Study on reliability growth models of repairable system

Reliability is very important for the systems in aeronautics and astronautics. Despite its appeal for attractive mathematical features the PLP model suffers from a few drawbacks. Duane and Crow/AMSAA models are widely used in the reliability growth assessment. But for the reliability growth case, the intensity function of the PLP has the rather unrealistic feature that it tends to infinite as time to zero. In the paper, the simple versions of the step-intensity models in which the jumps in the steps reflect the effect of fixes are studied. The models accommodate the philosophy of a TAAF program and evolve from the core of the Duane postulate. The MLE of the parameters are presented, consequently the estimation of the MTBF is also given. Finally, the numerical applications are carried out. Analysis shows that the models are very practicable and applicable, especially for the small samples.