Analytical prediction of springback in bending of tailor-welded blanks incorporating effect of anisotropy and weld zone properties

2016 ◽  
Vol 232 (4) ◽  
pp. 294-306 ◽  
Author(s):  
Vijay Gautam ◽  
Vinayak Manohar Raut ◽  
D Ravi Kumar
Keyword(s):  
Strain Hardening ◽  
Analytical Model ◽  
Yield Criterion ◽  
Weld Zone ◽  
Rolling Direction ◽  
Weld Line ◽  
Analytical Prediction ◽  
Tailor Welded Blanks ◽  
Weld Properties ◽  
Different Thickness

An analytical model for the prediction of springback in bending of longitudinally welded tailor-welded blanks of different thickness is presented in this paper. The effect of strain hardening, anisotropy and weld zone has been incorporated in the analytical model. Power law of strain hardening and Hill’s anisotropic yield criterion have been used in the development of the analytical model for prediction of springback in tailor-welded blanks. The predicted values of springback are validated with experiments on V-bending of laser-welded blanks of Extra Deep Drawing quality steel sheets. Longitudinally welded specimens of three different thickness combinations with weld line oriented at 0°, 45° and 90° to the rolling direction are tested to investigate the effect of anisotropy. The springback values predicted by the analytical model incorporating the weld properties are found to be in good agreement with the experimental results in all of the cases. The springback has been found to be maximum when the weld line is oriented at 45° to the rolling direction.

Experimental and numerical investigations on springback in V-bending of tailor-welded blanks of interstitial free steel

2017 ◽  
Vol 232 (12) ◽  
pp. 2178-2191 ◽  
Author(s):  
Vijay Gautam ◽  
D Ravi Kumar
Keyword(s):  
Finite Element ◽  
Weld Zone ◽  
Rolling Direction ◽  
Weld Line ◽  
Material Model ◽  
Finite Element Simulations ◽  
Interstitial Free ◽  
Tailor Welded Blanks ◽  
Interstitial Free Steel ◽  
Predicted Values

Tailor-welded blanks of interstitial free steel are commonly used in complex automotive skin panels. The presence of weld zone, difference in thickness and high anisotropic behaviour affect forming behaviour of tailor-welded blanks significantly. Therefore, incorporation of anisotropy of the sheets and properties of the weld zone in finite element simulations is very important for accurate prediction of springback in bending of tailor-welded blanks. In this study, experimental and finite element simulations of V-bending were carried out on tailor-welded blanks of three thickness combinations, prepared by Nd-YAG laser welding of interstitial free steel sheets of thicknesses 0.8, 1.2 and 1.5 mm. The orientation of the weld line in longitudinally welded blanks was kept at 0°, 45° and 90° with respect to the rolling direction to study the effects of anisotropy on springback in V-bending. The tensile properties of the weld zone in different thickness combinations were determined and incorporated in finite element simulations for prediction of springback. It was observed that springback results were mainly governed by the springback behaviour of the thicker sheet in a particular thickness combination. Weld zone properties affect the springback of tailor-welded blanks more significantly than the anisotropy of the sheets. Accuracy of predicted values of springback in simulations increased when the properties of the weld zone were incorporated in the material model.

Comparison of Analytical Model to Experimental Results and Numerical Simulations for Tailor Welded Blank Forming

2004 ◽  
Author(s):  
Matt Bravar ◽  
Brad Kinsey ◽  
Neil Krishnan
Keyword(s):  
Numerical Simulations ◽  
Analytical Model ◽  
Weld Line ◽  
Experimental Results ◽  
Forming Process ◽  
Tailor Welded Blanks ◽  
Industrial Utilization ◽  
Initial Placement ◽  
Weld Line Movement ◽  
Line Movement

Tailor Welded Blanks offer several notable benefits including decreased part weight, reduced manufacturing costs, and improved dimensional consistency. However the reduced formability and other characteristics of the forming process associated with TWBs has limited the industrial utilization of this blank type. One concern with TWB forming is that weld line movement occurs which alters the final location of the various materials in the TWB combination. In this paper, an analytical model to predict the initial weld line placement necessary to satisfy the desired, final weld line location is presented. Good agreement between the model, experimental results, and numerical simulations with respect to weld line movement and initial placement was obtained for a symmetric, steel TWB case and a non-symmetric, Aluminum TWB case.

