Stiffness (k) is a measure of the resistance offered by an elastic body to deformation. Mathematical

Airframes and aeroengines provide key examples of the importance of materials in a demanding environment. Lowering airframe weight, and increasing the operating temperature (and therefore the efficiency) of aeroengines are two continuing challenges for modern materials science.
Atomic spacing is about 1E-10m. There may be a dislocation for every 20-30 atoms after work hardening. 1E15 dislocations after work hardening (internal energy goes up) and when annealed this goes down to 1E10 (internal energy reduces).
Stiffness (k) is a measure of the resistance offered by an elastic body to deformation. Mathematically it is force/extension. The strength of a material is its ability to withstand a stress (force/cross-sectional area) without failure.
Aloha Airlines Flight 243 was a scheduled flight between Hilo and Honolulu in Hawaii. On April 28 th , 1988, a Boeing 737-297 serving state department travel advisory the flight suffered extensive damage after an explosive decompression in flight, but was able to land safely at Kahului Airport. The accident was caused by a small section on the left side of the roof rupturing. The resulting explosive decompression tore off a large section of the roof. As part of the design of the 737, stress may have been reduced by controlled are breakaway zones. Investigation by the United States state department travel advisory National Transportation Safety Board concluded that the accident was caused by metal fatigue exacerbated by crevice corrosion.
Carbon fibres increase the stiffness state department travel advisory and high tensile strength (strong in tension) of the materials they are added to. They have a high chemical resistance, high temperature tolerance and low thermal state department travel advisory expansion.