A constant circular cross-section bridge of diameter d, length l, and mass density t = 6300 kg/m3 is replaced by a similar bridge system formed of a rigid cylinder of diameter dc, length lc, mass...

A constant circular cross-section bridge of diameter d, length l, and mass density t = 6300 kg/m3 is replaced by a similar bridge system formed of a rigid cylinder of diameter dc, length lc, mass density tc = 7800 kg/m3 , and two identical flexible segments having the cross-section and material properties identical to the original bridge and are attached to the cylinder at one end and clamped at the opposite end; the total length of the altered bridge remains l. Determine the torsional change in both stiffness and inertia with respect to the bridge’s midpoint that occurred through the cylinder addition by graphically analyzing the stiffness and inertia ratios for 0.2l <><><><>