|
PROBABILISTIC METHODOLOGY FOR SOLID PROPELLANT CASE-BONDED GRAIN RELIABILITY ESTIMATION
Nikola GligorijeviĆ Military Technical Institute, Belgrade, nikola.gligorijevic@gmail.com RADUN JEREMIĆ Military Academy, Belgrade, radun@mail.com SAŠA ŽIVKOVIĆ Military Technical Institute, Belgrade, sasavite@yahoo.com VESNA RODIĆ Military Technical Institute, Belgrade, vesna_rodic@vektor.net RADENKO DIMITRIJEVIĆ Military Academy, Belgrade, radenkod@beotel.net SREDOJE SUBOTIĆ Military Technical Institute, Belgrade, sredoje.subotic@gmail.com
|
|
Abstract: A case-bonded solid propellant rocket grain is subjected to many stress inducing environments from the time it is cast until it has burned away. Propellant is a viscoelastic material with load-rate and temperature-dependent mechanical properties. The purpose of structural analysis is to estimate the grain reliability accounting viscoelastic effects, evaluation of initial propellant mechanical properties, aging, cummulative damage effects and load analysis. When the time-temperature dependent material properties, strains and stresses are evaluated, classical failure analysis recommends the stress-strength interference principle in the grain-case bond area, and strain criteria in the grain channel. For cycling loads the results of calculations are not so clear. Probabilistic methodology combines two different criteria in critical grain areas and enables more explicite values of reliability and service life.
|
