Fatigue Design of Light-Alloy Butt Welds: Validation Tests for a Proposed Check Procedure

The structures of a ship are in general subjected to cyclic loads but their complexity makes it difficult to perform reliable predictions of their fatigue life. On the other hand it is certainly advisable to get trustworthy information on the subject already from the early design stage. Recently particular attention has been given to the problems of fatigue in relation to the ever growing use of light alloys in the construction of cruise vessels and fast passenger or ro-pax ships. This paper deals with fatigue problems of light-alloy welds. An empirical relationship to concisely correlate the cumulated fatigue damage to the fatigue capability of the structural detail and the load history – which are synthesized through proper parameters – has been found. The influence of the welding technology on the fatigue strength of the joints has been investigated through measurements on actual welds made in accordance with the usual shipbuilding practice.