Reliability criteria in design and its application.pptx

This presentation provides a comprehensive exploration of the concept of reliability in engineering design, focusing on the importance of reliability, key terminologies, the development of product reliability, and system reliability. It is structured to guide engineers and designers through the principles and applications of reliability, ensuring that products perform consistently and effectively over their intended lifespan.

1. Reliability criteria in design and its application

2. OUTLINE What is Reliability ..? Importance of Reliability Terminology related with Reliability Development of Product Reliability System Reliability

3. What is Reliability..? The meaning of reliability is “soundness and consistence of quality” Reliability is defined “ Probability of a device performing its, purpose adequately for the period intended under the given operating condition ” NOTE: There is a relation between reliability and unreliability which depends on time. Since at any time t ,

4. Importance of Reliability Acc. To Manufacturer Customer satisfaction Acc. To Customer Availability of fit machine on time Cost of Repair

5. MEAN TIME TO FAILURE (MTTF) MEAN FAILURE RATE ( λ ) MEAN DOWN TIME (MDT) TEST INTERVAL MEAN TIME BETWEEN FAILURE (MTBF) AVAILABILITY UNAVAILABILITY MAINTAINABILITY CORRECTIVE MAINTENANCE PREVENTIVE MAINTENANCE AVAILABILITY INDEX RELIABILITY INDEX COST HAZARD RATE

6. For Non- Repairable items MEAN TIME TO FAILURE (MTTF) MEAN FAILURE RATE ( λ ) Reciprocal of mean time to failure

7. For Repairable items Mean Down Time (MDT) 2. TEST INTERVAL 3. MEAN TIME BETWEEN FAILURE ( MTBF) 4 . AVAILABILITY (A) 5 . UNAVAILABILITY (UA)

8. 6 . Availability Index (AI) 7. Reliability Index (RI)

9. Development of Product Reliability Product Definition Reliability Goals Design Analysis — Failure Mode and Effect Analysis (FMEA) — Multifunctional Design Reviews Testing — Laboratory and Stress Tests — Complete Machine Tests — Correlation Factor Reliability Growth Curves

10. Reliability Growth Curves The Reliability growth give the guidelines for reliability growth needed during a new product development program in order to achieve the reliability goals in customer service.

11. System Reliability The elements and sub-systems which constitute the given system and whose individual reliability factors can be estimated are identified Logical manner or configuration in which these units are connected to form the system is represented by a clock diagram or a circuit diagram The condition for the successful operation of the system is then determined , that is, it may be decided as to how the units should function. Finally, the combinational rules of probability theory (i.e.) addition rule, multiplication rule and their combinations are applied to arrive at the system reliability factor.

12. Series Configuration Components attached in series The overall Reliability system of components in series is given by R s =R 1 X R 2 X R 3 ……… X R n Where, R s = Reliability of system in series R 1 , R 2 = Reliability of each component Parallel Configuration Components attached in parallel The overall Reliability system of components in series is given by R p = 1 - (F 1 X F 2 X F 3 ……… X F n ) R p = 1- {(1-R 1 )( 1-R 2 )……… (1-R n )} Where, R P = Reliability of system in parallel R 1 , R 2 = Reliability of each component

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