摘要
传统的基于几何非线性假设的瞬态热力耦合计算方法由于忽略了几何非线性对耦合项的影响,在温度随时间剧烈变化的情况下结构传热与变形之间存在的耦合关系不能被真实的反映。针对上述问题,采用Galerkin和Newmark算法建立了一种能够在几何非线性假设下精确反映温度剧烈变化情况下结构传热与变形间耦合效应的瞬态热力耦合有限元方法。通过对各向正交异性材料薄板在热环境下的动力学问题的求解验证了该方法的准确性,并基于该方法对某型高超声速飞行器热防护系统的蜂窝结构进行了瞬态热力耦合计算。结果表明:热力耦合项使温度变化产生很小的波动,导致温度变化率发生震荡,其振动幅值与耦合项相关;热力耦合项对结构振动起到衰减作用,使结构形变速度趋于衰减,其衰减程度与结构温度成正比;几何非线性假设对增大结构温度变化率振幅作用显著,并且能够增大结构振动速度,影响热结构变形大小。
Ignoring the effect of geometry nonlinear on coupling, the traditional methods of calculating transient thermo-mechanical coupling under the hypothesis of geometry nonlinear cannot reflect the heat transfer and structural deformation coupling accurately within a wide extension of temperature. Hence, a transient finite element method considering geometry nonlinear is established to solve the problem of therrno-mechanical coupling based on Galerkin and Newmark algorithm. Thereafter, the method is validated by calculating the dynamic behaviors of an orthotropic thin plate under thermal environments, and it is further applied in solving the thermo-mechanical coupling problem of a honeycomb panel of the thermal protection system on a hypersonic flight vehicle. The results indicate that the coupling term with small effect on temperature can cause vibration of temperature, speed up the convergence of structural deformation and alleviate structural vibration with the damping proportional to temperature In addition, the hypothesis of geometry nonlinear can substantially increase the amplitude of the change of temperature, as well as the vibration velocity, and affects the structural deformation.
出处
《工程力学》
EI
CSCD
北大核心
2016年第8期221-230,共10页
Engineering Mechanics
关键词
几何非线性
热力耦合
瞬态响应
有限元方法
结构动力学
geometry nonlinear
thermo-mechanical coupling
transient response
finite element method
structural dynamics
