Abstract

A three-dimensional (3D) fiber stress formula was developed to reduce the deviation of the two-dimensional (2D) fiber stress formula in calculating the 3D stress. The on-axis and off-axis stress–strain relationship was first presented. The 3D fiber stress formula was then derived analytically. Finite element method (FEM) of filament-wound (FW) thick-walled cylinders with symmetrical/balanced-layers was built, and numeric results were calculated and analyzed. Good agreement of the fiber stresses in the fiber direction and the strength ratios were achieved. It was found that the 3D fiber stress formula yields more accurate stress and lower strength ratio than the 2D formula in the triaxial stress state.

摘要

开发了三维（3D）纤维应力公式，以减少二维（2D）纤维应力公式在计算3D应力时的偏差。首先提出了轴上和离轴应力-应变关系。然后分析得出 3D 纤维应力公式。建立了具有对称/平衡层的纤维缠绕（FW）厚壁圆柱体的有限元法（FEM），并对数值结果进行了计算和分析。获得了纤维方向上的纤维应力和强度比的良好一致性。研究发现，在三轴应力状态下，3D 纤维应力公式比 2D 公式产生更精确的应力和更低的强度比。