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Aviation Failure
Bucking, corrosion, creep, fatigue, fracture, melting, thermal shock and wear are all mechanical failure modes that can be extremely threatening in the field of aviation. Aviation failure can cause the death of a pilot protecting our country but also the deaths of infinite commercial airline passengers. The safety an integrity of airplanes, helicopters, and fighter jets is critical to the survival of our country and our people. Aviation failure, therefore, must be understood completely in order to prevent against such trauma. There have been several incidents of aviation failure, some killing many and some that take place on a test stand without harming anyone. Plane crashes that are not due to a mistake of the pilot are caused by a fracture or extreme corrosion that degrades material and causes them to no longer serve their purpose in the system.
Landing gear components are one source where aviation failure can occur. Examples of landing gear for aircraft are wheels with shock absorbers, skids, pontoons and skis. The most common are wheels for transportation aircraft and jets because they take off and land from solid ground. Nowadays most landing gear is considered retractable because they fold up mechanically to minimize drag. Aviation failure with landing gear components can arise as a result of the landing gear failing to actuate properly, forcing the aircraft to land on its body instead of on the wheels. This happens when electronic components fail; the pilot sends a message to open the landing gear and thinks it has opened so he proceeds with landing, causing much damage to the aircraft itself and possibly its passengers. This type of aviation failure can be avoided by routine maintenance and periodic checks to ensure that the electronics are functioning properly so the landing gear will always work.
Aviation failure due to the buckling of wing struts is often studied using finite element modeling. If a current design experiences aviation failure and the root cause determination points to the wing struts, it can be assumed that a redesign will ensue. The input variables for this type of aviation failure analysis are the wing strut length, thickness, precise shape and the temperatures and stresses that will be seen in the given system environment. Certain combinations of these variables will consistently experience aviation failure or some type of buckling that will eventually cause aviation failure. Other combinations are more promising, so those combinations are modeled in a computer software program to predict the ultimate conditions the wing struts will buckle under. Designing to these worst case scenarios gives the system a better chance of surviving the worst conditions with higher strength and higher quality wing strut designs.
Structural fatigue and corrosion occurs when a material or component is being exposed to a cyclic load for a long period of time, which can result in aviation failure. The word 'fatigue' was used to describe this result in the 19th century because the material was described as being tired. Aviation failure due to structural fatigue happens when a part undergoes more load cycles than the part can handle. Each material designed has a 'life' which tells us how many cycles until structural fatigue and corrosion begin to degrade the part and diminish functionality to the point of aviation failure. Aircraft components and electrical components are designed to handle a certain amount of fatigue and corrosion; they are built to perform in high stress high temperature environments usually. Structural fatigue is basically the development of small cracks in the high stressed areas, and if the undamaged material cannot withstand the high stresses, the cracked areas will liberate. Corrosion, or the wearing away of this material will eventually cause aviation failure.
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