 Welcome back Mechanical AI, did you know that shear stress distribution of a certain structure helps us determine the places to reinforce it so as to offer more resistance to shear? This makes us wonder, how is shear stress distributed? Before we jump in check out the previous part of this series to learn about what direct and bending stresses are. Now consider two basic cross sections for studying distribution of shear stress. The first is a rectangular cross section of length D and breadth B for any distance Y from the neutral axis that shear stress is given by the following equation. The term F in the equation stands for the shear force. The equation shows that there is a parabolic variation of shear stress with Y. The maximum shear force occurs at the neutral axis and is given by S equals 3 times the force upon twice the area. The second is an I section which is made up of two parts, two flanges and a web with capital B and small b denoting the breadth of flange and web respectively. Capital D and small d denote the length of total section and that of the web respectively. The equation of shear stress is given as so the maximum shear stress at the neutral axis is given as showing that the shear stress in the flanges varies from a maximum at the top web to zero at the outer tips. In practice however, this found that most of the shearing force about 90% is carried by the web and shear force in the flanges is negligible. The shear flow between a steel beam and reinforced concrete deck slab is a natural requirement for composite action. If there were no connection, a beam and slab would bend as two different layers causing the whole structure to weaken and eventually fail. The presence of a shear connection prevents the slip between the two components and achieves a much stiffer and stronger beam. Hence we saw how shear stress is distributed first on a rectangular cross section and then on an I section. And finally found out what shear connectors are. So here are the top mechanical years of our last videos. In the next episode of Mechanical Year, find out what torsion is.