复合材料壳体的应力和稳定性分析

一、引言 在现有的文献中,复合材料壳体的稳定性计算,大都采用环元针对轴对称分布载荷的轴对称旋转壳进行的。但是在实际结构中有大量的非轴对称壳体,壳壁大都是变厚度,实际载荷也大多是非轴对称分布,并且往往还有由温度改变而产生的热应力,或称它为“热载”。为了解决这些更为广泛的实际问题,开展了这项研究工作。

STRESS AND STABILITY ANALYSIS FOR COMPOSITE SHELL STRUCTURES

In this paper the stability problem of composite shell structures, such as single-ply shell, laminated shell and sandwich shell, is solved by displacement mode of finite element method. To suit different geometric shape and variable shell thickness. We select a Mindlin 8-node isoparametric quadratic shell element taking the coupling phenomenon between bending and inplane stretching and the effect of shear deformation into account. The external loads may be distributed aerodynamic pressure, body force or the so-called"heat load"created by temperature difference between external and internal plys. A generalized eigenvalue problem is solved by simultaneous iteration algorithm to find the eigenvalue, which is the smallest in terms of norm, and the corresponding eigenvector. A computer program has been written in standard FORTRAN-IV language. It possesses the advantages of less C. P. U. time, good versatility and convenience for use. Several examples have been tested by the use of the program, computational results are fairly satisfactory. Now this program has been used to check stability of practical composite shells and help engineer design shell structures.