Survival Technology and Efficiency Assessment of Aerospacecraft Laboratory

Beijing, China

Survival Technology and Efficiency Assessment of Aerospacecraft Laboratory

Beijing, China
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Zhou S.,China Institute of Technology | Qiang H.-F.,China Institute of Technology | Wang X.-R.,China Institute of Technology | Wang G.,China Institute of Technology | Zhou Z.-Q.,Survival Technology and Efficiency Assessment of Aerospacecraft Laboratory
Gongcheng Lixue/Engineering Mechanics | Year: 2014

When a corrugation structure is located in the bottom of original spherical-dished diaphragms, expulsion efficiency is low. In order to heighten the expulsion efficiency of diaphragms, a corrugation structure is located near a dished section. The buckling and post-buckling equilibrium configurations of original and modified diaphragms are numerically analyzed by the finite element method (FEM). By the comparison of research results about the two diaphragms, the conclusions are as follows: modified diaphragms are better for expulsion than the original ones, and the former has higher expulsion efficiency; severe eccentricity and folding problems, which are likely to cause fracture failure of the original diaphragms, do not happen in the modified ones; the maximum Von Mises stresses of modified diaphragms are much smaller than that of original ones, which indicates modified diaphragms are less probable to reach the limit stress of the material during an expulsion process.


Zhou S.,China Institute of Technology | Qiang H.-F.,China Institute of Technology | Wang G.,China Institute of Technology | Wang X.-R.,China Institute of Technology | Zhou Z.-Q.,Survival Technology and Efficiency Assessment of Aerospacecraft Laboratory
Tuijin Jishu/Journal of Propulsion Technology | Year: 2014

Arc length method can track nonlinear equilibrium configuration, but it is greatly affected by the initial setting load values. As a result, modified arc length method, aimed at solving the problem, works out expulsion process of diaphragms better. Several materials, such as 3012 titanium alloy, pure titanium and an ideal material, were chosen to study effects of residual stain on multi-expulsion behaviors for spherical-cone diaphragms based on modified arc length method by Finite Element Method(FEM). Positive expulsion and back reversal processes of 3012 titanium alloy diaphragms were not as good as that of pure titanium diaphragms. The former had severe eccentricity problems along with folding, and the eccentricity value reached at 60mm during back reversal process after 98 percent positive expulsion. Ideal material diaphragms all had severe eccentricity problems during back reversal process after positive expulsion of different percents, and the maximum eccentricity value was larger than 80mm. Pure titanium diaphragms had marked eccentricity phenomena only when back reversal process is at 98 percent positive expulsion, and the eccentricity value was about 10mm. Materials with no residual strain reduce structural stiffness of diaphragms, and coexist with the feature of initial elastic modulus being smaller. These factors are disadvantageous to multi-expulsion behaviors of diaphragms.


Zhou S.,China Institute of Technology | Qiang H.-F.,China Institute of Technology | Wang X.-R.,China Institute of Technology | Wang G.,China Institute of Technology | Zhou Z.-Q.,Survival Technology and Efficiency Assessment of Aerospacecraft Laboratory
Tuijin Jishu/Journal of Propulsion Technology | Year: 2013

Eccentricity problem occurred during metallic diaphragms for tanks expulsion test is likely to cause gas mixed with liquid and leakage of propellant. In order to solve the eccentricity problem of diaphragms, diaphragms expulsion process was numerically analyzed by Finite Element Method (FEM). Marked numerical eccentricity phenomena was obtained by means of elasto-plasticity constitution model, and the maximum numerical eccentricity value was about 60 mm. Numerical eccentricity phenomena caused by using elasto-plasticity constitution model was consistent with that happened during diaphragms expulsion test. Methods of modifying height of cone section and diaphragm thickness, ring-stiffened on diaphragms were raised to improve eccentricity problem and the results of different methods to improve numerical eccentricity phenomena were obtained. Research conclusions indicate that modifying diaphragm thickness is the best method among the three, but the method will significantly increase buckling load and structural mass, while modifying height of cone section follows the first method, but optimal height of cone section should regulate according to radius of arc section. Ring-stiffened on diaphragm ranks the end, but the method can be universally used to improve eccentricity problem of diaphragms, and it can not increase structural mass much.

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