带褶皱的等张力体航天服软关节设计与实验

面向未来行星表面探测任务,航天服的活动性能需要进一步提高。为此,应改进航天服软关节的结构形式。根据等张力体形状内部承压时不存在周向应力的理论,在该曲面周向上加入褶片结构,设计出了带褶皱的等张力体关节,使之能够沿周向弯曲或伸展。为验证关节性能,利用柔性单自由度关节测量设备,进行了多次加卸载和不同运动范围的力矩特性研究,分析了关节的几何形态、等容性以及主应力状态,并将该关节与无褶皱的等张力体关节和平褶式关节进行了比较,最后讨论了关节的优化方向。结果表明,在测试的0°~80°范围内,关节力矩较小,最大容积变化为1.6%。关节弯曲时,等张力体曲面上周向应力仍可忽略不计。首次加载与之后的加载有一定的差异,而不同的运动范围对关节活动性能无影响。与其他两种关节形式比较,带褶皱等张力体关节在几何尺寸、运动形态和活动性能上都具有一定的优势。此外,该关节可在结构和材料方面进一步优化。

Design and experiment of pleated isotensoid spacesuit soft joint

Toward future exploration programs on planetary surface, the flexibility of spacesuit needs to be further enhanced by improving structure forms of spacesuit soft joint. According to the theory that isotensoid shape can carry interior pressure without circumferential stress, pleated isotensoid joint is designed by introducing wrinkles onto isotensoid surface along the circumferential direction. So this joint can be bent and stretched in the direction of circumference. To verify the performance of joint, measuring equipment of flexible unidirectional joints is applied to investigating joint torque characteristics by repeatedly loading and unloading with different ranges of motion. The joint geometry, capacity to remain constant volume and principal stress state are analyzed. Then comparison of this joint, smooth isotensoid joint and flat pattern joint is carried out. Finally the optimization metrics of joint are discussed. Results show that joint torque is relatively low and the maximum volume change is 1.6% in the testing range of 0° to 80°. The circumferential stress on isotensoid surface can be basically negligible when the joint is flexed. There are some differences between the first time loading and subsequent loading. However, different ranges of motion have no influence on joint mobility. It can be concluded that pleated isotensoid joint has certain advantages on geometry, motility patterns and mobility property over the other two types of joint. In addition, this joint can be further optimized in terms of structure and material.