engleski

The solid propellant service life phenomena

The service life of the rocket motor is largely based on structural considerations. Service life prediction is based on the data obtained from tests of mechanical properties and some enviromentaly experienced cosequences. Materials characterization plays a key role in predicting service live. The primary causes for propellant degradation are slow chemical reactions, the gases these reactions produce and environment stresses placed on the materials. Aging of a propellant grain can result in cracking, surface hardening, modulus changes and other materials property changes. Both aging and environmental stresses can result in micro-cracking, fissuring of the propellant and de-bounding from the case or housing. In particle filled polymeric properties, aging can result in changes in particle to binder bonding (dewet strength) and binder elastic properties. These defects can result in abnormal burning rates and unsafe operation of the motor. It is essential to assess the mechanical properties in order to predict the remaining life of the propellant. In this work methods of the estimation of the service life proposed on stronger thermodynamic materials base. Influence climate, and scatter inspection date are reexamined in order to improve service life. The micromechanical model of the damage are coupled with environment factors and storage history. There are many advanced methods which can be used to manufacture a missile structure in order extend service life. The key structural component is the pressure vessel containing the solid propellant, which is subject to the most extreme physical and thermal conditions, since it needs to withstand the pressures and temperature generated during the burning phase of the propellants. Inspection and chemical analyses play a key role in determining the degree degradation.Visual, ultrasonic and X-ray inspection are needed to defect anomalies in the mechanical components. Inspection and chemical analyses play a key role in determine the degree of degradation. The mechanism of the moisture-related degradation are also required for some vital rocket engine components.

Service life prediction; rocket motor

nije evidentirano