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In order to solve the problem of sealing the cylinder of the steam catapult, a nested structure of inner and outer cylinders is developed. The openings of the inner and the outer cylinders are staggered after the installation. The materials of inner and outer cylinders are the same. The thermal deformations of the two types of cylinders are consistent at high temperature, so that the radial sealing can be guaranteed. Based on the basic working principle of this steam catapult, a dynamic mathematical simulation model is developed with some assumptions; relevant researches are carried out by simulating the dynamics and thermodynamics process of the steam launch system. The result indicates that the radius of cylinder and the initial steam pressure have significant effects on the takeoff speed and the takeoff acceleration. With a constant load, the radius of cylinder is inversely proportional to the initial steam pressure, and it is considered that the optimal choice should be 0.4 m/2 MPa. The headwind helps takeoff and reduces the dependence on the thrust force in the launch process. The simulation result could provide a reference for the design of the inner and outer nested cylinder-type steam catapult.

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This paper presents the thermo-magneto-electro-elastic (thermo-MEE) field in an annular plate of heterogeneous multiferroic composite medium subjected to thermal loadings uniformly distributed on the main boundaries. As a prior, the temperature distribution is determined by solving the thermo-conduction equation. Then, the direct displacement method is employed to derive the coupling thermo-MEE field. Finally, numerical calculations are performed to validate the present analysis and to investigate the influence of the material heterogeneity and the multifield coupling. The present solutions can be readily reduced to those for circular plate upon letting the inner radius tend to zero. The obtained solutions may serve as a benchmark to various numerical codes and simplified analyzes, since no ad hoc hypothesis is adopted in the present work.