Title of Work Package:

Finite element analysis of fatigue crack growth in welded tubular connections - WP5 of program HiPERCRACK.


European Union - program "Growth"



Contract No.:



SENER Ingenieria y Sistemas SA, Bilbao, Spain
Centro Ricerche Fiat SCPA, Torino, Italy
Volvo Aero Corporation, Sweden
MSC Software Gmbh, France
NCode International Linited, UK
Institute of Technical Seismology and Earthquake Engineering, Thessaloniki, Greece (ΙΤΣΑΚ)
Universidad Pontificia Comillas, Madrid, Spain
Dept. of Mechanical & Industrial Engineering, U. of Thessaly (subcontractor)


The program is aimed at developing a finite element formulation for the rigorous analysis of metal members and structures. The formulation is based on the "cohesive" elements. These elements operate in a finite element framework, and simulate the crack zone. To model fatigue damage due to cyclic load, an extrapolation algorithm is developed for increasing the computational efficiency of the numerical method.

In the specific Work Package (WP5), the above finite element technique is employed for the simulation of fatigue crack growth in welded tubular connections, a application of major interest for offshore joints in offshore platforms. The results from the present WP are aimed at simulating previous experimental observations, as well as assessing the efficiency and conservativeness of existing design tools, based on simplified analysis and design methods.

Principal Investigator for U. of Thessaly:

Spyros A. Karamanos

Total Budget :

Budget for Univ. of Thessaly:

15,000 Euros


12 months (2002 - 2003)


Figure A4 1

Figure 1: Stress distribution in a DT welded tubular connection under an axial load in one brace.

Figure A4 2
Figure 2: Experimental set up of fatigue test on a double T (DT) welded tubular connection.

Figure A4 3
Figure 3: Fatigue experiment on a tubular DT joint. Symmetry of joint configuration.

Figure A4 4
Figure 4: Fatigue experiment on a tubular DT joint. Crack direction through the chord thickness.

Figure A4 5
Figure 5: Finite element mesh of the two-dimensional representation of the welded tubular DT connection.

Figure A4 6
Figure 6: Finite element mesh of the two-dimensional representation of the welded tubular DT connection.
Area around the weld, where fatigue crack develops.

Figure A4 7
Figure 7: Deformed mesh of the welded tubular DT connection, after crack has been developed through the thickness; cycle number N=76.

Figure A4 8
Figure 8: Failure of elements (crack propagation) in terms of load cycles.

Spyros A. Karamanos, PhD

Department of Mechanical Engineering | University of Thessaly | Pedion Areos, Volos 38334, Greece
Phone: +30 - 24210 74086, 74360 | Fax : +30 - 24210 74360 | Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

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