Investigation of a Two-Step Rotary Rim-Thickening Process of Disc-Like Blanks

2018 ◽  
Vol 920 ◽  
pp. 89-94
Author(s):  
Dao Kuan Wang ◽  
Jun Song Jin ◽  
Xin Yun Wang
Keyword(s):  
Cross Section ◽  
Fe Simulation ◽  
Forming Limit Diagram ◽  
Second Step ◽  
Forming Limit ◽  
Trial And Error ◽  
Rectangular Shape ◽  
Factors Influencing ◽  
Main Factors ◽  
The Stability

A two-step rotary rim-thickening process of disc-like blanks was investigated by FE simulation and spinning experiments. The preforming shape of cross section for first step was designed as trapezium before forming rectangular-shape rim in the second step. The main factors influencing the blank forming in the first step were groove bottom height h1 and the inclination angle α of the roller. With the increase of h1 and α of the roller in FE simulation, the workpiece will be more prone to lose stability and cause defects. The forming limit diagram was obtained in first step, including stable forming zone, unstable forming zone and failed forming zone. Considering the stability and efficiency of thickening, four groups of h1 and α were selected for the second step simulation. Maximum rim thickness (h2) after second-step forming was 9 mm, obtained by trial and error in FE simulations. The spinning experiments were carried out to verify the validity of numerical simulation.

The Stability of Weft Insertion of CRT – 83 Carpet Rapier Loom

2013 ◽  
Vol 457-458 ◽  
pp. 684-687
Author(s):  
Yong Dong Cai ◽  
Shun Bin Ma
Keyword(s):  
Theoretical Analysis ◽  
Initial Deformation ◽  
Weft Yarn ◽  
High Grade ◽  
Release Times ◽  
Factors Influencing ◽  
Main Factors ◽  
The Stability ◽  
Theory Research

CRT- 83 carpet rapier loom is a kind of high-grade rigid rapier loom，the weft yarn will give looms to demand higher stability of the weft insertion. Theoretical analysis based on the theory research of the stability of clamping weft and weft handover shows that the rapier deformation，slipping force and the depth of clamping are main factors influencing the stability of weft insertion.In order to obtain reasonable process of weft insertion，concerned with the following factors：the grip length and outrigger length of rapier，release times of clip yarn device，initial deformation angle of spring piece.

Finite Element Analysis on Stability for Elastic-Jumping Membrane

2011 ◽  
Vol 287-290 ◽  
pp. 717-722 ◽  
Author(s):  
Zhen Ting Wu ◽  
Shun Jiang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Critical Load ◽  
Element Model ◽  
Structure Parameter ◽  
Element Analysis ◽  
Factors Influencing ◽  
Optimizing Design ◽  
Main Factors ◽  
The Stability

In order to increase the designing precision and study the main factors influencing the stability of metal elastic-jumping membrane, a set of experimental equipments have been designed to test the stability of metal elastic-jumping membrane. The laws of influencing the stability of elastic-jumping membrane were studies by changing the thickness, high, radius etc structure parameter. It shows that the increasing of high and thickness can enhance the distortion rigidity of metal elastic-jumping membrane, result in the increase of critical load at losing stability; the increasing of diameter can reduce the distortion rigidity of metal elastic-jumping membrane, result in the decrease of critical load at losing stability. At the same time, the correctness of finite element model was confirmed, and the basis was established for finite element method applying in optimizing design of metal elastic-jumping membrane.

scholarly journals MAIN FACTORS INFLUENCING THE CHOICE OF TRANSPORTATION METHOD

2021 ◽  
Vol 1 (1) ◽  
pp. 191-192
Author(s):  
Yuliya Poltavskaya
Keyword(s):  
Transport System ◽  
Factors Influencing ◽  
Main Factors ◽  
The Stability

An overview of the factors influencing the choice between intermodal and unimodal modes of transportation is presented. Determining the ranges of equally advantageous transportation distances will increase the stability of the transport system, considering the technical and operational characteristics of modes of transport

