scholarly journals NUMERICAL INVESTIGATION OF THE INFLUENCE OF PUNCH TIP RADIUS AND INTERPOLATOR TYPE IN MULTI-POINT FORMING

2019 ◽  
Vol 19 (2) ◽  
pp. 114-128
Author(s):  
Abdul Kareem J Kadhim ◽  
Ragad A Neama
Keyword(s):  
Three Dimensional ◽  
Thickness Variation ◽  
Work Piece ◽  
Finite Element Code ◽  
B Spline ◽  
Forming Technology ◽  
Different Shapes ◽  
Simulation Results ◽  
Tip Radius ◽  
Reconfigurable Die

Multi-point forming (MPF) is a new flexible forming technology in which the fixed shape of conventional dies is replaced by a pair of opposed matrices of movable punch elements called "punch group".By using multi-point die a variety of three dimensional sheet parts of different shapes can be produced. However due to the discrete contacts between the work piece and punches the dimple defects occurred. In this paper, B-spline technique was used to represent the profile of the final product shape by adjusting the punch height of reconfigurable die. Finite element code (ANSYS 11) was used to simulate the MPF process and to investigate the influence of punch tip radius the interpolator type on the stress distribution, thickness variation and dimpling defect .The simulation results show that the large tip radius and (4mm) rubber interpolator have a great effect in reducing the stress concentration, thickness variation and also prevent the dimpling defect.

Study on Precision Forging Schemes of Hypoid Driving Gear

2012 ◽  
Vol 472-475 ◽  
pp. 692-695
Author(s):  
Jian Hua Wang ◽  
Fu Xiao Chen
Keyword(s):  
Equivalent Stress ◽  
Three Dimensional ◽  
Equivalent Strain ◽  
Precision Forging ◽  
Forming Technology ◽  
Blank Shape ◽  
Simulation Results ◽  
Three Dimensional Models ◽  
3D Software ◽  
Deform 3D

By analyzing the characteristics and forming technology of hypoid driving gear, it was suitable for adopting fully enclosed die forging principle to form the gear. Based on different forging methods, three kinds of blank shape and corresponding forming schemes were designed. The three dimensional models of blank and die were created by the UG software. The three forming schemes were simulated by the Deform-3D software. The simulation results of distribution of equivalent stress, distribution of equivalent strain and load-stroke curve were comparatively analyzed. Then the most reasonable scheme was chosen. At last, the rationality of numerical simulation can be further verified by the optimized scheme was proved by experiment.

Numerical Simulation on Spiral Hot Bending Process for End Sheet of Tubular Pile

2012 ◽  
Vol 562-564 ◽  
pp. 1373-1376
Author(s):  
Shi Min Xu ◽  
Hua Gui Huang ◽  
Deng Yue Sun
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Radial Direction ◽  
Three Dimensional ◽  
Element Model ◽  
Manufacturing Method ◽  
Forming Technology ◽  
Bending Process ◽  
Simulation Results ◽  
The Moment

A new manufacturing method of spiral hot bending process for the end sheet of tubular pile was introduced in this paper. A three-dimensional (3-D) thermal-mechanical coupled elastic-plasticity finite element model was setup to simulate the hot bending process, and then, the section deformation mechanism from hot bar by rolling to the end sheet has been investigated from the simulation results. The industry manufacture conditions show that the efficiency and quality has been highly improved by the spiral hot bending process. The thickness variety along the radial direction of the workpiece has also been analyzed, the moment and force during the hot bending was also presented in this paper. These conclusions obtained can guide for the forming technology making for both the end sheet of tubular pile and other ring parts.

Evaluation of chilled casting and extrusion-shear forming technology based on numerical simulation and experiments

2021 ◽  
Vol 63 (8) ◽  
pp. 728-735
Author(s):  
H. J. Hu ◽  
S. L. Gan ◽  
Y. Tian ◽  
D. F. Zhang ◽  
J. K. Feng ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Three Dimensional ◽  
Hot Extrusion ◽  
Casting Process ◽  
Process Technology ◽  
The Third ◽  
Lateral Extrusion ◽  
Forming Technology ◽  
Deformation Behaviors ◽  
Simulation Results

