Mechanical properties and constitutive model of a composite solid propellant under the synergistic effects of accelerated aging time, pre-strain, and damage growth

Dewetting is the main damage mode of composite solid propellants, and the research on the initiation mechanism and evolution process of dewetting damage is an important way to predict the mechanical properties and evaluate the life of propellants. In this paper, the experimental research and analytical methods of dewettingare reviewed at domestic and foreign from three dimensions: macro, meso and micro. On this basis, the reference solutions to the existing research problems are proposed, and the key research directions of interface dewetting in the future are pointed out. The analysis shows that the dewetting behavior of composite solid propellant is affected by multiple factors such as internal factors (par-ticles, matrix, bonding agent) and external factors (temperature and humidity, aging, strain rate, confining pressure). At present, the mechanism of dewetting is not clear, so it is urgent to conduct experimental analysis and numerical simulation research on the interface at the micro level to analyze the physical and chemical properties of the interface. On the meso scale, it is necessary to increase research in the dewetting theoretical model considering multi factor coupling, the mechanical property experiment of particlematrix interface, and the fine construction of meso scale simulation model. On the macro scale, the dynamic analysis method of propellant dewetting under multiple complex loading conditions will be the focus of future research.

Section: Deficienciesmentioning

confidence: 87%

Section: Sem Methodsmentioning

confidence: 99%

Review on the Dewetting of the Particle‐Matrix Interface in Composite Solid Propellants

Zou

LI³

et al. 2023

“…From the previous analysis, the low temperature curve type of GCH propellant was found to be the same as that of HTPB and NEPE propellants. For this type of stress-strain curve, predecessors conducted more in-depth constitutive model research [27,28]. However, the constitutive model and model parameters for the special arc section of GCH propellant have not been studied.…”

Section: Constitutive Model Theorymentioning

confidence: 99%

Study on Tensile Mechanical Properties of GAP/CL‐20/HMX Propellant

Zhang

Liu

Zhang

et al. 2022

To study the tensile properties of GAP/CL-20/HMX (GCH) propellant, a new generation high energy solid propellant, uniaxial tensile test and dynamic mechanical analysis (DMA) test were performed at different temperatures (233.15-333.15 K) and strain rates (0.000476-0.9524 s À 1 ). The experimental results show that, unlike Hydroxyl-terminated Polybutadiene (HTPB) and Nitrate Ester Plasticized Polyether (NEPE) propellants, GCH propellant have special arc section in the initial tensile stage at room temperature and high temperature. This phenomenon may be caused by the stretching of the curled molecular chains. The variation of mechanical properties shows that the maximum tensile strength and initial elastic modulus increase with the decrease of temperature and the increase of strain rate. The variation of maximum elongation is complex, which increases with the increase of strain rate at room temperature and high temperature, and first increases then decreases with the increase of strain at low temperature. The constitutive model of the GCH propellant was established by introducing the chain extension and the debonding damage thresholds. Both of which show a linear double logarithmic increasing trend with the increase of strain rate at room and high temperature. The latter shows a linear double logarithmic decrease trend with the increase of strain rate at the low temperature.

“…Solid propellants therefore have a low modulus and fracture toughness compared to other components [3]. In addition, the rubbery binder with a low cross‐link density is susceptible to the effects of aging, which significantly affects the mechanical properties of the solid propellant, increasing the modulus [4] and increasing the tensile strength [5] but reducing the elongation at break [6]. The key to improving the launch reliability of solid rocket motors is in assessing the influence of aging on the mechanical properties of solid propellants.…”

Section: Introductionmentioning

confidence: 99%

A constitutive model of solid propellants considering aging and confinement pressure

Qin,

Zhang,

Zhang

et al. 2024

Self Cite

Aging during storage and confinement pressure during launch are the two major loading conditions that affect the integrity of solid rocket motors. In comparison to other component materials, solid propellants, as highly filled composites, have a low modulus and fracture toughness and are therefore common sources of failure. The key to improving the integrity of the solid rocket motor is in assessing the health of the solid propellants during storage or launch. To address this issue, we revised the previous model for the progressive damage viscoelasticity of solid propellants to include the effect of chemical aging during storage and the influence of confinement pressure during launch. Specifically, the increase in relaxation time due to aging and the nonequilibrium volume dilatation characteristics under triaxial tension and compression of solid propellants have been considered. To validate the developed model, standard relaxation tests and uniaxial tensile tests on solid propellants without aging were used to calibrate the model parameters. Furthermore, the model was validated by comparison with uniaxial tensile tests under confined pressure after aging and well predicts the aging temperature/time‐dependent mechanical responses of solid propellants. After validation, the developed model was used to study the influence of confinement pressure on microscopic damage evolution and macroscopic volume expansion. Overall, the developed model can be used for the analysis of the integrity of the solid rocket motor after the aging process.