Thermo Structural Analysis of Airborne Structure

An Airborne Flight Vehicle (AFV) is a self-propelled aerial vehicle meant for transportation of people, cargo, payloads or measuring instruments etc. AFV is constituted by Payload, propulsion, control, guidance and navigation systems. The structures inside airborne flight vehicles are intended for integrating the sub systems to the flight vehicles. Such structures are designed to carry intended subsystems under acceleration loads arising due to the movement of the flight vehicle. Outer shell of the flight vehicle is exposed to outer atmosphere and subjected to aerodynamic heating. This heat gets propagated to the internal structure and thus reducing the mechanical properties of the structure material. This paper deals with Thermo-Structural stress analysis of a structure which is designed for carrying 134 kg fuel tank under given loading conditions. In this paper, a cylindrical flight vehicle section is to be fitted with a toroidal fuel tank whose mass along with the fuel is given as 134 kg. During flight, flight vehicle section gets heated up due to aerodynamic heating with a heat input of 22.5 kW. In the total flight time of 90s, this heat gets propagated to internal structures through conduction. The heat transfer due to radiation is neglected due to rapid heating of airframe during flight. A structure is designed after several iterations. This structure consists of two rings joined together by a 2mm thick shell. One ring is attached to the flight vehicle section where as other ring carries the fuel tank. Intermediate shell acts as a connecting member. Ribs are added in the longitudinal direction to improve the stiffness of interface structure. Material is removed at intermitted location to reduce the weight of the section. The Thermo structural analysis is carried out on the structure and the design is continuously improved after each iteration. This paper shows the design of final configuration of structure. The structure is in realizable state and ready for fabrication