基于等效截面的复合材料板格弯曲正应力计算方法

复合材料板格作为复合材料基本板架结构力学性能的最小分析单元，是由不同厚度、不同材料和不同铺设角度的单层板叠合而成。利用材料力学理论和经典复合材料层合板理论，推导一般情况下的复合材料板格中性轴位置控制方程，并采用等效截面方法，提出复合材料板格各单层弯曲正应力的计算公式。复合材料板格各单层的最大正应力由模量比和距中性轴位置共同决定。此公式形式上和各向同性材料弯曲正应力的计算公式一致，从而将弯曲正应力计算公式由各向同性材料扩展到各向异性材料，为掌握复合材料板架结构应力水平提供方便。此公式形式简洁，便于工程应用。

Calculation Method for the Normal Bending Stress of Composite Panels Based on the Equivalent Section Method

Composite panel is the smallest analysis unit for the mechanical properties of the basic plate frame structure, which could be composed of different thickness, different materials, and different lamina with arbitrary angles. Based on the theory of mechanics materials and the classical theory of composite laminate, this paper derives the general control equation of neutral axis for composite panels. By employing the equivalent section method, the normal bending stress formula of each lamina is presented. To be more specific, the maximum normal bending stress for each lamina is determined by the modulus ratio and the distance from the neutral axis. This result is formally consistent with the isotropic material formula. Thus, the normal bending stress formulas can be extended from isotropic material application to anisotropic material application, which brings significant convenience to calculate the stress level of composite plate frames. The formula proposed in this paper is both clear and concise, which can greatly shorten the development cycle of composite structure design and be easily applied in future engineering applications.