New Test Method to Determine Modulus of Elasticity of Rocket Grain Material

摘要

A new testing technique was demonstrated for measuring the modulus of elasticityof low-modulus materials such as rocket propellant grains. The technique described herein offers substantial advantages over the dog bone testing method. The testing procedure is less complicated, and data reduction is simpler. More importantly, a biaxial stress field can be established in the test specimen to simulate conditions encountered during pressurization of a nonlinear and viscoelastic material (e.g., propellant used in solid rocket motors). For metals or linearly elastic materials, dog bone testing may be considered a viable technique through which material properties such as the modulus of elasticity can be extracted accurately. However, for highly filled materials or propellants that exhibit nonlinear and viscoelastic behavior, results obtained through the uniaxial stress data of dog bone tests do not provide material characteristics under biaxial strain conditions. Lack of such material properties will be detrimental to the ability in evaluating and predicting the integrity of the components. Propellant grain, Modulus, Test method.