Uniaxial tensile mechanical behavior research of HTPB propellant under wide temperature and confining pressure

Abstract

To investigate the effects of confining pressure, strain rates, and temperatures on the mechanical properties of the Hydroxyl-terminated Polybutadiene (HTPB) propellant, uniaxial tensile tests were performed utilizing wide-temperature-confining pressure systems. The resulting damage was subsequently analyzed and characterized through scanning electron microscopy and mirco-ct. The results indicate that the stress–strain curves of HTPB at 20 and 70 °C are comparable, and the propellant damage is primarily attributed to de-wetting at 20 and 70 °C with respect to the mechanism. At −50 °C, the maximum tensile strength and ultimate tensile strain at 8 MPa surpass those at 0 and 2 MPa to a significant degree and the damage shifts from de-wetting and ductile fracture of particles to severe particle breakage with the elevated confining pressure. Ultimately, the primary curve of the HTPB propellant's maximum tensile strength was constructed by the curve fitting analysis based on the time–temperature equivalent superposition principle (TTSP) and time–pressure equivalent superposition principle (TPSP). Comparing to the properties of TPSP, TTSP exhibits a wider range of applicability and greater fitting precision in relation to the HTPB propellant. This study mainly serves to establish a fundamental theory and furnish data support for the enhancement of mechanical properties and structural integrity of solid rocket motors.