Two Dimensional Quasi-Steady Molecular Statics Nanocutting Simulation for Cutting Copper Material with Point Defect

2011 ◽  
Vol 264-265 ◽  
pp. 1357-1363
Author(s):  
Zone Ching Lin ◽  
Jia Rong Ye
Keyword(s):  
Point Defect ◽  
Copper Atom ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Equivalent Strain ◽  
Two Dimensional ◽  
Molecular Statics ◽  
One Step ◽  
Copper Material ◽  
The Relationship

This article presents a quasi-steady molecular statics nanocutting simulation model for simulating orthogonal two dimension cutting copper materials with different point defects by using diamond cutters. The analyses of cutting action, cutting force, equivalent strain and equivalent stress are taken during nanocutting copper material with point defect. The two dimensional quasisteady molecular statics nanocutting model first assumes the trajectory of each atom of copper workpiece being cut whenever the diamond cutter goes forward one step. It then uses the Hooke- Jeeves search method to solve the force equilibrium equation of the Morse force in X and Y directions when each copper atom moves a small distance, so as to find the new movement position of each copper atom. Then, the displacement of the acquired new position of each atom combined with the concept of shape function of finite element method are employed to calculate the equivalent strain of the copper workpiece during nanocutting . By using the relationship equation of the flow stress-strain curve, the equivalent stress of the copper workpiece during cutting can also be calculated

Elasto-plastic and creep behaviour of axially loaded, shouldered tubes

1980 ◽  
Vol 15 (1) ◽  
pp. 21-29 ◽  
Author(s):  
R J Dawson ◽  
H Fessler ◽  
T H Hyde ◽  
J J Webster
Keyword(s):  
Finite Element ◽  
Creep Behaviour ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Equivalent Strain ◽  
Uniaxial Tensile ◽  
Plastic Strain Increment ◽  
Axially Loaded ◽  
Initial Strains ◽  
Creep Strains

This paper compares the finite element predictions of elasto-plastic and creep behaviour with experimental data for axially loaded, shouldered tube models. Four shouldered tube models were made of a lead alloy and tested at 61°C, using strain gauges to measure the elasto-plastic and creep strains in the plain tube and fillet regions of the models. Instantaneous stress-strain and creep data were obtained from strain-gauged, uniaxial tensile specimens. The finite element solutions are based on the incremental Prandtl-Reuss equations. The elasto-plastic iterative solutions use a ‘negative gradient’ from the calculated point to the equivalent stress-equivalent strain curve to get the next estimate of the plastic strain increment. A time incremental method is used to obtain the creep solutions. Tests with the mean tube stress below, at and above the yield stress showed very good agreement between prediction and measurement of initial strains in the fillets. Differences between predictions and measurements of creep strains are attributable to cast-to-cast variations.

Determining the Anisotropy Coefficients of an Ultra Fine Grained Al6082 Alloy Subjected to ECAP

2007 ◽  
Vol 537-538 ◽  
pp. 215-222
Author(s):  
György Krállics ◽  
Arpad Fodor
Keyword(s):  
Constitutive Equation ◽  
Yield Stress ◽  
Continuum Mechanics ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Equivalent Strain ◽  
Rigid Plastic ◽  
Fine Grained ◽  
Anisotropy Coefficients

Bulk Al6082 alloy is subjected to ECAP using route Bc. This paper focuses on the determination of the anisotropy coefficients and equivalent stress-equivalent strain curve using continuum mechanics equations. Assuming the material to be rigid-plastic, the parameters of the constitutive equation are determined with the aid of measuring the deformation and the uniaxial yield stress during upsetting tests in three perpendicular directions.

Analysis on the Temperature Rise Produced by Plastic Deformation Heat for Nanoscale Orthogonal Cutting of Copper Workpiece

2012 ◽  
Author(s):  
Zone-Ching Lin ◽  
Ying-Chih Hsu ◽  
Liang-Kuang Chen
Keyword(s):  
Plastic Deformation ◽  
Temperature Distribution ◽  
Temperature Rise ◽  
Calculation Method ◽  
Orthogonal Cutting ◽  
Equivalent Stress ◽  
Equivalent Strain ◽  
Perfect Crystal ◽  
Molecular Statics ◽  
Cutting Model

