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Young's modulus is defined as the ratio of the stress (force per unit area) applied to the object and the resulting axial strain (displacement or deformation) in the linear elastic region of the material. Although Young's modulus is named after the 19th-century British scientist Thomas Young, the concept was developed in 1727 by Leonhard Euler.
Elastic properties describe the reversible deformation (elastic response) of a material to an applied stress. They are a subset of the material properties that provide a quantitative description of the characteristics of a material, like its strength .
This stress is calculated by multiplying the change in temperature, material's thermal expansion coefficient and material's Young's modulus (see formula below). E {\displaystyle E} is Young's modulus , α {\displaystyle \alpha } is thermal expansion coefficient , T 0 {\displaystyle T_{0}} is initial temperature and T f {\displaystyle T_{f}} is ...
It measures the resonant frequencies in order to calculate the Young's modulus, shear modulus, Poisson's ratio and internal friction of predefined shapes like rectangular bars, cylindrical rods and disc shaped samples. The measurements can be performed at room temperature or at elevated temperatures (up to 1700 °C) under different atmospheres. [2]
The first stage is the linear elastic region. The stress is proportional to the strain, that is, obeys the general Hooke's law, and the slope is Young's modulus. In this region, the material undergoes only elastic deformation. The end of the stage is the initiation point of plastic deformation.
The bulk modulus is an extension of Young's modulus to three dimensions. Flexural modulus ( E flex ) describes the object's tendency to flex when acted upon by a moment . Two other elastic moduli are Lamé's first parameter , λ, and P-wave modulus , M , as used in table of modulus comparisons given below references.
The time-temperature superposition principle of linear viscoelasticity is based on the above observation. [5] Moduli measured using a dynamic viscoelastic modulus analyzer. The plots show the variation of elastic modulus E′(f, T) and the loss factor, tan δ(f, T), where δ is the phase angle as a function of frequency f and temperature T.
Strictly speaking, the bulk modulus is a thermodynamic quantity, and in order to specify a bulk modulus it is necessary to specify how the pressure varies during compression: constant-temperature (isothermal ), constant-entropy (isentropic), and other variations are possible.