Physical and Geometrical Non-Linearities in Contact Problems of Elastic Turbine Blade Attachments

Abstract

The paper presents briefly the theoretical basis of linear and non-linear contact problems of linear elasticity as applied to the kinetostatic analysis of turbomachinery blade attachments. The physical and geometrical non-linearities of the problem are due to friction and unilateral constraints respectively. For three classes of contact problems finite element calculations of a real fir-tree turbine blade attachment with and without clearances within the contact surfaces are performed. The results for effective stresses of the root and disc hooks are thoroughly analysed and compared. Furthermore, the results for contact node status and nodal slips between the blade root and the disc sector are presented. The significance of the physical and geometrical non-linearities to the stress, displacement and contact states of the attachment is then discussed.