Study On Spherical Propellant Tank With Load-bearing Structure

In recent years, it has put forward the new requirement for the tanks of launch vehicles, especially that of the upper stages. In order to meet the requirement of the propellant management and to enhance the structure efficiency, a spherical tank with load-bearing function is firstly selected in of the structure design of the upper stages. The ability of bearing of the spherical thin-walled structure is relatively weak, so the overall layout design with the spherical tanks is hard to achieve. There are very little examples that spherical tanks were used to be the main structure of bearing all over the world. And for the upper stage or satellite, at present, the spherical tank without load-bearing function had be adapted, therefore, an additional main structure that is used to bear these tanks need to be designed, which will lead to reduce the efficiency of weight. So if we could achieve the structure design the spherical tank with load-bearing function, it would make a great contribution to increase the efficiency for launch vehicles.For the requirement of the spherical tanks with load-bearing, the article developed the structural design and the test of prototype and so on. We achieved the key technology about the manufacturing of the spherical tanks with load-bearing. This approach provides technical support to realize the lightweight structural configurations of the upper stages.Based on the foreign productions of the same launch vehicles, the bearing capacity and the characteristic of the spherical sheet is carried out through the theoretical analyses. It is found that the best place to set the load point is near the latitude about 60 degrees. A structural platform based on spherical tanks with load-bearing is developed, and the detailed drawings of its components are designed. Meanwhile, the strength and stability of the spherical tanks with load-bearing is numerically simulated by means of the finite element software. The evaluation result shows that the strength index meets the design requirements. Furthermore, in order to verify the accuracy of the design above and the manufacturability of the process, a mechanical test method for the spherical tanks is developed; a test platform for a single spherical tank is built. And the subscale destructive test for the spherical tanks with load-bearing is carried out. The test results indicate that the ability of the spherical tanks with load-bearing can meet the requirements in engineering.