Determine the failure rate for a Six items that are tested t

Determine the failure rate for:

a. Six items that are tested to failure. Failure times are 220, 176, 451, 205, 99, and 270 hours.

b. Eighteen components that are tested for 30 hours. At the end of the test, four parts had failed at 4, 10, 11, and 13 hours.

c. Sixty parts are tested for 1000 cycles each. When are part fails it is replaced with a working part. At the end of the test, 8 parts in total had failed.

Solution

b> Failure rate = total failure time/total time

since 18 components are tested for 30 hours , so total time = 30*18 = 540 hours

4 components failed at = 4+10+11+13 = 35 hours

so the failure rate is = failure hours/total hours * 100

                                    = 35/540 * 100 = 6.48 %