Contact Stresses in Dovetail Attachments: Alleviation via Precision Crowning

Abstract

Previous studies of contact stresses in dovetail attachments provide verified finite element stresses as well as some simple physical models of such stresses. Generally there is good agreement between the finite element analysis and the simple physical models. Together the two identify a pinching mechanism as leading to large fluctuations in hoop stresses at the edges of contact. These fluctuating hoop stresses can be expected to be a major contributor to the fatigue of dovetail attachments. The present study investigates a method of alleviating the fluctuating hoop stresses. This method entails crowning of the contacting flat on a blade. Such crowning is in two orthogonal directions on the blade flat. Two-dimensional finite element analyses are made in both directions. These analyses indicate that significant reductions in fluctuating hoop stresses can be achieved by the method, provided the crowning is controlled sufficiently precisely.

Cyclic plastic behavior of dovetail under fretting load

“…Nevertheless, the FEM has become the most adaptable method to calculate the contact stress accurately for non-conforming contact produced by the complex configuration and loading condition. Sinclair gave the contact stresses in dovetail assemblies [10][11][12], their results show that there are high stress gradients at the edge of contact zone for traditional dovetail assemblies, and the solution accuracy is dependent on the density of FE mesh. It is accepted that we should pay more attention to the computational meshes when using numerical methods, i.e.…”

Numerical Study on Vibration Response of Compressor Stator Blade Considering Contact Friction of Holding Ring

“…The equivalent linearization method was used to deal with the nonlinear response and the correlation between vibration and friction damping of the model was studied by using statistical characteristics. Sinclair [14][15][16] concluded through research that the nonlinear characteristics of system vibration were caused by friction caused by contact structure deformation. Petrov [9] summarized effective methods for the study of blade disk structures with clearance and friction damping.…”

Effect of mistuning parameters on dynamic characteristics of mistuned bladed disk

“…Cha [1] proposed an analysis method based on the equivalent linearization method to calculate the statistical characteristics of the nonlinear response, and studied the relationship between the vibration mode of the system and the performance of the friction damper. Sinclair [2][3][4] found that the non-linearity of the tenon system is caused by the friction caused by the deformation of the tenon. Petrov [5] developed an effective method to analyze the forced response of nonlinear periodic symmetric structures, and used this method to analyze the tuned bladed disk system with friction damping and gap.…”