Numerical and Experimental Investigation of the Rotor Blade Joint

The paper presents an experimental and numerical study of the tapered socket of the aluminum blade root of the mine main ventilation fan, which is based on the tests of a simplified full-scale model with a discarded airfoil and its subsequent finite element analysis. The calculation model takes into account elastoplastic properties of materials and non-linear contacts with friction. The proposed joint consists of an aluminum tapered blade root, two steel retainers with similar tapered surfaces, and two steel bolts that join the retainers around the root. Pre-tightening the bolts is taken into account in the nonlinear static finite element analysis of the elastoplastic behavior of the structure which allows determining the destructive loads that cause the bolts to break with the subsequent disconnection of the fasteners and the blade to fly out of the seat. The graphs of the von Mises equivalent stresses indicate that the maximum stresses are reached in the working part of the bolts, which fully corresponds to the nature of the destruction of the structure upon reaching the maximum equivalent load on it. The experimental study confirms the correctness of the determination of contact stresses at the tapered socket location. Correspondence of the results of the static analysis with the results of the full-scale experiment makes it possible to draw a conclusion about the correctness of the conducted finite element modelling.