Finite element analysis model

The composite structure launch tube is a thin-walled structure made of composite laminate, composite reinforcement and metal flange. The material parameters are shown in Table 1. This finite element model fully simulates the actual structure. During the modeling process, The composite material shell is used to simulate the composite laminate, the composite body unit is used to simulate the launching tube rib, the body element is used to simulate all metal flanges, the flange and the composite structure are glued together, and the front and rear covers are simplified as shell elements. . Considering that the rocket has a great influence on the structure of the launch tube, the model simplifies it into a cylinder with equal mass, equal centroid position, equal moment of inertia and equal outer diameter.

The upper and lower rocket slides in the launch tube are simulated by the body unit and the composite shell unit, and the boundary element is used to simulate the connection between the rocket and the track. The coordinate system in the model is a Cartesian coordinate system that satisfies the right-hand rule. The origin of the coordinate system is defined as the center point below the bottom flange. The X-axis of the coordinate system is defined as pointing from the origin to the right in the left view, and the Y-axis of the coordinate system is defined as Pointing from the origin in the left view, the Z axis of the coordinate system is defined as determined according to the right hand rule.

It can be seen from the calculation results that the natural frequency of the composite pipe structure is lower than that of the rocketless structure, and the first two modes are more regular, that is, the role of the rocket can make the pipe structure The natural frequency of the first 2 orders is reduced by about 50. According to the finite element calculation and analysis of the composite tube, the stress and deformation of the tube in the storage and transportation state basically meet the design requirements. However, when the part is in a dangerous state in an instant, the stress exceeds the allowable value.