提出了一种新的结构热应力、热模态求解方法。采用多变量有限元方法进行几何非线性单元列式，将温度的影响转化成热载荷进行静力学非线性有限元分析得到结构内部热应力，然后计算受热应力影响的结构非线性热刚度矩阵。由热刚度矩阵和质量矩阵进行广义特征值分析得到结构的热模态及其模态频率。最后，给出了热屈曲的计算方法。针对典型壁板结构计算了热应力和热模态，计算结果与Nastran相差在10%以内，分析了热应力对壁板结构动力学特性的影响。%A new method solving for thermal stress and thermal modals has been developed. The method takes geometrical nonlinearity into the formulation which is based on multi-variable finite element method. Thermal stress is calculated with nonlinear static finite element analysis by transforming the effect of temperature into thermal load. After the nonlinear stiffness matrix affected by thermal stress has been computed, a general eigenvalue analysis procedure could be performed to get the thermal modal and the corresponding frequencies by using the thermal stiffness matrix and mass matrix. Finally, the method of calculating thermal buckling problem is presented. Computation of thermal stress and thermal modal of a typical panel is compared with that of Nastran, of which the relative error is lower than 10%. The effect of thermal stress on characteristic of the panel is also analyzed.
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