A review on material characterization of composite solid propellant

Composite solid propellants (CSPs) are extensively used in solid rocket motors (SRMs) due to their excellent mechanical properties, stability, and high energy density. Lack of structural integrity in a propellant grain is identified as a major cause of solid rocket motor failure. Thermal and mechanical loads act on the propellant grains in SRMs throughout handling, shipping, storage, and operation (ignition, pressurization, acceleration, etc.). Studying the mechanical behavior of the propellant grains under these loading conditions is essential, as it could lead to a loss in structural integrity, resulting in irregularities in the burning characteristics. Experimental techniques that simulate different loading conditions are used to characterize the mechanical response of CSPs. This article provides a comprehensive review of the various material testing techniques used for studying the mechanical response of CSPs. Different material characterization techniques: relaxation test, uniaxial tensile test, uniaxial compressive test, biaxial test and cyclic test have been discussed in detail in this review article. Further, the research gaps in the material characterization of the CSPs have been identified, and future research suggestions are provided.