Effect of Internal Pressure and Dent Depth on Strain Distribution of Pressurized Pipe Subjected to Indentation

2013 ◽  
Vol 376 ◽  
pp. 135-139 ◽  
Author(s):  
Maziar Ramezani ◽  
Thomas Rainer Neitzert
Keyword(s):  
Plastic Deformation ◽  
Internal Pressure ◽  
Cross Section ◽  
Strain Distribution ◽  
Fe Simulation ◽  
Circular Cross Section ◽  
Numerical Results ◽  
Rectangular Shape ◽  
Longitudinal Strains ◽  
Dent Depth

A dent in a pipeline is a permanent plastic deformation of the circular cross section of the pipe. This paper discusses numerical results obtained from finite element (FE) simulation of pressurized pipe subjected to radial denting by a rigid indenter. Dent produced by rectangular shape indenter is assessed and the strain distribution of the pipe is investigated. The effect of internal pressure and dent depth on the distribution of strain is also studied. The results show that the circumferential and longitudinal strains increase with increasing the internal pressure and the depth of the dent. Numerical results are compared with an empirical theoretical model in order to demonstrate the accuracy of the analysis.

Prediction of load requirement and instabilities during end forming of friction stir processed AA 6063-T6 thin-walled tubes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Arvind K. Agrawal ◽  
R. Ganesh Narayanan
Keyword(s):  
Fe Simulation ◽  
Forming Limit Diagram ◽  
Mapping Method ◽  
Forming Limit ◽  
Strain Mapping ◽  
Content Type ◽  
Simulation Methodology ◽  
Anisotropic Properties ◽  
Friction Stir ◽  
Failure Theories

PurposeThe current work aims to propose a finite element (FE) simulation methodology to predict the formability of friction stir processed (FSPed) tubes by end forming. Moreover, a strain mapping method is also presented to predict the end forming instabilities.Design/methodology/approachIn this work, FE simulation of end forming of raw tubes and FSPed AA6063-T6 tubes are done using Abaqus (explicit) incorporating anisotropic properties of the raw tube and FSPed zone. Actual thickness of the FSPed zone is also implemented. Expansion, reduction and beading are the end forming operations considered. Load requirement and instabilities are predicted. A new method “strain mapping method” is followed to predict the failure instabilities in expansion and beading, while during reduction, wrinkling is predicted by FE simulations. Lab scale experiments on FSP and end forming are done for validation at various rotational speeds.FindingsResults reveal that in the case of expansion and reduction of FSPed tubes, forming load predictions are accurate, while in beading, after initiation of bead, predictions are not accurate. Experimental observation on the type of instability is consistently predicted during numerical simulations. Prediction of displacement at failure by strain mapping method is encouraging in most of the cases including those that are FSPed. Hence, it is suggested that the method can be utilized to evaluate the onset of failure during tube expansion and beading.Originality/valueFE simulation methodology including anisotropic properties of raw tube and FSPed tubes is proposed, which is not attempted until now even for normal tubes. Strain mapping method is easy to implement for instability predictions, which is done usually by failure theories and forming limit diagram.

Comparison of Experimental and Numerical Failure Criterion for Formability Prediction of Automotive Part

2013 ◽  
Vol 658 ◽  
pp. 354-360 ◽  
Author(s):  
Jun Seok Yoon ◽  
Hak Gon Noh ◽  
Woo Jin Song ◽  
Beom Soo Kang ◽  
Jeong Kim
Keyword(s):  
Sheet Metal ◽  
Failure Criterion ◽  
Fe Simulation ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Forming Process ◽  
Gtn Model ◽  
Numerical Result ◽  
Automotive Part ◽  
Nakajima Test

The ability to predict the forming severity with respect to crack and failure is essential to analysis of sheet metal forming process. The forming limit diagram (FLD) is commonly used to gauge the formability of sheet metal. In this article, forming limit diagrams of cold rolled carbon steel (JIS-SPCC), which widely used to produce the parts of automobile, are obtained by performing experiment and FE simulation with the Nakajima-test. By using the GTN (Gurson-Tvergaard -Needleman) damage mechanical model, a failure criterion based on void evolution was examined in this FE simulation. The parameters of GTN model are determined through comparison of experimental and numerical result with Nakajima-test. These parameters acceptably can be used in GTN model using given material. In application case, the reliability of the GTN model for failure criterion in simulation with automotive part was confirmed.

