scholarly journals Piercing and Surface-Crack Defects in Cold Combined Forward-Backward Extrusion

2021 ◽  
Vol 11 (9) ◽  
pp. 3900
Author(s):  
Heng-Sheng Lin ◽  
Chien-Yu Lee ◽  
Wen-Shun Li
Keyword(s):  
Surface Crack ◽  
Metal Flow ◽  
Forming Limit Diagram ◽  
Extrusion Ratio ◽  
Forming Limit ◽  
Element Analysis ◽  
Backward Extrusion ◽  
The Finite Element Analysis ◽  
Fracture Damage ◽  
Fracturing Mechanism

Metal flow tends to be complex and difficult to predict in the combined forward-backward extrusion (CFBE) process. Piercing and surface-crack defects are phenomenal in forming fasteners featuring a forward extruded pin and a backward extruded cup. In this work, a series of the CFBE tests with various combinations of the forward extrusion ratio (FER) and the backward extrusion ratio (BER) were conducted. A forming limit diagram, detailed with the piercing and surface-crack defects on the forward extruded pin or the backward extruded cup, was developed to provide a conception in choosing appropriate extrusion ratios in forming fasteners with such pin-and-cup features. With the aid of the forming load-stroke curves and the finite element analysis of fracture damage, the fracturing mechanism for the CFBE process was provided.

Research on Finite Element Simulation and Test of Two-Pass Deep Drawing Forming for Conical Parts

2013 ◽  
Vol 652-654 ◽  
pp. 1966-1970
Author(s):  
Zhi Ren Han ◽  
Ze Bing Yuan
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Deep Drawing ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Element Analysis ◽  
Element Simulation ◽  
The Finite Element Analysis ◽  
Deep Drawing Test ◽  
As Stress

This paper is focus on two-Pass Deep Drawing Forming of conical axisymmetric parts, study on the finite element simulation and test of multi-Pass deep drawing part. It carry on the finite element analysis and calculation using the ANSYS/LS-DYNA software platform, analyzing the simulation results such as stress , strain distribution and formability by post-processing LSPOST software. It was done multi-Pass deep drawing test using a set of combined type mould. Based on the multi-Pass forming test by using a set of combined type mould, comparison of simulation and test data can be obtained through the forming limit diagram. The result of simulation and test is basically the same and both reflect the formability.

scholarly journals A Study on the Forming Characteristics of AZ 31B Mg Alloy in a Combined Forward–Backward Extrusion at Warm Temperatures

2018 ◽  
Vol 8 (11) ◽  
pp. 2187 ◽  
Author(s):  
Duk Yoon ◽  
Eung-Zu Kim ◽  
Kyoung Na ◽  
Yong-Shin Lee
Keyword(s):  
Finite Element ◽  
Experimental Studies ◽  
Extrusion Ratio ◽  
Mg Alloy ◽  
Forming Limit ◽  
Analysis Model ◽  
Element Analysis ◽  
Backward Extrusion ◽  
Forward Extrusion ◽  
Forming Characteristics

This paper was on the forming characteristics of AZ 31B Mg alloy in a combined forward–backward extrusion (CFBE) at warm temperatures. Both experimental studies and thermomechanical finite element analyses were performed. A finite element analysis model coupled with damage evolution was presented. Based on our previous work, the forward extrusion ratio, backward extrusion ratio, forming temperature, and punch speed were chosen as the most important process parameters. Two punch speeds of 2 mm/s and 20 mm/s were examined for the forming temperatures of 180 °C and 200 °C. Forward extrusion ratios were 2.25, 4.0, and 9.0, while backward extrusion ratios were 1.33, 2.16, 4.02, and 7.75. Effects of those parameters on the forming limit, deformation behaviors, extrusion load, and the mechanical properties of an extruded product were discussed in detail.

