Fmeca
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The analysis of mode and effect of a failure means the determination of the failure rate and the failure mechanism. The failure rate yields the probability that an item (device or complete technical system) will fail during a discrete time interval under consideration. The failure mode analysis, also known as FMEA (Failure Mode Effect Analysis) or FMECA (Failure Mode Effect and Critically Analysis), represents the systematic investigation of all possible failure modes and their effect on the functionality and safety of an item or technical system under consideration. Taking failure modes and causes of failures into consideration, FMEA requires the close cooperation between engineers for development and quality control. ICR has profound experiences to determine failures occurring in electronic devices and technical systems, in process engineering and in material science. Although analysis procedures depend strongly on kind of device or technology, FMEA procedures are the same for the majority of items, devices or technical systems.
Failure analysis
The failure rate describing the surviving probability of an item or technical system is often assumed to be constant during operating time. Memory effects, dependencies on time as well as dependencies on environmental conditions are neglected. Nevertheless, various investigations show that the failure rate exhibits three phases:
Phase 1: The failure rate decreases rapidly with time. These early failures can be related to randomly distributed weaknesses in materials.
Phase 2: : The failure rate is constant (independent from time). In this phase the occurrence of failure is Poisson distributed.
Phase 3: : In the wear out phase the failure rate increases with time. Failures can be related to aging, wear and fatigue.