Modelling of Instability and Fracture Effects in the Sheet Metal Forming Based on an Extended X-FLC Concept

2016 ◽  
Vol 725 ◽  
pp. 15-32
Author(s):  
Pavel Hora ◽  
Bekim Berisha ◽  
Maysam Gorji ◽  
Holger Hippke
Keyword(s):  
Sheet Metal ◽  
Cross Section ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Forming Limit Diagram ◽  
Al Alloys ◽  
Forming Limit ◽  
Section Method ◽  
The Real ◽  
Cross Section Method

The industrial necking prediction in sheet metal forming is still based on the Forming Limit Diagram (FLD) as initially proposed by Keeler. The FLD is commonly specified by the Nakajima tests and evaluated with the so called cross section method. Although widely used, the FLC concept has numerous serious limitations. In the paper the influences of bending on the FLC as well as postponed crack limits will be discussed. Both criteria will be combined to an extended FLC concept (X-FLC). The new concept demonstrates that the Nakajima tests are not only appropriate for the evaluation of the necking instability, but also for the detection of the real crack strains. For the evaluation of the crack strains, a new local thinning method is proposed and tested for special 6xxx Al-alloys.

scholarly journals Factors Influencing the Corrosion of Infantry Weapons’ Barrels

2021 ◽  
Vol 27 (3) ◽  
pp. 92-96
Author(s):  
Stelian Popescu
Keyword(s):  
Factors Influencing ◽  
Inner Surface ◽  
Main Factors ◽  
The Stability ◽  
Design And Construction ◽  
Weapons Systems

Abstract The condition of the inner surface of the barrels greatly influences the stability of the bullet and the accuracy of firing with infantry weapons. Therefore, it is of particular importance to keep the inside of the barrels in perfect condition and to protect them against corrosion. For this reason, the article aims to highlight the possible degradation of the inside of the barrels in operation and the main factors influencing their corrosion, in order to counteract their effect. The whole issue is addressed both to the personnel specialized in the design and construction of infantry weapons systems and to the personnel that uses them.

scholarly journals Insight into the Influence of Punch Velocity and Thickness on Forming Limit Diagrams of AA 6061 Sheets—Numerical and Experimental Analyses

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2010
Author(s):  
Sasan Sattarpanah Karganroudi ◽  
Shahab Shojaei ◽  
Ramin Hashemi ◽  
Davood Rahmatabadi ◽  
Sahar Jamalian ◽  
...  
Keyword(s):  
Finite Element ◽  
Fe Simulation ◽  
Forming Limit Diagram ◽  
Material Model ◽  
Forming Limit ◽  
Forming Limit Diagrams ◽  
Punch Velocity ◽  
Experimental Analyses ◽  
Insight Into ◽  
Good Agreement

In this article, the forming limit diagram (FLD) for aluminum 6061 sheets of thicknesses of 1 mm and 3 mm was determined numerically and experimentally, considering different punch velocities. The punch velocity was adjusted in the range of 20 mm/min to 200 mm/min during the Nakazima test. A finite element (FE) simulation was carried out by applying the Johnson–Cook material model into the ABAQUSTM FE software. In addition, a comparison between the simulation and the experimental results was made. It was observed that by increasing the punch velocity, the FLD also increased for both thicknesses, but the degree of the improvement was different. Based on these results, we found a good agreement between numerical and experimental analyses (about 10% error). Moreover, by increasing the punch velocity from 20 mm/min to 100 mm/min in 1 mm-thick specimens, the corresponding FLD increased by 3.8%, while for 3 mm-thick specimens, this increase was 5.2%; by increasing the punch velocity from 20 mm/min to 200 mm/min in the 3 mm-thick sheets, the corresponding FLD increased by 9.3%.

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