Analytical Modeling of Shear Localization in Orthogonal Cutting Processes

2021 ◽  
pp. 1-45
Author(s):  
Mohammadreza Fazlali ◽  
Mauricio Ponga ◽  
Xiaoliang Jin
Keyword(s):  
Shear Band ◽  
Orthogonal Cutting ◽  
Shear Bands ◽  
Chip Morphology ◽  
High Strength ◽  
Shear Localization ◽  
Shear Band Formation ◽  
Workpiece Material ◽  
Band Formation ◽  
Cutting Processes

Abstract This paper presents an analytical thermo-mechanical model of shear localization and shear band formation in orthogonal cutting of high-strength metallic alloys. The deformation process of the workpiece material includes three stages: homogeneous deformation, shear localization, and chip segmentation. A boundary layer analysis is used to analytically predict the temperature, stress, and strain rate variations in the primary shear zone associated with the shear localization. The predictions of shear band spacing and width from the proposed model are verified by experimental characterization of the chip morphology. The rolling of shear bands on the tool rake face is discussed from the experimental observations. The cutting tool temperature, which is influenced by the heat generated during the shear band formation, is simulated and compared with the finite element simulations. The proposed analytical model reveals the fundamental mechanism of the complete shear localization process in orthogonal cutting, and predicts the stress and temperature variations with high computational efficiency.

The Effect of Cold Rolling Reduction on Shear Band and Texture Formation in Fe-3%Si Alloy

2012 ◽  
Vol 715-716 ◽  
pp. 158-163 ◽  
Author(s):  
Kenichi Murakami ◽  
N. Morishige ◽  
Kohsaku Ushioda
Keyword(s):  
Shear Band ◽  
Cold Rolling ◽  
Crystal Orientation ◽  
Shear Bands ◽  
Rolling Direction ◽  
Orientation Distribution ◽  
Rolling Reduction ◽  
Shear Band Formation ◽  
Band Formation ◽  
Cold Rolling Reduction

The effect of cold rolling reduction on shear band formation and crystal orientation within shear bands and annealing texture were investigated in Fe-3%Si {111}<112> single crystals. Several types of shear bands were observed with different angles to rolling direction, dependent on rolling reduction. As for shear band formation, those with smaller angles were formed earlier and those with larger angles were formed later. Regarding crystal orientation along shear bands after rolling reduction, orientation distribution from the initial became large in accordance with reduction and even exceeded Goss orientation when rolling reduction became larger than 40%. After annealing, however, recrystallized grains along shear bands were mainly Goss grains regardless of reduction. The speculated reason for the dominance of Goss after annealing is that Goss subgrains with less density of dislocations were surrounded by largely deformed areas.

Large-Scale Deformation Patterning in Geomaterials Associated with Grain Rotation

2014 ◽  
Vol 891-892 ◽  
pp. 872-877 ◽  
Author(s):  
Maxim Esin ◽  
Arcady V. Dyskin ◽  
Elena Pasternak
Keyword(s):  
Shear Band ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Shear Bands ◽  
Physical Models ◽  
Image Correlation ◽  
Deformation Pattern ◽  
Shear Band Formation ◽  
Band Formation ◽  
Subsequent Formation

Modelling of large-scale deformation patterning in geomaterials is important for predicting instabilities and failures in the Earths crust. Shear band formation and the evolution of the bands is a predominant mechanism of deformation patterning. Independent rotations of separate grains/particles can affect the pattern formation by adding the effect of rotational degrees of freedom to the mechanism of instability. To model this mechanism we use a special experimental technique based on digital image correlation in order to recover both displacement and independent rotation fields in 2D physical models of granular material. In the physical model the particles are represented by smooth steel monodispersed disks with speckles painted on them to enable the rotation reconstruction. During the loading the deformation pattern undergoes stages of shear band formation followed by its dissolution due to re-compaction and particle rearrangement with the subsequent formation of multiple shear bands merging into a single one and the final dissolution. Also, patterns of rotations are observed at an intermediate scale between the scale of the particles and the scale of the shear band.

