Failure mode

The Manner by whick a failure is observed; it generally describes the way the failure occurs and its impact on equipment operation.

Logistics: Principles and Applications, J. W. Langford, McGraw Hill, 1995, pp 48.

Rather than the simple description of symptoms that many product users or process participants might use, the term failure mode refers to a rather complete description, including the pre-conditions under which failure occurs, how the thing was being used, proximate and ultimate/final causes (if known), and any subsidiary or resulting failures that result.

Each discrete failure type x root cause represents a different failure mode.

The term is part of the engineering lexicon, especially of engineers working to test and debug products or processes. Carefully observing and describing failure conditions, identifying whether failures are reproducible or transient, and hypothesizing what combination of conditions and sequence of events led to failure is part of the process of fixing design flaws or improving future iterations. The term may be applied to mechanical failure, structural failure, electrical failure and systems failure. Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware thus making it behave as expected. ... Structural failure refers to loss of the load-carrying capacity of a component or member within a structure or of the structure itself. ...

Mechanical Failure Modes

There are many different kinds of mechanical failure, and they include overload, impact, fatigue, creep rupture, stress relaxation, stress corrosion cracking corrosion fatigue and so on. Each produces a different type of fracture surface, and other indicators near the fracture surface(s). The way the product is loaded, and the loading history are also important factors which determine the outcome. Overload can refer to: Electrical overload, a situation where an electrical machine or system is subjected to a greater load than it was designed for. ... IMPACT [1] The mission of IMPACT is to inform and connect emerging leaders through economic empowerment, civic engagement, and political involvement. ... In materials science, fatigue is the progressive, localised, and permanent structural damage that occurs when a material is subjected to cyclic or fluctuating strains at nominal stresses that have maximum values less than (often much less than) the static yield strength of the material. ... Look up creep in Wiktionary, the free dictionary. ... Stress relaxation is a term that describes the decrease in stress over time that occurs when a body is suddenly strained and the strain is maintained at a constant magnitude afterward. ... Stress corrosion cracking (SCC) is the unexpected sudden failure of normally ductile metals subjected to a constant tensile stress in a corrosive environment, especially at elevated temperature. ... Wikipedia does not have an article with this exact name. ... For other uses, see Fracture (disambiguation). ...

Over time, as more is understood about a failure, the failure mode evolves from a description of symptoms and outcomes (that is, effects) to a systematic and relatively abstract model of how, when, and why the failure comes about (that is, causes). An abstract model (or conceptual model) is a theoretical construct that represents something, with a set of variables and a set of logical and quantitative relationships between them. ...

The more complex the product or situation, the more necessary a good understanding of its failure modes is to ensuring its proper operation (or repair). Cascading failures, for example, are particularly complex failure modes. Edge cases and corner cases are situations in which complex, unexpected, and difficult-to-debug problems often occur. A cascading failure is failure in a system of interconnected parts, where the service provided depends on the operation of a preceding part, and the failure of a preceding part can trigger the failure of successive parts. ... An edge case is a problem or situation that occurs only at an extreme (maximum or minimum) operating parameter. ... It has been suggested that this article or section be merged with Boundary case. ...

See also

• Failure analysis
• Failure mode and effects analysis (FMEA)
• Failure rate
• Forensic electrical engineering
• Forensic engineering
• Hazard analysis