UNIT 4

QUESTIONS

1. What is thin cylinder? Give practical examples of thincylinder.
2. What is thick cylinder? Give practical examples of thickcylinder.
3. What is autofretteage? Explain any one method of pre-stressing the cylinder.
4. Derive Lame’s theory.
5. Derive Clavarino’s and Bernies’s equation and state its applicability.
6. Discuss the classification of unfired pressure vessels based on IS 2825 : 1969
7. Explain various categories of welded joints.
8. An air receiver, consisting of a 500 mm diameter cylinder closed by hemispherical ends, is made of steel FeE 200 and the factor of safety is 2.5. The operating pressure is limited to 3 MPa. Treating the receiver as a thin cylinder, calculate the thickness of the cylinder wall and the hemispherical ends. Neglect the effect of weldedjoints.
9. Acylinderwithinnerdiameterof300mmand internal pressure of 1 MPa is closed by a cast iron cover with 12 bolts of 25 mm nominal diameter.Theratioofstiffnessofthebolt(kb) tothecombinedstiffness(kc)ofthetwoflanges and the asbestos gasket is 1.5. The initial pre-load of each bolt is 10 kN. Determine the maximumtensileloadoneachbolt.
10. A pressure vessel consists of a cylindrical shell with an inside diameter of 1650 mm, which is closed by torispherical heads with   a crown radius of 1300 mm. The operating pressure inside the vessel is 1.5 MPa. The yield strength of the material used for the shell and head is 255 N/mm2 and the weld joint efficiency may be assumed to be 0.8. The corrosion allowance is 2 mm.Determine the thickness of the cylindrical shell and the torispherical head.
11. A cast iron pipe used in a hydraulic circuit is subjected to an internal pressure of 50 MPa. The inner and outer diameters of the pipe are 20 mm and 40 mm respectively. Determine the distribution of principal stresses across the pipe thickness.

12. A pressure vessel, subjected to a design pressureof0.75MPa,consistsofacylindrical shell with 2 m inside diameter and 10 mm thickness. An opening with inner diameter of 300 mm and wall thickness of 10 mm is providedintheshell.Thecorrosionallowance is2mmandtheweldjointefficiencyistaken as 0.85. The extension of the opening inside the shell is 15 mm. The yield strength of the material used for the shell and the opening is 210 N/mm2. A reinforcing pad made of a 10mmthickplateisprovidedfortheopening. Determine the inner and outer diameters of the pad.