• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>IUTAM Symposium on Dynamics of Advanced Materials and Smart Structures May 20-24, 2002 Yonezawa, Japan >SIMULATION OF IMPACT-INDUCED MARTENSITIC PHASE-TRANSITION FRONT PROPAGATION IN THERMOELASTIC SOLIDS
【24h】

SIMULATION OF IMPACT-INDUCED MARTENSITIC PHASE-TRANSITION FRONT PROPAGATION IN THERMOELASTIC SOLIDS

机译：冲击诱导的马氏体相变前沿在热弹性体中的传播模拟

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Most experiments in martensitic phase transformations are performed under quasi-static loading of a specimen. The results of the quasi-static experiments usually characterize the bulk properties of the material in the specimen, but not the local behavior of phase transition fronts. The only well-documented experimental investigation concerning the impact-induced austenite-martensite phase transformations is given by Escobar and Clifton. As Escobar and Clifton noted, measured velocity profiles provide a difference between the particle velocity and the transverse component of the projectile velocity. This velocity difference, in the absence of any evidence of plastic deformation, is indicative of a stress induced phase transformation that propagates into the crystals from the impact face. But the determination of this velocity difference is most difficult from the theoretical point of view. In fact, the above mentioned velocity difference depends on the velocity of a moving phase boundary. However, the extensive study of the problem of moving phase boundaries shows that the velocity of a moving phase boundary cannot be determined in the framework of classical continuum mechanics without any additional hypothesis. What continuum mechanics is able to determine is the so-called driving force acting on the phase boundary. The propagation of a phase boundary is thus expected to be described by a kinetic relation between the driving traction and the rate at which the transformation proceeds. We develop a thermomechanical approach to the modeling of phase transition front propagation based on the balance laws of continuum mechanics in the reference configuration and the thermodynamics of discrete systems . Phase boundaries are treated as discontinuity surfaces of zero thickness. Jump conditions following from continuum mechanics are fulfilled at the interface between two phases. We introduce the so-called contact quantities for the description of non-equilibrium states of the discrete elements representing a continuous body. The values of contact quantities for adjacent elements are connected by means of so-called thermodynamic consistency conditions. The thermodynamic consistency manifests itself only at the discrete level of description (e.g., in numerical approximation). It simply means that the thermodynamic state of any discrete element (grid cell) of the computational domain should be consistent with the corresponding state of its sub-elements (sub-cells). These thermodynamic consistency conditions are different for processes with and without entropy production. The latter consideration dictates us the rule of application of the consistency conditions: one is used in the bulk and another at the phase boundary (where the entropy is produced). A thermodynamic criterion for the initiation of the phase transition process follows from the simultaneous satisfaction of both homogeneous and heterogeneous thermodynamic consistency conditions at the phase boundary. A critical value of the driving force is determined that corresponds to the initiation of the phase transition process. It is shown that the developed model captures the experimentally observed particle velocity difference.
机译：马氏体相变的大多数实验都是在准静态载荷下进行的。准静态实验的结果通常表征材料在试样中的整体性质，而不是相变前沿的局部行为。 Escobar和Clifton给出了唯一的有据可查的关于冲击引起的奥氏体-马氏体相变的实验研究。正如Escobar和Clifton所指出的，测得的速度分布提供了粒子速度与弹丸速度的横向分量之间的差。在没有任何塑性变形迹象的情况下，该速度差表明应力引起的相变，该相变从冲击面传播到晶体中。但是，从理论的角度来看，确定该速度差是最困难的。实际上，上述速度差取决于运动相边界的速度。但是，对运动相边界问题的广泛研究表明，在没有任何其他假设的情况下，无法在经典连续介质力学的框架内确定运动相边界的速度。连续力学能够确定的是作用在相边界上的所谓驱动力。因此，期望通过驱动牵引力与转换进行速度之间的动力学关系来描述相界的传播。我们根据参考结构中连续力学的平衡律和离散系统的热力学，开发了一种热力学方法，用于相变前沿传播的建模。相界被视为零厚度的不连续表面。在两个阶段之间的接口处满足了来自连续力学的跳跃条件。我们介绍了所谓的接触量，用于描述代表连续物体的离散元素的非平衡状态。相邻元件的接触量值通过所谓的热力学一致性条件进行连接。热力学一致性仅在离散的描述级别（例如，以数值逼近）表现出来。它仅表示计算域中任何离散元素（网格单元）的热力学状态应与其子元素（子单元）的相应状态一致。这些热力学一致性条件对于产生和不产生熵的过程是不同的。后一个考虑因素决定了我们应用一致性条件的规则：一种用于整体，另一种用于相界（产生熵）。引发相变过程的热力学判据来自相边界处均质和非均质热力学一致性条件的同时满足。确定与相变过程的开始相对应的驱动力的临界值。结果表明，所开发的模型捕获了实验观察到的粒子速度差。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号