三维自适应形状记忆合金壳结构的关键力学问题研究

自适应结构技术作为未来飞行器的关键技术，对提高飞行器的性能具有重要作用。自适应结构可以根据飞行速度、高度等条件，自适应地改变飞行器气动外形。形状记忆合金(SMA)以其优异的材料特性，被广泛应用于自适应结构中。但目前大多数在SMA力学行为的研究主要局限于一维、二维结构，且多物理场作用下的力学行为研究还不够充分。本项目以SMA三维壳结构在自适应进气道上的应用为背景，对SMA壳结构在气动载荷作用下加热变形过程中的关键力学行为展开研究，通过理论分析、数值仿真和实验验证相结合的办法，着重解决以下关键问题：1）三维形状记忆合金双程效应的力学行为建模以及有限元仿真的实现；2）考虑气动加热和对流冷却的SMA温度场、流场、变形的耦合分析；3）不同温度场和流场作用下SMA三维壳结构的气动弹性稳定性分析；4）SMA自适应结构非线性控制系统的实现。展开这一探索性研究对促进SMA的自适应结构的发展具有重要的意义。

Adaptive structure technology, which is considered as a key technology for the next-generation aircraft, plays an important role in improving the aircraft performance.According to the speed, altitude, task or other conditions, adaptive structure can adaptively change the shape of the aircraft structure. Shape memory alloys are widely used in adaptive structures because of its excellent properties. However, most of studies on mechanical behavior of shape memory alloy are mainly limited to one or two dimensional structures, and multi-physical coupling effect is not sufficiently considered. With the application of SMA in the adaptive inlet of aircraft as the background, the study will focus on mechanical behavior of SMA under the multi-physical coupling field. The following key problems will be solved by theoretical analysis, numerical simulation and experimental investigations: (1) establishment of the constitutive model of the 3-D SMA shell structure and implementation of the finite element simulation; (2) coupling analysis of temperature field, deformation and flow field with the aerodynamic heating and convectional cooling taken into consideration; (3) analysis of aeroelastic stability of the SMA shell under different temperature fields and flow fields; (4)design and implementation of the non-linear control system for SMA shell. The study will play the important role for promoting the appliaction of SMA in adaptive aerospace structures.