Analysis of structural deformation and damage in accelerated aging NEPE propellant grain
NING Yuhao
LI Yonghua
QIAN Gui'an
LIU Xiaohan
SUN Jianjun
WU Guoqing
SUN Jingyu
Abstract：[Objective]To investigate the effects of accelerated thermal aging and grain geometry on the mechanical response of nitrate ester plasticized polyether(NEPE)propellant grains under storage and ignition conditions,the influences of aging state,temperature,and structural parameters on the strain behavior of NEPE propellant grains were studied.[Methods]NEPE propellant was subjected to accelerated aging in a constant-temperature chamber for 25 days,and uniaxial tensile tests were conducted at-40,23,and 70℃.Based on the Wiechert viscoelastic constitutive model,material parameters under different aging states and temperature conditions were calibrated using experimental data,and the effects of thermal aging on the mechanical properties of NEPE propellant were analyzed.Furthermore,a parametric modeling plug-in for typical grain structures was developed,and finite element models of grains were established.Numerical simulations were performed for the grains before and after aging under storage and ignition conditions.The effects of the number of star points,star-tip fillet radius,and angle fraction on the strain distribution of the grains were investigated.[Results]The results show that thermal aging reduces the tensile strength and elastic modulus of NEPE propellant and weakens its strain-rate sensitivity.Under storage conditions,the strain of the aged grain is mainly concentrated in the top star-tip fillet region,and increasing the number of star points can improve the strain distribution.Under ignition conditions,compared with the unaged grain,the maximum strain of the aged grain increases by approximately 20.33％,137.50％,and 162.13％at-40,23,and 70℃,respectively.When the star-tip fillet radius increases from 2 mm to 5 mm,the average maximum strain of grains with different aging states decreases by 31.53％,26.05％,and 24.57％,respectively.When the angle fraction increases from 0.70 to 0.95,the corresponding average maximum strain increases by 36.21％,46.51％,and 48.05％,respectively.The results provide a reference for structural design,storage safety assessment,and deformation-damage analysis of NEPE propellant grains under ignition conditions.
Keywords：NEPE propellantThermal agingMechanical propertyFast modelingStructural integrity
Publication Date：2026-07-31
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：8( 67-74 )