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Buffer the collision of air launch box

Author: ChenMaXu
Tutor: LeGuiGao
School: Nanjing University of Technology and Engineering
Course: Armament Launch Theory and Technology
Keywords: launch box cushion foam paper honeycomb explicit nonlinear dynamicmethod
CLC: TJ393
Type: Master's thesis
Year: 2014
Downloads: 33
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Abstract

A launch box is airdropped. When it is landing, in order to reduce the possibility of damage which occurs, cushioning material is applied under the box. Finite element software is used to do the simulation for the collision process with explicit nonlinear dynamic method.The model about the launch box collides with the ground directly is built. Vertical acceleration peaks of four rockets are greater than the permissible value.A foam pad is used to buff. Two different material properties are considered. The simulation results show that it is required to select the appropriate material parameters. After that, it makes the rocket acceleration and the stress of the box frame safe.Foam is connected to the top of the paper honeycomb. Both things form a buffer device together. The height of the paper honeycomb is taked as a variable. The process is simulated at twice. At the end of the second analysis, the displacement map of the paper honeycomb core is given. In the rear of the honeycomb core, the deformation of this part is very large. The reason is that the launch box’s centre of gravity is partial to the backside.In the case of the same overall size, two kinds of foam are assembled respectively by the way of serial connection and parallel connection. They are to cushion the system of the launch box. The time history curves of overall internal energy and overall kinetic energy are given. When the parallel foam is used, at the end of the analysis, the displacement map of the polyethylene foam is given. Severe deformation of the foam occurred. The reason is that the compressibility and the resilience of the foam that parallel connection used are different. Based on the foregoing conditions, when serial connection is compared with parallel connection, serial connection mode should be selected preferentially.This study provides a reference for the airdrop test of the launch box and structural improvements. It also has a positive significance for buffer design of common products.

Buffer the collision of air launch box

Abstract

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