静水压下复合材料圆柱壳力学特性研究

Research on Mechanical Properties of Composite Cylindrical Shells under Hydrostatic Pressure

研究了复合材料圆柱耐压壳强度和稳定性的理论计算方法,建立了静水压下单一螺旋纤维缠绕复合材料圆柱壳的数值模型,并对多种缠绕角下圆柱壳的强度特性进行了分析。讨论了不同长径比、径厚比下复合材料圆柱壳临界屈曲载荷与缠绕角的关系,给出了静水压下复合材料圆柱壳临界屈曲载荷的近似计算公式。开展了纤维缠绕复合材料圆柱壳压力筒试验,得到了壳体的失效载荷,并分析了壳体在静水压下的变形及失效过程。研究结果表明:单一螺旋玻璃纤维缠绕复合材料圆柱壳强度状态最优的缠绕角区间为50°~60°;半径和长度一定时,壳体越厚,缠绕角对其屈曲特性的影响越大;半径和厚度一定时,在论文研究的壳体长度与缠绕角区间范围内,壳体越长,其较佳屈曲特性对应的缠绕角区间越向大角度偏移。将材料参数替换后,米塞斯公式可作为静水压下缠绕角为54°~58°的复合材料薄圆柱壳的屈曲临界载荷近似计算公式;静水压下复合材料圆柱壳在整体屈曲前发生了局部的纤维损伤,壳体的失效模式是由于纤维断裂引起的强度破坏。

Theoretical method for composite cylindrical pressure shells was investigated.Numerical models of filament-wound composite cylindrical shells under hydrostatic pressure were presented,and their strength properties at different winding angle were analyzed.Relationships between the critical buckling loading of the composite cylindrical shell and winding angle were studied under different length-diameter ratios and diameter-thickness ratios.An approximate formula for calculating the critical buckling load of composite cylindrical shells under hydrostatic pressure was proposed.Experiment of filament-wound composite cylindrical shell was carried out in a pressure tank,obtaining failure load of the shell.Deformation and failure process of the shell under hydrostatic pressure was analyzed.Results show that the interval of the winding angle in the sense of optimal strength state is 50°~60°for single spiral wound glass fiber composite cylindrical shell.At a given radius and length,winding angle will have greater influence on buckling characteristics of the thicker shell.And for a given radius and thickness,there is bigger angle winding angle interval for longer shell in the sense of optimum buckling property.It is found that Mises formula can be applied as an approximate formula to calculate the critical buckling load of the composite thin cylindrical shell under hydrostatic pressure with winding angle lies in the range of 54°~58°.Local delamination and fiber damage will occur before global buckling,and this strength failure mode is caused by fiber breakage.