As threaded connections are submitted to variable loading they can suffer from fatigue. The objective of this project was to analyse the critical geometric factors affecting the fatigue resistance and to develop adequate testing equipment.


To study the fatigue resistance of welded and threaded pipe joints, a large scale resonant bending test was developed. Finite element simulation of the threads using parametric modelling was used to optimise the geometry. Stress concentration factors and critical positions were determined.


The critical locations for fatigue were determined and confirmed by experiments. The large scale resonant bending test proved to be valuable test equipment.