For a rectangular beam section, the ratio of maximum shear stress (tau_max) to average shear stress (tau_avg) across the depth is:

Explanation

In a rectangular beam section subjected to transverse shear force, shear stress distribution across depth is parabolic. Maximum shear stress occurs at the neutral axis and tau_max = 1.5 * tau_avg. For a circular section, tau_max = 1.33 * tau_avg.