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Constitutive modeling, fracture mechanics and finite element analysis for ferroelectric ceramics.

机译：铁电陶瓷的本构模型，断裂力学和有限元分析。

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摘要

Ferroelectric materials are coming widely into use. They are characterized by their nonlinear behavior. In order to assess the reliability of ferroelectric devices, certain tools are necessary; nonlinear constitutive laws, which describe the material behavior; nonlinear finite element programs which are capable of predicting the switching behavior; and the knowledge of which conditions cause damage to occur. This thesis contributes to all three areas. A phenomenological constitutive law for ferroelectric switching is described. This law follows ideas of plasticity. In analogy to plasticity, different hardening approaches (i.e. isotropic versus kinematic) are considered. Also a nonlinear finite element code is developed, in which such a phenomenological law is implemented. In order to verify the benefits of our finite element program, a design study of a stack actuator is done. One single layer of an actuator is investigated and the electric field, remanent polarization and stresses are assessed. With the information obtained from the numerical calculations, a design law is developed. Also some fracture mechanics aspects of ferroelectric materials are covered. The energy release rate is obtained for different crack configurations via analytical as well as finite element calculations. Although ferroelectric materials have been used for a long time there is still no consensus about the appropriate electrical boundary condition on the surface of a crack. The energy release rate for a permeable crack with extrinsic surface charge in a linear piezoelectric compact tension specimen is obtained in a finite element calculation. The results are compared with data from the literature and with results for a permeable crack without surface charges and an impermeable crack. With the linear approach, the energy release rate for a Griffith crack in a poled material, in which the remanent polarization is locked-up, is calculated by an analytical method. The results are obtained and compared with each other for different boundary conditions. Finally, with the nonlinear finite element code, the energy release rate for an impermeable edge crack under only electrical loading but with polarization switching is assessed.
机译：铁电材料正在广泛使用。它们以其非线性行为为特征。为了评估铁电设备的可靠性，必须使用某些工具。非线性本构定律，描述材料的行为；能够预测切换行为的非线性有限元程序；并了解哪些情况会造成损坏。本论文对这三个领域都有贡献。描述了铁电开关的现象本构定律。该法则遵循可塑性的思想。与塑性类似，考虑了不同的硬化方法（即各向同性与运动学）。还开发了非线性有限元代码，其中实现了这种现象学定律。为了验证我们有限元程序的好处，完成了对堆栈执行器的设计研究。研究致动器的单层，并评估电场，剩余极化和应力。利用从数值计算中获得的信息，开发了设计定律。还涵盖了铁电材料的一些断裂力学方面。通过分析以及有限元计算获得不同裂纹形态的能量释放率。尽管铁电材料已经使用了很长时间，但对于裂纹表面的适当电边界条件仍未达成共识。通过有限元计算获得线性压电致密拉伸试样中带有外部表面电荷的渗透性裂纹的能量释放速率。将结果与文献数据进行比较，并与无表面电荷的渗透性裂缝和渗透性裂缝的结果进行比较。使用线性方法，通过解析方法计算了极化材料中格里菲斯裂纹的能量释放速率，其中剩余极化被锁定。获得了结果，并针对不同的边界条件相互比较。最后，利用非线性有限元编码，评估了仅在电负载下但具有极化转换的不渗透边缘裂纹的能量释放速率。

著录项

  • 作者

    Haug, Anja.;

  • 作者单位

    University of California, Santa Barbara.;

  • 授予单位 University of California, Santa Barbara.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 178 p.
  • 总页数 178
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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