双向梯度复合材料板瞬态热应力分析

该文通过编写一种8节点高阶双向梯度单元建立了结构的连续梯度有限元模型，采用细观力学方法结合混合律准则描述了双向梯度单元变化的热物理属性。分别采用有限单元-有限差分法和有限单元法分析了在循环热载荷作用下双向梯度板Al 1100/Ti-6Al-4V/ZrO2的瞬态热传导和热弹性问题，给出了温度场和瞬态热应力场的时间响应历程和空间分布形式。最后讨论了相关参数的影响规律，得到了一些重要的结论:冷却阶段更加容易萌生表面裂纹；沿x方向组分的分布形式影响了瞬态热应力的大小，但对其时间响应和分布形式影响很小；沿y方向组分的分布形式影响了瞬态热应力的时间响应和分布形式，但对其大小影响很小。

TRANSIENT THERMAL STRESS ANALYSIS OF TWO-DIRECTIONAL GRADED COMPOSITE PLATES

A continuous gradient finite element model is established based on eight-node high-order two-directional graded elements with spatially varying thermo-elastic properties described by micromechanics and rules of mixture. The transient heat conduction and thermo-elasticity of a 2D graded Al 1100/Ti-6Al-4V/ZrO2 plate under a thermal cyclic load are analyzed by finite element-finite difference and finite element methods respectively, and the time response and spatial distribution of temperature and transient thermal stress field are calculated. Finally the effects of several parameters are discussed and some important conclusions are obtained: surface cracks are more likely to initiate during the cooling stage; the component distribution along the x direction influences the magnitude of the transient thermal stress and has few effects on its time response and spatial distribution, while the reverse is true for the component distribution along the y direction.