The quasi-steady molecular statics nanoscale orthogonal cutting model developed by this paper not only can calculate cutting force, equivalent stress and equivalent strain, but also can calculate the temperature rise of the cut perfect crystal copper workpiece. This paper considers that during nanoscale orthogonal cutting, the temperature rise of the cut perfect crystal copper workpiece is produced by plastic deformation heat only. The calculation method of equivalent stress and equivalent strain uses three-dimensional quasi-steady molecular statics nanocutting model to calculate and simulate the phenomenon. The model for plastic deformation heat developed by this paper can be used to calculate the equivalent stress and equivalent strain of the cut copper workpiece. Furthermore, the calculation method of temperature rise of the cut workpiece produced by plastic deformation heat is developed. Afterwards the analysis of temperature distribution is also conducted. And the obtained temperature distribution of the cut copper workpiece computed by this paper is qualitatively compared with the temperature distribution obtained by molecular dynamics method in the reference.

scholarly journals Exploring Strong Spinning Formation Mechanisms of GH3030 Superalloy Tapered Rotary Part with Wall Thickness Gradient

2019 ◽  
Vol 37 (4) ◽  
pp. 785-793
Author(s):  
Xuedao Shu ◽  
Zewei Cen ◽  
Yu Wang ◽  
Zixuan Li ◽  
Ying Zhu
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Wall Thickness ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Element Model ◽  
Equivalent Strain ◽  
Formation Mechanisms ◽  
Distribution Law ◽  
Metal Casing

In order to effectively control the deformation of tapered spinning parts with gradually changing wall thickness, the precise forming of such sheet metal casing parts can be realized. This paper uses experiments to establish the true stress-strain curve equations of GH3030 superalloy at normal temperature. Based on the equations, it establishes the finite element model of the strong spinning forming of a GH3030 superalloy tapered rotary part with wall thickness gradient. The equivalent stress field for the strong spinning forming is used to combine the finite element simulation with experiments. The strong spinning forming is simulated, and the distribution characteristics of the equivalent stress field and the equivalent strain field for the strong spinning forming are analyzed in some detail, and their distribution law is obtained. The strong spinning forming mechanisms for the GH3030 superalloy tapered rotary part with wall thickness gradient is clarified. The experimental and simulation results are verified with the conical flange plane degree.

Constitutive Equations Study in Biaxial Stress Experiments

1982 ◽  
Vol 104 (1) ◽  
pp. 1-11 ◽  
Author(s):  
C. Oytana ◽  
P. Delobelle ◽  
A. Mermet
Keyword(s):  
Constitutive Equations ◽  
Biaxial Tension ◽  
Equivalent Stress ◽  
Equivalent Strain ◽  
Biaxial Stress ◽  
Plastic State ◽  
State Of Stress ◽  
Equivalent Strain Rate ◽  
The Relationship

An experimental study of high temperature creep constitutive equations is reported. The experiments are performed in uniaxial and biaxial (tension-torsion) state of stress. Stress drop experiments starting from a given plastic state (i.e., fixed creep rates, stresses and temperature) lead to the flow rules. It is so pointed out: that hardening is essentially kinematical (as well as creep induced anisotropy), that in steady creep the components of this hardening are proportional to those of applied stress. Then, constitutive equations can be derived from that, the identification of which is reduced to the determination of three hardening and recovery scalar functions and to the knowledge, easily open to measure, of the relationship between the equivalent strain rate and the effective equivalent stress. In the case of our experiments, this relationship is a power law.

scholarly journals Investigation on Ultra-high Temperature Forging Process Based on DEFORM-3D Simulation

2021 ◽  
Author(s):  
Wu Yong-qiang ◽  
Wang Kai-kun
Keyword(s):  
High Temperature ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Green Manufacturing ◽  
Equivalent Strain ◽  
Temperature Fields ◽  
Forging Process ◽  
Reheating Process ◽  
Deform 3D ◽  
Ultra High Temperature

Abstract Green manufacturing and forming technology is becoming increasingly important in modern industry. In this study, a new forging technology with the ultra-high temperature demoulding is introduced, in which conventional reheating process could be avoided. The DEFORM-3D software simulated the forging process and the temperature fields were obtained. The traditional forging process was simulated when the initial forging temperature was 1220℃. The highest temperature of the ingot in the new forging technology was about 200℃ higher than that of the traditional forging process. We cut the ingot longitudinally along the centerline. Nine points on the axis of the cutting plane and nine points on the radial direction were selected. The equivalent stress and the equivalent strain of these points were compared respectively under the two forging processes by using the particle tracking method. The variation laws of the equivalent stress and the equivalent strain with the reduction were obtained. According to the variation laws, the typical points which were easy to crack under two different forging processes were found. Based on the flow stress-strain curve calculated by the software JMatPro®, the new forging technology could avoid hot cracking.

