Winding Molding Trajectory Planning Of Heat Insulation Based On Geodesic Numerical Method

As an important part of the solid rocket motor,the heat insulation in the combustion chamber case of a solid rocket motor is a layer of thermal insulation material between the propellant and the case.Its main function is to prevent the case from endangering its structural integrity due to high temperature.When the combustion chamber is working,the gas temperature is as high as 2500～3900K,and heat insulation protects the normal operation of the engine case through its own decomposition and ablation.EPDM rubber,as an ideal thermal insulation material in the case,has the advantages of strong heat absorption,low density,good heat resistance,high oxidation resistance,and high thermal decomposition temperature,and has been widely used.At present,the domestic solid rocket motor heat insulation is formed,the front and rear heads are molded,and the barrel section is manually laid.The product production cycle is long,the degree of automation is low,the process is numerous,and the quality stability is poor,which seriously hinders the production efficiency and product quality.Therefore,it is urgent to carry out research on the automatic winding molding technology of heat insulation.The winding trajectory planning of the variable curvature heat insulation is an important prerequisite for ensuring the high-quality winding molding of heat insulation.This article focuses on the winding molding trajectory planning of heat insulation.First,based on the shape characteristics of the variable curvature mandrel and the winding molding characteristics,the process plan of winding molding of heat insulation and the automatic winding equipment plan were designed,the calculation method of universal tape width that meets the different types of mandrels and the design method of the shape of the winding roller were proposed;Then,the winding molding trajectory planning algorithm of heat insulation was proposed.The algorithm is based on the geodesic numerical method to obtain the geodesic on the surface of the variable curvature mandrel to meet the tape gap error requirements,avoid wrinkles or tears of the tape,and at the same time,the heat insulation deforms less during the winding process,and ensure the winding quality of heat insulation.During the winding process of heat insulation,the depth of the winding roller entering the rubber heat insulation along its supporting axis must be controlled at each winding position so that the winding pressure of the rubber surface of heat insulation meets the winding requirements.According to the Hertz contact theory,by analyzing the minimum stress of the winding normal pressure surface of the rubber deformation zone of heat insulation,the amount of deformation and the corresponding position,when the winding pressure is met,Through calculation,the depth of the winding roller entering heat insulation along its supporting axis at each winding position was obtained,and the winding pressure control on the surface of heat insulation was achieved.guaranteed the bonding quality and winding quality of heat insulation,and completed the winding molding trajectory planning.Then,the kinematic analysis and speed coordination analysis of the winding equipment were carried out to lay the foundation for the subsequent trajectory programming;Finally,the "winding molding trajectory planning of heat insulation and simulation" system was developed.The system passed the simulation verification of winding molding process of heat insulation,which showed that heat insulation winding along the geodesic line can effectively complete winding molding of heat insulation and meet heat insulation winding quality requirements.