Fine Crystalline Phase Dispersion in Zr-Based Bulk Metallic Glass by Laser Irradiation

2007 ◽  
Vol 26-28 ◽  
pp. 747-750
Author(s):  
R. Ikutomo ◽  
Masato Tsujikawa ◽  
Makoto Hino ◽  
Hisamichi Kimura ◽  
Kunio Yubuta ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Shear Band ◽  
Metallic Glass ◽  
Laser Irradiation ◽  
Bulk Metallic Glass ◽  
Crystalline Phase ◽  
Shear Bands ◽  
High Strength ◽  
Band Formation ◽  
Phase Dispersion

Bulk metallic glass (BMG) exhibits remarkable properties such as high strength, good stiffness and good corrosion resistance. However, the wear resistance of amorphous metals is not excellent as expected their high strength. It is thought that large local shear bands easily change into cracks for debris formation. The effective obstruction of shear band formation might be applied to improve the wear resistance of BMG. In this study, we tried to suppress shear band deformation by fine crystalline phase dispersion formed by semi-conductor laser irradiation. The microstructures of irradiated Zr-based BMG specimens were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The fine dispersions of crystalline phases are observed in the amorphous matrix. The optimum condition for laser irradiation was discussed.

scholarly journals Molecular Dynamics Simulation of Structural Signals of Shear-Band Formation in Zr46Cu46Al8 Metallic Glasses

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2564
Author(s):  
Shi-Dong Feng ◽  
Keith Chan ◽  
Lei Zhao ◽  
Li-Min Wang ◽  
Ri-Ping Liu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Shear Band ◽  
Metallic Glasses ◽  
Orientational Order ◽  
Shear Bands ◽  
Dynamics Simulation ◽  
Shear Band Formation ◽  
Band Formation ◽  
Average Size

The evolution from initiation to formation of a shear band in Zr46Cu46Al8 metallic glasses is presented via molecular dynamics simulation. The increase in number and the decrease in average size of clusters with the quasi-nearest atoms being 0 correspond to the shear-band evolution from initiation to formation. When the shear band is completely formed, the distribution of the bond orientational order q6 reaches a minimum. The maximum of the number of the polyhedral loss of Cu-centered <0, 0, 12, 0> and the minimum of the number of the polyhedral loss of Zr-centered <0, 2, 8, 5> correspond to the shear-band formation. These findings provide a strong foundation for characterizing the evolution from initiation to formation of shear bands.

scholarly journals ADAPTIVE FINITE ELEMENT COMPUTATIONS OF SHEAR BAND FORMATION

2010 ◽  
Vol 20 (03) ◽  
pp. 423-448 ◽  
Author(s):  
TH. BAXEVANIS ◽  
TH. KATSAOUNIS ◽  
A. E. TZAVARAS
Keyword(s):  
Finite Element ◽  
Shear Band ◽  
Shear Bands ◽  
Adaptive Finite Element ◽  
Shear Band Formation ◽  
Adaptive Finite Element Methods ◽  
Band Formation ◽  
Scaling Properties ◽  
Stress Diffusion ◽  
Variable Step

We study numerically an instability mechanism for the formation of shear bands at high strain-rate deformations of metals. We use a reformulation of the problem that exploits scaling properties of the model, in conjunction with adaptive finite element methods of any order in the spatial discretization and implicit Runge–Kutta methods with variable step in time. The numerical schemes are of implicit–explicit type and provide adequate resolution of shear bands up to full development. We find that from the initial stages, shear band formation is already associated with collapse of stress diffusion across the band and that process intensifies as the band fully forms. For fully developed bands, heat conduction plays an important role in the subsequent evolution by causing a delay or even stopping the development of the band.

scholarly journals Understanding and suppressing shear band formation in strut-based lattice structures manufactured by laser powder bed fusion

2021 ◽  
Vol 199 ◽  
pp. 109416
Author(s):  
Xiaoyang Liu ◽  
Takafumi Wada ◽  
Asuka Suzuki ◽  
Naoki Takata ◽  
Makoto Kobashi ◽  
...  
Keyword(s):  
Shear Band ◽  
Lattice Structures ◽  
Shear Band Formation ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Band Formation ◽  
Powder Bed

Studies of Elastic-Plastic Instabilities

1999 ◽  
Vol 66 (1) ◽  
pp. 3-9 ◽  
Author(s):  
V. Tvergaard
Keyword(s):  
Shear Band ◽  
Plastic Flow ◽  
Continuum Mechanics ◽  
Shear Band Formation ◽  
Band Formation ◽  
Elastic Plastic ◽  
Localized Necking ◽  
Focus On Results ◽  
Metal Sheets ◽  
Bifurcation Behavior

Analyses of plastic instabilities are reviewed, with focus on results in structural mechanics as well as continuum mechanics. First the basic theories for bifurcation and post-bifurcation behavior are briefly presented. Then, localization of plastic flow is discussed, including shear band formation in solids, localized necking in biaxially stretched metal sheets, and the analogous phenomenon of buckling localization in structures. Also some recent results for cavitation instabilities in elastic-plastic solids are reviewed.

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