Assignment $1-$ Analysis of Reliability Problems

The purpose of this task is analysis of reliability problems and best possible capital investment decision. Students are expected to read the study guide and where necessary refer to appropriate texts to deepen their understanding of reliability and associated activities.

Before attempting this assignment, I suggest the students should work through Study Guides $1$ and Annexes C$,$ H$,$ and G$.$

Please include all relevant assumptions and detailed calculations where required.

Part $1(9$ Marks$)$

A mining company has a fleet of $7$ Large Mining Trucks $($LMT$).$ These LMT are utilised $20$ hours per day, $7$ days a week. Production requires a minimum of $5$ LMT operational at any time to meet the minimum operational performance and achieve their targets. Maintenance records show that the LMT have broken down $18$ times over a period of $4340$ hours.

The maintenance manager has asked you as the reliability engineer on site to conduct an investigation into the fleet. The areas they would like investigated include:

Q$1.$

What is the breakdown rate per $1000$ hours?

Q$2.$

How many maintenance events would we expect over a $7-$day operational cycle?

Q$3.$

What is the probability that ALL $7$ LMT will function without failure over a day of operation?

Q$4.$

What is the probability that the fleet of LMT will achieve the minimum operational performance over a day of operation?

Q$5.$

The repair times $($hours$)$ from the $18$ breakdown events are provided in the table below. The maintenance manager would like to know:

a$.$

What the mean corrective maintenance time $($MCMT$)$ is$?$

b$.$

What percentage of CM tasks can be completed in under $1$h$?$

c$.$

What is the time that $95\%$ of breakdowns will have been repaired by$?$

d$.$

The MCMT value you provided is a different value to the MTTR value $(1\mathrm{.}31-$ to $2$ decimal places$)$ that the fleet management tool computed. Please explain why this is the case and provide some details$/$examples as to outline your reasoning.

$0\mathrm{.}33$

$1\mathrm{.}37$

$0\mathrm{.}66$

$1\mathrm{.}15$

$2\mathrm{.}00$

$1\mathrm{.}18$

$3\mathrm{.}16$

$1\mathrm{.}2$

$2\mathrm{.}72$

$1\mathrm{.}25$

$1\mathrm{.}02$

$0\mathrm{.}92$

$1\mathrm{.}75$

$0\mathrm{.}5$

$1\mathrm{.}3$

$0\mathrm{.}80$

$0\mathrm{.}75$

$1\mathrm{.}50$