Mumerical Simulation Of Solidification Process Of High Energy Solid Propellant

Solidification and cooling process is an important part in solid propellant production.Propellant can be affected by many factors during solidification and cooling,such as temperature gradient and thermal stress.To improve and enhance the design capability of high-performance solid rocket motor technology,a meticulous study of numerical simulation is required for the high-energy solid propellant solidification process.The analysis should cover aspects such as temperature field fluctuations and solidification degree during the propellant’s solidification and cooling process,in addition to stress and strain changes in the same period.As such,this paper aims to comprehensively investigate and report on the following main research topics:(1)A comprehensive analysis of the curing process was carried out by developing a thermochemical model for simulating heat conduction,and a thermo-mechanical model for calculating the stress-strain field.Additionally,the curing dynamic equation was implemented to accurately simulate and calculate the mentioned aspects.Thus,this research work aims to provide an in-depth investigation on the behavior of the curing process.The constitutive models of solidification and cooling processes were derived,and numerical calculations were carried out with the help of finite element software and custom user subroutine.(2)The distribution and evolution law of the internal temperature and curing degree of the propellant composite during the solidification process was analyzed by using the thermochemical model.The residual stress and strain generated by the propellant composite during the solidification stage were analyzed by using the thermomechanical model and the constitutive model during the solidification stage,and the influence of the thermal stress and curing shrinkage stress on the propellant composite was analyzed.The numerical model of propellant with different m number was used to analyze the effect of size effect of propellant column on residual stress and strain during solidification stage.(3)The viscoelastic constitutive model was adopted in the cooling stage and the combination of the two constitutive models was realized by the UMAT user subroutine.The numerical simulation of propellant column in the cooling stage was completed on the basis of the end of solidification.The influence of cooling rate on the residual stress and strain of propellant solidification cooling was analyzed in different cooling rates.Numerical models of propellant with different m numbers were used to analyze the influence of size effect of propellant column on the residual stress and strain of cooling stage.The zero stress temperature is calculated by numerical simulation,and the influence of different m number on the zero stress temperature is analyzed.It is of great significance to accurately analyze the stress-strain response of the engine propellant under the action of curing stage and cooling stage to ensure the safe and reliable application of the engine.