Dynamic shearing resistance of hydroxyl-terminated polybutadiene (HTPB)

Abstract

Hydroxyl-terminated polybutadiene (HTPB) is a widely used polymeric binder in polymer-bonded explosives (PBXs) and solid rocket propellants. Even though used in small fractions, the elastomeric binder absorbs much of the impact energy and therefore requires careful modeling of its mechanical behavior to accurately simulate the response of PBXs when they are subjected to large strains and strain rates. While the normal response of HTPB has been characterized under uniaxial stress and uniaxial strain loading, shear strength measurements under large pressures and large shear strain rates have not been made so far. Such measurements are critical for modeling localization and failure in PBXs and accurate prediction hotspot formation. In this study, pressure-shear plate impact (PSPI) experiments have been used to measure the shearing resistance of HTPB at different pressures. The shearing resistance of HTPB is found to be strongly pressure dependent. A quasi-linear viscoelastic model with pressure-dependent shear wave speeds and shearing resistance is used to describe the experimentally observed dynamic response of HTPB. The model consists of an instantaneous elastic response and viscoelastic relaxation of the elastic response.

Impact Velocity and Temperature Effects on the Shock Wave Propagation and Spallation of Hydroxyl-Terminated Polybutadiene: A Molecular Dynamics Study

“…Even though used in small fractions, the elastomeric binder absorbs much of the impact energy and therefore requires careful modeling of its mechanical behavior to accurately simulate the response of HTPB composite, when they are subjected to large strains and strain rates. 15 For example, the main role of the polymer binder in PBX is to cushion the explosive crystals from mechanical insults such as vibration, impact, and friction. Therefore, knowing how shock wave propagates and how spallation happens within the HTPB material can help us understand the failure mode of its composite under impact, especially in the bonding interface with other materials.…”

“…HTPB is a widely used polymeric binder in HTPB composites such as polymer-bonded explosives (PBX) and solid rocket propellants. Even though used in small fractions, the elastomeric binder absorbs much of the impact energy and therefore requires careful modeling of its mechanical behavior to accurately simulate the response of HTPB composite, when they are subjected to large strains and strain rates . For example, the main role of the polymer binder in PBX is to cushion the explosive crystals from mechanical insults such as vibration, impact, and friction.…”