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Development of a high resolution computational model of adiabatic shear banding in machining
Hawa, Homar López
Hawa, Homar López
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2023-05
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This study presents the development of a high-resolution finite element analysis (FEA) to model machining under conditions that produce adiabatic shear banding (ASB). The simulation assumes the deforming material behaves following Johnson-Cook constitutive models and implements an adaptive re-meshing algorithm. The model implements a fully thermo-mechanically coupled solver to calculate heat conduction inside the deforming specimen and cutting tool. The FEA is used to study the effect of tool oscillation while cutting Ti-6Al-4V and found that increasing oscillation frequency reduces the prominence of shear bands.
Additionally, the study establishes a new experimental configuration called fin cutting to study material behavior under extreme thermomechanical conditions. The configuration involves a rigid and hard tool striking a fin-like specimen that protrudes from a substrate, creating a one-dimensional shear band characterized by uniform stress, strain, strain rate, and temperature. The deformation force, stress, strain, strain rate, and temperature obtained from this numerical experiment are used to infer the constitutive model of the material, which is compared to the Johnson-Cook model for AISI 4340. The newly obtained Johnson-Cook material constants are found to correlate well with the original material model. However, experimentally observable proxies are still needed to estimate the imposed strain, strain rate, and temperature during fin cutting.
This study's contributions lie in the development of a high-resolution FEA model for ASB machining and the establishment of a new experimental configuration for studying material behavior under extreme conditions. The study's findings on tool oscillation's effect on ASB and the accurate measurement of flow stress through the one-dimensional shear band provide insights for further research in the field.
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Thesis (Ph.D.)-- Wichita State University, College of Engineering, Dept. of of Industrial, Systems and Manufacturing Engineering
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Wichita State University
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© Copyright 2023 by Homar López Hawa
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