Development of a Novel Friction Model for Machining Simulations in Unidirectional Composite Materials.

Oscar Seward,Fernando Cepero-Mejías,J Patrick A Fairclough,Kevin Kerrigan

doi:10.3390/polym14050847

Oscar Seward, Fernando Cepero-Mejías + Show 2 more

Open Access

https://doi.org/10.3390/polym14050847

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Abstract

Constant coefficients of friction (COFs) are currently used in the literature to describe the contact mechanics between tool and workpiece for finite element (FE) machining simulation of carbon fibre-reinforced polymers (CFRPs). However, these are solely based on closed-loop tribology experimentation, which insufficiently represent machining conditions. To overcome this gap in the knowledge, this work proposes a novel experimental open-loop tribological testing method to produce a dynamic FE friction model for CFRP machining simulations. The newly proposed dynamic friction model is based on a function of fibre angle, contact pressure and slip rate, and it has been validated to both experimental results and constant COF FE simulations. The main aim of this article is to create a link between machining, tribology and FE simulation, by implementing cutting-edge tribological testing that results in highly accurate FE simulations. This dynamic model has been shown to improve the accuracy of open-loop tribological simulations, giving confidence in future implantation in CFRP machining simulations.

Highlights

Carbon fibre-reinforced polymers (CFRPs) are being increasingly adopted in many engineering applications
The multi-linear regression (MLR) was carried out using MATLAB’s ‘regress’ function—this allowed for a dynamic APP coefficients of friction (COFs) to be created with respect to a given fibre angle (Fi ), pressure (Pi ) and cutting speed (Vi )
Some caution should be taken with this set as the R2 values for θ (90 and 112.5) were relatively low due to experimental difficulties when machining these negative angles

Summary

Introduction

Carbon fibre-reinforced polymers (CFRPs) are being increasingly adopted in many engineering applications. The fundamental contact mechanics that occurs in machining is still relatively undefined. These tool–workpiece interactions give rise to extremely high pressures, temperatures and slip rates, affecting the machined surface and further affecting the contact between tool and surface. The predictive capability of a given FE simulation can provide a significant benefit, both in enabling the development of advanced cutting tools and cost savings over experimental testing [3]. This section will discuss the issues faced when implementing dynamic experimental frictional data—collected from the previous experimental section—into an explicit machining simulation though the use of ABAQUS CAE finite element solver. Dynamic friction coefficients are not possible in ABAQUS CAE GUI, and this section will discuss how this problem was overcome. CFRPs have the added difficulty of having a fibre orientation-dependent coefficient of friction, further highlighting the need for a detailed friction model to remove key uncertainties in FE modelling of CFRP machining operations

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