Abstract Magnesium alloys on the surface of billets might be refined by chilled casting process, but the grains of the center of billets are coarse, and there are a lot of void defects in the center of billets. These defects can be eliminated by hot extrusion, while fibrous microstructures and strong basal textures might be formed. This paper presents a new short process technology which includes chilled casting and extrusion-shear (CCES). It is crucial to understand the effects of die structures on the deformation behaviors, strain distribution and load requirements. Three selections of processes and die structures were done by simulations and experiments which include CCES process with 4 times consecutive shearings plastic deformation, CCES process by lateral extrusion with 90° shearing angle, and combined CCES process mode. The research results show the third selection is recommended. Three-dimensional (3D) geometric models with different channel angles (30°, 45°) for the third selection CCES dies were designed. The heterogeneities of plastic deformation by CCES dies with different channel angles were analyzed from the simulation results. The simulation results show strains decrease with rising of channel angles. The lower channel angles improve the deformation heterogeneity of magnesium alloy billets. Smaller channel angles obtain higher strains and produce tinier sub-grains. The forces of the CCES process decrease with rising of channel angles. The analysis results showed that finer and uniform microstructures can be obtained if channel angles in the CCES dies are appropriate.

Design of finite-time guidance law based on observer and head-pursuit theory

2021 ◽  
pp. 095441002098456
Author(s):  
Chenqi Zhu
Keyword(s):  
Finite Time ◽  
Three Dimensional ◽  
Hypersonic Vehicle ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Reaching Law ◽  
Guidance Law ◽  
Fast Power ◽  
Simulation Results ◽  
Guidance Laws

In order to improve the guiding accuracy in intercepting the hypersonic vehicle, this article presents a finite-time guidance law based on the observer and head-pursuit theory. First, based on a two-dimensional model between the interceptor and target, this study applies the fast power reaching law to head-pursuit guidance law so that it can alleviate the chattering phenomenon and ensure the convergence speed. Second, target maneuvers are considered as system disturbances, and the head-pursuit guidance law based on an observer is proposed. Furthermore, this method is extended to a three-dimensional case. Finally, comparative simulation results further verify the superiority of the guidance laws designed in this article.

Experimental Examination of the Impact of Tool Radius on Specific Energy in Microcutting of Granite

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Miloš Pjević ◽  
Ljubodrag Tanović ◽  
Goran Mladenović ◽  
Biljana Marković
Keyword(s):  
Cutting Force ◽  
Penetration Depth ◽  
Specific Energy ◽  
Brittle Materials ◽  
Experimental Examination ◽  
Workpiece Surface ◽  
Different Shapes ◽  
Tip Radius ◽  
The Impact ◽  
Force Intensity

The paper presents experimental results of microcutting brittle materials (granite). The analysis was conceived on the observed interaction between the workpiece and two tools of different shapes. Experiment was based on scratching the workpiece surface with diamond tools. Applied tools had tip radius R0.2 and R0.15 mm. The experiment determined the changes in the value of perpendicular and tangential components of the cutting force based on the geometric properties of tools, as well as the changes of the specific energy of microcutting granite (Jošanica and Bukovik types). The experiment has shown that reduction of tool radius causes reduction of the cutting force intensity and specific cutting energy. Because of its physical/mechanical properties, more energy is required for micromachining granite “Jošanica” than “Bukovik.” Based on the topography of the surface, the value of critical tool penetration depth was established, after which the brittle fracture is no longer present. For granite “Jošanica” values of critical penetration depth are 6 and 5 μm when micromachining with tools R0.2 and R0.15 mm, while for Bukovik those values are 6.5 and 5.5 μm. The paper should form the basis for understanding the phenomena which occur during microcutting brittle materials.

Direct simulation of evolution and control of three-dimensional instabilities in attachment-line boundary layers

1995 ◽  
Vol 291 ◽  
pp. 369-392 ◽  
Author(s):  
Ronald D. Joslin
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Computationally Efficient ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
Attachment Line

The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier–Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic-source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in flat-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

Key Technologies Research on Color Contour Map of 3D Injection Molding Simulation Results

2012 ◽  
Vol 217-219 ◽  
pp. 1998-2001
Author(s):  
Tie Geng ◽  
Qing Hai Ren ◽  
Wei Qing Tu ◽  
Dan Dan Liu
Keyword(s):  
Injection Molding ◽  
Color Image ◽  
Three Dimensional ◽  
Physical Field ◽  
Contour Map ◽  
Image Rendering ◽  
Color Range ◽  
Key Technologies ◽  
Injection Molding Simulation ◽  
Simulation Results

According to the color contour map of the 3D injection molding simulation results, the commonly used color contour map drawing algorithm was researched, and a three-dimensional color image rendering algorithm which based on the "physical field values and color range mapping" was given too. And the key technologies of the algorithm which was used to draw 3D color contour map were introduced in detail. In the end, an example was given.

