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为了研究含初始裂纹蒙皮薄膜的抗撕裂行为,选用Kevlar纤维增强的具有预制初始裂纹切口(PIC)的平流层飞艇用蒙皮薄膜,采用弹塑性断裂力学平面应力分析方法,考虑经纬向纱束之间的滑移摩擦效应,分析了薄膜裂纹尖端的撕裂强度与变形形式,建立了裂纹尖端撕裂物理模型和基于摩擦效应修正的等差法拉伸变形计算模型,获得了裂纹尖端应力集中区的应力分布。为验证计算模型的合理性,分别对PIC长度为10、20、30及40mm的试样进行了撕裂强度试验。结果表明:当PIC宽度比率不超过0.50时,模型计算值与试验值的误差小于4.12%;与改进的应力强度因子法相比,所建计算模型具有更高的计算精度,为平流层飞艇蒙皮撕裂强度的设计提供了一种有效的方法。
In order to study the tearing behavior of the film with the initial crack, a Kevlar fiber reinforced skin film for a stratospheric airship with prefabricated initial crack incision (PIC) was used. The elastic-plastic fracture mechanics plane stress analysis method was used to consider the warp and weft yarns Slipping friction effect between the beam and the beam, the tear strength and the deformation mode of the crack tip of the film are analyzed, the physical model of the crack tip is established, and the calculation model of the tensile deformation by the isometric method based on the friction effect correction is established, and the crack tip stress Concentration zone stress distribution. In order to verify the rationality of the calculation model, the tear strength of the samples with PIC length of 10, 20, 30 and 40mm were tested respectively. The results show that when the PIC width ratio does not exceed 0.50, the error between the model calculated value and the experimental value is less than 4.12%. Compared with the improved stress intensity factor method, the calculated model has higher accuracy and is more suitable for the stratospheric airship skin Tear strength design provides an effective method.