Two pipes (L1
= 2.5 m and L2
= 1.5 m) are joined at B by flange plates (thickness tf
= 14 mm) with five bolts (dbf
= 13 mm) arranged in a circular pattern (see figure). Also, each pipe segment is attached to a wall (at A and C, see figure) using a base plate (tb
= mm) and four bolts (dbb
= 16 mm). All bolts are tightened until just snug. Assume E1
= 110 GPa, E2
=73 GPa, v1
= 0.33, and v2
= 0.25. Neglect the self-weight of the pipes, and assume the pipes are in a stress-free state initially. The crosssectional areas of the pipes are A1
= 1500 mm2
and A2
= (3/ 5)A1. The outer diameter of Pipe 1 is 60 mm. The outer diameter of Pipe 2 is equal to the inner diameter of Pipe 1. The bolt radius r = 64 mm for both base and flange plates.
(a) If torque T is applied at x = L1, find an expression for reactive torques R1
and R2
in terms of T.
(b) Find the maximum load variable T (i.e., Tmax) if allowable torsional stress in the two pipes is tallow
= 65 MPa.
(c) Draw torsional moment (TMD) and torsional displacement (TDD) diagrams. Label all key ordinates. What is
max?
(d) Find Tmax
if allowable shear and bearing stresses in the base plate and flange bolts cannot be exceeded. Assume allowable stresses in shear and bearing for all bolts are Tallow
=45 MPa and
allow
=90 MPa.
(e) Remove torque T at x = L1. Now assume the flange-plate bolt holes are misaligned by some angle β (see figure). Find the expressions for reactive torques R1
and R2
if the pipes are twisted to align the flange-plate bolt holes, bolts are then inserted, and the pipes released.
(f) What is the maximum permissible misalignment angle
max
if allowable stresses in shear and bearing for all bolts [from part (d)] are not to be exceeded?