Young's modulus

Young's modulus (also known as the elastic modulus, the tensile modulus, or modulus of elasticity) is a measure of the stiffness of a solid material. It defines the relationship between stress (force per unit area) and strain (proportional deformation) in a material. Young's modulus is named after the 19th-century British scientist Thomas Young.

Etymology

The term "Young's modulus" is named after the British scientist Thomas Young, who first introduced the concept in the 19th century. The term "modulus" comes from the Latin word for "measure", while "elastic" refers to the property of a material to return to its original shape after being deformed.

Definition

Young's modulus, E, can be defined as the ratio of tensile stress (σ) to tensile strain (ε) within the elastic deformation phase of a material:

E = σ / ε

This equation implies that the stress and strain in a material are linearly related, which is a characteristic of elastic materials.

Units

In the International System of Units (SI), Young's modulus is measured in pascals (Pa). The unit is named after the French mathematician and physicist Blaise Pascal.

Related Terms

• Stress: Force per unit area within materials that arises from externally applied forces, uneven heating, or permanent deformation.
• Strain: Deformation of materials in response to stress.
• Elasticity: The ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed.
• Pascal: The SI unit of pressure, defined as one newton per square meter.

See Also

• Hooke's law
• Shear modulus
• Bulk modulus

References

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  Stress-strain curve for a ductile material
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  Spider graph showing Young's modulus
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  Illustration from "De Abditis Morborum Causis"