Caracterização do comportamento mecanico do propelente solido composito como material estrutural




Composite solid propellant is the unique material that is the source of propulsive energy and basic structural component. The structural integrity of a rocket motor must be kept during manufacturing, storage, ignition and flight. These steps .can last from mille seconds (ignition). to several years (storage) and the propellant grain is subject to several types of stress and strain that, if. greater than its capacity, may lead to a flaw or fracture, that increases the burning Burface of the propellant and causes. an. explosion. of the rocket motor. The propellant is -a mixture of a high content of solids suspended in a polymeric matrix. The solids s content in weight can reach up to. 88% and should have a god level. of adhesion to the polymeric binder, promoting mechanical properties that would confer the structural i-integrity of the propellant. The response of the propellant to the imposed loads are nonlinear viscoelastic. The characterization of the propellant s mechanical behaviour was done with. uniaxi-al tensile test until rupture, dynamic mechanical analysis and stress relaxation s experiments. With the WLF equation and the superposition of time-temperature s concept, the results at several temperatures could. be superposed in a master curve that characterizes the propellant at any situation. The failure envelop_ is presented. toa, as a form of complementary characterization. The most important contribution of this thesis is the presentation of methods of characterization by using the module B .master. curves. . Correlation. of the Young s . modulus with the relaxation s modulus was made and can be useful to obtain. the results of one from the other -ar to extend the results to periods of time not covered by one of the methods. The results are. the first characterization. of a VLS s composite solid propellant, and provides essential data to calculate the mechanical behaviour of the propellant from igniticm to storage, and them a project of a rocket motor that operates. safely, without catastrophic failures feasible


compositos polimericos propriedades mecanicas propelentes solidos

Documentos Relacionados