ADVANCE Fellows Award: Thermomechanical Models of Martensitic Phase Transitions

DMS奖摘要奖#：0137634年度首席研究员：Vainchtein，Anna研究所：匹兹堡大学NSF计划：基础结构标题：高级研究员奖：马氏体相变的热力学模型本提案涉及物理激励的马氏体相变的热力学模型，例如形状记忆合金。这些材料具有温度和变形场强耦合的特点，在循环机械载荷作用下表现出明显的滞回行为。磁滞起源、相界动力学和热力相互作用是马氏体相变模拟中的重要问题。该提案包括几个同时考虑惯性和热效应的连续介质模型。模型的重要组成部分是非凸弹性能、相变潜热和随时间变化的载荷。主要目标是开发一种能够捕捉最重要的实验观测结果的模型，例如磁滞回线的大小和特征、材料相的体积分数和界面动力学的细节。文中将对形状记忆材料的锯齿形滞后、内环、热陷和孪晶微结构演化等重要现象进行研究，其结果将对形状记忆材料在复合材料结构中的损伤、振动和声传输控制等新兴应用具有重要意义。通过促进对形状记忆合金耗散特性的科学理解，这项研究将可能有助于开发用于建筑和桥梁的创新的抗震减震装置。拟议工作的教育部分包括让研究生和高级本科生参与研究计划，开发新课程，创建外展中学计划，以及指导女研究生。

DMS Award AbstractAward #: 0137634 Principal Investigator: Vainchtein, AnnaInstitution: University of PittsburghNSF program: InfrastructureTitle: ADVANCE Fellows Award: Thermomechanical models of martensitic phase transitionsThis proposal is concerned with physically-motivated thermomechanical models of materials, such as shape memory alloys, that undergo martensitic phase transitions. These materials are characterized by a strong coupling between temperature and deformation fields and exhibit markedly hysteretic behavior when subjected to cyclic mechanical loading. The origin of hysteresis, kinetics of phase boundaries and thermomechanical interactions are important open problems in modeling of martensitic phase transitions. The proposal includes several continuum models that account for both inertia and thermal effects. The important components of the models are nonconvex elastic energy, latent heat of transformation and time-dependent loading. The main goal is to develop a model capable of capturing the most significant experimental observations, such as size and features of hysteresis loops, volume fractions of material phases and details of interface dynamics. Important phenomena such as serrated hysteresis, inner loops, thermal trapping and evolution of twin microstructures will be investigated.The results of the proposed work will be important for the emerging applications of shape memory materials, such as damage, vibration and acoustic transmission control in composite structures. By advancing the scientific understanding of the dissipative properties of shape memory alloys, this research will potentially contribute toward the development of innovative seismic damping devices for buildings and bridges. The educational component of the proposed work includes involving graduate and advanced undergraduate students in the research program, developing new courses, creating an outreach middle-school program and mentoring women graduate students.