The transient response of two coplanar cracks in a piezoelectric ceramic under antiplane mechanical and inplane electric impacting loads is investigated in the present paper. Laplace and Fourier transforms are used to...The transient response of two coplanar cracks in a piezoelectric ceramic under antiplane mechanical and inplane electric impacting loads is investigated in the present paper. Laplace and Fourier transforms are used to reduce the mixed boundary value problems to Cauchy-type singular integral equations in Laplace transform domain, which are solved numerically. The dynamic stress and electric displacement factors are obtained as the functions of time and geometry parameters. The present study shows that the presence of the dynamic electric field will impede or enhance the propagation of the crack in piezoelectric ceramics at different stages of the dynamic electromechanical load. Moreover, the electromechanical response is greatly affected by the ratio of the space of the cracks and the crack length.展开更多
针对柯西声学反问题,即部分边界信息未知的声学问题,本文采用局部基本解法,对基于局部基本解法的声学反问题模拟及Matlab实现进行研究。采用新型半解析无网格配点法,将中心节点处的声压表示成局部支撑域内支撑节点处声压的线性组合,再...针对柯西声学反问题,即部分边界信息未知的声学问题,本文采用局部基本解法,对基于局部基本解法的声学反问题模拟及Matlab实现进行研究。采用新型半解析无网格配点法,将中心节点处的声压表示成局部支撑域内支撑节点处声压的线性组合,再通过可测边界节点的已知物理量,使内部节点和不可测边界节点的声压值满足控制方程,建立一个大型稀疏线性方程,获得不可测边界的声压值。同时,给出局部基本解法的计算模型及其数值离散格式,并以Matlab为软件平台,设计了声学反问题仿真计算程序,开发了图形用户界面(graphics user interface,GUI)。仿真结果表明,该方法计算精度高,数值稳定,对含有噪声的边界数据可得到较好的反演结果。该研究为声学反问题的数值模拟提供了一种新的思路。展开更多
By using the well-developed integral transform methodology, the dynamic response of stress and electric displacement around a finite crack in an infinite piezoelectric strip are investigated under arbitrary dynamic an...By using the well-developed integral transform methodology, the dynamic response of stress and electric displacement around a finite crack in an infinite piezoelectric strip are investigated under arbitrary dynamic anti-plane loads. The dynamic stress intensity factors and electric displacement are obtained analytically. It is shown that the dynamic crack-tip stress and electric field still have a square-root singularity. Numerical computations for the dynamic stress intensity factor show that the electric load has a significant influence on the dynamic response of stress field. The higher the ratio of the crack length to the width of the strip, the higher the peak value of the dynamic stress intensity factor is. On the other hand, the dynamic response of the electric field is determined solely by the applied electric load. The electric field will promote or retard the propagation of the crack depending on the time elapse since the application of the external electro-mechanical loads. (Author abstract) 9 Refs.展开更多
文摘The transient response of two coplanar cracks in a piezoelectric ceramic under antiplane mechanical and inplane electric impacting loads is investigated in the present paper. Laplace and Fourier transforms are used to reduce the mixed boundary value problems to Cauchy-type singular integral equations in Laplace transform domain, which are solved numerically. The dynamic stress and electric displacement factors are obtained as the functions of time and geometry parameters. The present study shows that the presence of the dynamic electric field will impede or enhance the propagation of the crack in piezoelectric ceramics at different stages of the dynamic electromechanical load. Moreover, the electromechanical response is greatly affected by the ratio of the space of the cracks and the crack length.
文摘针对柯西声学反问题,即部分边界信息未知的声学问题,本文采用局部基本解法,对基于局部基本解法的声学反问题模拟及Matlab实现进行研究。采用新型半解析无网格配点法,将中心节点处的声压表示成局部支撑域内支撑节点处声压的线性组合,再通过可测边界节点的已知物理量,使内部节点和不可测边界节点的声压值满足控制方程,建立一个大型稀疏线性方程,获得不可测边界的声压值。同时,给出局部基本解法的计算模型及其数值离散格式,并以Matlab为软件平台,设计了声学反问题仿真计算程序,开发了图形用户界面(graphics user interface,GUI)。仿真结果表明,该方法计算精度高,数值稳定,对含有噪声的边界数据可得到较好的反演结果。该研究为声学反问题的数值模拟提供了一种新的思路。
基金Project (2011BAG03B03) supported by the National Key Technologies R&D Program of China: Development of Advanced Forming Technologies of High Strength Steel and Integration Applications in Target Car
基金The project supported by the National Natural Science Foundation of Chinathe Post-Doctor Science Foundation of China
文摘By using the well-developed integral transform methodology, the dynamic response of stress and electric displacement around a finite crack in an infinite piezoelectric strip are investigated under arbitrary dynamic anti-plane loads. The dynamic stress intensity factors and electric displacement are obtained analytically. It is shown that the dynamic crack-tip stress and electric field still have a square-root singularity. Numerical computations for the dynamic stress intensity factor show that the electric load has a significant influence on the dynamic response of stress field. The higher the ratio of the crack length to the width of the strip, the higher the peak value of the dynamic stress intensity factor is. On the other hand, the dynamic response of the electric field is determined solely by the applied electric load. The electric field will promote or retard the propagation of the crack depending on the time elapse since the application of the external electro-mechanical loads. (Author abstract) 9 Refs.
