Abstract

A shock absorber based on the progressive failure of a composite tube was developed. The composite tube is subjected to axial compression from the pressing cap at one end and folds inward at the other end under the effect of the crush cap without debris overflow. The crushed composite is compacted into a hollow tube and increases the resisting force once it reaches the pressing cap. For larger strokes without a load increase, a hole is made in the pressing cap for the crushed composite. Three crush caps with different curvatures of the inward-folding surface and two composite tubes were evaluated through static and dynamic tests. The crush cap lowered the initial peak load and varied the specific energy absorption (SEA). We also investigated the effects of connection rivets. Aluminum rivets were severed and had little effect on the load curve while steel rivets did not shear but cut the composite tube into strips, resulting in a lower sustained load because failure was induced. A set of shock absorbers with larger strokes was tested for use in the legged landing gear of a drone assumed to crash with a speed of 10 m/s, energy of 5000 J, and overload of less than 25 g. The maximum SEA of the absorbers, including the two caps, was 20 kJ/kg.

摘要

开发了一种基于复合管逐渐失效的减震器。复合管一端受到压盖的轴向压缩，另一端在压盖的作用下向内折叠，无碎屑溢出。压碎的复合材料被压制成中空管，并在到达压盖时增加阻力。为了在不增加负载的情况下进行更大的冲程，在压盖上为压碎的复合材料开一个孔。通过静态和动态测试评估了三个具有不同曲率向内折叠表面和两个复合管的挤压帽。挤压帽降低了初始峰值载荷并改变了比能量吸收 (SEA)。我们还研究了连接铆钉的影响。铝铆钉被切断，对载荷曲线影响不大，而钢铆钉不剪切而是将复合管切割成条状，导致持续载荷较低，因为引发了故障。测试了一组具有较大冲程的减震器，用于假设以 10 m/s 的速度、5000 J 的能量和小于 25 g 的过载坠毁的无人机的腿式起落架。吸收器的最大 SEA，包括两个帽，为 20 kJ/kg。