Currently, in the oil and gas industry, finite element method (FEM)-based commercial software (such as ANSYS and abaqus) is commonly employed for determining the stress intensity factor (SIF). In their earlier work, the authors proposed an adaptive Gaussian process regression model (AGPRM) for the SIF prediction of a crack propagating in topside piping, as an inexpensive alternative to FEM. This paper is the continuation of the earlier work, as it focuses on the experimental validation of the proposed AGPRM. For validation purposes, the values of SIF obtained from experiments available in the literature are used. The experimental validation of AGPRM also consists of the comparison of the prediction accuracy of AGPRM and FEM relative to the experimentally derived SIF values. Five metrics, namely, root-mean-square error (RMSE), average absolute error (AAE), mean absolute percentage error (MAPE), maximum absolute error (MAE), and coefficient of determination ($R2$), are used to compare the accuracy. A case study illustrating the development and experimental validation of the AGPRM is presented. Results indicate that the prediction accuracy of AGPRM is comparable with and even higher than FEM, provided the training points of AGPRM are chosen aptly. Good prediction accuracy coupled with less time consumption favors AGPRM as an alternative to FEM for SIF prediction.

## References

1.
Keprate
,
A.
,
Ratnayake
,
R. M. C.
, and
Sankararaman
,
S.
,
2017
, “
Minimizing Hydrocarbon Release From Offshore Piping by Performing Probabilistic Fatigue Life Assessment
,”
Process Saf. Environ
,
106
, pp.
34
51
.
2.
Det Norske Veritas (DNV)
,
2010
, “
Risk Based Inspection of Offshore Topsides Static Mechanical Equipment
,” DNV aS, Høvik, Norway, Standard No.
DNV-RP-G101
.https://rules.dnvgl.com/docs/pdf/DNV/codes/docs/2010-10/RP-G101.pdf
3.
Energy Institute (EI)
,
2007
,
Guidelines for the Avoidance of Vibration Induced Fatigue Failure in Process Pipework
,
The Energy Institute
,
London
.
4.
Keprate
,
A.
, and
Ratnayake
,
R. M. C.
,
2017
, “
Generic Approach for Risk Assessment of Offshore Piping Subjected to Vibration Induced Fatigue
,”
ASCE-ASME J. Risk Uncertainty Eng. Syst., Part B
,
4
(
2
), p. 021006.
5.
Naess
,
A. A.
,
2009
,
Fatigue Handbook: Offshore Steel Structures
,
Tapir Publisher
,
Trondheim, Norway
, Chap. 3.
6.
Keprate
,
A.
,
Ratnayake
,
R. M. C.
, and
Sankararaman
,
S.
,
2017
, “
Adaptive Gaussian Process Regression as an Alternative to FEM for Prediction of Stress Intensity Factor to Assess Fatigue Degradation in Offshore Piping
,”
Int. J. Pressure Vessels Piping
,
153
, pp.
45
58
.
7.
Keprate
,
A.
,
Ratnayake
,
R. M. C.
, and
Sankararaman
,
S.
,
2017
, “
Comparison of Various Surrogate Models to Predict Stress Intensity Factor of a Crack Propagating in Offshore Piping
,”
ASME J. Offshore Mech. Arct.
,
139
(
6
).
8.
McFarland
,
J. M.
,
2008
, “
Uncertainty Analysis for Computer Simulations Through Validation and Calibration
,”
Ph.D. dissertation
, Vanderbilt University, Nashville, TN.https://pdfs.semanticscholar.org/33b8/30209e2d5d52f050d2ec6eb4b8ff490dd01a.pdf
9.
Sankararaman
,
S.
,
2012
, “
Uncertainty Quantification and Integration in Engineering Systems
,” Ph.D. dissertation, Vanderbilt University, Nashville, TN.
10.
Tamimi
,
A. A.
,
2014
, “
Improved Probabilistic Life Estimation in Engineering Structures. Modelling Multi-Site Fatigue Cracking
,”
Ph.D. dissertation
, University of Maryland, College Park, MD.https://drum.lib.umd.edu/handle/1903/16092
11.
Newman
,
J. C.
, and
Raju
,
I. S.
,
1981
, “
An Empirical Stress Intensity Factory Equation for the Surface Crack
,”
Eng. Fract. Mech.
,
15
(
1–2
), pp.
185
192
.
12.
Rooke
,
D. P.
,
Baratta
,
F. I.
, and
Cartwright
,
D. J.
,
1981
, “
Simple Methods of Determining Stress Intensity Factors
,”
Eng. Fract. Mech.
,
14
(
2
), pp.
397
426
.