Verification of Friction Models Implemented in the Simulation Software

2020 ◽  
Vol 994 ◽  
pp. 223-231 ◽  
Author(s):  
Emil Evin ◽  
Miroslav Tomáš
Keyword(s):  
Fem Simulation ◽  
High Strength ◽  
Simulation Software ◽  
Analytical Models ◽  
Friction Coefficients ◽  
Steel Sheets ◽  
Drawing Test ◽  
Strip Drawing ◽  
Friction Models ◽  
Model Of Friction

Modern approaches in simulations of sheet metal stamping processes are based on definition the friction coefficient as not constant, but the different value in different regions, considering the nature of the actual deformation process in each individual region. In this contribution the regression and analytical models to determine the friction coefficients under blankholder and on the die drawing edge by strip drawing test are presented. These models were verified by experimental strip drawing test under the same contact conditions. Zn coated steel sheets for the automotive industry were used in experiments and simulations – extra deep drawing quality DX54D and high strength steel TRIP. The results indicate, that friction coefficients are not constant and depend on the pressure on the die contact surfaces. Friction coefficients were determined also at the cup test by the regression model of drawing versus blankholding force. Conformity of friction coefficients obtained by the cup and the strip tests was confirmed. Model of friction applied in FEM simulation was verified by cup test and good conformity was found out.

scholarly journals Experimental Assessment of Friction Coefficient in Deep Drawing and Its Verification by Numerical Simulation

2021 ◽  
Vol 11 (6) ◽  
pp. 2756
Author(s):  
Emil Evin ◽  
Naqib Daneshjo ◽  
Albert Mareš ◽  
Miroslav Tomáš ◽  
Katarína Petrovčiková
Keyword(s):  
Friction Coefficient ◽  
Deep Drawing ◽  
Fem Simulation ◽  
Simulation Software ◽  
Analytical Models ◽  
Friction Coefficients ◽  
Aisi 304 ◽  
Steel Sheets ◽  
Strip Drawing ◽  
Steel Aisi

The friction coefficient in the simulation of stamping processes should be defined. Modern simulation software allows its definition as constant or its dependence on pressure or temperature. It is also useful in stamping processes to define different values in different regions, as it often reflects the nature of deformation process. This article deals with the regression and analytical models commonly used to determine the friction coefficients in specified areas of the stamping process. Analytical models were verified by an experimental strip drawing test under the same contact conditions. Steel sheets for the automotive industry were used in experiments and simulations—extra deep drawing quality DC 05 and austenitic stainless steel AISI 304. Friction coefficients were also evaluated when the cup test was performed. A regression model of drawing to the blankholding force was applied to the results. Conformity of friction coefficients when measured by cup tests and strip tests was confirmed. The values of the friction coefficient reached from the experiment were applied in FEM simulation software.

scholarly journals TRIBOLOGY PROPERTIES EVALUATION FOR FRICTION PAIR Zn COATED STEEL –TiCN MP COATED/UNCOATED TOOL STEEL

2019 ◽  
Vol 25 (4) ◽  
pp. 208
Author(s):  
Emil Evin ◽  
Miroslav Tomáš
Keyword(s):  
Friction Coefficient ◽  
Tool Steel ◽  
Friction Pair ◽  
High Strength ◽  
Analytical Models ◽  
Drawing Test ◽  
Coated Tool ◽  
Metal Stamping ◽  
Strip Drawing ◽  
Low Alloyed Steel

<p class="AMSmaintext1"><span lang="EN-GB">When the sheet metal stamping processes are simulated, different values of the friction coefficient need to be defined in different regions, considering the nature of the deformation process. Thus, the regression and analytical models to determine the friction coefficient under the blankholder and on the die drawing edge by the strip drawing test are presented in the article. These models were verified by experimental strip drawing test under the same contact conditions. Zn coated high strength low alloyed steel sheet H220PD+Z100 was used at experiments and friction tests were done against the tool steel and TiCN MP coated tool steel. The results indicate, that values of friction coefficients evaluated by linear regression are lower than evaluated from analytical models. The positive effect of coating TiCN MP when applied on the contact surfaces was found, thus, decreases the friction coefficient and the drawing force scattering during the strip drawing test.</span></p>

Reproducibility of Wear Tests and the Effect of Load on Tool Life in Sheet Metal Forming

2014 ◽  
Vol 1018 ◽  
pp. 293-300 ◽  
Author(s):  
Matthias Christiany ◽  
Peter Groche
Keyword(s):  
Tool Life ◽  
High Strength Steels ◽  
High Strength ◽  
Load Level ◽  
Wear Behaviour ◽  
New Approach ◽  
Advanced High Strength Steels ◽  
Drawing Test ◽  
Strip Drawing ◽  
Wear Tests

The increasing use of advanced high strength steels challenges the forming industry. Data on tool life are not available, thus causing uncertainties in the choice of suitable tribological systems. This paper investigates the reliability of a strip drawing test and the effect of the load level on tool life. Reproducibility of wear tests is barely discussed in literature. This study shows that a wear analysis on the base of a strip drawing test allows reproducible data. However, even small differences of the initial parameters can affect the result. A further investigation shows a distinct relationship between tool life and load level. Furthermore, the predominant wear mechanism is also influenced by the applied load. The findings on wear behaviour and reproducibility can be used for a new approach to estimate tool life in industrial forming processes on the base of a model test.

