Swaging is one method of autofrettage, a means of prestressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed along and through the bore of the tube. A finite element (FE) model of the swaging process, developed previously by the author in ANSYS, was configured for comparison with an earlier model; this allowed the accuracy of further properties of the ANSYS model to be investigated. Driving force was the main property of interest, specifically how it varied with mandrel slopes and parallel midsection, to allow direct comparison with the earlier model. The variation of driving force with respect to coefficient of friction was investigated; driving force increased in near proportion, but a subtle trend indicated a further study of stress component be made. This was followed by a two-pass swage process. Close agreement was found with empirical data and the discrepancies observed between the two models are explained by the relatively coarse mesh used by the earlier model. This further verifies the sensitivity of the model described here.

References

1.
de Matos
,
P. F. P.
,
Moreira
,
P. M. G. P.
,
Camanho
,
P. P.
, and
de Castro
,
P. M. S. T.
, 2005, “
Numerical Simulation of Cold Working of Rivet Holes
,”
Finite Elements in Analysis and Design
,
41
(
9–10
), pp.
989
1007
.
2.
de Matos
,
P. F. P.
,
Moreira
,
P. M. G. P.
,
Pina
,
J.
,
Dias
,
A. M.
, and
de Castro
,
P. M. S. T.
, 2004, “
Residual Stresses Around an Expanded Hole in an Aluminum Clad Sheet
,”
Proceedings of the 7th International Conference on Residual Stress (ICRS7)
,
CD ROM, Xi’an
,
China
, June
14
16
.
3.
Gibson
,
M. C.
,
Hameed
,
A.
, and
Hetherington
,
J. G.
, 2009, “
Investigation of Residual Stress Development During Swage Autofrettage, Using Finite Element Analysis
,”
Proceedings of the ASME 2009 International Mechanical Engineering Congress and Exposition (IMECE2009)
, Nov. 13–19,
Lake Buena Vista
,
Florida
, Paper No. IMECE2009-13289.
4.
O’Hara
,
G. P.
, 1992, “
Analysis of the Swage Autofrettage Process
,”
Benét Laboratories
,
Watervliet Arsenal
,
NY
, US Army ARDEC Technical Report No. ARCCB-TR-92016.
5.
Iremonger
,
M. J. I.
, and
Kalsi
,
G. S.
, 2003, “
A Numerical Study of Swage Autofrettage
,”
J. Pressure Vessel Technol.
,
125
(
3
), pp.
347
351
.
6.
ANSYS Contact Technology Guide, ANSYS Release 11.0 Documentation, ANSYS, Inc.
7.
Bihamta
,
R.
,
Movahhedy
,
M. R.
, and
Mashreghi
,
A. R.
, 2007, “
A Numerical Study of Swage Autofrettage of Thick-Walled Tubes
,”
Mater. Des.
,
28
, pp.
804
815
.
8.
1974, Tribology article, Encyclopædia Britannica, Vol.
11
.
9.
Gibson
,
M. C.
, 2008, “
Determination of Residual Stress Distributions in Autofrettaged Thick-Walled Cylinders
,” Doctoral Thesis, Cranfield University, Shrivenham, United Kingdom.
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