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Reliability Engineering

Reliability engineering (RA) studies machine trouble. Because machine trouble may break human life and give damage to the company, the concept of risk is important.

Present RA deals with not only for machines and tools but computer system. Mathematics in RA is classical. But it is applied in various fields.

Risk Evaluation

Reliability evaluation is one of risk evaluation. Risk evaluation in RE has total procedure to evaluate, quantification, classification, reasoning and management.

FMEA and FTA are popular tools. Those tools use knowledge and experience effectively. It is called that "FMEA is bottom-up approach. FTA is top-down approach."


FMEA stands for "Failure Mode and Effect Analysis".

At first, we make scenario as many as we can. Then, we score frequency, find ability and damage for each scenario. Multiplication of them is the quantity of risk.


FTA stands for "Fault Tree Analysis".

In FTA, we take part of the reason of troubles. FTA considers that the reason is not one. And FTA indicates the cause of trouble is combination of the reason. The combination is made by "and" or "or" relationship between the reason.

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