Investigation of acoustic characterization of ultrasonic air coupling testing of NEPE propellant under strain control

To explore the acoustic characterization of composite solid propellant materials, wave equation viscoelastic body was derived based on linear constitutive model, and theoretical relationship between ultrasonic sound velocity attenuation coefficient, which are closely related to mechanical properties, such as elastic modulus, viscosity complex obtained. Ultrasonic air-coupled testing experiments NEPE (Nitrate Ester Plasticized Polyether) under different tensile strain states were carried out obtain variation law transmission peak amplitude, velocity, coefficient with variables in combination porosity strain. Furthermore, parameters fitted by regression equation, effect mesoscopic damage macroscopic properties analyzed. The results show that increase strain, increases exponentially. With porosity, decreases first polynomials, amplitude second third polynomials.