The Reliability Engineering Glossary
Reliability engineering and related fields use a vocabulary unique to our field of endeavor. For example, the term ‘reliability’ has the meaning of ‘trustworthy’ in everyday English use. For us, ‘reliability’ has a precise engineering definition.
Glossary description and plans
This glossary is meant to help us learn the language of reliability engineering. The category of ‘Terms’ is like a dictionary, including terms and their definitions as used by engineers. The category of ‘Methods’ is a listing of the techniques, tools, approaches, or concepts that may be found within a reliability plan. In the near future, we expect to expand the ‘Methods’ pages to include guidelines on use or application, examples, and additional references.
We also plan to expand the glossary to include formulas and failure mechanisms. Please let us know if there is another list of terms that should be added if you do not find a term that should be included or if you would like to recommend a change to an existing entry.
Method Categories
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- CorrosionThe gradual deterioration of a metal or alloy as a result of chemical interaction with its environment. Read More
- Corrosion, aluminum and copperA failure mechanism in semiconductor devices. Corrosion failures can occur when ULSI devices are exposed to moisture and contaminants. Corrosion failures are usually classified as one of two broad groups: bonding pad corrosion or internal chip corrosion. Bonding pad corrosion is usually more(...) Read More
- Cost effectivenessReferring to a favorable cost-benefit ratio; the criterion of task effectiveness in preventing any functional failure that has economic, but not safety, consequences (see effectiveness criterion). Read More
- Cost of failureFor a failure that has operational consequences, the combined cost of the operational consequences and the cost of corrective maintenance; for a failure that has nonoperational consequences, the direct cost of corrective maintenance. Read More
- CovariatesParameters that change during an experiment that had not been anticipated to change (e.g., temperature or humidity). Read More
- Crack initiationThe first appearance of a fatigue crack in an item subject to repeated loads, usually based on visual inspection, but sometimes based on the use of nondestructive testing techniques. Read More
- Crack-propagation characteristicsThe rate of crack growth, and the resulting reduction in residual strength, from the time of crack initiation to a crack of critical length. Read More
- CriticalA condition that may cause severe injury, occupational illness, or major property damage to facilities, systems; also of essential importance, vital, or indispensable as in “critical” design parameters. Frequently used to cover both “critical” and “catastrophic.” Read More
- Critical crack lengthThe length of a fatigue crack at which the residual strength of the item is no longer sufficient to withstand the specified damage-tolerant load. Read More
- Critical defectAn item defect that presents a hazardous or unsafe condition during assembly, installation, use, maintenance, transportation, storage, or retirement. Read More
- Critical defectiveAn item with one or more critical defects and may also have defects (major or minor). Read More
- Critical design review (CDR)The comparative evaluation of an item and program parameters. It is usually held just prior to production release after the item has reached a degree of completion permitting a comprehensive examination and analysis. Read More
- Critical failureA failure involving a loss of function or secondary damage that could have a direct adverse effect on operating safety. Read More
- Critical failure modeA failure mode whose ultimate effect can be a critical failure. Read More
- Critical moisture limitFor electronic device packages it is the maximum safe equilibrium moisture content for a device at reflow assembly or rework. Read More
- CriticalityA relative measure of the consequence and frequency of occurrence of a failure mode. Read More
- Cumulative distribution function (CDF)" The probability that a device will have failed by a specified time t1, or the fraction of units that have failed by that time. The value of this function is given by the integral of the probability density function, f(t), from t = 0 to t = t1 and is generally expressed in percent (%) or in(...) Read More
- Cumulative fraction failing (CFF)Over a stated duration, the total fraction failing for a given starting sample size. Read More
- Cumulative hazard functionThe fraction of units that have failed referenced to the survivors (not to the initial number of units). The value of this function at a specified time t1 is given by the integral of the instantaneous failure rate (hazard rate), h(t), from t = 0 to t = t1. Read More
- Cumulative reliability functionThe probability that a device will still be functional at a specified time t1, or the fraction of units surviving to that time. R(t) = 1 – F(t). Read More
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