Improving Formability in Sheet Metal Stamping With Active Drawbead Technology

2000 ◽  
Vol 123 (4) ◽  
pp. 504-510 ◽  
Author(s):  
M. L. Bohn ◽  
S. G. Xu ◽  
K. J. Weinmann ◽  
C. C. Chen ◽  
A. Chandra
Keyword(s):  
Strain Distribution ◽  
Forming Limit Diagram ◽  
Temporal Variations ◽  
Forming Limit ◽  
Sheet Metal Stamping ◽  
Metal Stamping ◽  
Comparison Of The Results ◽  
Restraining Force ◽  
Diagram Analysis ◽  
Good Agreement

Aluminum is expected to gain popularity as material for the bodies of the next generation of lighter and more fuel-efficient vehicles. However, its lower formability compared with that of steel tends to create considerable problems. A controllable restraining force caused by adjusting the penetration of drawbeads can improve the formability. This paper describes the effects of temporal variations in drawbead penetration on the strain distribution in a symmetric stamped part. Comparison of the results of numerical simulations with the corresponding experimental results shows that the predictions of strain distribution on the panel are in very good agreement. Furthermore, forming limit diagram analysis indicates that the active drawbead concept is beneficial to the formability of AA 6111-T4.

Improving Formability in Sheet Metal Stamping With Active Drawbead Technology

2000 ◽  
Author(s):  
M. L. Bohn ◽  
S. G. Xu ◽  
K. J. Weinmann ◽  
C. C. Chen ◽  
A. Chandra
Keyword(s):  
Strain Distribution ◽  
Forming Limit Diagram ◽  
Temporal Variations ◽  
Forming Limit ◽  
Sheet Metal Stamping ◽  
Metal Stamping ◽  
Comparison Of The Results ◽  
Restraining Force ◽  
Diagram Analysis ◽  
Good Agreement

Abstract Aluminum is expected to gain popularity as material for the bodies of the next generation of lighter and more fuel-efficient vehicles. However, its lower formability compared with that of steel tends to create considerable problems. A controllable restraining force caused by adjusting the penetration of drawbeads can improve the formability. This paper describes the effects of temporal variations in drawbead penetration on the strain distribution in a symmetric stamped part. Comparison of the results of numerical simulations with the corresponding experimental results shows that the predictions of strain distribution on the panel are in very good agreement. Furthermore, forming limit diagram analysis indicates that the active drawbead concept is beneficial to the formability of AA 6111-T4.

Analysis of Tube Hydroforming by Means of an Inverse Approach1

2003 ◽  
Vol 125 (2) ◽  
pp. 369-377 ◽  
Author(s):  
Ba Nghiep Nguyen ◽  
Kenneth I. Johnson ◽  
Mohammad A. Khaleel
Keyword(s):  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Computational Time ◽  
Forming Limit ◽  
Hydraulic Pressure ◽  
Computational Tool ◽  
Incremental Method ◽  
Inverse Approach ◽  
Initial Geometry ◽  
Good Agreement

This paper presents a computational tool for the analysis of freely hydroformed tubes by means of an inverse approach. The formulation of the inverse method developed by Guo et al. [1] is adopted and extended to the tube hydroforming problems in which the initial geometry is a round tube submitted to hydraulic pressure and axial feed at the tube ends (end-feed). A simple criterion based on a forming limit diagram is used to predict the necking regions in the deformed workpiece. Although the developed computational tool is a stand-alone code, it has been linked to the Marc finite element code for meshing and visualization of results. The application of the inverse approach to tube hydroforming is illustrated through the analyses of the aluminum alloy AA6061-T4 seamless tubes under free hydroforming conditions. The results obtained are in good agreement with those issued from a direct incremental approach. However, the computational time in the inverse procedure is much less than that in the incremental method.

