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Firstly, the analytical formulas of the dynamic magnification factor with the pulse time of the response spectrum of a single degree of freedom system under the rectangular and half sine pulse are derived. Then the parachute inflation and ejection low frequency high shock load dynamic simulation model of the Mars entry vehicle is built based on abaqus explict dynamics, and the influence of the shock load shape, load time and load damping are analyzed. Finally, the experiments of the opening parachute load suspension impact dynamic load and the parachute load real parachute impact dynamic load are carried out.The results show that the structure responds decline when the shock load time is less than 1 ms , and the static equivalence load becomes steady when the load time is longer than 5 ms; the dynamics equivalence load of the parachute inflation is about 1 time than static because of the smooth time wave, but the parachute ejection’s is about 1~2 times than static due to the steep rectangle wave. 相似文献
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A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual(GMRES) method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor(HHT) time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC(Harten–Lax–van Leer contact) scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel(LUSGS) approximate factorization is applied to accelerate the numerical convergence speed. Finally,the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature. 相似文献
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针对星敏感器的杂光抑制需求,设计了一种可以实现轴向展开的圆柱状展开式薄膜遮光罩,包括充气支撑管、薄膜蒙皮和挡光环,并完成了各构件的结构和材料设计。建立了薄膜蒙皮的运动学模型,分析了构型随着二面角的变化情况,验证了薄膜蒙皮采用hexagonal折纸样式可以完全折叠和展开。通过试验研究了遮光罩的重复展开精度,包括轴向和径向展开精度等。研制了遮光罩原理样机,并开展了地面展开试验,表明在充气支撑管的驱动下能够顺利展开,为大尺寸遮光罩的工程应用提供了新的技术方案。 相似文献