Crack Opening and Extension in Inert Solid Propellant. An Experimental Study

摘要

When cracks occur in rocket motor grains, they may significantly alter the subsequent motor performance. Consequently as performance requirements are advanced, it becomes critical to incorporate fracture control concepts into the evaluation of the structural integrity of motor grains. While most such concepts are typically based upon two dimensional analysis, the motor geometry and conditions of use suggest the presence of significant three dimensional effects. Over the past decade, attempts have been made to develop mathematical models for predicting fracture behavior in rocket motors but model validation has been inhibited by lack of an extensive data base for validating three dimensional effects. Moreover, certain such effects have only recently been identified, and have not been evaluated for rocket propellant. In particular, the near tip behavior of cracks in solid propellant material during opening and extension of the crack needs to be quantified experimentally.