Measurement of Embrittlement Temperatures (Brittle Points) of Composite Propellants by the Bending Beam Method

摘要

A bending-beam method for measuring embrittlement temperatures has been reintroduced and evaluated by comparing the results obtained with it using three different kinds of composite propellant (based on polyisobutylene, polyurethane or carboxy-terminated polybutadiene binders) with master curves of strain-at-rupture as a function of 'reduced' strain-rate (itself a function of strain-rate and of temperature) derived independently. Three degrees of bending, imposing strains of 5, 10 and 25 per cent, were used. Good agreement between the two groups of results was found, and it is concluded that this bending-beam method is in principle suitable as a routine inspection test. (Author)