Machine Design Multiple Choice Questions on “Cylinder Pressure Vessels”.
1. A cylinder is considered thin when the ratio of inner diameter to wall thickness is more than 5.
a) True
b) False
Answer: b
Clarification: A cylinder is considered thin when the ratio of inner diameter to wall thickness is more than 15.
2. Tangential stress in a cylinder is given by [symbols have their usual meanings].
a) PD/2t
b) 2PD/t
c) PD/4t
d) 4PD/t
Answer: a
Clarification: Considering equilibrium in half portion of cylinder of unit length, DP=2σt.
3. Longitudinal stress in a cylinder is given by [symbols have their usual meanings].
a) PD/2t
b) 2PD/t
c) PD/4t
d) 4PD/t
Answer: c
Clarification: Considering equilibrium PxπD²/4=σxπDt.
4. A seamless cylinder of storage capacity of 0.03mᵌis subjected to an internal pressure of 21MPa. The ultimate strength of material of cylinder is 350N/mm².Determine the length of the cylinder if it is twice the diameter of the cylinder.
a) 540mm
b) 270mm
c) 400mm
d) 350mm
Answer: a
Clarification: 0.03=πd²L/4 and L=2d.
5. A seamless cylinder of storage capacity of 0.03mᵌis subjected to an internal pressure of 21MPa. The ultimate strength of material of cylinder is 350N/mm².Determine the thickness of the cylinder if it is twice the diameter of the cylinder.
a) 12mm
b) 4mm
c) 8mm
d) 16mm
Answer: c
Clarification: t=PD/2σ.
6. Cylinder having inner diameter to wall thickness ratio less than 15 are
a) Thin cylinders
b) Thick Cylinders
c) Moderate cylinders
d) None of the listed
Answer: b
Clarification: Smaller dia to thickness ratio implies more thickness and hence these are classified under thick cylinder.
7. Lame’s equation used to find the thickness of the cylinder is based on maximum strain failure.
a) True
b) False
Answer: b
Clarification: It is based on maximum principal stress theory.
8. Lame’s equation is generally used for ductile materials.
a) True
b) False
Answer: b
Clarification: Lame’s equation is used to determine thickness of the brittle as it used principal stress theory.
9. The piston rod of a hydraulic cylinder exerts an operating force of 10kN. The allowable stress in the cylinder is 45N/mm². Calculate the thickness of the cylinder using Lame’s equation. Diameter of the cylinder is 40mm and pressure in cylinder is 10MPa.
a) 2.05mm
b) 4.2mm
c) 5.07mm
d) None of the listed
Answer: c
Clarification: t=D/2[√[σ+ P /σ-P] -1 ].
10. The piston rod of a hydraulic cylinder exerts an operating force of 10kN. The allowable stress in the cylinder is 70N/mm². Calculate the thickness of the cylinder using Clavarinoe’s equation. Diameter of the cylinder is 240mm.μ=0.3 and pressure in cylinder is 15MPa.
a) 35mm
b) 30mm
c) 27mm
d) None of the listed
Answer: c
Clarification: t=D/2[√[σ+(1-2μ) P /σ-(1+μ)P] -1 ].