Abstract:
This study addresses the fatigue life of the head–to–skirt welds of tall distillation columns.
Fatigue tests were done on two types of weld geometries which approximate the head–toskirt
configurations. From the fatigue tests it was determined that the fatigue life of the
experimental samples can be substantially improved by applying weld build–up between
the head and the skirt.
The expected fatigue life of the test samples was determined by way of calculation
employing the so called Nominal–Stress–Approach, the Effective–Notch–Stress–Approach
and the Stress–Life–Approach.
For both the Nominal–Stress–Approach and the Effective–Notch–Stress–Approach the
predicted fatigue life was found to be overly conservative compared to the experimental
results. The Stress–Life–Approach predicted the fatigue life to within a factor of 1.3 for
both the geometries under investigation when displacements due to welding are taken
into account. If displacements due to welding is omitted this factor is increased, for the
geometry without weld build–up, to 2. For the geometry with weld build–up the factor
remains 1.3.
