Concept explainers
A steel riser pipe hangs from a drill rig located offshore in deep water (see figure). Separate segments are joined using bolted flange plages (see figure part b and photo). Assume that there are six bolts at each pipe segment connection. Assume that the total length of the riser pipe is L = 5000 ft: outer and inner diameters are d2= l6in.and d1= 15 in.; flange plate thickness t1= 1.75 in.; and bolt and washer diameters are db= 1.125 in..and dW. = 1.875 in., respectively.
(a) If the entire length of the riser pipe is suspended in air. find the average normal stress a in each bolt, the average bearing stress abbeneath each washer, and the average shear stress t through the flange plate at each bolt location for the topmost bolted connection.
(b) If the same riser pipe hangs from a drill rig at sea. what are the normal, bearing, and shear stresses in the connection? Obtain the weight densities of steel and sea water from Table I-1. Appendix I. Neglect the effect of buoyant foam casings on the riser pipe
(a)
The stresses on a steel riser pipe suspended in air.
Answer to Problem 1.8.13P
The average normal stress in each bolt is
The bearing stress for each washer is
The average shear stress at each bolt location in flange is
Explanation of Solution
Given information:
Steel riser pipe length is
Write the expression for average normal stress in each bolt for steel riser pipe suspended in air.
Here, the area of the riser pipe is
Write the expression for the area of pipe.
Here, the area of pipe is
Write the expression for the area of a bolt.
Here, the diameter of bolt is
Write the expression for bearing stress for each washer.
Here, the area of a washer is
Write the expression for the washer area.
Here, the diameter of bolt is
Write the expression for average shear stress at each bolt location in flange.
Here, the thickness of flange is
Calculation:
Substitute
Substitute
Substitute
Substitute
Substitute
Substitute
Conclusion:
The average normal stress in each bolt is
The bearing stress for each washer is
The average shear stress at each bolt location in flange is
(b)
The stresses on a steel riser pipe hanging from a drill rig at sea water.
Answer to Problem 1.8.13P
The average normal stress in each bolt is
The average bearing stress beneath each washer is
The average shear stress at each bolt location in flange is
Explanation of Solution
Write the expression for average normal stress in each bolt for a steel riser pipe hanging from a drill rig in sea water.
Here, the net weight density is
Write the expression for average bearing stress beneath each washer.
Here, the area of a washer is
Write the expression for average shear stress at each bolt location in flange.
Substitute
Substitute
Substitute
Conclusion:
The average normal stress in each bolt
The average bearing stress beneath each washer
The average shear stress at each bolt location in flange
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Chapter 1 Solutions
Mechanics of Materials (MindTap Course List)
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- Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning