scholarly journals Analysis and Modeling of the Micro-Cutting Process of Ti-6Al-4V Titanium Alloy with Single Abrasive Grain

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5835
Author(s):  
Łukasz Rypina ◽  
Dariusz Lipiński ◽  
Błażej Bałasz ◽  
Wojciech Kacalak ◽  
Tomasz Szatkiewicz
Keyword(s):  
Constitutive Model ◽  
High Speed ◽  
Geometric Model ◽  
Triaxial Compression ◽  
Geometrical Parameters ◽  
Machining Processes ◽  
Forming Process ◽  
Abrasive Grains ◽  
Abrasive Grain ◽  
Selection Of

Modeling of material displacements in the microcutting zone is complex due to the number and interdependence of factors affecting the results of the process. An important problem in the modeling process is the selection of the constitutive model and its parameters, which will correctly describe the properties of the material under the conditions of triaxial compression, which is characteristic for the areas of the contact zone of the blade and the processed material in abrasive machining processes. The aim of the work was to develop computer models (with the use of the finite element method) of the microcutting process with a single abrasive grain, which were verified with the results of experimental tests. The paper presents the methodology of modeling the processes of microcutting with abrasive grains, whose geometrical models were created based on optical scanning methods. Observations of the microcutting process were carried out with the use of a high-speed camera and an optical profilometer. This enabled a detailed observation of the chip formation process, as well as the analysis of the surface topography of microcutting traces. The results presented in the paper indicate the convergence of the results of the numerical and experimental simulations with regard to the geometric parameters describing the scratches formed in the microcutting process and the compliance of the chip-forming process. Thus, the correctness of the selection of the constitutive model (Johnson Cook equation) and its parameters was demonstrated, as well as the correctness of the applied methodology for creating a geometric model that allowed for a reflection of the geometrical parameters of the abrasive grains that coincided with the real objects, thanks to which it was possible to reflect in detail the phenomena occurring in the vicinity of the abrasive grain tip.

Experimental Study of Geometrical Parameters of Abrasive Grains in Modeling their Cutting Edges with the Surface of Rotation

2014 ◽  
Vol 698 ◽  
pp. 529-533
Author(s):  
Alexander Petrovich Osipov ◽  
Victor Vassilevich Fedotov ◽  
Alexander Alexandrovich Zharov
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Grain Size ◽  
Penetration Depth ◽  
Apex Angle ◽  
Geometrical Parameters ◽  
Abrasive Material ◽  
Abrasive Grains ◽  
Abrasive Grain ◽  
Basic Parameters

In machining with grinding, it is necessary to know values of geometrical parameters of cutting edges of abrasive grains. In this paper for modeling of cutting edges of abrasive grains with rotation surfaces based on generatrix as a power function and for division cutting edges on both plowing and forming a chip, values of basic parametersBP,NPwere obtained experimentally. The influence of abrasive grain size, sieve-shaking procedure, mechanical properties of workpiece and type of abrasive material on these parameters was determined. The restrictions of this model were designated. It is established that traditional parameters such as corner radiusrand apex angle 2θ can be used in case of microcutting with small grain penetration depth.

Generalized Three-Dimensional Mathematical Models for Force and Stiffness in Axially, Radially, and Perpendicularly Magnetized Passive Magnetic Bearings With “n” Number of Ring Pairs

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Siddappa I. Bekinal ◽  
Soumendu Jana
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Speed ◽  
Three Dimensional ◽  
Magnetic Bearings ◽  
Axial Stiffness ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Selection Of ◽  
Vector Approach

This work deals with generalized three-dimensional (3D) mathematical model to estimate the force and stiffness in axially, radially, and perpendicularly polarized passive magnetic bearings with “n” number of permanent magnet (PM) ring pairs. Coulombian model and vector approach are used to derive generalized equations for force and stiffness. Bearing characteristics (in three possible standard configurations) of permanent magnet bearings (PMBs) are evaluated using matlab codes. Further, results of the model are validated with finite element analysis (FEA) results for five ring pairs. Developed matlab codes are further utilized to determine only the axial force and axial stiffness in three stacked PMB configurations by varying the number of rings. Finally, the correlation between the bearing characteristics (PMB with only one and multiple ring pairs) is proposed and discussed in detail. The proposed mathematical model might be useful for the selection of suitable configuration of PMB as well as its optimization for geometrical parameters for high-speed applications.

