Q1. Figure 1 shows a cantilever I-beam subjected to a distributed load whose maximum intensity is \( q \) at the free end. The dimensions of the I-section of the beam are indicated in Figure 2.
Figure 1
Figure 2
Considering the \( x \)-axis to be parallel to the longitudinal axis of the beam, the \( z \)-axis to be perpendicular to the plane of loading and the origin of the \( x-y-z \) axes to coincide with the centroid of the I-section at the fixed end,
(a) Evaluate the shear stress \( \tau_{x z} \) in the top flange of the I-section at \( x=L / 2 \) and at a variable distance \( z \in\left[-b / 2,-t_{w} / 2\right] \cup\left[t_{w} / 2, b / 2\right] \) along its width. Plot the variation of this stress with \( z \). Assume that this stress does not vary across the thickness \( t_{f} \) of the flange.
(b) Evaluate the shear stress \( \tau_{x y} \) in the web of the I-section at \( x=L / 2 \) and at variable distance \( y \in[-h / 2, h / 2] \) along its depth. Plot the variation of this stress with \( y \). Assume that this stress does not vary across the thickness \( t_{w} \) of the web.
(c) Using the shear stress obtained in (b), determine the fraction of the total shear force at \( x=L / 2 \) that is borne by the web.
(d) Consider a horizontal plane (parallel to \( x-\mathrm{z} \) plane) passing through the beam's web at \( y=h / 4 \). Evaluate and plot the variation of the shear stress \( \tau_{x y} \) on this plane as a function of the distance \( x \in[0, L] \) from the fixed-end of the beam.