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Widespread Fatigue Damage
Widespread fatigue damage (WFD) in a structure is characterised by the simultaneous presence of fatigue cracks at multiple points that are of sufficient size and density that while individually they may be acceptable, link-up of the cracks could suddenly occur and the structure could fail. For example, small fatigue cracks developing along a row of fastener holes can coalesce increasing the stress on adjacent cracked sites increasing the rate of growth of those cracks. The objective of a designer is to determine when large numbers of small cracks could degrade the joint strength to an unacceptable level."Federal Register, Aging aeroplane program" The in-flight loss of part of the fuselage from Aloha Airlines Flight 243 Aloha Airlines Flight 243 (IATA: AQ243, ICAO: AAH243) was a scheduled Aloha Airlines flight between Hilo and Honolulu in Hawaii. On April 28, 1988, a Boeing 737-297 serving the flight suffered extensive damage after an explosive decompression ... was attribute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aloha Airlines Flight 243 Fuselage
''Aloha'' ( , ) is the Hawaiian word for love, affection, peace, compassion and mercy, that is commonly used as a simple greeting but has a deeper cultural and spiritual significance to native Hawaiians, for whom the term is used to define a force that holds together existence. The word is found in all Polynesian languages and always with the same basic meaning of "love, compassion, sympathy, kindness", although the use in Hawaii has a seriousness lacking in the Tahitian and Samoan meanings. Mary Kawena Pukui wrote that the "first expression" of ''aloha'' was between a parent and child. Lorrin Andrews wrote the first Hawaiian dictionary, called ''A Dictionary of the Hawaiian Language''. In it, he describes ''aloha'' as "A word expressing different feelings: love, affection, gratitude, kindness, pity, compassion, grief, the modern common salutation at meeting; parting". Mary Kawena Pukui and Samuel Hoyt Elbert's ''Hawaiian Dictionary: Hawaiian-English, English-Hawaiia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structure
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as biological organisms, minerals and chemicals. Abstract structures include data structures in computer science and musical form. Types of structure include a hierarchy (a cascade of one-to-many relationships), a network featuring many-to-many links, or a lattice featuring connections between components that are neighbors in space. Load-bearing Buildings, aircraft, skeletons, anthills, beaver dams, bridges and salt domes are all examples of load-bearing structures. The results of construction are divided into buildings and non-building structures, and make up the infrastructure of a human society. Built structures are broadly divided by their varying design approaches and standards, into categories including building structures, arch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fatigue (material)
In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts of the fracture surface. The crack will continue to grow until it reaches a critical size, which occurs when the stress intensity factor of the crack exceeds the fracture toughness of the material, producing rapid propagation and typically complete fracture of the structure. Fatigue has traditionally been associated with the failure of metal components which led to the term metal fatigue. In the nineteenth century, the sudden failing of metal railway axles was thought to be caused by the metal ''crystallising'' because of the brittle appearance of the fracture surface, but this has since been disproved. Most materials, such as composites, plastics and ceramics, seem to experience some sort of fatigue-related failure. To aid in predicting th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aloha Airlines Flight 243
Aloha Airlines Flight 243 (IATA: AQ243, ICAO: AAH243) was a scheduled Aloha Airlines flight between Hilo and Honolulu in Hawaii. On April 28, 1988, a Boeing 737-297 serving the flight suffered extensive damage after an explosive decompression in flight, caused by part of the fuselage breaking due to poor maintenance and metal fatigue. The plane was able to land safely at Kahului Airport on Maui. The one fatality, flight attendant Clarabelle "C.B." Lansing, was ejected from the airplane. Another 65 passengers and crew were injured. The substantial damage inflicted by the decompression, the loss of one cabin crew member, and the safe landing of the aircraft established the incident as a significant event in the history of aviation, with far-reaching effects on aviation safety policies and procedures. Aircraft and crew The aircraft involved was a Boeing 737 200 series and was the 152nd Boeing 737 airframe built at the Renton assembly plant. It was built in 1969 and delivered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fatigue Testing
Fatigue testing is a specialised form of mechanical testing that is performed by applying cyclic loading to a ''coupon'' or structure. These tests are used either to generate fatigue life and crack growth data, identify critical locations or demonstrate the safety of a structure that may be susceptible to fatigue. Fatigue tests are used on a range of components from coupons through to full size test articles such as automobiles and aircraft. Fatigue tests on coupons are typically conducted using servo hydraulic test machines which are capable of applying large ''variable amplitude'' cyclic loads. ''Constant amplitude'' testing can also be applied by simpler oscillating machines. The ''fatigue life'' of a coupon is the number of cycles it takes to break the coupon. This data can be used for creating stress-life or strain-life curves. The rate of crack growth in a coupon can also be measured, either during the test or afterward using fractography. Testing of coupons can also be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerospace Engineering
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is similar, but deals with the electronics side of aerospace engineering. "Aeronautical engineering" was the original term for the field. As flight technology advanced to include vehicles operating in outer space, the broader term "aerospace engineering" has come into use. Aerospace engineering, particularly the astronautics branch, is often colloquially referred to as "rocket science". Overview Flight vehicles are subjected to demanding conditions such as those caused by changes in atmospheric pressure and temperature, with structural loads applied upon vehicle components. Consequently, they are usually the products of various technological and engineering disciplines including aerodynamics, Air propulsion, avionics, materials science, stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Materials Degradation
Material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geological origin or biological function. Materials science is the study of materials, their properties and their applications. Raw materials can be processed in different ways to influence their properties, by purification, shaping or the introduction of other materials. New materials can be produced from raw materials by synthesis. In industry, materials are inputs to manufacturing processes to produce products or more complex materials. Historical elements Materials chart the history of humanity. The system of the three prehistoric ages (Stone Age, Bronze Age, Iron Age) were succeeded by historical ages: steel age in the 19th century, polymer age in the middle of the following century (plastic age) and silicon age in the second half of the 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
