Abstract
Fatigue assessment is an important step during the design of automotive structural parts. For weight saving reasons, aluminium alloy components are now developing rapidly in suspension parts and an appropriate fatigue life prediction is necessary. Cradles or axles are often made with extrusions, rolled products and cast parts which are joined by arc welding. Individual component parts are checked under complex loads using multiaxial criterions but welded joints should be calculated in a different way. This paper presents a fatigue life prediction method for aluminium welded components based on the hot spot stress concept.
Hot spot stresses are principal stresses in the welded joint, provided by finite element calculations on the whole aluminium component using some special meshing rules. The method also needs the knowledge of a single S-N curve associated with the industrial process and depending only on the applied load. The results of finite element calculations and the use of the S-N curve allow the fatigue life prediction of the aluminium welded component. The validation of this hot spot approach on aluminium alloys and some examples of applications are described.