复合推进剂药柱拔模过程的力学响应实验与仿真研究OA

In the mandrel drawing process of composite propellant grain forming,interfacial adhesion and friction between the mandrel and the grain are key factors affecting structural integrity of the grain.In order to explore the mechanical response of the grain under different working conditions,the material properties of the grain,as well as the friction coefficient and interfacial adhesion strength between the grain and the mandrel were obtained through experiments,and the finite element simulation model for the mandrel-drawing process was established.In this study,a linear viscoelastic constitutive model and a bilinear cohesive zone model were adopted to characterize the material mechanical behavior and the interfacial debonding process,respectively.By simulating the mandrel-drawing process under different temperatures(30,40,50℃)and mandrel-drawing speeds(1,2,3 mm/s),the evolutionary laws of the mandrel-drawing force and the stress-strain distribution of the propellant grains were systematically analyzed.The results show that the mandrel-drawing process of the propellant grains can be divided into three stages:bonding,debonding,and separation.Stress concentration occurs at the contact end of the grain inner wall,the fillet transition zone,and the dynamic contact point with the mandrel.Both stress and strain gradually accumulate as the mandrel is drawn out.Within the tested parameter range,when the temperature increases from 30  ℃to 50 ℃,the maximum mandrel-drawing force decreases from 117.0  N to 85.8  N,while the maximum stress remains stable at 0.118  MPa,and the maximum strain rises from 0.020 to 0.035.As the mandrel-drawing speed increases from 1 mm/s to 3  mm/s,the maximum mandrel-drawing force increases from 117.0  N to 133.2  N,while the maximum stress still stays at 0.118  MPa,and the maximum strain drops from 0.020 to 0.012.