Investigation of the Strain Hardening and Bauschinger Effect of Low and High Strength Steel Application in Drawbead-Tester by Experiment and Numerical Simulation

2008 ◽  
Vol 55-57 ◽  
pp. 761-764
Author(s):  
K. Sirivedin ◽  
K. Krueger ◽  
V. Thoms ◽  
Dietmar Suesse ◽  
Roland Mueller ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Strain Hardening ◽  
Sheet Metal ◽  
Bauschinger Effect ◽  
Strain Analysis ◽  
High Strength ◽  
Local Strain ◽  
Simulation Method ◽  
Forming Process ◽  
Three Point Bending

The research is aimed to investigate Bauschinger effect and strain hardening by the application of drawbead-tester. Generally, the drawbead is used to control the material flow into the die cavity in sheet metal forming process. When the material is flowing into the drawbead, it may cause the development of strain hardening and/or Bauschinger effect. This work consists of two main equipment particularly developed for the experiments. They are drawbead-tester and three-point bending device. The drawbead-tester provides the possibility to integrate the optical in-process strain analysis system. Whereas the sheet metal was being formed in the drawbead, the local strain of the sheet metal was evaluated. At the same time, the drawbead restraining and holding forces were measured. The three point bending device and numerical simulation method are used to investigate the Bauschinger effect. In the experiment, the cyclic bending forces were measured and compared with the result obtained by numerical simulation.

Numerical Simulation of Sheet Deforming Caused by Laser Shocking

2004 ◽  
Vol 471-472 ◽  
pp. 860-864 ◽  
Author(s):  
Jian Zhong Zhou ◽  
Yong Kang Zhang ◽  
Dun Wen Zuo ◽  
Chao Jun Yang ◽  
Lan Cai
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Simulation Method ◽  
Laser Shock ◽  
Forming Process ◽  
Laser Shock Forming ◽  
Simulation Results ◽  
A New Technique ◽  
Sheet Deformation ◽  
Abaqus Software

Laser shock forming (LSF) is a new technique realized by applying a compressive shock wave generated by laser shocking on the surface of sheet metal. It is a mechanical, not a thermal process. After briefly reviewing the mechanism of LSF, instead of previously reported experimental research, a numerical simulation method of sheet deforming caused by laser shock waves is presented. The process of laser-shock plastic deforming of sheet metal is simulated with ABAQUS software, the simulation results are compared and agree well with the experiments on the condition of single laser shocking. It is shown that numerical simulation is available for optimizing laser parameters and predicting the sheet deformation contour of laser shock forming process.

Deformation Characteristics of Advanced High Strength Steel under Cyclic Bending and Reversed Bending

2015 ◽  
Vol 651-653 ◽  
pp. 175-180
Author(s):  
Fuh Kuo Chen ◽  
Sin Liang Lin ◽  
Heng Kuang Tsai ◽  
Yi Wei Lin ◽  
I Kai Lin
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Metal Forming ◽  
Bauschinger Effect ◽  
High Strength ◽  
Bending Test ◽  
Forming Process ◽  
Element Analysis ◽  
Bending Tests ◽  
The Finite Element Analysis

In the present study, the Bauschinger effect exhibited in the advanced high strength steel under cyclic bending and reversed bending deformation was examined by both the experimental approach and the finite element analysis. The cyclic tension-compression tests were first conducted for the DP590 steel sheet to determine the material constants required in the Yoshida-Uemori model used in the finite element simulations. Since the deformation mode occurred in the reversed bending tests is similar to that presented in the sheet metal passing across the draw bead or die corner, a three-point reversed bending test apparatus was also developed and the experiments were conducted in the present study. The reversed bending test results clearly demonstrate that the Bauschinger effect presents in the reversed bending process. It confirms that the cyclic reversed bending tests can be applied to examine the Bauschinger effect exhibited in the sheet metal forming process. The finite element analysis was also performed to simulate both the U-hat bending and cyclic reversed bending processes. The comparison of the simulation results with the experimental data reveals that the finite element predictions in both springback and reversed bending load are more accurate if the Yoshida-Uemori model is adopted. It implies that consideration of the Bauschinger effect is necessary in the sheet metal forming if a reversed loading path is present during the forming process.

scholarly journals Laser Welding of High-strength Aluminium Alloys for the Sheet Metal Forming Process

Procedia CIRP ◽  
2014 ◽  
Vol 18 ◽  
pp. 203-208 ◽  
Author(s):  
J. Enz ◽  
S. Riekehr ◽  
V. Ventzke ◽  
N. Sotirov ◽  
N. Kashaev
Keyword(s):  
Laser Welding ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Aluminium Alloys ◽  
High Strength ◽  
Forming Process ◽  
Metal Forming Process

Comparison between an Advanced Numerical Simulation of Sheet Incremental Forming Using Adaptive Remeshing and Experimental Results

2013 ◽  
Vol 554-557 ◽  
pp. 1375-1381 ◽  
Author(s):  
Laurence Giraud-Moreau ◽  
Abel Cherouat ◽  
Jie Zhang ◽  
Houman Borouchaki
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Sheet Metal ◽  
Metal Forming ◽  
Tool Path ◽  
Incremental Forming ◽  
Computation Time ◽  
Experimental Results ◽  
Forming Process ◽  
Adaptive Remeshing

