Repairable and Non-Repairable Another measure of reliability is availability (probability that the system provides its functions when needed). Maximum Reliability level With Repairs No Repairs Pp…PDi Time System Engineering by J.J. CLGO Gao 6
+ - System Engineering by J. J. Gao 6 Maximum Reliability level Reliability With Repairs Time No Repairs Another measure of reliability is availability (probability that the system provides its functions when needed). Repairable and Non-Repairable
Some Initial Thoughts Warranty Will you buy additional warranty? Burn in and removal of early failures. (Lemon Law). Early Failures Increasing Constant Failure Failure Rate Rate Time CLGO 7
+ - Some Initial Thoughts Warranty Will you buy additional warranty? Burn in and removal of early failures. (Lemon Law). Time Failure Rate Early Failures Constant Failure Rate Increasing Failure Rate 7
Reliability Definitions Reliability is a time dependent characteristic. It can only be determined after an elapsed time but can be predicted at any time. It is the probability that a product or service will operate properly for a specified period of time (design life)under the design operating conditions without failure. CLGO 8
+ - 8 Reliability Definitions Reliability is a time dependent characteristic. It can only be determined after an elapsed time but can be predicted at any time. It is the probability that a product or service will operate properly for a specified period of time (design life) under the design operating conditions without failure
Today's Agenda Reliability is important s Single component model Multiple components model CLGO System Engineering by J.J.Gao 9
+ - 9 Today’s Agenda Reliability is important Single component model Multiple components model System Engineering by J. J. Gao
Basic Concepts We will introduce four important measures for the reliability of a nonrepairable item. The reliability(survivor)function R(t) The failure rate function z(t) The mean time to failure(MTTF) The mean residual life (MRL) We use variable X(t)to describe the state of an item X0= 1 if the item is functioning at time if the item is failed state at time The time to failure of item is denoted by T.Thus,T is a random variable. The time to failure T is not always the calender time.It may be other time concept:number of times a switch is operated,number of kilometers driven by a car,number of working cycles of a item.... CLGO System Engineering by J.J.Gao 10
+ - System Engineering by J. J. Gao 10 Basic Concepts