The analysis has been done on behalf of ABB Ventilation Products AB (now Fläkt Woods AB). The fan is modelled by solid elements. The various parts are coupled together with the aid of contact conditions taking into account both static and dynamic friction. The pre-tension, of the various bolted connections, is included in the analysis.

The stress state, at several rpm settings, has been calculated as basis for sizing with respect to fatigue.

The figure shows the distribution of stress, for a particular setting of rpm and blade angle.

Keywords: Fläkt Woods AB, FE-analysis, PERMAS, MEDINA, rotor, fan blade, pre-tension of bolt, fatigue analysis