WORLD FOR CIVIL

Statics & Strength of Materials

Topic 7.6a :Pressure Vessels - Problem Assignment 1

1. A welded water pipe has a diameter of 8 ft. and a wall of steel plate 3/4 in. thick. After fabrication, this pipe was tested under an internal pressure of 230 psi. Calculate the circumferential stress developed in the walls of the pipe. (14,700 psi)

2. Calculate the tensile stresses developed (circumferential and longitudinal) in the walls of a cylindrical boiler 5 ft. in diameter with a wall thickness of 1/2 in. The boiler is subjected to an internal gage pressure of 155 psi. (9300 psi, 4650 psi)

3. Calculate the internal water pressure that will burst a 15 in. diameter cast-iron water pipe if the wall thickness is 1/2 in. Use an ultimate tensile strength of 62,500 psi. for the pipe. (8333 psi)

4. Calculate the wall thickness required for a 5 ft. diameter cylindrical steel tank containing gas at an internal gage pressure of 600 psi. The allowable tensile stress for the steel is 17,500 psi. (1.03")

5. A spherical gas container, 50 ft. in diameter, is to hold gas at a pressure of 40 psi. Calculate the thickness of the steel wall required. The allowable tensile stress is 20,000 psi. (.3")

6. Calculate the tensile stresses (circumferential and longitudinal) developed in the walls of a cylindrical pressure vessel. The inside diameter is 15 in. The wall thickness is 1/4 in. The vessel is subjected to an internal gage pressure of 450 psi. and a simultaneous external axial tensile load of 45,000 lb. (13,500 psi, 10,570 psi)

7. A thin wall pressure vessel is composed of two spherical regions and a cylindrical region is shown in Diagram 5.

The larger spherical region has a radius of 3 ft and a wall thickness of 1.25". The smaller spherical region has a radius of 2.5 ft and a wall thickness of 3/4". The cylindrical region has a radius of 2 ft and a wall thickness of 1/2".

Determine the axial and hoop stress in the cylindrical region, and the wall stresses in the two spherical regions. Which stress is the largest? (1: 5,760 psi, 2: 19,200 psi, 9600 psi, 3: 8,000 psi)

8. A thin wall pressure vessel is composed of two spherical regions and is shown in Diagram 4. The larger spherical region has a radius of 3 ft , and the smaller spherical region has a radius of 2.5 ft. The vessel is made of steel with an allowable tensile stress of 24,000 lb/in².

If we wish the maximum stress in both spherical sections to at the allowable stress, Determine wall thickness for each spherical region.(.45", .375")