Optimization of Sheet Metal Process Parameters of a Shield Case Piece Using Computer Simulation

2006 ◽  
Vol 510-511 ◽  
pp. 330-333
Author(s):  
M.C. Curiel ◽  
Ho Sung Aum ◽  
Joaquín Lira-Olivares
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Physical Processes ◽  
Forming Process ◽  
Element Analysis ◽  
One Step ◽  
Range Of Values ◽  
Principal Strains

Numerical simulations based on Finite Element Analysis (FEA) are widely used to predict and evaluate the forming parameters before performing the physical processes. In the sheet metal industry, there are basically two types of FE programs: the inverse (one-step) programs and the incremental programs. In the present paper, the forming process of the shield case piece (LTA260W1-L05) was optimized by performing simulations with both types of software. The main analyzed parameter was the blankholding force while the rest of the parameters were kept constant. The criteria used to determine the optimum value was based on the Forming Limit Diagram (FLD), fracture and wrinkling of the material, thickness distribution, and the principal strains obtained. It was found that the holding force during the forming process deeply affects the results, and a range of values was established in which the process is assumed to give a good quality piece.

Stress and Strain Distribution in the Upsetting Process

2021 ◽  
pp. 288-301
Author(s):  
Japheth Obiko ◽  
Fredrick Madaraka Mwema
Keyword(s):  
Finite Element ◽  
Strain Distribution ◽  
Metal Flow ◽  
Stress Strain ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Contact Surfaces ◽  
Stress Behaviour ◽  
Stress And Strain Distribution ◽  
Forging Load

Numerical simulation of metal flow behaviour was studied using DeformTM3D software. The simulation process was done on X20 steel taken from the software database at 1073-1273K temperature, 10mm/s die speed, and 67% height reduction. From the simulation results, forging load, damage, and stress/strain distributions were obtained. The results show that the forging load increased with a decrease in temperature or decreased with an increase in temperature. The maximum damage values increased as the temperature increased. The obtained maximum damage values were 0.42 (1073K), 0.43 (1173K), and 0.45 (1273K). The damage distribution was inhomogeneous in the deformed cylinder. The stress/strain distributions were inhomogeneous in the deformed cylinder. The location of the maximum strain was at the centre of the deformed cylinder while the maximum stress occurred at the die-cylinder contact surfaces. The study showed that flow stress behaviour can be predicted using finite element method. This shows the feasibility of applying the finite element analysis to analyse the forging process.

Study on the Finite Element Numerical Simulation of Automobile Crossbeam Stamping Forming

2011 ◽  
Vol 55-57 ◽  
pp. 2104-2108
Author(s):  
Xiao Chun Ma ◽  
Wei Bing Shen ◽  
Yi Qiang Zhuang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Optimal Parameter ◽  
Thickness Distribution ◽  
Metal Flow ◽  
Forming Limit Diagram ◽  
Design Parameters ◽  
Forming Limit ◽  
Explicit Finite Element ◽  
Finite Element Numerical Simulation

This paper is concerned with the quantitative effect of design parameters on the stamping process of automobile crossbeam. The considered parameters in this paper are the friction coefficient, the die fillet radius and the blank holding force, which greatly affect the metal flow during stamping. Based on the finite element numerical simulation, the stamping shaped process of the automobile crossbeam is numerical simulated with the explicit finite element method with various parameters by dint of Dynaform software. According to the simulation results, the forming limit diagram(FLD) and the wall thickness distribution of cloud on the stamping processes are technologically analyzed, the reasons and control methods of wrinkling are also pointed out, and then the optimal parameter combination of the automobile crossbeam is obtained by orthogonal experiments. It is noted that the parametric study of design parameters such as µ , BHF and RD are very important in the process design of the complicated member.

Prediction of Limiting Strains for Square Pattern – Square Hole Perforated Commercial Pure Aluminium Sheets

2012 ◽  
Vol 548 ◽  
pp. 382-386 ◽  
Author(s):  
G. Venkatachalam ◽  
S. Narayanan ◽  
Narayanan C. Sathiya
Keyword(s):  
Sheet Metal ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Pure Aluminium ◽  
Element Analysis ◽  
Material Condition ◽  
Geometrical Features ◽  
Perforated Sheet ◽  
Commercial Aluminium ◽  
Aluminium Sheets

Forming limit diagram (FLD) is the most appropriate tool used to obtain the safe strain region in sheet metal forming industries. This FLD is based on limiting values of major and minor strains. This Limiting strain is the strain at the onset of fracture / necking in a sheet metal. It is influenced by the material / condition of the material, strain condition in geometrical features of a sheet metal. In this paper, square pattern – square holed, perforated commercial aluminium sheets are considered for the study. The limiting strain for the above perforated sheet metals is predicted using finite element analysis. It is found that the limiting strain is controlled by percentage of open area, ligament ratio and hole size.

