复合材料闭剖面加筋薄壁梁刚度系数计算分析

摘要

Composite designs offer the advantage of achieving favorable deformation modes through elastic tailor ing. Structural coupling such as extension-twist and bending-torsion are created as a result of the anisotropic properties of composite materials. Based on the structural mechanics theory of two-dimensional thin-walled shell and progressive approximation method, in-depth study on the stiffness coefficient of orthotropic thin-walled box beam with opened and closed cross-sections is made. Taking assumption of homogeneous isotropic thin-walled box beam, different theoretical approaches are used to validate the comprehensive applicability of the anisotropic shell theory constructed. With application of the above-mentioned theory, a complete algorithm is designed and programmed through Fortran algorithmic language to numerically compute the stiffness coefficients of complex closed-cross-section thin-walled box beam with circumferentially non-uniform thickness and discrete concentrat- ed area. Some numerical examples are studied and the bending, twisting and coupling stiffness coefficients are obtained respectively for two composite ply layouts of rectangular thin-walled box beam with closed-section. The reseults are valuable in academic and engineering applications for the controlling of the stiffness of thin-walled box beams.%复合材料的可设计性为通过弹性剪裁来获得想要的变形模式带来了优势，其结构的耦合特性如拉扭耦合和弯扭耦合可以利用复合材料的各向异性来实现。以薄壁壳结构力学理论为基础，采用多种理论方法研究分析正交各向异性壳体本构关系，给出适合复合材料层压板矩形闭剖面薄壁梁截面的刚度系数解析表达；采用逐阶近似方法，完整设计复杂闭剖面的刚度系数数值算法；针对两种典型的复合材料铺层的矩形闭剖面梁截面布局构型，进行刚度特性的计算分析与讨论，获得铺层角度对复合材料薄壁梁弯曲、扭转及弯扭耦合刚度特性的定量结果。对分析设计闭剖面薄壁结构刚度条件具有应用价值。