A Novel Approach to Thin-Wall Machining of Aerospace Structures - Stability Margin Prediction Using a New Damping Modelling Approach
The eco-friendly and economic challenges are driving more and more aerostructure components with thin wall and deep pocket features. These features are getting thinner and deeper and become impractical during part manufacturing. Therefore, there is a need to better understand the mechanics, kinematics and dynamics of thin wall machining (which is the focus in this paper). In this paper, the application of a newly discovered relationship between the workpiece geometry and its damping parameters in the machining of aerospace structures is presented. This relationship allows for the prediction of damping ratios, without the use of experimental results for any wall with a different thickness compared to a reference wall. A previously proposed ‘improved stability lobes model’ is used to validate the damping model, as this model considers the nonlinearity of the cutting force coefficients. While a finite element method (FEM) is used to obtain natural frequencies and modal stiffness’s at different locations along the workpiece or toolpath, required in the stability model. The advantage of this new damping model is that, it alleviates the burden of having to carry out modal experiments to obtain the damping parameters required for subsequent stability margin predictions, as the work-piece thickness changes during machining.
W. M. Sim et al., "A Novel Approach to Thin-Wall Machining of Aerospace Structures - Stability Margin Prediction Using a New Damping Modelling Approach", Advanced Materials Research, Vol. 223, pp. 632-641, 2011