Papers by Author: Shang Yang Meng

Abstract: The stress-release boot is always used in the fore and rear of SRM grain to relief stress-strain concentration under thermal loading. Since the debonded crack in the stress-release boot may be propagation unstable when the internal pressure entered the debonded crack cavity, the SRM with debonded cracks is very dangerous when it is lunched. So the stability analysis of the debonded cracks is very important to evaluate the defect grain structure integrity. In order to investigate the stability of debonded cracks in the stress-release boot of SRM grain during ignition pressurization, three-dimension (3-D) viscoelastic finite element models of the SRM grain with debonded cracks are established. The 3-D singular crack elements at the tips of cracks are developed to simulate the stress-release boot debonded crack propagation. And all the singular crack elements are included in the 3-D J-integral loop surface to improve the calculation precision. Along with the debonded crack propagation, the 3-D J-integrals of the debonded crack tips are respectively calculated to prejudge its expanding trend. The results show that the most dangerous situation will occur in the fore stress-release boot debonded cracks during the rocket being launched.

Abstract: The plate rubber support is widely used in railroad bridge. To analyse its capability of transverse displacement resistance and increase its life-span, the finite element model of profiled plate rubber support is established by nonlinear finite element method. The influence of flex gradient of stiffened steel plate to the function of the plate rubber support is analyzed and the optimal gradient is obtained.The method and conclusions are available for designing of plate rubber support.

Abstract: The surface cracks are easy to occur in the solid missile motor grain. The solid missile motor grain with cracks is very dangerous when it is lunched, because the surface cracks might be propagation unstable when the internal pressure enters the surface cracks cavity. In order to analyze the surface crack of solid motor grain, with accelerated aging test, the variation law of mechanics properties of propellant in the storage period is obtained. Under internal pressure and axial acceleration loading, the three-dimension finite element models of the motor grain are established, three-dimension singular crack elements at the tips of surface cracks are established to simulate the cracks propagation. Along with the surface crack propagation, the stress intensity factors of the crack tips in different storage period are calculated to prejudge its stability respectively. The method and conclusions are available for using solid missile motor grain with surface cracks.