Studies on Stress-Strain Curves of Aged Composite Solid Rocket Propellants

Himanshu Shekhar

doi:10.14429/dsj.62.773

Himanshu Shekhar High Energy Materials Research Laboratory

DOI: https://doi.org/10.14429/dsj.62.773

Keywords: Composite propellants, Mechanical Properties, Ageing, Degradation, Tensile testing.

Abstract

Mechanical property evaluation of composite solid rocket propellants is used as a quick quality control tool for propellant development and production. However, stress-strain curves from uni-axial tensile testing can be utilised to assess the shelf-life of propellants also. Composite propellants (CP) of two varieties cartridge-loaded (CLCP) and case-bonded (CBCP) are utilized in rocket and missile applications. Both classes of propellants were evaluated for mechanical properties namely tensile strength, modulus and percentage elongation using specimens conforming to ASTM D638 type IV at different ageing time. Both classes of propellants show almost identical variation in various mechanical properties with time. Tensile strength increases with time for both classes of propellants and percentage elongation reduces. Initial modulus is also found to decrease with time. Tensile strength is taken as degradation criteria and it is observed that CLCP has slower degradation rate than CBCP. This is because of two facts–(i) higher initial tensile strength of CLCP (1.39 MPa) compared to CBCP (0.665 MPa) and (ii) lower degradation rate of CLCP (0.0014 MPa/day) with respect to CBCP (0.0025 MPa/day). For the studied composite propellants, a degradation criterion in the form of percentage change in tensile strength is evaluated and shelf life for different degradation criteria is tabulated for quick reference.

Defence Science Journal, 2012, 62(2), pp.90-94, DOI:http://dx.doi.org/10.14429/dsj.62.773

Author Biography

Himanshu Shekhar, High Energy Materials Research Laboratory

Dr Himanshu Shekhar received PhD from University of Pune and MTech (Mechanical Engineering) from IIT, Kanpur. Prsently he is working as Joint Director at High Energy Materials Research Laboratory, Pune.
He has been associated with advanced solid rocket propellants for the last 15 years. It includes development of infrastructure for solid rocket propellant processing, processing of solid rocket propellants, Mechanical properties evaluation, structural analysis and performance prediction of solid rocket propellants. He has 30 papers in peer reviewed journals and an equal number of publications in seminar and conference proceedings.