FINITE ELEMENT STUDIES OF ORTHOGONAL MACHINING OF ALUMINUM ALLOY A2024-T351

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Patel, J. (2018). FINITE ELEMENT STUDIES OF ORTHOGONAL MACHINING OF ALUMINUM ALLOY A2024-T351. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

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.

Details
Author

Patel, Jaimeen

Title

FINITE ELEMENT STUDIES OF ORTHOGONAL MACHINING OF ALUMINUM ALLOY A2024-T351

Physical Description

1 online resource (156 pages) : PDF

Date

2018

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

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.

Genre

masters theses

Subjects--Topics

Mechanical engineering
Mechanics

Degree

M.S.

Keywords

Chip Formation
FE Simulation
Finite Element Analysis
Machining Simulation
Serrated Chip

Subject Area

Mechanical Engineering

Advisor(s)

Cherukuri, Harish

Committee Members

Schmitz, Tony
Pando, Miguel

Degree Note

Thesis (M.S.)--University of North Carolina at Charlotte, 2018.

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Rights Holder Information

Copyright is held by the author unless otherwise indicated.

Identifier

Patel_uncc_0694N_11777

Permalink

http://hdl.handle.net/20.500.13093/etd:318