Author: haroonkhan
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Hardness test
Simply stated, hardness is the resistance of a material to permanent indentation. Hardness is not a precisely defined engineering property, such as elastic modulus or yield strength, but it is still widely used to describe the resistance of materials to plastic deformation. The hardness of ductile materials is related to their yield strength, and the…
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Flexure test
The flexure test measures the mechanical properties of materials when subjected to bending load. A flat rectangular specimen is loaded at three or four points, as shown in Fig. 5.14. The load causes the specimen to flex, thus inducing a compressive strain on the concave side, tensile strain on the convex side, and shear along the mid-plane.…
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Compression test
The compression test determines the mechanical properties of materials under crushing loads. There are many aircraft structures that carry compression loads, such as the undercarriage during take-off and landing or the upper wing surface during flight, and therefore the mechanical behaviour of their materials must be determined by compression testing. It is often assumed that…
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Tension test
Basics of the tension test The tension test is one of the most common and important methods for measuring the mechanical properties of materials. The tension test is popular because a large number of properties can be determined in a single test: elastic modulus, strength, ductility, and other properties. The test is also popular because it…
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Introduction
The selection of materials for aircraft structures and engines is assessed according to a multitude of parameters such as cost, ease of manufacture, weight and a host of other factors. Central to the selection of materials is their mechanical properties such as stiffness, strength, fatigue resistance and creep performance. The durability properties of structural and…
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Space shuttle structures
The space shuttle is a complex system consisting of an external fuel tank, two solid rocket boosters and the Space Transportation System (STS) orbiter vehicle. In this section, we only examine the structure and materials of the orbiter. The orbiter resembles a conventional aircraft with double-delta wings, and uses many of the same materials. The…
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Helicopter structures
Figure 3.10 shows the main sections and internal structure for a typical modern helicopter. The main body (or airframe) of the helicopter is most heavily loaded at two points: the connection to the tail boom and the connection to the main rotor drive shaft or turbine engine. The tail boom applies torsion and bending loads to the…