Young❼Modulus: Definition, Values, and Examples

What Are the Young's Modulus Values?

Young's modulus values cover a huge range, but they still provide a well-used measure of the elastic capability of many materials. The lowest values of Young’s modulus are for materials like natural rubber, at 0.01–0.1 GPa, whereas the highest values are typically for carbon nanotube materials (up to 1,000 GPa). Other examples are for obscure metals (such as iridium, 570 GPa) and for carefully alloyed and heat-treated steels used in spring manufacture (up to 220 GPa).

How Does the Values of Young's Modulus Expressed?

Young’s modulus is expressed as pressure. In the metric system, this is in pascals or gigapascals (Pa or GPa). In American/imperial units, pressure is expressed in pounds per square inch (PSI)

What Material Has the Highest Young's Modulus?

Diamond is considered to have the highest Young’s modulus at around 1,210 GPa. A material identified in several meteorites is a carbon allotrope like a diamond, but instead of being cubic in structure, it is formed from a hexagonal carbon matrix. This material, named Lonsdaleite, doesn’t yet exist in samples large enough to be Young’s modulus tested, but it is known to be harder and stronger than diamond.

What Is a Large Young's Modulus Value Indicates?

A high Young's modulus value indicates the high stiffness of a material and its resistance to (elastic) deformation under load. A high value of Young’s modulus points to a material that does not stretch easily.

What Is a Small Young's Modulus Value Indicates?

A low Young's modulus value indicates a material that undergoes large (elastic) deformation under a relatively low load. Such materials stretch easily. Natural rubbers stretch very easily, confirmed by a low Young’s modulus value. Some silicone rubbers have almost unmeasurably low Young’s modulus values, stretching under their own weight.

What Is the Young's Modulus Symbol?

Young’s modulus is expressed as a capital E (Epsilon) or, less commonly, Y (Young).

How Does the Young's Modulus Determined?

Young’s modulus is determined by suspending a wire/thread/strand of the uniform cross-sectional area from a strong point and loading the lower end with enough weight to just straighten it. Weights are then added and measurements of extension are taken. It is important to validate that the elastic limit of the material is not exceeded, or the numbers will include some plastic deformation and will be invalid as an informative test.

From the values of load, extension, and cross-sectional area, two values can be calculated:

  • Stress, σ, is defined as the force per unit area. This is calculated by applying two load values to tension the strand under test and dividing the Δ load (the load increase) by the cross-sectional area of the strand:

Young❼Modulus: Definition, Values, and Examples