Constitutive Modelling of Anisotropy, Hardening and Failure of Sheet Metals

2011 ◽  
Vol 473 ◽  
pp. 631-636 ◽  
Author(s):  
Ivaylo N. Vladimirov ◽  
Yalin Kiliclar ◽  
Vivian Tini ◽  
Stefanie Reese
Keyword(s):  
Kinematic Hardening ◽  
Plastic Anisotropy ◽  
Forming Limit Diagram ◽  
Material Model ◽  
Constitutive Modelling ◽  
Forming Limit ◽  
Isotropic Hardening ◽  
Continuum Damage ◽  
Aluminium Sheets ◽  
Good Agreement

The paper discusses the application of a newly developed coupled material model of finite anisotropic multiplicative plasticity and continuum damage to the numerical prediction of the forming limit diagram at fracture (FLDF). The model incorporates Hill-type plastic anisotropy, nonlinear Armstrong-Frederick kinematic hardening and nonlinear isotropic hardening. The numerical examples investigate the simulation of forming limit diagrams at fracture by means of the so-called Nakajima stretching test. Comparisons with test data for aluminium sheets display a good agreement between the finite element results and the experimental data.

Forming Defects Analysis of Auto-Panel Stamped Part with Experimental Strain Approach

2004 ◽  
Vol 471-472 ◽  
pp. 503-507
Author(s):  
H.Y. Xiang ◽  
Yue Xian Zhong
Keyword(s):  
Experimental Method ◽  
Strain Distribution ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Practical Case ◽  
Stamping Process ◽  
Automobile Panel ◽  
Defects Analysis ◽  
Forming Defects ◽  
Stamped Part

This document explains and demonstrates an experimental method to determine principal plastic strains in industrially stamped sheet panels. The principal strains distribution after a given stamping process can be obtained using computer aided grid experimental method. In contrast with FLD (Forming Limit Diagram) obtained by the material testing, the measured results of strain distribution can be used to determine the sheet metal’s formability allowing to determine at which point the sheet metal cracks or uneven stretch occurs and other forming defects. The main principle and related theory of this approach are discussed. One automobile panel stamped part as a practical case was studied, the strain distribution of the part after a given stamping process was measured and calculated, a demonstration of how to deal with the results in comparison with FLD to determine and solve forming problems is analyzed.

An Analysis of Forming Limit in Micro Deep Drawing of the Square Cup for Anisotropic Foil

2011 ◽  
Vol 105-107 ◽  
pp. 344-347
Author(s):  
Fung Huei Yeh ◽  
Ching Lun Li ◽  
Kun Nan Tsay
Keyword(s):  
Deep Drawing ◽  
Thickness Distribution ◽  
Forming Limit Diagram ◽  
Experimental Results ◽  
Forming Limit ◽  
Drawing Ratio ◽  
Micro Deep Drawing ◽  
Alloy Foil ◽  
Explicit Dynamic ◽  
Good Agreement

This paper presents an explicit dynamic finite element method (FEM) in conjunction with the forming limit diagram (FLD) to analyze the forming limit for the SPCC foil in micro deep drawing of square cup. In the present study, the tensile, anisotropic and friction test are performed to obtain the material parameters of the alloy foil according to the ASTM standards. Importing these properties, the numerical analysis is conducted by the explicit dynamic FEM. The FLD in numerical simulation is used as the criterion of the forming limit in micro deep drawing of the square cup. The forming limit, punch load-stroke relationship, deformed shape and thickness distribution of square cup, are discussed and compared with the experimental results. It shows that a good agreement is achieved from comparison between simulated and experimental results. The limit drawing ratio in micro deep drawing of square cup is 2.08 in this paper. From this investigation, the results of this paper can be used as reference in the relative researches and applications of micro forming.

