MECHANICAL ENGINEERING: Reliability of a product, failure, failed products, total manufactured

R = 1 - f/m


where:

R = reliability of a product, a measure of the product's probability that it will not fail when used

f = number of failed products

m = number of manufactured products


1. A certain bearing and gear manufacturer has produced a total of 4000 ball bearings and 5000 spur gears. It was later found out that there were 35 ball bearings and 70 spur gears that failed. Determine the Reliability of the class of ball bearings and these kinds of spur gears.


ball bearings:

find:

R = Reliability of these kinds of ball bearings


given:

f = 35

m = 4000


solution:

R = 1 - f/m

R = 1 - 35/4000

R = 1 - 0.0088

R = 0.9912  or 99.12%


spur gears:

find:

R = Reliability of these specific types of spur gears


given:

f = 70

m = 5000


solution:

R = 1 - f/m

R = 1 - 70/5000

R = 1 - 0.014

R = 0.986  or 98.6%