The modulus of longitudinal elasticity of a structural material, or Young's modulus, is the physical quantity that characterizes the property of materials, providing their resistance to deformations acting in the longitudinal direction.
The parameter characterizes the degree of rigidity of a particular material.
The name of the module corresponds to the surname of Thomas Jung - a famous English physicist and scientist who was engaged in the study of compression and tensile processes for solid materials. This physical quantity is denoted by the Latin letter E. The Young's modulus is measured in Pascals.
The Young's modulus, or the modulus of longitudinal elasticity, is used in various calculations when testing materials for the degree of deformation under tension-compression, as well as in bending.
I must say that most of the structural materials used are characterized by a Young's modulus of sufficiently large values, which, as a rule, are of the order of 10 9 Pa. Therefore, for the convenience of calculations and recordings, a multiple prefix "gig" (GPa) is used.
The following are indicators of the Young's modulus for some structural materials, which are often used for various practical purposes. The durability of building structures and other objects depends on their strength properties.
According to the table, the maximum indicator of the module belongs to steel, and the minimum to wood.
The value of Young's modulus for some structural materials| Material Name | Indicator E, [GPa] | Material Name | Indicator E, [GPa] |
| chromium | 300 | brass | 95 |
| nickel | 210 | duralumin | 74 |
| steel | 200 | aluminum | 70 |
| cast iron | 120 | glass | 70 |
| chromium | 110 | tin | 35 |
| gray cast iron | 110 | concrete | 20 |
| silicon | 110 | lead | 18 |
| bronze | 100 | tree | 10 |
A graphical determination of the Young's modulus is possible with the help of a special stress diagram, which shows the curve obtained during repeated tests of the same material for strength.
In this case, the physical meaning of the Young's modulus is to find the mathematical ratio of normal stresses to the corresponding strain indicators in a certain section of the diagram to a specific proportionality limit Ο pc.
In the form of a mathematical expression, Young's modulus is as follows: E = Ο / Ξ΅ = tgΞ±
It should also be said that Young's modulus is also a proportionality coefficient in the mathematical description of Hooke's law, which is as follows: Ο = EΞ΅
Therefore, a direct relationship between the longitudinal elastic modulus and the measured cross-sectional characteristics of the materials involved in the rigidity tests is expressed using indicators such as EA and E1.
EA is an indicator of tensile-compression stiffness of a material in its cross section, where A is the value of the cross-sectional area of ββthe rod.
E1 is an indicator of the bending stiffness of the material in its cross section, where 1 is the value of the axial moment of inertia that occurs in the section of the material being tested.
Thus, Young's modulus is a universal indicator that allows characterizing the strength properties of a material from several sides.