Difference Between Young Modulus and Tensile Strength

Young Modulus vs Tensile Strength
 

Young’s modulus and tensile strength are two properties of solids. These properties play a vital role in fields such as material science, mechanical engineering, constructions and physics. It is very important to have a proper understanding of these concepts in order to excel in such fields. In this article, we are going to discuss what Young’s modulus and tensile strength are, their definitions, applications of young’s modulus and tensile strength, the similarities of these two and finally the difference between Young’s modulus and tensile strength.

Young’s Modulus

Young’s modulus is a very valuable property of matter and is used to characterize the stiffness of the material. Young’s modulus is the ratio of the pressure on the object (stress) to the strain of the object. Since strain is dimensionless, the units of Young’s modulus are equal to the units of pressure, which is Newton per square meter. For some materials, the Young’s modulus is constant over some range of stress. These materials obey the Hooke’s law and are said to be linear materials. Materials, which do not have a constant Young’s modulus, are known as non-linear materials. It must be clearly understood that Young’s modulus is a property of the material, not the object. Different objects made of the same material will have the same Young’s modulus. The Young’s modulus is named after the physicist Thomas Young. Young’s modulus can also be defined, as the pressure required to have a unit strain on the material. Even though, the units of Young’s modulus are Pascal, it is not widely used. Large units such as Mega Pascal or Giga Pascal are the useful units.

Tensile Strength

Tensile strength is the common term used for the ultimate tensile strength (UTS). When a material is pulled it stretches. The force, which is stretching the material, is known as the stress. The ultimate tensile strength is the maximum stress a material can withstand before necking. Necking is the event of the cross section of the specimen becoming significantly small. This can be explained using the intermolecular bonds of the specimen. When the stress is applied, the intermolecular attraction forces act on the opposite direction, to keep the specimen in shape. When the stress is released, the specimen fully or partially returns to its initial state. When the necking starts, the molecules are stretched apart so that the intermolecular forces are not enough to hold them together. This causes a sudden strain due to the stress and necking happens. Tensile strength is also a property of the material. This is measured in Pascal, but larger unit such as Mega Pascal is used in practical conditions.