Thermomechanical Analysis of Functionally Graded Shape Memory Alloys

该研究项目涉及加州大学洛杉矶分校生产的功能分级薄膜形状记忆材料（镍钛）。形状记忆合金有一种特性，即加热后能恢复到记忆的形状。加州大学洛杉矶分校开发的这种材料具有独特的双向驱动能力，也就是说，它在冷却后会恢复到第二种形状。本项目将为这种新材料建立一个热力学模型，包括热模型、力学模型、本构关系和相变模型。该研究为形状记忆合金器件的设计提供了可能。例如，它可以在飞机表面制造小型装置，以减少阻力或控制飞行。它将使新的MEMS（微机电系统）设备的发展成为可能。由于钛镍具有生物相容性，这一进展在生物医学应用中可能特别有价值。

This research program addresses functionally graded thin film shapememory material (nickel titanium) being produced at UCLA. Shapememory alloys have the property that they return to a memorizedshape when heated. The material developed at UCLA has the uniquecapability of two-way actuation, that is it returns to a secondshape when cooled. This project will develop a thermomechanical modelfor this new material, consisting of a thermal model, a mechanicalmodel, a constitutive relation, and a phase transformation model.This research will enable the design of shape memory alloy devices.For example, it may make it possible to produce small devices on thesurfaces of aircraft to reduce drag or control flight. It will enablethe development of new MEMS (micro-electro-mechanical systems)devices. This advancement may be especially valuable in biomedicalapplications since nickel titanium is biocompatible.