An Integrated Micromechanics Approach to Physics-Based Modeling of Deformation and Failure of Superelastic Materials

基于物理的超弹性材料变形与破坏建模的综合细观力学方法P. Papadopoulos和R.O. Ritchie提出的工作的目标是发展一个综合的实验，理论和计算描述的变形，断裂和循环疲劳行为的多晶超弹性/形状记忆合金。智力优势：所提出的工作旨在表征经历一系列固-固相变的复杂织构材料的力学行为，这对材料的多轴应力-应变响应和疲劳特性有着至关重要的影响。该研究的智力价值源于它所解决的具有挑战性的问题以及所提出的方法的综合性质（实验，理论，计算）。更广泛的影响：超弹性合金的使用正在经历爆炸性的增长，主要是在生物医学设备中，但也在许多其他民用和军事应用中。例如，仅在美国，2003年的心血管支架工业估计为每年50亿美元，并且超弹性Ni-Ti合金正迅速成为这些支架的主要材料。与此同时，这类合金的力学响应，特别是在多轴载荷和循环疲劳下的力学响应，也存在很大的不确定性。 拟议的研究旨在解决这些不确定性，从而有助于在工程实践中更安全，更合理地使用这些材料。

An Integrated Micromechanics Approach to Physics-basedModeling of Deformation and Failure of Superelastic MaterialsP. Papadopoulos and R.O. RitchieThe objective of the proposed work is to develop an integrated experimental,theoretical and computational description of the deformation, fracture and cyclic fatigue behavior of polycrystalline superelastic/shape-memory alloys. Intellectual Merit: The proposed work seeks to characterize the mechanical behavior of a complextextured material that undergoes a series of solid-solid phase transitions, which crucially affect its multiaxial stress-strain response and its fatigue characteristics. The intellectual merit of the research stems from the challenging questions that it addresses and from the integrated nature(experiments, theory, computing) of the proposed methodologies. Broader Impact: Superelastic alloys are experiencing an explosive growth in use, mostly inbiomedical devices, but also in a number of other civilian and militaryapplications. As an example, the cardiovascular stent industry in 2003 is estimated at 5 billion dollars per year in the US alone and superelasticNi-Ti alloys are fast becoming the principal material for these stents. At the same time, there exist significant uncertainties regarding the mechanical response of such alloys, especially under multiaxial loading and cyclic fatigue. The proposed research intends to address these uncertainties, thus contributing to the safer and more rational use of these materials in engineering practice.