After designing the structural steel torsion member shown in Figure P6.4a, a mechanical en...

After designing the structural steel torsion member shown in Figure P6.4a, a mechanical engineer discovered that the design torque had to be increased appreciably. The engineer decided to redesign the member by welding a structural steel sleeve, with inner diameter of 80 mm and outer diameter of 86 mm, to the member as shown in Figure P6.4b. The working shear stress is restricted to τ = 60.0 MPa.

a. Determine the design torque for each of the members in Figures P6.4a and P6.4b.

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b. Calculate the increase in torque resulting from the sleeve.

FIGURE P6.4a

FIGURE P6.4b