Service life assessment of solid rocket propellants considering random thermal and vibratory loads

Yılmaz, Okan
In this study, a detailed service life assessment procedure for solid propellant rockets under random environmental temperature and transportation loads is introduced. During storage and deployment of rocket motors, uncontrolled thermal environments and random vibratory loads due to transportation induce random stresses and strains in the propellant which provoke mechanical damage. In addition, structural capability degrades due to environmental conditions and induced stresses and strains as well as material capability parameters have inherent uncertainties. In this proposed probabilistic service life prediction, uncertainties along with degradation mechanisms are taken into consideration. Vibration loads are accounted by utilizing acceleration spectral density values which are induced during various deployment scenarios of ground, air and sea transportation. Furthermore, thermal loads are represented with a mathematical model being a harmonic function of time. Throughout the finite element analyses, a linear viscoelastic material model is to be used for the propellant. Change in the structural capability of the propellant with time is calculated using Laheru's cumulative damage model. Moreover, to include aging effect of the propellant, Layton model is used. To determine the effects of induced stress and strains under variations and uncertainties in the random loads and material constants, mathematical surrogate models are constructed using response surface method. Limit state functions are utilized to predict failure modes of the solid rocket motor. First order reliability method is used to calculate reliability and probability of failure of the propellant grain. With the proposed methodology, instantaneous reliability of the propellant grain is determined within a confidence interval.


Application of ultrasonic burning rate measurement method on closed bombs
Mumcu, Berkan; Kurtuluş, Dilek Funda; Arkun, Uğur; Department of Aerospace Engineering (2013)
In this thesis study, detailed information about solid rocket motors and ultrasonic burning rate measurement method is given. An experimental setup is prepared for applying the ultrasonic burning rate measurement method. Before performing the burning tests, some pre-tests are performed for affirming the ultrasonic sensor and obtaining some experimental coefficients. Two different types of propellants, which do not include aluminum, are produced for the burning tests. The first type of the propellants has tw...
Ballistic design optimization of three-dimensional grains using genetic algorithms
Yücel, Osman; Aksel, Mehmet Haluk; Department of Mechanical Engineering (2012)
Within the scope of this thesis study, an optimization tool for the ballistic design of three-dimensional grains in solid propellant rocket motors is developed. The modeling of grain geometry and burnback analysis is performed analytically by using basic geometries like cylinder, cone, sphere, ellipsoid, prism and torus. For the internal ballistic analysis, a quasi-steady zero-dimensional flow solver is used. Genetic algorithms have been studied and implemented to the design process as an optimization algor...
Ultrasonic measurement of solid propellant burning rates in closed bombs and subscale motors
Atak, Özen; Yamalı, Cemil; Department of Mechanical Engineering (2016)
In the scope of this thesis, applications of ultrasonic measurement method on closed bombs and test motors were investigated with various aluminized and nonaluminized propellants with the main target of evaluation of burning rates. Detailed comparison between conventional methods for solid propellant burning rate measurements such as strand burner, firing of subscale test motors and ultrasonic measurement was performed. Burning rate evaluation of eight propellant batches were determined by thirty three clos...
Performance prediction of nozzleless solid propellant rocket motors
Özer, Ali Can; Özyörük, Yusuf; Department of Aerospace Engineering (2015)
Integral rocket ramjet (IRR) type propulsion systems have many advantages over conventional solid rocket motors when used in tactical missile systems. Nozzleless boosters are one of the applicable concept choices for the system [1]. During the design and development phase of solid propellant rocket motors, simulation and prediction of behavior of a given motor by numerical tools is important in terms of decreasing the development duration and costs. The present approach includes performance prediction of no...
Numerical analysis of regenerative cooling in liquid propellant rocket engines
Ulaş, Abdullah (2013-01-01)
High combustion temperatures and long operation durations require the use of cooling techniques in liquid propellant rocket engines (LPRE). For high-pressure and high-thrust rocket engines, regenerative cooling is the most preferred cooling method. Traditionally, approximately square cross sectional cooling channels have been used. However, recent studies have shown that by increasing the coolant channel height-to-width aspect ratio and changing the cross sectional area in non-critical regions for heat flux...
Citation Formats
O. Yılmaz, “Service life assessment of solid rocket propellants considering random thermal and vibratory loads,” M.S. - Master of Science, Middle East Technical University, 2012.