A Thermovisco-Hyperelastic Constitutive Model of NEPE Propellant Over a Large Range of Strain Rates

Abstract

The uniaxial compressive mechanical curves of nitrate ester plasticized polyether (NEPE) propellant under different temperatures and strain rates have been obtained with a universal testing machine and modified split Hopkinson pressure bar (SHPB). The experimental results show that the mechanical properties of NEPE propellant are both rate dependent and temperature dependent. With decreasing temperature or increasing strain rate, the modulus and rigidity obviously increase. Based on the previous models proposed by Yang and Pouriayevali, we propose a modified viscohyperelastic constitutive model which can describe the mechanical response over a large range of strain rates. Then we add a rate-dependent temperature item into the modified model to make a thermovisco-hyperelastic constitutive model. By comparing the experimental results with the model, we find that the thermovisco-hyperelastic constitutive model can correctly describe the uniaxial compressive mechanical properties of NEPE propellant at different temperatures and over a large range of strain rates from the static state to 4500 s-1.

Dynamic Mechanical Response and Damage Mechanism of HTPB Propellant under Impact Loading

“…Drodge et al quantified the impact damage of the RDX-HTPB composites at a strain rate of 1000 s −1 , by measuring four damage metrics, the compressive strength, the modulus, the thermal conductivity and the porosity [ 22 ]. Zhang et al obtained the high strain rate (up to 4500 s −1 ) compressive stress–strain curves for a novel NEPE propellant over a temperature range from −40 °C to +40 °C, using a modified SHPB device [ 23 ]. Sunny conducted a modified SHPB testing on an HTPB polymer and its composite for comparison [ 24 ], the strain rate dependence indicated a remarkable transition at 2100 s −1 .…”

A general hyperelastic model for rubber-like materials incorporating strain-rate and temperature

“…This research aids in the analysis of the launch process of rockets and missiles and provides insights for further optimization of rocket and missile designs. Zhang et al 27 conducted compression experiments on NEPE propellant using a universal machine in an insulated box.…”

“…Tensile experiments were performed at five different constant strain rates: 0.003 s À1 , 0.01 s À1 , 0.03 s À1 , 0.06 s À1 and 0.1 s À1 . As the reference strain rate, the minimum strain rate of 0.003 s À1 was chosen and the constitutive equation is expressed as equation (27). Afterwards, the constitutive parameters were fitted using GWO.…”

“…Chevalier et al 26 investigated the temperature impact on the viscous component of Polyethylene Terephthalate (PET) and utilized the Williams-Landel-Ferry (WLF) temperature product term to account for it. Similarly, Zhang et al 27 utilized an exponential function to reflect the temperature influence on the stress-strain relationship of nitrate ester plasticized polyether (NEPE) propellant with varying ambient temperatures.…”

Strain rate and temperature dependence of the compressive behavior of a composite modified double-base propellant

“…Nonetheless, most propellant responses under high strain rate loading are not clearly understood. Zhang obtained low and high strain rate uniaxial compression curves for a nitrate ester plasticized polyether composition (NEPE) propellant for the first time over a temperature range of −40 °C to +40 °C, using a split Hopkinson pressure bar (SHPB) apparatus [20]. After Kolsky [21] introduced the SHPB technique for dynamic testing, SHPB apparatuses have been widely used to obtain the stress-strain responses of materials at high strain rates of around 10 2~1 0 4 s -1 , such as metals [22], rocks [23], and composite materials [24].…”