FINITE ELEMENT STUDIES OF ORTHOGONAL MACHINING OF ALUMINUM ALLOY A2024-T351
1 online resource (156 pages) : PDF
University of North Carolina at Charlotte
In this work, a new machining model using the commercial finite element software ABAQUS is developed. The model regards material separation, chip serration and breakage as ductile fracture processes where energy is required to form new surfaces. The main hypothesis is that the critical energy release rate for chip separation is different from the critical energy release rate for chip serration. The Johnson-Cook damage model is used to account for damage initiation in the workpiece material. The damage evolution leading to chip separation, serration and possible breakage is assumed to be governed by Hillerborg’s fracture model. Two separate forms of Hillerborg fracture model are investigated and the appropriate forms for chip separation and serration are identified. A unique feature of the model is that the threshold value for the critical energy release rate for chip separation is determined from the existing experimental results. In addition, the model also uses a novel stress-based method for accounting for the frictional characteristics of the tool-chip interface. The model is verified and validated using the data available in the open literature. Various parametric studies involving cutting speed, uncut chip thickness and rake angles have been carried out to study their effect on cutting force, mechanical and thermal fields, and the chip morphologies. Our results indicate that the model is robust and the numerical predictions are in agreement with the trends observed in experiments.
CHIP FORMATIONFE SIMULATIONFINITE ELEMENT ANALYSISMACHINING SIMULATIONSERRATED CHIP
Schmitz, TonyPando, Miguel
Thesis (M.S.)--University of North Carolina at Charlotte, 2018.
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