Types of cylinder

1 THICK CYLINDER

2 THIN CYCLINDER

1. SHANTILAL SHAH ENGINEERING COLLEGE BRANCH :- MECH(5 th ) Subject :- Design of machine element NAME ENROLLMENT NO CHAVDA MAYUR 170433119006 DOSHI PARAS 170433119008 GUIDED BY :- B.D.UPADHYAY

2. TYPES OF CYLINDER 1 THICK CYLINDER 2 THIN CYCLINDER

3. THIN CYLINDER • If the wall thickness of the cylinder is less than 1/20th of the internal diameter ‘ di’,the variation of the tangential stresses through the wall thickness is small & the radial stresses may be neglected. The solution can be then treated as statically determinate & the vessel is said to be thin pressure vessel. Thus a thin pressure vessel is one whose thickness to inner radius ratio is not greater than 1/10.

4. TYPES OF STRESS Circumferential or Hoop Stress : The stress which resists the failure of thin cylinder along the circumference is called circumferential stress or hoop stress. It is given by formula  

5. Longitudinal Stress : The stress which resists the failure of cylinder in longitudinal direction is called longitudinal stress. It is given by formula        From the two equations it is obvious that the circumferential stress is TWICE the longitudinal stress.  

6. THICK CYLINDER   A cylinder is said to be 'THICK' if the ratio of its inner diameter to the thickness of wall is less than 20. Examples are Hydraulic cylinders, high pressure pipes and gun barrels.

7. TYPES OF STRESS Tangential stress.(Highest magnitude at inner surface an gradually decreases towards outer surface) Radial stress. (This is neglected in thin cylinders) Axial or longitudinal stres s.

8. LAMIS THEROM E Lame's equation is used to find the thickness of the thick cylinder subjected to internal pressure, It is given by, Where, t= thickness of thick cylinder Di= Internal diamter of thick cylinder,  = Allowable tensile stress in the material of thick cylinder Pi= Internal pressure in the thick cylinder. Use of Lame's Equation : Lame's equation is based on maximum principal stress theory of failure, as this theory is more suitable for brittle materials, Lame's equation is also applicable to brittle materials like Cast i ron or Cast Steel.

9. DIFFERENCE BETWEEN THICK & THHI CYLINDER Thick Cylinder Thin Cylinder 1.Circumferential stress varies along the thickness of the shell. 1. Circumferential stress ‘f’ is constant throughout the thickness of the shell. 2. Radial stress is no longer negligible since a thick cylinder is required to have a heavy internal pressure 2.Radial stress ‘p’ is negligible in comparison of ‘f’ and ‘f0  

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