辐射换热下瞬态热-结构分析的一种空间薄壁杆单元  

A kind of thin-walled beam element for transient thermal-structural analysis considering radiation heat transfer

作　　者：段进[1] 薛明德[1] 向志海[1] 李伟[1] 

机构地区：[1]清华大学工程力学系,北京100084

出　　处：《计算力学学报》2007年第3期345-351,共7页Chinese Journal of Computational Mechanics

基　　金：国家'八六三'高技术项目(863-2-2-1-9)资助项目

摘　　要：发展了一种用于辐射换热条件下瞬态热-结构分析的空间薄壁杆单元,其截面形式可以是任意形状的闭口截面和单支开口截面。该单元温度场分解为平均温度和多谐摄动温度,沿杆轴方向采用两结点线性插值,沿杆截面周向用三角函数展开,每结点含多个解耦的自由度,其中结点平均温度方程同传统一维温度有限元方程为非线性,各谐摄动温度方程为线性,然后利用Wilson-θ法求解结构的瞬态温度场。本文选择了两节点Ber-noulli直梁单元得到准静态热弹性有限元方程并求解,针对非对称开口截面考虑了翘曲变形及弯扭耦合的影响。温度场引起的等效热载荷不仅包括常规的热轴力,还包括热弯矩以及热双力矩。本文针对不同截面形式的梁单元给出了瞬态温度场以及热变形的验证算例,并通过与商业程序中二维壳元计算结果的比较说明了本文所提出方法的正确性和高效性。In this paper, a kind of thin-walled beam element is presented for transient thermal-structural analysis considering radiation heat transfer. The cross-section of the beam element could be an arbitrary shape of closed or open cross-section with single branch. The temperature field in the beam element is decomposed into an average part and a family of perturbation parts, which are interpolated by linear functions in the axial direction. Besides, the temperature variations in the circumferential direction are simulated by a set of triangular functions. Each nodal temperature has several variables which are decoupied each from other and the nonlinear analysis caused by the radiation heat transfer is restricted to solving the equations of the average temperature. The transient temperature field is calculated by the Wilson-θ method. Straight Euler-Bernoulli beam element including the effect of warping deformation is adopted. The coupling of bending and torsion deformation for asymmetry cross sections is taken into account. The thermal loads involve not only thermal forces, but also thermal moments and bimoments. Furthermore, the verification examples of thermal and deflection analysis for various kinds of cross-section beams are presented, and the comparison with the conventional two dimensional FEM results demonstrates the consistency, accuracy and superior numerical oerformance of the proposed element.

关 键 词：热一结构分析 辐射换热 薄壁杆件 弯扭耦合 有限元法 

分 类 号：O302[理学—力学]