Multi-Objective Selection of Cutting Conditions in Advanced Machining Processes via an Efficient Global Optimization Approach

2014 ◽  
Author(s):  
Mohamed Aly ◽  
Karim Hamza ◽  
Mohammed Tauhiduzzaman ◽  
Mouhab Meshreki ◽  
Ashraf O. Nassef ◽  
...  
Keyword(s):  
Global Optimization ◽  
High Speed ◽  
Diamond Turning ◽  
Cutting Conditions ◽  
Efficient Global Optimization ◽  
Experimental Sample ◽  
Machining Processes ◽  
Multi Objective ◽  
Ultra Precision ◽  
Selection Of

Optimum selection of cutting conditions in high-speed and ultra-precision machining processes often poses a challenging task due to several reasons; such as the need for costly experimental setup and the limitation on the number of experiments that can be performed before tool degradation starts becoming a source of noise in the readings. Moreover, oftentimes there are several objectives to consider, some of which may be conflicting, while others may be somewhat correlated. Pareto-optimality analysis is needed for conflicting objectives; however the existence of several objectives (high-dimension Pareto space) makes the generation and interpretation of Pareto solutions difficult. The approach adopted in this paper is a modified multi-objective efficient global optimization (m-EGO). In m-EGO, sample data points from experiments are used to construct Kriging meta-models, which act as predictors for the performance objectives. Evolutionary multi-objective optimization is then conducted to spread a population of new candidate experiments towards the zones of search space that are predicted by the Kriging models to have favorable performance, as well as zones that are under-explored. New experiments are then used to update the Kriging models, and the process is repeated until termination criteria are met. Handling a large number of objectives is improved via a special selection operator based on principle component analysis (PCA) within the evolutionary optimization. PCA is used to automatically detect correlations among objectives and perform the selection within a reduced space in order to achieve a better distribution of experimental sample points on the Pareto frontier. Case studies show favorable results in ultra-precision diamond turning of Aluminum alloy as well as high-speed drilling of woven composites.

scholarly journals Characterization of Ottawa Sand and Application to Blast Simulations

2021 ◽  
Vol 250 ◽  
pp. 02009
Author(s):  
Sidney Chocron ◽  
Alexander Carpenter ◽  
Arthur Nicholls ◽  
James Walker ◽  
Ohad Elbaz ◽  
...  
Keyword(s):  
Constitutive Model ◽  
High Speed ◽  
Steel Plate ◽  
Triaxial Compression ◽  
Mechanical Tests ◽  
Test Configuration ◽  
Ottawa Sand ◽  
Laboratory Characterization ◽  
Different Depths

The present work aims at presenting consistent data both from laboratory characterization and from blast tests to see how a computer model performs when only data from mechanical tests are being fed to the constitutive model. A sand (Ottawa 20-30) that meets ASTM C778 requirements, i.e., well characterized microscopically, was tested in triaxial compression under confinement pressures ranging from 50 to 300 MPa and moisture contents of 0 to 15% as well as high strain-rates. These tests provided both the experimental equation of state (pressure vs. volume) and compaction curves as well as the strength vs. pressure properties to build a constitutive model both in LS-DYNA and CTH. Blast tests were subsequently performed by burying explosive at three different depths inside a sand pot with a rigid steel plate on top. During flight, the height of the steel plate was tracked with Phantom high-speed cameras to determine the impulse transmitted to the plate as well as the maximum jump height. Simulations were performed with both an Eulerian code (CTH) and a Lagrangian/ALE code (LS-DYNA) using the constitutive model determined during the material characterization. The predictions of both codes are as close as 7% and as far as 22%, depending on the test configuration.

Study of the process of forming a hole for a thread at manufacturing a high nut

2020 ◽  
Vol 76 (8) ◽  
pp. 841-846
Author(s):  
I. G. Shubin ◽  
A. A. Kurkin
Keyword(s):  
Metal Flow ◽  
Nonlinear Dependence ◽  
Geometrical Parameters ◽  
Relative Height ◽  
Forming Process ◽  
Normal Height ◽  
Accuracy Class ◽  
Limit Values ◽  
Program Complex ◽  
Class B

During manufacturing nuts of increased height, a problem of obtaining correct cylindrical form of the hole for thread and overall geometrical parameters arises. To solve the problem it is necessary to know regularity of the blank forming process. Results of the study of a technological process of high hexahedral nuts forming presented. The nuts were M18 of 22 mm height, M16 of 19 mm height and M12 of normal height 10 mm according to GOST 5915–70, accuracy class B, steel grade 10 according to GOST 10702–78. The volumetric stamping was accomplished at the five-position automatic presses of АА1822 type. It was determined, that unevenness of the metal flow in the process of plastic deformation of blanks of increased height nuts was caused by different stress conditions by their sections. To simulate the mode of deformation, the program complex QForm-3D was chosen. The complex ensured to forecast with necessary accuracy the metal flow in a blank, as well as to define the deformation force and arising stress in the working instrument. The simulation showed the presence of regularity between preliminary formed buffle and deviation of dimensions and form of a blank wall after its finishing piercing, which can be expressed by a nonlinear dependence. The limit values of the relative height of the buffle С/D = 0.56–0.588 defined, exceeding which will result in rejection of the finished product. Accounting the limit values of the relative height of the buffle will enable to correct a mode of technological operations and technological instruments at stamping of high hexahedral nuts.