scholarly journals Viscous Backpressure Forming And Feasibility Study of Hemispherical Aluminum Alloy Parts

2021 ◽  
Author(s):  
Tiejun Gao ◽  
Jiabin Zhang ◽  
Kaixuan Wang
Keyword(s):  
Finite Element Analysis ◽  
Aluminum Alloy ◽  
Forming Limit Diagram ◽  
Loading Path ◽  
Forming Limit ◽  
Distribution Law ◽  
Forming Process ◽  
Element Analysis ◽  
Technical Feasibility ◽  
Forming Limit Diagrams

Abstract Hemispherical aluminum alloy parts are extensively used in modern aerospace and other manufacturing fields. However, wrinkling and cracking easily occur due to the large deformation of the parts, which leads to a complicated forming process. This research proposes a viscous backpressure forming method for hemispherical aluminum alloy parts. The forming limit diagram of LF2 sheet is established through the forming limit experiments. By the combination of finite element analysis and experimental verification, the forming process of the parts under different viscous backpressure and loading path conditions as well as the distribution law of stress-strain and wall thickness of the parts, are obtained. By comparing with the forming limit diagrams, technical feasibility of this forming process is discussed. The research results show that qualified parts can be formed using the viscous backpressure forming method under the conditions of viscous backpressure loading throughout the process with the backpressure at or above 12MPa. This provides a reference for the backpressure forming of hemispherical aluminum alloy parts.

Development and Application of the Finite Element Analysis Program of the Stress-Based Forming Limit Criterion for Sheet Metal Forming

2007 ◽  
Vol 561-565 ◽  
pp. 1995-1998
Author(s):  
Ming He Chen ◽  
J.H. Li ◽  
Lin Gao ◽  
Dun Wen Zuo ◽  
Min Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Forming Limit ◽  
Analysis Program ◽  
Element Analysis ◽  
The Finite Element Analysis

In order to solve the problem existed in the numerical simulation of sheet metal forming for its use the strain-based forming limit diagram as criterion, which has the flaw of dependence on the strain paths, this paper develops the finite element analysis program based on the stress forming limit criterion applicable to the blank plastic forming technique, which follows the stress-strain transformation relationship when the sheet metal is undergoing plastic deformation, chooses Hill’s quadratic normal anisotropic criterion as computational model and selects the commercial finite element code Dynaform as its development environment. Also it be analyzed the finite element numerical simulation results of two deep drawing parts by the developed program module and realizes the prediction of sheet metal forming limit adopting the FLSD as criterion. The stress-based forming limit criterion for the developed program provides a new means to analyze the forming limit for the multistage sheet metal forming.

scholarly journals PADDLE SHAPE OPTIMIZATION FOR HOLE-FLANGING BY PADDLE FORMING THROUGH THE USE OF A PREDEFINED STRAIN PATH IN FINITE ELEMENT ANALYSIS

2019 ◽  
Vol 19 (2) ◽  
pp. 83-98 ◽  
Author(s):  
Lemopi Isidore BESONG ◽  
Johannes BUHL ◽  
Markus BAMBACH
Keyword(s):  
Finite Element ◽  
Strain Path ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Element Analysis ◽  
High Speeds ◽  
The Right ◽  
Hole Flanging ◽  
Bulge Formation ◽  
Principal Strains

This research investigates a novel hole-flanging process by paddle forming through the use of finite element (FE) simulations. Paddles of different shapes rotating at high speeds were used to deform clamped sheets with pre-drilled holes at their centers. The results of the simulations show that the paddle shape determines the geometry and principal strains of the formed flanges. A convex-shaped paddle forms flanges with predominant strains in the left quadrant of the forming limit diagram (FLD). However, the convex paddle promotes unwanted bulge formation at the clamped end of the flange. A concave paddle forms flanges with no bulge but the principal strains of elements in the middle section of the flange are in the right quadrant of the FLD which indicates an increased probability for crack occurrence. An optimization of the paddle shape was conducted to prevent bulging at the clamped end while avoiding crack occurrence. The paddle shape was optimized by mapping the deformation of some elements along the flange length to a pre-defined strain path on the FLD while maintaining the bulge height within the desired geometric tolerance. The radii and lengths of the paddle edge were varied to obtain an optimum paddle shape.

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