Contact finite element analysis of hinge joints for large deployable antenna in space satellite

Various malfunctions have been observed in space structures. These include failure of precise positioning control, such as the failure of the ASTRO-G parabolic antenna, failure of piston sliding parts, and instability due to incomplete expansion of IKAROS´ membrane. One reason for such failures is the friction at the contact points. Owing to the presence of various particles in air, an adhesive layer of particles is formed on metal surfaces. When metals get rubbed with each other, these particles are removed from the metal surfaces. In the atmosphere, the adhesive particle layer forms again on the metal surface. However, this layer cannot be formed in space. Therefore, the coefficient of friction in vacuum is larger than that in air. Generally, the coefficient of friction between metals is about 0.3. In vacuum, the coefficient of friction between metals may exceed 1.0. In the design stage, it is important to understand the friction behavior of a hinge joint in vacuum. Many parts of space structures are attached to each other via hinged joints. The frictional force on the contacts is used to fix the positions of these parts. The mechanical behavior of space structures varies with the friction of the hinge joints. The reliability of the space structure depends on these hinge joints. In 2012, it has become possible to conduct a detailed analysis owing to the improvements in computational performance and numerical simulation techniques. The entire space structure can be computed, including the friction model of the contacts of hinge joints. To develop high-reliability satellites, we attempted the development of contact modeling techniques by using a high-performance computer (JSS) and the Advance/FrontSTR in this study. The contact behaviors were verified by using computational models of the hinge joints.