Selection of the Optimal Type of Bored-Injection Piles Strengthening of Weak Bases of High-Speed Railway Lines

2019 ◽  
pp. 40-44
Author(s):  
N.S. SOKOLOV ◽  
◽  
S.S. VIKTOROVA ◽  
I.P. FEDOSEEVA ◽  
G.M. SMIRNOVA ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Railway ◽  
Weak Bases ◽  
Selection Of ◽  
Optimal Type

scholarly journals Internal face finishing for a cooling channel using a fluid containing free abrasive grains

2021 ◽  
Author(s):  
Mitsugu Yamaguchi ◽  
Tatsuaki Furumoto ◽  
Shuuji Inagaki ◽  
Masao Tsuji ◽  
Yoshiki Ochiai ◽  
...  
Keyword(s):  
High Speed ◽  
Flow Behavior ◽  
Flow Simulation ◽  
Cooling Channel ◽  
H13 Steel ◽  
Channel Diameter ◽  
Abrasive Grains ◽  
Low Viscosity ◽  
Short Period ◽  
Internal Pressures

AbstractIn die-casting and injection molding, a conformal cooling channel is applied inside the dies and molds to reduce the cycle time. When the internal face of the channel is rough, both cooling performance and tool life are negatively affected. Many methods for finishing the internal face of such channels have been proposed. However, the effects of the channel diameter on the flow of a low-viscosity finishing media and its finishing characteristics for H13 steel have not yet been reported in the literature. This study addresses these deficiencies through the following: the fluid flow in a channel was computationally simulated; the flow behavior of abrasive grains was observed using a high-speed camera; and the internal face of the channel was finished using the flow of a fluid containing abrasive grains. The flow velocity of the fluid with the abrasive grains increases as the channel diameter decreases, and the velocity gradient is low throughout the channel. This enables reduction in the surface roughness for a short period and ensures uniform finishing in the central region of the channel; however, over polishing occurs owing to the centrifugal force generated in the entrance region, which causes the form accuracy of the channel to partially deteriorate. The outcomes of this study demonstrate that the observational finding for the finishing process is consistent with the flow simulation results. The flow simulation can be instrumental in designing channel diameters and internal pressures to ensure efficient and uniform finishing for such channels.

scholarly journals Procedure for the Selection of Rubber Compound in Rubber-Metal Springs for Vibration Isolation

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1737
Author(s):  
Milan Banić ◽  
Dušan Stamenković ◽  
Aleksandar Miltenović ◽  
Dragan Jovanović ◽  
Milan Tica
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Vibration Isolation ◽  
Correct Selection ◽  
Virtual Experiment ◽  
Rubber Compound ◽  
Key Factor ◽  
Railway Engineering ◽  
Selection Of

The selection of a rubber compound has a determining influence on the final characteristics of rubber-metal springs. Therefore, the correct selection of a rubber compound is a key factor for development of rubber-metal vibration isolation springs with required characteristics. The procedure for the selection of the rubber compound for vibration isolation of rubber-metal springs has been proposed, so that the rubber-metal elements have the necessary characteristics, especially in terms of deflection. The procedure is based on numerical simulation of spring deflection with Bergström-Boyce constitutive model in virtual experiment, with a goal to determine which parameters of the constitutive model will lead to spring required deflection. The procedure was verified by case study defined to select rubber compound for a rubber–metal spring used in railway engineering.

Collision-Free Tool Path Generation for Five-Axis High Speed Machining

2011 ◽  
Vol 474-476 ◽  
pp. 961-966 ◽  
Author(s):  
Li Qiang Zhang ◽  
Min Yue
Keyword(s):  
Image Analysis ◽  
Collision Detection ◽  
High Speed ◽  
Tool Path ◽  
Geometric Model ◽  
High Speed Machining ◽  
Analysis Method ◽  
Geometric Information ◽  
Detection Approach ◽  
Five Axis

Collision detection is a critical problem in five-axis high speed machining. Using a combination of process simulation and collision detection based on image analysis, a rapid detection approach is developed. The geometric model provides the cut geometry for the collision detection and records a dynamic geometric information for in-process workpiece. For the precise collision detection, a strategy of image analysis method is developed in order to make the approach efficient and maintian a high detection precision. An example of five-axis machining propeller is studied to demonstrate the proposed approach. It has shown that the collision detection task can be achieved with a near real-time performance.

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