Experimental Investigation and Modeling the Compressive Behavior of NEPE Propellant under Confining Pressure.

In order to study the effects of confining pressure and strain rate on the mechanical properties of the Nitrate Ester Plasticized Polyether (NEPE) propellant, compressive tests were conducted under various confining pressure conditions and strain rates using a new-designed active gas confining pressure testing machine. The stress-strain curves and mechanical properties of the NEPE propellant under varying confining pressure conditions and strain rates were obtained. The results show that the compressive mechanical properties of the NEPE propellant are remarkably influenced by the confining pressure and strain rate. The compressive strength under confining pressure is obviously larger than those without applied confining pressure. With the coupled effects of the confining pressure and strain rate, the compressive strength under 5.4 MPa and 6.67× 10^-2 s^-1 is 2.17 times of its value at room condition and 6.67×10^-4 s^-1. Then, based on previous tensile results, the quantified comparisons of tensile and compressive mechanical properties under different experimental conditions were presented. Finally, a nonlinear constitutive model with damage was constructed to model the effect of pressure. The statistical damage model parameters were defined as ExpDec1 function of pressure P. The calibrated model can accurately predict the mechanical behaviour of the NEPE propellant under different confining pressure conditions and strain rates. [ABSTRACT FROM AUTHOR]