Question

Question 3 A typical load case for a cylindrical pressure vessel which is on the back of a truck is estimated to include the d 1.5 m t10 mm internal pressure of p = 2 MPa torsion of and a p = 2 MPa T= 1000 kNm. The internal diameter of the pressure vessel is 1.5 m and the wall thickness is 10 mm. The vessel is made of steel with a yield stress of Sy = 400 MPa Based on a yield failure criteria determine the factor of safety for this load case. What other failure modes should you consider in assessing the likely failure of this pressure vessel? End-capped pressure vessel (Polar moment of inertia for a circle, J= nd*/32)

Answer 1

First compute the hoop stress and longitudinal stress in the wall of the vessel,

Page No. Heop ztren of 0eN15x) the ua th ves 3 2 .SX0N mm 15o N Anial lonpitudaheers, N St mm

Now compute the torsional shear stress,

Tonsional hua stus Page No. Date TD/e T = T(D:/22 7T 32 16TD; [D. D 16T D 3 2 T D 16 T T- +8 0 T-16T

Page No Date t- 8Dt 2T 7T D 23 SOlolx0aX R8.3N 2 t)

Now draw all stresses on element of the cylinder,

t-1om Aukoment P2MPA 1-5m lement A Oa レて

Now calculate the principle stresses for this element A,

Date fn dling the Valu ofprinapal steses ,2+ 2 150-751 2r3) 150 t 75 2 2 hH2.5+67.5)+3) 112-5 +46.98 153 48 1]

+ 9a +T 2 112-5- 46.98 th-

Now factor of safety is calculated below for yield stress criteria,

Thuy Lactar efsafey A1

Factor of safety is 2.5 for yield stress criteria.

Now, one can also use distortion energy theory for this problem as a failure theory.

Factor of safety is calculated for distortion energy failure criteria,

According to Diotoahion eney thoy 2

Sy fros 151.48t6552-59.45 2 4o0138-84 fos

Fos is 2.88 distortion energy failure criteria.