Effect of Strain Rate on Mechanical Properties and Failure Mechanisms of HTPB Propellant with High Solid Content.

The correlation between strain rates and the mechanical properties of HTPB propellant with 90% solid content (mass fraction) was investigated by uniaxial tensile tests at different tensile rates, and the tensile fracture surface was observed by scanning electron microscope (SEM). The effects of strain rate on the mechanical properties and failure mechanisms of the propellant were analyzed. The results show that the stress--strain curve of the propellant appears an arc segment phenomenon at low tensile rates. With the increase of tensile rates, the stress--strain curves of propellant gradually changes from 5 segment to 4 segment. The initial modulus and the maximum tensile strength of the propellant show an increasing trend with an increase in the tensile rates. The maximum elongation of the propellant decreases with an increase in the strain rate, and the maximum elongation of propellant is only 33.9% when the strain rate is 1 190.48 X 10 4s 1 . With the increase of strain rate, the failure mechanism of propellant gradually changes from particle dehumidification to matrix tearing, without particle fragmentation. [ABSTRACT FROM AUTHOR]