ADVANCE Fellows Award: Thermomechanical Models of Martensitic Phase Transitions

奖项编号：0137634首席研究员：Vainchtein， ann机构：匹兹堡大学hnsf项目：基础设施标题：ADVANCE Fellows Award：马氏体相变的热力学模型本提案涉及经历马氏体相变的材料（如形状记忆合金）的物理动机热力学模型。这些材料的特点是温度场和变形场之间的强耦合，并且在受到循环机械载荷时表现出明显的滞后行为。迟滞的起源、相边界动力学和热力相互作用是马氏体相变建模中的重要开放性问题。该提案包括几个连续介质模型，这些模型既考虑了惯性效应，也考虑了热效应。模型的重要组成部分是非凸弹性能、转换潜热和时变载荷。主要目标是开发一个能够捕获最重要的实验观察的模型，例如迟滞回路的大小和特征，材料相的体积分数和界面动力学的细节。重要的现象，如锯齿形滞后，内环，热俘获和孪晶组织的演变将进行研究。本文的研究结果对于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。通过推进对形状记忆合金耗散特性的科学理解，本研究将潜在地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级本科生参与研究项目，开发新课程，创建一个扩展的中学项目，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.