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It is also known as the stiffness to weight ratio or specific stiffness. High specific modulus materials find wide application in aerospace applications where minimum structural weight is required. The dimensional analysis yields units of distance squared per time squared.
High strength steel and aluminum alloys do not exhibit a yield point, so this offset yield point is used on these materials. [14] Upper and lower yield points Some metals, such as mild steel, reach an upper yield point before dropping rapidly to a lower yield point. The material response is linear up until the upper yield point, but the lower ...
In an experimental situation the hardness of the uppermost layer of material in the contact may not be known with any certainty, consequently, the ratio is more useful; this is known as the dimensional wear coefficient or the specific wear rate. This is usually quoted in units of mm 3 N −1 m −1. [5]
The shear modulus is one of several quantities for measuring the stiffness of materials. All of them arise in the generalized Hooke's law: . Young's modulus E describes the material's strain response to uniaxial stress in the direction of this stress (like pulling on the ends of a wire or putting a weight on top of a column, with the wire getting longer and the column losing height),
The wire drawing process is quite simple in concept. The wire is prepared by shrinking the beginning of it, by hammering, filing, rolling or swaging, so that it will fit through the die; the wire is then pulled through the die. As the wire is pulled through the die, its volume remains the same, so as the diameter decreases, the length increases.
In some applications wire sizes are specified as the cross sectional area of the wire, usually in mm 2. Advantages of this system include the ability to readily calculate the physical dimensions or weight of wire, ability to take account of non-circular wire, and ease of calculation of electrical properties.
As the definition of the unit contains π, it is easy to calculate area values in circular mils when the diameter in mils is known. The area in circular mils, A , of a circle with a diameter of d mils, is given by the formula: { A } c m i l = { d } m i l 2 . {\displaystyle \{A\}_{\mathrm {cmil} }=\{d\}_{\mathrm {mil} }^{2}.}
Stress is the ratio of force over area (S = R/A, where S is the stress, R is the internal resisting force and A is the cross-sectional area). Strain is the ratio of change in length to the original length, when a given body is subjected to some external force (Strain= change in length÷the original length).