Forming limit diagram of Al-Cu two-layer metallic sheets considering the Marciniak and Kuczynski theory

2016 ◽  
Vol 232 (5) ◽  
pp. 848-854 ◽  
Author(s):  
Ramin Hashemi ◽  
Ehsan Karajibani
Keyword(s):  
Forming Limit Diagram ◽  
Computational Approach ◽  
Forming Limit ◽  
Experimental Investigations ◽  
System Of Equations ◽  
Forming Limit Diagrams ◽  
Theoretical Predictions ◽  
Experimental Works ◽  
Quasi Newton ◽  
Good Agreement

The aim of this research was to introduce a computational approach for prediction of the forming limit diagram of Al-Cu two-layer metallic sheets. The computational approach was based on the modified Marciniak and Kuczynski theory. In this study, the forming limit diagrams of aluminum–copper two-layer metallic sheets were obtained through the modified Marciniak and Kuczynski theory and experimental investigations. In the present modified Marciniak and Kuczynski theory, there existed four nonlinear equations which were solved simultaneously. The Quasi-Newton Method was applied for a solution to the system of equations. To verify the theoretical predictions, the experimental works were accomplished on the Al-Cu two-layer metallic sheets and a good agreement between the proposed method and experimental works was observed.

An Analysis of Forming Limit for Various Arc Radii of Punch in Micro Deep Drawing of the Square Cup

2012 ◽  
Vol 433-440 ◽  
pp. 660-665
Author(s):  
Fung Huei Yeh ◽  
Ching Lun Li ◽  
Kun Nan Tsay
Keyword(s):  
Deep Drawing ◽  
Thickness Distribution ◽  
Forming Limit Diagram ◽  
Experimental Results ◽  
Forming Limit ◽  
Drawing Ratio ◽  
Micro Deep Drawing ◽  
Punch Load ◽  
Explicit Dynamic ◽  
Good Agreement

This paper presents an explicit dynamic finite element method (FEM) in conjunction with the forming limit diagram (FLD) to analyze the forming limit for the various arc radii of punch in micro deep drawing of square cup. In the present study, the tensile test and friction test are performed to obtain the material parameters of the electro-deposited copper foil according to the ASTM standards. Importing these properties, the numerical analysis is conducted by the explicit dynamic FEM. The FLD in numerical simulation is used as the criterion of the forming limit in micro deep drawing of the square cup. The forming limit, deformed shape, punch load-stroke relationship, height of cup and thickness distribution of square cup, are discussed and compared with the experimental results. It shows that a good agreement is achieved from comparison between simulated and experimental results. When the arc radii of punch increase with Rp=0.2, 0.5 and 0.8mm, the limit drawing ratio increases from 1.90 to 2.03 and 2.10. The forming limit of square cup increases with an increase of the arc radii of punch. From this investigation, the results of this paper can be used as reference in the relative researches and applications of micro forming.

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%.

Failure Prediction of Tubular Hydroforming Process Following Pre-Bending

2003 ◽  
Author(s):  
Z. C. Xia
Keyword(s):  
Forming Limit Diagram ◽  
Forming Limit ◽  
Straight Tube ◽  
Production Environment ◽  
Damage Growth ◽  
Complex Process ◽  
Metal Stamping ◽  
Bending Process ◽  
Hydroforming Process ◽  
Automotive Parts

Tubular hydroforming process for a majority of automotive parts is a complex process where the initially straight tube undergoes a series of pre-bending, pre-forming, die closure and then the final pressurization. The pre-bending process is usually carried out by a rotary bending machine and utilizes an inside mandrel to prevent the tube from collapsing during bending. Because of the high pressure exerted by the mandrel in the normal direction of the tube sheet, the failure mechanism for the tube in the subsequent hydroforming process will differ significantly from that experienced in sheet metal stamping process, which can be well characterized by the Forming Limit Diagram (FLD). The presentation begins with experimental evidence of material failure during hydroforming following pre-bending, and continues with two predictive models for analysis. One is a Gurson-type void growth model, and the other a damage based model which takes into account the effect of hydrostatic pressure in damage growth. Numerical examples are given to illustrate the effectiveness of both models and are compared to experimental data. Their applicability in an industrial production environment is discussed.

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