RELIABILITY IN MAINTENANCE: Need for reliability of Maintenance, Failure pattern of equipment


The concept of reliability has found increased use in industries engineering maintenance and management.

Need for reliability of Maintenance:

The reliability of a system, equipment and product is very important aspect of quality for its consistent performance over the expected life span. Reality is defined as the probability that ac component / system, when operating under given condition will perform it intended functions adequate for a specified period of time. It refers to the like hood that equipment will not fail during its operation. The four important factors required in the determination of reliability are

⦁ Reliability expressed as probability 

⦁ Adequate performance acquirements

⦁ Duration of adequate performance.

⦁ Environmental or operating conditions.

i) Realiability expressed as probability

it is the ratio of the number of times we can expect an event to occur to the total number of trail undertaken. A Reliability factor can be expressed as probability. A reliability factor equal to one means that device performs satisfactorily for the prescribed duration under the give environmental condition.

ii) Adequate Performance Requiement

a system may perform satisfactorily even though one or more components may not be functioning. In reliability analysis there is a need to define the magnitude of satisfactory or adequate performance of the system.

iii) Duration of Adequate Performance

The duration of adequate performance is used to state the time up to which the desired performance of the system is achieved under the given operating conditions.

iv) Environmental or Operating condition:

environmental condition indicate the prevailing conditions at which the system is under operation. 

Failure pattern of equipment

The failure pattern of equipment over its whole life cycle can be represented in the diagram given below. In phase I, the failure pattern inherent in a new product because of manufacturing or design defects. Phase II shows the useful life period of an equipment when the failure rates are normally modulate at the equipment gets set to the working environment. In Phase III, the failures are excusing due to wear out failure that are caned due to again of the equipment. 

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