板多物理场三维有限元分析模型,求解了含微裂纹铝板的涡流、磁场及洛伦兹力分布,模拟了微裂纹对铝板中超声波传播的影响。基于非线性弹簧原理,分别建立了金属闭合裂纹的数学模型和有限元分析模型,仿真了闭合裂纹的波动过程对金属板中超声波传播特性的影响。建立了含闭合裂纹金属结构中电磁超声的二维有限元仿真模型,模拟了电磁超声表面波传播过程中振动质点的位移场及其幅频特性,通过分析二次谐波分量研究了电磁超声表面波在含闭合裂纹金属铝板中的非线性传播特性。
[Abstract]:Under the loading of high frequency eddy current, the metal plate in the static magnetic field will produce stress wave under the action of Lorentz force. When there is a discontinuous interface in the plate, the eddy current will be concentrated here, and the effect of Lorentz force will be greatly enhanced. The propagation of ultrasonic wave in metal plate will be affected. In this paper, the coupling theory of electromagnetic field, force field and displacement field of metal plate under high frequency eddy current loading is studied in detail, and the coupling equation of high frequency eddy current loading based on Lorentz force mechanism is given. On this basis, the wave mechanism of metal microcrack interface under high frequency eddy current loading is studied, and the three-dimensional finite element analysis model of multi-physical field of metal plate is established, and the eddy current, magnetic field and Lorentz force distribution of aluminum plate with micro-cracks are solved. The effect of microcracks on ultrasonic propagation in aluminum plate was simulated. Based on the principle of nonlinear spring, the mathematical model and finite element analysis model of metal closed crack are established, and the influence of the wave process of closed crack on the ultrasonic propagation characteristics of metal plate is simulated. A two-dimensional finite element simulation model of electromagnetic ultrasound in metal structures with closed cracks is established. The displacement field and amplitude and frequency characteristics of vibrating particles in the process of surface wave propagation are simulated. The nonlinear propagation characteristics of electromagnetic ultrasonic surface waves in aluminum plates with closed cracks are studied by analyzing the second harmonic component.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG115.28
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本文编号：1776944