Two mark Questions and Answers

TWO MARK QUESTIONS AND ANSWERS

1. When will you call a cylinder as thin cylinder?

A cylinder is called as a thin cylinder when the ratio of wall thickness to the diameter of cylinder is less than 1/20.

2. In a thin cylinder will the radial stress vary over the thickness of wall?

No, In thin cylinders radial stress developed in its wall is assumed to be constant since the wall thickness is very small as compared to the diameter of cylinder.

3. What is the ratio of circumferential stress to longitudinal stress of a thin cylinder? 

4. In a thin cylinder maximum principle stress is ―――― .

Circumferential stress.

5. In a thin cylinder the maximum shear is ―――― .

6. For the thin cylinder, write down the equation for strain along the circumferential direction.

7. For a thin cylinder, write down the equation for strain along the longitudinal direction.

8. Write down the expression for hoop stress in thin cylinder due to internal pressure p.

9. Write the expression for longitudinal stress in thin cylinder due to internal pressure p.

10. For a thin cylinder, write down the expression for volumetric strain.

11. What is the circumferential stress in a thin spherical shell subjected to internal pressure 'p'.

12. Write down the volumetric strain in a thin spherical shell subjected to internal pressure ‘p'.

13. Write the circumferential strain in thin spherical shell.

14. In a thin cylindrical shell if hoop strain is 0.2 × 10-3 and longitudinal strain is 0.05 × 10-3, find out volumetric strain.

15. Differentiate between thin cylinder and thick cylinder.

Thin cylinder

1. Ratio of wall thickness to the diameter of cylinder is less than 1/20.

2. Circumferential stress is assumed to be constant throughout the wall thickness.

Thick cylinder

1. Ratio of wall thickness to the diameter of cylinder is more than 1/20.

2. Circumferential stress various from inner outer wall thickness.

16. Distinguish between cylindrical shell and spherical shell. 

Cylindrical shell

1. Circumferential stress is twice the longitudinal stress.

2. It withstands low pressure than spherical shell for the same diameter.

Spherical shell

1. Only hoop stress presents. 

2. It withstands more pressure than cylindrical shell for the same diameter.

17. Write the equation for the change in diameter and length of a thin cylinder shell, when subjected to an internal pressure.

18. What is the effect of riveting a thin cylindrical shell?

Rivetting reduces the area offering the resistance. Due to this, the circumferential and longitudinal stresses are more. It reduces the pressure carrying capacity of the shell.

19. In thin spherical shell, volumetric strain is ―――― times the circumferential strain. 

Three

20. What do you understand by the term wire winding of thin cylinder?

In order to increase the tensile strength of a thin cylinder to withstand high internal pressure without excessive increase in wall thickness, they are sometimes pre-stressed by winding with a steel wire under tension.