Analytical modeling of shear localization in machining processes and its effects on the tool-chip interface
department or school: Applied Science, Faculty of
department or school: Mechanical Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Fazlali, Mohammad Reza
issued: 2023-05-26T08:04:27Z
issued: 2023
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Advanced metals, such as titanium and nickel alloys, have been widely used in the production of high-value and high-performance components in various industries, including aerospace, biomedical, automotive, etc. Shear localization is the dominant chip formation mechanism in machining of these metallic components, limiting the cutting productivity due to high cutting temperature, rapid tool wear, and tool breakage. The machined surface integrity is also affected by shear localization with wavy topography of the finished surface and residual stress fluctuation. Therefore, it is of practical importance to investigate shear localization and its effects during machining processes. This thesis proposes a new analytical thermo-mechanical model for shear localization by assuming an extended primary deformation zone and complete localization of plastic deformation inside shear bands after their formations. Unlike the classical cutting mechanics, the extended primary deformation zone enables capturing the material behavior from homogeneous deformation, to instability onset, and finally, to localization. It will be shown that localization changes the contact mechanism between the tool and the chip, where both sticking and sliding lengths change with respect to time in each localization cycle. Subsequently, the thermal load on the tool’s rake face is affected by the shear band formation in front of the tool. The model predicts: 1) shear band’s stress, temperature, and strain rate inside the primary deformation zone; 2) shear band spacing (subsequently, cutting force frequency) and width, 3) shear band’s displacement, its distribution and chip morphology; 4) time-varying sticking-sliding contact lengths; 5) time-varying cutting forces; 6) normal stress and shear stress distributions on the tool’s rake face; and 7) transient temperature distribution at the tool-chip interface. It is experimentally shown that: 1) the produced shear bands roll on the cutting tool’s rake face, causi…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/84691
note: Analytical Modeling of Shear Localization in MachiningProcesses and Its Effects on the Tool-Chip InterfacebyMohammad Reza FazlaliA THESIS SUBMITTED IN PARTIAL FULFILLMENTOF THE REQUIREMENTS FOR THE DEGREE OFDoctor of PhilosophyinTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES(Mechanical Engineering)The University of British Columbia(Vancouver)May 2023© Mohammad Reza Fazlali, 2023The following individuals certify that they have read, and recommend to the Faculty of Graduateand Postdoctoral Studies for acceptance, the thesis entitled:Analytical Modeling of Shear Localization in Machining Processes and ItsEffects on the Tool-Chip Interfacesubmitted by Mohammad Reza Fazlali in partial fulfillment of the requirements for the degree ofDoctor of Philosophy in Mechanical Engineering.Examining Committee:Xiaoliang Jin, Associate Professor, Mechanical Engineering, UBCSupervisorGary Schajer, Professor, Mechanical Engineering, UBCSupervisory Committee MemberMatthias Militzer, Professor, Materials Engineering, UBCUniversity ExaminerAdam Clare, Professor, Mechanical Engineering, UBCUniversity ExaminerAdditional Supervisory Committee Members:Steve Cockcroft, Professor, Materials Engineering, UBCSupervisory Committee MemberYusuf Altintas, Professor, Mechanical Engineering, UBCSupervisory Committee MemberiiAbstractAdvanced metals, such as titanium and nickel alloys, have been widely used in the production ofhigh-value and high-performance components in various industries, including aerospace, biomedi-cal, automotive, etc. Shear localization is the dominant chip formation mechanism in machining ofthese metallic components, limiting the cutting productivity due to high cutting temperature, rapidtool wear, and tool breakage. The machined surface integrity is also affected by shear localiza-tion with wavy topography of the finished surface and residual stress fluctuation. Therefore, it isof practical importance to investigate shear localization and its effects during machining processes…
has type: Thesis/Dissertation
date issued: 2023-11
is shown at: 10.14288/1.0432646
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Jin, Xiaoliang
type: Text
identifier URI: http://hdl.handle.net/2429/84691