带剪切销抗爆容器定向泄压特性研究OA北大核心CSTPCD

Once an explosion accident occurs on a civil aviation aircraft,it will cause fatal damage to the aircraft structure. In order to provide a scientific basis for the structural design and engineering application of airborne anti-explosion vessel,the directional explosion venting characteristics of anti-explosion vessel with a shear pin are studied. The structure system is mainly composed of a cylindrical vessel,a venting cover,a shear pin and an aluminum alloy panel. Firstly,the numerical model of the anti-explosion vessel under implosion is established with LS-DYNA. The critical diameter of shear pin was obtained in explosion tests and the effectiveness of the model is verified. Then,the propagation of shock wave and distribution of blast loading in the anti-explosion vessel are elucidated by analyzing the distribution of explosion flow field and changes in shock wave pressure. Meanwhile,the motion law of venting cover during the process of explosion venting is studied by varying the TNT charge mass and shear pin diameter. Finally,a functional relationship between the charge weight and shear pin diameter is established with different venting cover masses,to investigate the critical fracture issue of the shear pin. The results show that the critical diameter of the shear pin is found to be 22 mm through 100 g TNT internal explosion tests.Following the TNT explosion,the shock wave propagates reciprocally in the vessel. At approximately 3.8 ms,the venting cover is ejected from the vessel,while the residual pressure at the bottom of the vessel is approximately 0.5 MPa at 5 ms. During the explosion venting process,the peak overpressure at the bottom of the vessel is about 144 MPa,and the peak overpressure at the corner formed by the intersection of the vessel wall and the venting cover is about 149 MPa. Moreover,the vessel wall experiences strain growth at the corner,where it becomes a new critical point of failure. The deformation and fracture process of the shear pin can influence the motion characteristics of the venting cover,resulting in a decrease in the velocity curve. Therefore,the duration of the decreasing segment in the velocity curve is directly proportional to the diameter of the shear pin,with larger diameters leading to longer durations. The inertia of the venting cover and the stiffness of the shear pin are the main reasons for the fluctuation of the velocity of the venting cover during the explosion venting process. The TNT mass and the critical diameter of shear pin displays a proportional relationship. However,the change of the venting cover mass does not affect the linear relationship between the critical diameter and the TNT mass.