What are Stress and Strain?

Welcome back MechanicalEI, Did you know that all major shape changing operations make use of stress and strain to achieve the desired output? This makes us wonder, What are Stress and Strain? Before we jump in check out the previous part of this series to learn about what Moment of Inertia is? Now, stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting a weight, each particle in the bar pushes on the particles immediately below it. The between the bar particles is called stress and the actual deformation of the particles is called strain. According to the Hooke’s law, when a material is loaded within elastic limit, the stress induced in the material is directly proportional to the strain produced. It means that the ratio of stress with the corresponding strain gives us a constant within elastic limit. The constant is known as Modulus of Elasticity or Modulus of Rigidity or Young's Modulus. The stress induced in a body due to temperature changes is called thermal stress. These thermal stresses cause deformation delta T in the body which is given by the product of alpha which is thermal expansion coefficient, length of the body and the difference in temperature delta T. Hence, We first saw what stress and strain are then studied the Hooke's law and finally saw what thermal stresses are ?

In the next episode of MechanicalEI find out what elastic constants are?

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