Recently, new sheet metal forming technique, incremental forming has been introduced. It is based on using a single spherical tool, which is moved along CNC controlled tool path. During the incremental forming process, the sheet blank is fixed in sheet holder. The tool follows a certain tool path and progressively deforms the sheet. Nowadays, numerical simulations of metal forming are widely used by industry to predict the geometry of the part, stresses and strain during the forming process. Because incremental forming is a dieless process, it is perfectly suited for prototyping and small volume production [1, 2]. On the other hand, this process is very slow and therefore it can only be used when a slow series production is required. As the sheet incremental forming process is an emerging process which has a high industrial interest, scientific efforts are required in order to optimize the process and to increase the knowledge of this process through experimental studies and the development of accurate simulation models. In this paper, a comparison between numerical simulation and experimental results is realized in order to assess the suitability of the numerical model. The experimental investigation is realized using a three-axis CNC milling machine. The forming tool consists in a cylindrical rotating punch with a hemispherical head. A subroutine has been developed to describe the tool path from CAM procedure. A numerical model has been developed to simulate the sheet incremental forming process. The finite element code Abaqus explicit has been used. The simulation of the incremental forming process stays a complex task and the computation time is often prohibitive for many reasons. During this simulation, the blank is deformed by a sequence of small increments that requires many numerical increments to be performed. Moreover, the size of the tool diameter is generally very small compared to the size of the metal sheet and thus the contact zone between the tool and the sheet is limited. As the tool deforms almost every part of the sheet, small elements are required everywhere in the sheet resulting in a very high computation time. In this paper, an adaptive remeshing method has been used to simulate the incremental forming process. This strategy, based on adaptive refinement and coarsening procedures avoids having an initially fine mesh, resulting in an enormous computing time. Experiments have been carried out using aluminum alloy sheets. The final geometrical shape and the thickness profile have been measured and compared with the numerical results. These measurements have allowed validating the proposed numerical model. References [1] M. Yamashita, M. Grotoh, S.-Y. Atsumi, Numerical simulation of incremental forming of sheet metal, J. Processing Technology, No. 199 (2008), p. 163 172. [2] C. Henrard, A.M. Hbraken, A. Szekeres, J.R. Duflou, S. He, P. Van Houtte, Comparison of FEM Simulations for the Incremental Forming Process, Advanced Materials Research, 6-8 (2005), p. 533-542.

Blechkomponenten aus hochfestem Aluminium*/Sheet metal components made of high-strength aluminium

2018 ◽  
Vol 108 (10) ◽  
pp. 639-645
Author(s):  
P. Groche ◽  
J. Günzel ◽  
T. Suckow
Keyword(s):  
Heat Treatment ◽  
Sheet Metal ◽  
Construction Material ◽  
High Strength ◽  
Process Chain ◽  
Lightweight Construction ◽  
Forming Process ◽  
Specific Strength ◽  
Treatment Processes ◽  
High Specific Strength

Zur Ausnutzung der hohen spezifischen Festigkeit und folglich Eignung als Leichtbauwerkstoff von EN AW-7075 bedarf es neben den Umform- auch Wärmebehandlungsprozessen, die im Folgenden in den Umformprozess integriert werden und die Prozesskette somit deutlich kürzer und effizienter gestalten. Dieser Fachbeitrag zeigt, welches Produktivitäts- und Leichtbaupotenzial durch eine Inline-Wärmebehandlung erschlossen werden kann.   To be able to exploit the high specific strength and thus suitability of EN AW-7075 as a lightweight construction material, it requires not only forming but also heat treatment processes. The latter become integrated into the forming process and thus make the process chain significantly shorter and more efficient. This paper points out the potential for productivity and lightweight construction to be tapped by inline heat treatment.

Investigating Bauschinger Effect and Plastic Hardening Characteristics of Sheet Metal under Cyclic Loading

2017 ◽  
Vol 4 (2) ◽  
pp. 1-14 ◽  
Author(s):  
Jasri Mohamad
Keyword(s):  
Cyclic Loading ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Bauschinger Effect ◽  
Low Carbon Steel ◽  
Cyclic Hardening ◽  
Low Carbon ◽  
Forming Process ◽  
Metal Forming Process

To improve sheet metal forming process simulation using finite element method, there is a need to incorporate an appropriate constitutive equation capable of describing the Bauschinger effect and the so-called cyclic transient, derived from a near to actual sheet metal forming process testing tool. A cyclic loading tool has been developed to test and record the characteristics of sheet metal deformation by investigating the Bauschinger effect factors (BEF) and cyclic hardening behaviour. Experimental investigation conducted on low carbon steel and stainless steel demonstrates that the tool is able to record sheet metal behaviour under cyclic loading. The results are analysed for signs of the Bauschinger effect and cyclic hardening effect. It was found that the Bauschinger effect does occur during bending and unbending loadings in sheet metal forming process.