An experimental and theoretical study of the abrasion performance of digital light processing parts

2020 ◽  
pp. 095440542098133
Author(s):  
Mehdi Kazemi ◽  
Abdolreza Rahimi
Keyword(s):  
Layer Thickness ◽  
Normal Load ◽  
Digital Light Processing ◽  
One Step ◽  
Pin On Disk ◽  
The Relationship ◽  
Influential Parameters ◽  
Disk Method ◽  
Normal Angle

Generally, interactions at surface asperities are the cause of wear. Two-Thirds of wear in industry occurs because of the abrasive or adhesive mechanisms. This research presents an analytical model for abrasion of additive manufactured Digital Light Processing products using pin-on-disk method. Particularly, the relationship between abrasion volume, normal load, and surface asperities’ angle is investigated. To verify the proposed mathematical model, the results of this model are verified with the practical experiments. Results show that the most influential parameters on abrasion rate are normal load and surface’s normal angle. Abrasion value increases linearly with increasing normal load. The maximum abrasion value occurs when the surface’s normal angle during fabrication is 45°. After the asperities are worn the abrasion volume is the same for all specimens with different surface’s normal angle. Though layer thickness does not directly affect the wear rate, but surface roughness tests show that layer thickness has a great impact on the quality of the abraded surface. When the thickness of the layers is high, the abraded surface has deeper valleys, and thus has a more negative skewness. This paper presents an original approach in abrasion behavior improvement of DLP parts which no research has been done on it so far; thus, bringing the AM one step closer to maturity.

scholarly journals Investigation of Deformation Inhomogeneity and Low-Cycle Fatigue of a Polycrystalline Material

2021 ◽  
Vol 11 (6) ◽  
pp. 2673
Author(s):  
Mu-Hang Zhang ◽  
Xiao-Hong Shen ◽  
Lei He ◽  
Ke-Shi Zhang
Keyword(s):  
Cyclic Loading ◽  
Low Cycle Fatigue ◽  
Strain Tensor ◽  
Equivalent Strain ◽  
Differential Entropy ◽  
Strain Components ◽  
Deformation Inhomogeneity ◽  
Standard Deviations ◽  
Number Of Cycles ◽  
The Relationship

Considering the relationship between inhomogeneous plastic deformation and fatigue damage, deformation inhomogeneity evolution and fatigue failure of superalloy GH4169 under temperature 500 °C and macro tension compression cyclic loading are studied, by using crystal plasticity calculation associated with polycrystalline representative Voronoi volume element (RVE). Different statistical standard deviation and differential entropy of meso strain are used to measure the inhomogeneity of deformation, and the relationship between the inhomogeneity and strain cycle is explored by cyclic numerical simulation. It is found from the research that the standard deviations of each component of the strain tensor at the cyclic peak increase monotonically with the cyclic loading, and they are similar to each other. The differential entropy of each component of the strain tensor also increases with the number of cycles, and the law is similar. On this basis, the critical values determined by statistical standard deviations of the strain components and the equivalent strain, and that by differential entropy of strain components, are, respectively, used as fatigue criteria, then predict the fatigue–life curves of the material. The predictions are verified with reference to the measured results, and their deviations are proved to be in a reasonable range.

scholarly journals Template-Free Self-Assembly of Two-Dimensional Polymers into Nano/Microstructured Materials

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3310
Author(s):  
Shengda Liu ◽  
Jiayun Xu ◽  
Xiumei Li ◽  
Tengfei Yan ◽  
Shuangjiang Yu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Recent Progress ◽  
Two Dimensional ◽  
Subsequent Removal ◽  
The Past ◽  
2D Polymers ◽  
Template Free ◽  
Self Assembled ◽  
The Relationship ◽  
Polymer Tubes

In the past few decades, enormous efforts have been made to synthesize covalent polymer nano/microstructured materials with specific morphologies, due to the relationship between their structures and functions. Up to now, the formation of most of these structures often requires either templates or preorganization in order to construct a specific structure before, and then the subsequent removal of previous templates to form a desired structure, on account of the lack of “self-error-correcting” properties of reversible interactions in polymers. The above processes are time-consuming and tedious. A template-free, self-assembled strategy as a “bottom-up” route to fabricate well-defined nano/microstructures remains a challenge. Herein, we introduce the recent progress in template-free, self-assembled nano/microstructures formed by covalent two-dimensional (2D) polymers, such as polymer capsules, polymer films, polymer tubes and polymer rings.

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