Thick Cylindrical vessel-3 Pre-stresses Refer to Fig. below: Fig. Pre-stresses Fig. Resultant stress variation PRE-STRESSES (due to hoop shrinking) Stress AB = –2psr22/ (r22 –r12) compressive Stress CD = ps(r32+r22)/ (r32 –r22) Tensile STRESSES DUE TO FLUID PRESSURE Stress AA’ = p((r32+r12)/ (r32 –r12) Stress CC’ = […]
Radial deflection-thick shell Hoop shrinking Hot Outer cylinder (called the jacket with radii as r2 and r3) is put on to the inner cylinder (with radii as r1 and r2). Then it is allowed to cool. A pressure will be developed both on the jacket and the cylinder. Let ps is the shrinkage pressure developed […]
Thick Cylindrical Shell-2 1. Only internal pressure pi is there and po =0 σhmax = [pi(ri2+ro2]/ (ro2 –ri2) σhmax > pi σr max = pi σhmax > σr max Both σhmax and σr max occur at the innermost radius and σhmax is always greater than the σr max. This shown in the Fig. This […]
LAME’S EQUATIONS Lame’s Equations are σh = β/r2 + α σr = β/r2 – α Where α and β are Lame’s constants There is a thick vessel subjected to internal fluid pressure pi at the inner radius ri and external fluid pressure po at the outer radius ro respectively. We want to find the equations […]
Thick shell-1 We have already learnt about thin shells where stresses are assumed to be uniform in the thickness of the vessel. i.e. stresses at the inner or outer radius are same. There is no variation of hoop stress, longitudinal stress and radial stress. However when pressure is high, thin walled vessels cannot be used. […]
mcq- Thin And Thick Shells-2 Which one is most important in a thin shell? d/t <20 d/t> 10 Stresses are uniform None (Ans:c) Hoop strain in a thin shell is σh /E σl /E 3 σh /E None (Ans:d) Longitudinal strain in a thin shell is σh /E σl /E σr /E None (Ans:d) […]
Mcqs: Thin-thick shells-1 A vessel is said to be thin if Its wall has less thickness Stresses are uniform over the entire thickness Stresses vary at inner and at outer radius None of the above (Ans:b) In a thin vessel, the true ratio of D/t is D/t =20 D/t=10 D/t >20 D/t >10 (Ans:c) Hoop […]
Short Interview Question Answers– Thin and thick shells What is a thin sell? where D/t > 20 and where stress are uniform from the inner surface to the outer surface of the shell. What are the various types of thin shells? Two types: (i) Cylindrical like a pipe (ii) Spherical like a ball What is […]