四组元HTPB推进剂不同热老化状态下贮存蠕变失效研究OA北大核心CSTPCD

To study the storage creep characteristics of a four-component HTPB propellant,high-temperature accelerated aging tests were carried out at 70℃.Subsequently,uniaxial tensile creep tests were conducted on the aged HTPB propellant under stresses of 0.3～0.6 MPa.The parameters of the propellant's isothermal constant-stress creep constitutive equation were fitted,and the creep behavior of the propellant dumbbell-type specimen was numerically simulated by using the ABAQUS finite element software,and the average creep results in the middle section of the propellant specimen were extracted and compared with the experimental data for verification.The three-dimensional high-fidelity microscale models of four-component HTPB propellants were constructed by means of micro-CT technology in conjunction with the Python programming language to construct.The creep constitutive equation was em-ployed to perform numerical simulations on the propellant.The results show that the four-component HTPB propellant exhibits differ-ent mechanical stages during the creep process.As the aging time increases,the maximum tensile strength of the propellant gradually increases,while the maximum elongation and fracture elongation rates decrease by 62.39%and 57.26%,respectively.The power-law creep constitutive equation has a fitting degree of over 0.93 for the creep failure analysis of the four-component HTPB propellant,ac-curately describing the creep failure behavior of the propellant under various thermal aging conditions.The tensile damage of the four-component HTPB propellant is positively correlated with the stress level and the degree of aging it undergoes.It has also been observed that the stress concentration in the binder matrix is distributed in the areas in contact with the AP particles,and the debonding between the matrix and particles will evolve starting from the AP particles.