Title of Work Package:
Finite element analysis of fatigue crack growth in welded tubular connections - WP5 of program HiPERCRACK.
European Union - program "Growth"
SENER Ingenieria y Sistemas SA, Bilbao, Spain
Centro Ricerche Fiat SCPA, Torino, Italy
Volvo Aero Corporation, Sweden
MSC Software Gmbh, France
SEMTECH SA, Belgium
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:
12 months (2002 - 2003)
Figure 1: Stress distribution in a DT welded tubular connection under an axial load in one brace.
Figure 2: Experimental set up of fatigue test on a double T (DT) welded tubular connection.
Figure 3: Fatigue experiment on a tubular DT joint. Symmetry of joint configuration.
Figure 4: Fatigue experiment on a tubular DT joint. Crack direction through the chord thickness.
Figure 5: Finite element mesh of the two-dimensional representation of the welded tubular DT connection.
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 7: Deformed mesh of the welded tubular DT connection, after crack has been developed through the thickness; cycle number N=76.
Figure 8: Failure of elements (crack propagation) in terms of load cycles.