scholarly journals The Effect of Swinging Ball Heads with Different Arrangements in Multi-Point Stretch-Forming Process

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 337 ◽  
Author(s):  
Jian Xing ◽  
Yan-yan Cheng ◽  
Zhuo Yi
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Sheet Metal ◽  
Strain Distribution ◽  
Finite Element Models ◽  
Stretch Forming ◽  
Forming Process ◽  
Forming Quality ◽  
Staggered Arrangement ◽  
Simulation Results

To improve the effect of multi-point stretch forming of sheet metal, it is proposed in this paper to replace a fixed ball head with a swinging ball head. According to the multi-point dies with different arrangements, this research establishes finite element models of the following stretch forming, i.e., fixed ball heads with conventional arrangement, swinging ball heads with conventional arrangement, swinging ball heads with declining staggered arrangement, and swinging ball heads with parallel staggered arrangement, and then numerical simulation is performed. The simulation results show that by replacing a fixed ball head with a swinging ball head, the surface indentation of the part formed was effectively suppressed, the stress and tension strain distribution of the part formed was improved, and the forming quality was improved; the thickness of the elastic pad was reduced, the springback was reduced and the forming accuracy was improved; and when the ball head was applied to a multi-point die with staggered arrangement, a better forming result was achieved, where the best forming result was achieved in combining the swinging ball heads with the multi-point die with a parallel staggered arrangement. Forming experiments were carried out, and the experimental results were consistent with the trend of numerical simulation results, which verified the correctness of the numerical simulation.

scholarly journals Investigation of a partial, inductive short-time heat treatment of thin metal sheets integrated into the forming process

2018 ◽  
Vol 190 ◽  
pp. 12008
Author(s):  
Benjamin Clausius ◽  
Petra Maier
Keyword(s):  
Heat Treatment ◽  
Strain Hardening ◽  
Sheet Thickness ◽  
Local Strain ◽  
Single Step ◽  
Thin Metal ◽  
Recrystallization Annealing ◽  
Forming Process ◽  
Metal Sheets ◽  
Short Time

Flanging is a widespread method in the sheet metal working industry to connect same or different materials by forming. Especially the sealing technology makes high demands on the flanging process: a low sheet thickness of the inner eyelet is necessary for proper sealing. The outer edges of the neck rings are mostly manufactured by shear cutting. The quality of the cut surface and the level of the local strain hardening influence decisively the limit of the flanging process by possible cracking. This paper is focused on the dependencies of these factors regarding thin metal sheets of different materials with a thickness down to 100 μm. It could be shown that strain hardening has a stronger effect on the process limits compared to the notch effect of the sheet edges when using standard values for the clearance of the shear cutting tool. Furthermore, a process is investigated with a partial inductive short-time heat treatment of the most deformed edge area. Due to the low thickness of the material and low heat capacities related thereto, it is possible to integrate a recrystallization annealing as single step into the forming process. As a result, the strain hardening can be removed from the affected zone directly between two forming steps to increase the process limits.

SPRINGBACK EFFECT OF AUTOMOTIVE LOWER ARM COMPONENT PREPARED VIA BURRING PROCESSING

2015 ◽  
Vol 75 (8) ◽  
Author(s):  
Muhamad Sani Buang ◽  
Shahrul Azam Abdullah ◽  
Juri Saedon ◽  
Hashim Abdullah
Keyword(s):  
Sheet Metal ◽  
High Strength ◽  
Forming Process ◽  
Shape Accuracy ◽  
Automotive Components ◽  
Stamping Process ◽  
Tool Profile ◽  
Stretch Flanging ◽  
Metal Forming Process ◽  
Made In

Complex components of the sheet metal forming process need to be designed with high precision and accuracy in order to prevent defects and misalignment of the end products. One of the sheet metal cool stamping process for these complex automotive components is burring which is the forming of a flange around a hole made in a piece of sheet metal. Springback is a common defect during the burring process. The aims of this paper are to investigate the springback effect and improve shape accuracy of hole burring by inner burring process of lower arm part for automotive lower arm part. The springback defects at hole burring usually happened on the inner burring process. Experimental stretch flanging for cold stamping process of inner burring process was used to investigate the reasons of springback effect around the burred hole for a lower arm part of high strength steel (HSS) sheets SPFH590. From the two designs of burring punch dies, the result shows the values of springback effect for clearance -0.15 which have a big gap at hole burring A arm and B arm diameters, are larger than clearance -0.34 which have small gap for inner burring process of lower arm part. The experimental analysis shows that springback is proportionally related to the punch-die clearance parameter of the tool profile where the springback increase as the clearance increases. 

scholarly journals Modelling and Simulation of Sheet Metal Forming Processes

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1356 ◽  
Author(s):  
Marta C. Oliveira ◽  
José V. Fernandes
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Modelling And Simulation ◽  
Forming Process ◽  
Household Appliances ◽  
Indispensable Tool

Numerical simulation of sheet metal forming processes has become an indispensable tool for the design of components and their forming process, in industries ranging from the automotive, to the aeronautics, packing and household appliances [...]

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