Reliability 1

Probability a product will perform as promoted for a given time period under given conditions Functional Failure: does not operate as designed Reliability Failure: does not operate as designed as long as it is supposed to Maintainability: related to durability and refers to once a product breaks, what is the probability it can become functional again 2

Inherent Reliability is Designed Reliability Found by reliability testing 3

Achieved Reliability is Empirical 4

Infant Mortality Period: if it makes it by time x, then the constant failure rate takes over 5

Failure Rate, lambda, is units per hour lambda = number of failures/total unit operating hours 6

Mean Time to Failure MTTF (non repairable) or Mean Time Between Failure MTBF (repairable items) is theta = 1/lambda 7

For a given p of failure, what is the p of failure in a given time interval p = e ^ (- lambda (t2-t1)) number happening in given time that is Poisson distributed which means the interval between is exponentially distributed 8

Reliability Function R of given time (R T = e^(-lambda * T) 9

Reliability of process with Tasks in Serial R 1 times R 2 … times R N 10

Reliability of process with steps in parallel 1-(1-R 1 )(1-R 2 )(1-R n ) 11

Redundancy and Apollo 13 12