autofrettage in pressure vessels
TRANSCRIPT
-
8/19/2019 Autofrettage in Pressure Vessels
1/28
Autofrettage in pressure
vessels
-
8/19/2019 Autofrettage in Pressure Vessels
2/28
Residual stress analysis of Autofrettaged thick-walledspherical pressure vessel
•
Results are obtained by developing an extension of variable materialproperties (VMP) method ( Find out the Autofrettaged stress and strains byusing the formula).
• By performing a parametri study! the optimum autofrettage pressure andorresponding autofrettage per ent for reating desirable residual stress
state are introdu ed and determined.•
"he modi# ation ma$es VMP method appli able for analyses of spheri alvessels based on a tual material behavior both in loading and unloadingand onsidering variable Baus hinger e%e t.
• &n addition! the optimum pressure for autofrettage of the spheri al pressurevessels made of A' and *B' steels is dis ussed here.
-
8/19/2019 Autofrettage in Pressure Vessels
3/28
Residual stress analysis of Autofrettaged thick-walledspherical pressure vessel
Boundary conditions:
The maximum applied working pressure for A723 steel. the maximum internal pressure without causingyielding! is
The yield strength of A723 steels are considered ""3#$%a.
+,- MPa
outer radius/inner radius+
-
8/19/2019 Autofrettage in Pressure Vessels
4/28
Residual stress analysis of Autofrettaged thick-walledspherical pressure vessel
• &y using the 'ame(s e)uations for calculating the hoop stress* radial stress* along thethickness of the cylinder* when the ends of the cylinder are open and unconstrained so that thecylinder is in a condition of plane stress.
• "he radial displa ement is
-
8/19/2019 Autofrettage in Pressure Vessels
5/28
Residual stress analysis of Autofrettaged thick-walledspherical pressure vessel
Calculation of autofrettage pressure (Pa):0et 1n2 be denoted as the ratio of operating pressure to yield stress.
0et 1m2 be the ratio of Autofrettaged radius to inner radius
3in e! the value of autofrettaged radius 4as not found! an e5uation
4hi h gives a relation bet4een 1n2 and 1m2 4as used to found thevalue of 1m2 based on von Misses riterion.
+ .,-
-.,-
-
8/19/2019 Autofrettage in Pressure Vessels
6/28
Residual stress analysis of Autofrettaged thick-walledspherical pressure vessel
+67 MPa
Determination of autofrettaged radius (ρ)
Calculation of maximum von-Mises stress (σvon-max)
-
8/19/2019 Autofrettage in Pressure Vessels
7/28
F8M A9A0:3&3
;A< Model and F8 model=
Slno
Speci cations value
-
-
8/19/2019 Autofrettage in Pressure Vessels
8/28
Bi and Multi linear stress strainurve=
-
8/19/2019 Autofrettage in Pressure Vessels
9/28
Boundary ondition
Pressure is applied ,- MPaA : axis free! Both !C axis #xedB axis free! Both :!C axis #xed
-
8/19/2019 Autofrettage in Pressure Vessels
10/28
linear isotropi Results=•
Pressure is applied for - y le.
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
11/28
axial stress*oop stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
12/28
Bilinear isotropi Results=•
Pressure is applied for - y le.
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
13/28
*oop stressAxial stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
14/28
Bilinear isotropi Results=•
Pressure is applied for ' y le.
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
15/28
*oop stressAxial stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
16/28
Bilinear isotropi Results=•
Pressure is applied for ' y le 4ithD extra.
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
17/28
*oop stressAxial stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
18/28
Bilinear isotropi Results=•
Pressure is applied for ' y le 4ith?D extra.
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
19/28
*oop stressAxial stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
20/28
Multi linear isotropiResults=
•
Pressure is applied for - y le.
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
21/28
Axial stress*oop stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
22/28
Multi linear isotropiResults=
• Pressure is applied for ' y le 4ithautofrettage .
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
23/28
Axial stress*oop stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
24/28
Multi linear isotropiResults=
• Pressure is applied for ' y le 4ith Dautofrettage .
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
25/28
Axial stress*oop stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
26/28
Multi linear isotropiResults=
• Pressure is applied for ' y le 4ith ? Dautofrettage .
• 85uivalent stress=
-
8/19/2019 Autofrettage in Pressure Vessels
27/28
Axial stress*oop stress
Radial stress
-
8/19/2019 Autofrettage in Pressure Vessels
28/28
;on lusion• "he residual stress distribution indu ed in autofrettaged spheri al
pressure vessels made of A' steels! based on their a tual
behavior in loading and unloading 4as evaluated by numeri almethod (Bilinear and multilinear analysis).• &t 4as investigated that usage of isotropi hardening model in
analysis leads to signi# ant overestimation in residual hoop stress.• "he autofrettage per ent by 4hi h high ompressive and relatively
lo4 tensional hoop residual stress are simultaneously attainablenear the inner and outer radii of the vessel 4as introdu ed as theoptimum per entage of autofrettage.
• &t 4as observed that in the ase of A' spheri al vessel 4ithradius ratio of ! by in reasing autofrettage per ent up to ? D!the inner ompressive hoop residual stress de reases and the
outer hoop tensional stress gradually in reases (Both in bilinearand multilinear analysis.