# Repairable Systems Analysis Reference Example

 Repairable Systems Analysis

This example validates the results for a repairable systems analysis in RGA.

Reference Case

Crow, L.H., Reliability Analysis for Complex Repairable Systems, Reliability and Biometry: Statistical Analysis of Lifelength, pg. 385, 1974.

For this example, the Power Law model parameters will be calculated.

Data

The following table shows the data.

System 1 System 2 System 3
4.3 0.1 8.4
4.4 5.6 32.4
10.2 18.6 44.7
23.5 19.5 48.4
23.8 24.2 50.6
26.4 26.7 73.6
74 45.1 98.7
77.1 45.8 112.2
92.1 72.7 129.8
197.2 75.7 136
98.6 195.8
120.1
161.8
180.6
190.8
Simulated Data for 3 Systems with End Time = 200 hours

Result

The book has the following results:

Beta = 0.615, Lambda = 0.461

Results in RGA

Since $\,\!S_{1}=S_{2}=S_{3}=0$ and $\,\!T_{1}=T_{2}=T_{3}=200$ then the maximum likelihood estimates of $\,\!\hat{\beta}$ and $\,\!\hat{\lambda }$ are given by:

\begin{align} \hat{\beta} =&\frac{\underset{q=1}{\overset{K}{\mathop \sum }}N_{q}}{\underset{q=1}{\overset{K}{\mathop \sum }}\,\underset{i=1}{\overset{N_{q}}{\mathop \sum }}\ln \left ( \frac{T}{X_{iq}} \right )}\\ \\ =&0.6153 \end{align}\,\!

\begin{align} \hat{\lambda }=&\frac{{\underset{q=1}{\overset{K}{\mathop \sum }}N_{q}}}{KT^{\hat{\beta }}}\\ \\ =&0.4605 \end{align}\,\!

The model parameters are: