J. H. Yoon, H. S. Lee, Y. M. Yi, Korea Aerospace Research Institute, Daejeon, South Korea
In the current study, Ti-6Al-4V tank has been superplastically blow formed from initially diffusion bonded envelope, rather than using two separated blank, and the performance was experimentally verified throughout pressure loading test. A finite element analysis has been carried out in order to establish blow forming process and to obtain the optimal pressure profile. When using initially diffusion bonded envelope, the forming process was divided into three steps; initial opening, free bulging to reduce the diameter of the envelope, and then final sizing. The thickness distribution of the formed tank and deformed shape showed a reasonable agreement with the simulation. In addition, it is construed that the performance of the tank is satisfactory with the design requirement throughout pressure loading test. In the future, more precise control of the diffusion bonding condition should be followed to enhance the reliability of bonded area.
Summary: In the current study, Ti-6Al-4V tank has been superplastically blow formed from initially diffusion bonded envelope, rather than using two separated blank, and the performance was experimentally verified throughout pressure loading test. A finite element analysis has been carried out in order to establish blow forming process and to obtain the optimal pressure profile. When using initially diffusion bonded envelope, the forming process was divided into three steps; initial opening, free bulging to reduce the diameter of the envelope, and then final sizing. The thickness distribution of the formed tank and deformed shape showed a reasonable agreement with the simulation. In addition, it is construed that the performance of the tank is satisfactory with the design requirement throughout pressure loading test. In the future, more precise control of the diffusion bonding condition should be followed to enhance the reliability of bonded area.
