ADVANCE Fellows Award: Thermomechanical Models of Martensitic Phase Transitions

DMS Award AbstractAward #：0137634主要研究员：Vainchtein，AnnaInstitution：University of Bennburg NSF program：结构标题：高级研究员奖：马氏体相变的热机械模型这个建议涉及材料的物理驱动的热机械模型，例如形状记忆合金，经历马氏体相变。这些材料的特点是温度场和变形场之间的强耦合，并表现出显着的滞后行为时，受到循环机械载荷。滞后的起源、相界动力学和热力学相互作用是马氏体相变模拟中的重要问题。该提案包括几个连续模型，考虑到惯性和热效应。该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负载。主要目标是开发一个模型，能够捕捉最重要的实验观察，如磁滞回线的大小和功能，材料相的体积分数和界面动力学的细节。研究结果对形状记忆材料在复合材料结构损伤、振动和声传输控制等方面的应用具有重要意义。通过推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物和桥梁的创新地震阻尼装置。拟议工作的教育部分包括让研究生和高年级本科生参与研究方案，开发新课程，创建一个推广中学方案，并指导女研究生。

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.