 Welcome back MechanicalEI. Did you know that for a load to develop strain energy in a beam and achieve elongation, the most preferred way is through impact loading? This makes us wonder, what are impact loads? Before we jump in, check the previous part of the series to learn about what strain energy is. Now, consider that load P is applied suddenly over the body and therefore will be constant throughout the deformation process of the body. The strain energy stored in such a body is given by the product of stress squared and volume divided by the Young's modulus. Therefore, we can say here that maximum stress induced in the body due to sudden applied load will be twice the stress induced in the body with same value of load applied gradually. Unlike suddenly applied load, impact load is so called when the load has a certain velocity and strikes the beam from say height edge which results in the extension of the bar by x. The shear stress in this case will be given by the following equation. If a moment M acts on a beam of length L, the strain energy stored in the beam is given by integrating a small element of length ds over the intervals 0 to L. Here, EI is the flexural rigidity. Similarly, strain energy stored for a transfer shear force of magnitude V is given when the elemental length ds is integrated from 0 to L. Here K is a form factor which is dependent on the cross section of the beam and G is the modulus of elasticity. The last case is that of a strain energy stored due to a torque T on a shaft of length L and radius R. The key change in the integral is the inclusion of polar moment of inertia denoted by J. Hence, we first saw how strain energy is stored due to suddenly applied load and impact load and then went down to see how strain energy is stored due to bending shear and torsion. So like, subscribe and comment with your feedback to help us make better videos. Thanks for watching. Also, thanks a lot for those constructive comments. You help the channel grow. So, here are the top mechanical EIs of our last videos. In the next episode of Mechanical EI, find out what deflection of a beam is.