The modulus of longitudinal elasticity of a structural material, or Young's modulus, is a physical quantity that characterizes the property of materials that ensures 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 name of Thomas Young, a famous English physicist and scientist who studied the processes of compression and tension for solid materials. This physical quantity is denoted by the Latin letter E. Young's modulus is measured in Pascals.
The parameter Young's modulus, or modulus of longitudinal elasticity, is used in various calculations when testing materials for the degree of deformation in tension-compression, as well as in bending.
It must be said that most of the used structural materials are characterized by Young's modulus index of sufficiently large values, which, as a rule, are of the order of 109 Pa. Therefore, for the convenience of calculations and recording, a multiple prefix "giga" (GPa) is used.
Below are Young's modulus values for somestructural 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 above, the maximum modulus belongs to steel, and the minimum to wood.
| Material name |
IndicatorE, [GPa] |
Material name |
IndicatorE, [GPa] |
| chrome | 300 | brass | 95 |
| nickel | 210 | duralumin | 74 |
| steel | 200 | aluminum | 70 |
| cast iron | 120 | glass | 70 |
| chrome | 110 | tin | 35 |
| grey cast iron | 110 | concrete | 20 |
| silicon | 110 | lead | 18 |
| bronze | 100 | tree | 10 |
Graphic determination of Young's modulus is possible with the help of a special stress diagram, which shows a curve obtained from repeated strength tests of the same material.
In this case, the physical meaning of Young's modulus is to find the mathematical ratio of normal stresses to the correspondingdeformation indicators in a certain section of the diagram up to a specifically given limit of proportionality σpc.
In the form of a mathematical expression, Young's modulus looks like this: E=σ/ε=tgα
It should also be said that Young's modulus is also a proportionality factor in the mathematical description of Hooke's law, which looks like this: σ=Eε
Therefore, the direct relationship of the modulus of elasticity with the measured characteristics of the cross-sections of materials participating in stiffness tests is expressed using indicators such as EA and E1.
EA is a measure of the tensile-compressive stiffness of the material in its cross section, where A is the value of the cross-sectional area of the rod.
E1 is the flexural stiffness of the material in its cross section, where 1 is the value of the axial moment of inertia that occurs in the cross section of the material being tested.
Thus, Young's modulus is a universal indicator that allows you to characterize the strength properties of a material from several sides.
