Study On High-Throughput Accelerated Experiment Method For Mechanical Properties Of Solid Propellants

Chemical aging and mechanical damage will occur in solid propellant grain during long-term storage.Accelerated aging experiment of propellants is a basic experiment to evaluate the storage life of propellant grain.At present,the traditional thermalmechanical coupling accelerated aging experiment of solid propellants has some limitations,such as large sample consumption,small amount of test data,poor consistency of test results of different samples,and inconsistency between real stress state of samples and propellant grain.Based on the thought of material high-throughput experiment,this paper presents a high-throughput accelerated experiment method for solid propellants.A high-throughput accelerated experiment system of propellants is developed,and a high-throughput accelerated experiment is carried out on a certain HTPB propellant sample,and an aging model of propellant relaxation modulus based on the high-throughput experiment is established.The main research contents are as follows:A high-throughput accelerated experiment method of solid propellants with "gradient aging,relaxation of gradient temperature and in-situ detection" on a sample is proposed,and the feasibility of the method is preliminarily verified by finite element numerical simulation.Aiming at the limitations of the traditional thermal-mechanical coupling aging experiment of propellants at present,the highthroughput experiment idea of "getting as much data as possible in one experiment" in the field of material genetic engineering is used for reference.The high-throughput accelerated experiment scheme of solid propellants and two propellant samples with rectangular and trapezoidal surface shapes are designed.Based on the finite element numerical simulation technology,the feasibility of the propellant high-throughput accelerated experiment scheme is verified.A high-throughput accelerated experiment system of solid propellants with "high safety,high stability and high consistency" is developed,and highthroughput accelerated experiments of two special propellant samples are carried out.A high-throughput accelerated experiment system of propellant with the functions of safety ladder temperature loading,stable strain loading and in-situ nondestructive testing is developed.Using this experiment system,the high-throughput accelerated experiments of propellant samples with equal and variable cross-sections are carried out.The variation law of local stress and strain of propellant samples with aging time is obtained,and the expected effect of high-throughput accelerated experiment scheme of propellant is achieved.The aging model of propellant relaxation modulus considering biaxial strain is established and verified.The stress-strain relationship of constant and variable crosssection propellant samples during long-term constant strain relaxation is studied.The relaxation modulus is extracted as the aging characteristic parameter,and the aging model of propellant relaxation modulus based on high-throughput experiment is derived.Taking the traditional thermo-mechanical coupling aging experiment of standard propellant samples as reference,the aging model of propellant relaxation modulus is verified.The research method in this paper can provide reference for the new thermalmechanical coupling accelerated aging experiment method of nonmetallic materials,and the research results and conclusions can support the rapid prediction of the storage life of solid propellants.