Coating of Deep Rolled and Hammer Peened Deep Drawing Tools

2013 ◽  
Vol 769 ◽  
pp. 245-252 ◽  
Author(s):  
Manuel Steitz ◽  
Kai Weigel ◽  
Martin Weber ◽  
Jan Scheil ◽  
Clemens Müller
Keyword(s):  
Deep Drawing ◽  
Wear Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Coated Tools ◽  
Wear Protection ◽  
Drawing Test ◽  
Strip Drawing ◽  
Hammer Peening ◽  
Die And Mold

Mechanical surface treatments like machine hammer peening and deep rolling can substitute an essential part of the manual polishing time in the conventional process chain of die and mold production. However, the increasing use of high strength steels in the automotive industry and the associated wear of deep drawing tools require further wear-protection methods. In this context it is still unknown if hammer peened and deep rolled surfaces can ensure a sufficient adhesive strength of a coating. Therefore, in the present work different coatings are applied on hammer peened and deep rolled surfaces. Finally, the wear behavior is examined in the strip drawing test. The evaluation of the experimental results proves the potential for an industrial application of the mechanically treated and coated tools.

Experimental investigation on resistance spot welding of dissimilar weld joints

2020 ◽  
pp. 095440892096835
Author(s):  
Rohit Verma ◽  
Kanwer Singh Arora ◽  
Lochan Sharma ◽  
Rahul Chhibber
Keyword(s):  
Welding Process ◽  
High Strength ◽  
Dynamic Resistance ◽  
Interstitial Free ◽  
Resistance Spot ◽  
Dissimilar Weld ◽  
Steel Sheets ◽  
Weld Joints ◽  
Resistance Spot Weld ◽  
Weld Current

In the present study, galvanized High Strength Interstitial Free (HIF) steel sheets, and Dual Phase (DP780) steel sheets were used for the investigations. Resistance spot weld joints were fabricated between dissimilar steel sheets. The variation in dynamic resistance (DR) with the change in welding process parameters such as weld current, weld time and electrode force were used for establishing the range of adequate weld nugget formation parameters. Effect of these parameters over tensile strength, nugget diameter and the observed failure mode was studied using one factor at a time (OFAT) approach. Microstructure and hardness of parent metal, fusion & HAZ region has also been studied.

scholarly journals Mechanical clinching and self-pierce riveting for sheet combination of 780-MPa high-strength steel and aluminium alloy A5052 sheets and durability on salt spray test of joints

2021 ◽  
Vol 113 (1-2) ◽  
pp. 59-72
Author(s):  
Yohei Abe ◽  
Ken-ichiro Mori
Keyword(s):  
Aluminium Alloy ◽  
High Strength Steel ◽  
Salt Spray ◽  
High Strength ◽  
Alloy Sheet ◽  
Galvanized Steel ◽  
Load Reduction ◽  
Minimum Thickness ◽  
Steel Sheets ◽  
Mechanical Clinching

AbstractTo increase the usage of high-strength steel and aluminium alloy sheets for lightweight automobile body panels, the joinability of sheet combinations including a 780-MPa high-strength steel and an aluminium alloy A5052 sheets by mechanical clinching and self-pierce riveting was investigated for different tool shapes in an experiment. All the sheet combinations except for the two steel sheets by self-pierce riveting, i.e., the two steel sheets, the two aluminium alloy sheets, and the steel-aluminium alloy sheets, were successfully joined by both the joining methods without the gaps among the rivet and the sheets. Then, to show the durability of the joined sheets, the corrosion behaviour and the joint strength of the aged sheets by a salt spray test were measured. The corrosion and the load reduction of the clinched and the riveted two aluminium alloy sheets were little. The corrosion of the clinched two steel sheets without the galvanized layer progressed, and then the load after 1176 h decreased by 85%. In the clinched two galvanized steel sheets, the corrosion progress slowed down by 24%. In the clinched steel and aluminium alloy sheets, the thickness reduction occurred near the minimum thickness of the upper sheet and in the upper surface on the edge of the lower aluminium alloy sheet, whereas the top surface of the upper sheet and the upper surface of the lower sheet were mainly corroded in the riveted joint. The load reduction was caused by the two thickness reductions, i.e., the reduction in the minimum thickness of the upper sheet and the reduction in the flange of the aluminium alloy sheet. Although the load of the clinched steel without the galvanized coating layer and aluminium alloy sheets decreased by about 20%, the use of the galvanized steel sheet brought the decrease by about 11%. It was found that the use of the galvanized steel sheets is effective for the decrease of strength reduction due to corrosion.

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