A thin-walled hollow tube AB of conical shape has constant thickness t and average diameters dA and

Question:

A thin-walled hollow tube AB of conical shape has constant thickness t and average diameters dA and dB at the ends (see figure).
(a) Determine the strain energy U of the tube when it is subjected to pure torsion by torques T.
(b) Determine the angle of twist ( of the tube.
Use the approximate formula IP ( (d3t/4 for a thin circular ring; see Case 22 of Appendix D.