The effect of pressure on the mechanical properties of hydroxyl-terminated polybutadiene-based propellants

Context: In order to estimate the mechanical behavior of the propellant under working pressures, the effect of pressure on the mechanical properties of hydroxyl-terminated polybutadiene (HTPB) propellants was studied by analyzing the uniaxial tensile strength and maximum strain master curves under the test conditions of – 20 ~ 70 °C, 0.5 mm/min ~ 500 mm/min with different pressures from 0 to 10 MPa. The results show that the master curves for tensile strength are obviously affected by the pressure in the range of 0.15 ~ 3 MPa, while the master curves for tensile strength are insensitive to pressures below 0.15 MPa or above 3 MPa. The master curves for maximum strain are unaffected in the whole concerned pressure range. A power function can be used to study the relationship between tensile strength and temperature or strain rate and to predict the change trend of the temperature and strain rate sensitive indexes with the pressure, which may be useful in the formulation designing of HTPB solid propellants. Methods: The uniaxial tensile propellant test was used to obtain the tensile strength and maximum strain master curves under different pressures, which were plotted at a reference temperature of 20 °C under different pressures by means of the overlap joints method. A power function method was developed to study the relationship between tensile strength and temperature or strain rate.