장력을 받는 유연한 전개형 Solar Array의 열적 진동 응답에 관한 연구

Abstract

Since humans have used airplanes to fly in the sky, space structures such as artificial satellites and the International Space Station (ISS) with various missions are launched into the orbit of the earth and operated in order to continue a more prosperous life. These space structure are independently operated for a long time in outer space, it has a characteristic that it must generate and maintain the power required for operation by a solar cell system. In addition, recent space structures tend to be enlarged in accordance with the increase in the required mission and accuracy. The solar cell system, which is the power source, is also required to be reduced in weight as much as possible because it has to be transported by rockets from the ground to orbit in terms of economy and efficiency in spite of increasing in size by the required power increases. A space structure with these requirements does not require high rigidity to support a load due to its own weight, unlike the ground. Therefore, space structures such as solar cells are characterized in that they tend to be light and flexible structures such as beams, membranes, and plates, compared to structures on the ground. A light and flexible structure has a high tendency to easily deform and vibrate by a slight load or disturbance, and may have a fatal effect on the structure. Flexible space structures that perform missions in space environments are apt to vibrate by the rapid change of solar heat flux and temperature gradient inside the structure during the night-day transition. The phenomenon that causes such a dynamic response is generally referred to as "thermal induced vibration", and is one of the phenomena occurring in space. The cause of this phenomenon is that, the structure on the ground have high rigidity, the influence of the inertial force can be neglected, but in a flexible structure, it is easily affected by the inertial force, which causes vibration. If the thermal induced vibration problem is predicted in an analytical method and it is not reflected in the design, the unstable dynamic response will have a great effect on the space structure, and high-resolution images and data cannot be obtained. Therefore, in order to operate an efficient mission in space, it is necessary to effectively control the vibration of the satellite body due to interference and force caused by thermal induced vibration in flexible structures such as solar panels and antenna booms. An example of this actually happening is the problem that occurred in the Hubble Space Telescope (HST) launched in 1990. The problem that occurred in this HST is the problem of spherical aberration of the main reflector and the vibration problem called “Pointing Jitter”, which occurred from the beginning of the first image data transmission. Among them, the vibration problem was determined to be caused by the solar array. Through this repair and replacement mission, damage to the solar array boom and distortion deformation of the solar array were discovered. Therefore, in this paper, the solar array of HST is modeled as a simple model with beams and membranes, and the phenomenon of thermal induced vibration is verified and analyzed by natural vibration analysis and dynamic response analysis and experimental method considering the coupling of bending and torsion, and heat and structure.