Modeling Recrystallization for 3D Multi-Pass Forming Processes

2007 ◽  
Vol 558-559 ◽  
pp. 1201-1206 ◽  
Author(s):  
Mihaela Teodorescu ◽  
Patrice Lasne ◽  
Roland E. Logé
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Present Model ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
The Other ◽  
Finite Element Code ◽  
3D Numerical Simulation ◽  
Fraction Distribution ◽  
Simulation Results

The present work concerns the simulation of metallurgical evolutions in 3D multi-pass forming processes. In this context, the analyzed problem is twofold. One point refers to the management of the microstructure evolution during each pass or each inter-pass period and the other point concerns the management of the multi-pass aspects (different grain categories, data structure). In this framework, a model is developed and deals with both aspects. The model considers the microstructure as a composite made of a given (discretized) number of phases which have their own specific properties. The grain size distribution and the recrystallized volume fraction distribution of the different phases evolve continuously during a pass or inter-pass period. With this approach it is possible to deal with the heterogeneity of the microstructure and its evolution in multi-pass conditions. Both dynamic and static recrystallization phenomena are taken into account, with typical Avrami-type equations. The present model is implemented in the Finite Element code FORGE2005®. 3D numerical simulation results for a multi-pass process are presented.

scholarly journals A study about signal variation with minor receiver displacement in a meeting room at 60 GHz: measurements and simulations

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Muhammad Usman Sheikh ◽  
Kalle Ruttik ◽  
Riku Jäntti ◽  
Jyri Hämäläinen
Keyword(s):  
Power Level ◽  
Three Dimensional ◽  
60 Ghz ◽  
System Configuration ◽  
Conference Room ◽  
Channel Characteristics ◽  
Received Power ◽  
Simulation Results ◽  
Small Change ◽  
The Impact

AbstractThe aim of this work is to study the impact of small receiver displacement on a signal propagation in a typical conference room environment at a millimeter wave frequency of 60 GHz. While channel measurements provide insights on the propagation phenomena, their use for the wireless system performance evaluation is challenging. Whereas, carefully executed three-dimensional ray tracing (RT) simulations represent a more flexible option. Nevertheless, a careful validation of simulation methodology is needed. The first target of this article is to highlight the benefits of an in-house built three-dimensional RT tool at 60 GHz and shows the effectiveness of simulations in predicting different characteristics of the channel. To validate the simulation results against the measurements, two different transmitter (Tx) positions and antenna types along with ten receiver (Rx) positions are considered in a typical conference room. In first system configuration, an omnidirectional antenna is placed in the middle of the table, while in the second system configuration a directed horn antenna is located in the corner of the meeting room. After validating the simulation results with the measurement data, in the second part of this work, the impact of a small change, i.e., 20 cm in the receiver position, is studied. To characterize the impact, we apply as performance indicators the received power level, root mean square delay spread (RMS-DS) and RMS angular spread (RMS-AS) in azimuth plane. The channel characteristics are considered with respect to the direct orientation (DO), i.e., the Rx antenna is directed toward the strongest incoming path. Different antenna configurations at the Tx and Rx side are applied to highlight the role of antenna properties on the considered channel characteristics. Especially, in the second system configuration the impact of different antenna half power beamwidth on different considered channel characteristics is highlighted through acquired simulation results. The validation of results shows the RMS error of only 2–3 dB between the measured and simulated received power levels for different Tx configurations in the direction of DO. Results indicate that only a small change of the Rx position may result a large difference in the received power level even in the presence of line-of-sight between the Tx and Rx. It is found that the STD of received power level across the room increases with the decrease in HPBW of the antenna. As can be expected, directed antennas offer lower value of RMS-DS and RMS-AS compared with isotropic antenna.

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