Methodology and Model to Determine Key Process Parameters for Tailor Welded Blank Forming

2003 ◽  
Author(s):  
Brad Kinsey ◽  
Matt Bravar ◽  
Jian Cao
Keyword(s):  
Analytical Model ◽  
Cross Section ◽  
Weld Line ◽  
Cross Sectional ◽  
Environmental Friendliness ◽  
Sheet Metal Parts ◽  
Tailor Welded Blanks ◽  
Tailor Welded Blank ◽  
Weld Line Movement ◽  
Line Movement

Tailor Welded Blanks (TWBs) offer several notable benefits compared to traditional sheet metal parts including decreased part weight, reduced manufacturing costs, increased environmental friendliness, and improved dimensional consistency. In order to take advantage of these benefits, however, designers must overcome formability concerns related to stamping TWBs and be able to accurately predict unique characteristics related to the forming of this blank type. In this research, an analytical model using a 2D cross-sectional approach was devised and implemented to predict the weld line movement and forming height for a uniform binder force TWB application. The inputs into the analytical model are the desired strain at the weld line location, the geometry of the 2D cross-section, material properties, and the frictional condition. From this information, the model predicts the stress and strain at several key locations on the 2D cross-section as well as the movement of the material in the binder area and in the formed walls.

scholarly journals Comparative study of dissimilar tailor-welded blanks between DP590 and DP980 dual phase steels

2018 ◽  
Vol 192 ◽  
pp. 01041
Author(s):  
Rittichai Phaoniam ◽  
Jesada Kaewwichit ◽  
Komgrit Lawanwong
Keyword(s):  
Weld Zone ◽  
Rolling Direction ◽  
Ferrite Matrix ◽  
Butt Joint ◽  
Welding Parameters ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Dissimilar Weld ◽  
Tailor Welded Blanks ◽  
Gtaw Process

This research aims to study the dissimilar tailor-welded blanks between DP590 and DP980 dual phase steels using the autonomous GTAW process. The summarized results are as follows. It was found that utilized welding parameters in DP590 and DP980 steel butt joint were able to achieve complete penetration joint and there were not any defects. Furthermore, the dissimilar weld zone produced the hardness profilevalue between the DP590 and DP980 base metal. In particularly, DP590-HAZ region resulted in harden zone. Meanwhile, DP980-HAZ region induced a soften zone. By the way, the harden DP590-HAZ exhibited fine columnar martensite with a ferrite matrix. On the other hand, the soften DP980-HAZ represented a tempered martensite structures. Comparing the tensile test was carried out in order to investigate dissimilar welded joint strength in the different rolling directions. It was suggested that the specimen welded along to rolling direction was evidently larger tensile strength (1092 MPa) than the welding transverse to rolling direction (638 MPa). Moreover, the weakest fracture occurred apparently on the region of DP590-BM rather than the HAZ region.

An Analytical Model for Tailor Welded Blank Forming

2003 ◽  
Vol 125 (2) ◽  
pp. 344-351 ◽  
Author(s):  
Brad L. Kinsey ◽  
Jian Cao
Keyword(s):  
Analytical Model ◽  
Weld Line ◽  
Manufacturing Costs ◽  
Environmental Friendliness ◽  
Tailor Welded Blanks ◽  
Die Surface ◽  
Tailor Welded Blank ◽  
Simulation Results ◽  
Weld Line Movement ◽  
Line Movement

Tailor Welded Blanks (TWBs) offer several notable benefits including decreased part weight, reduced manufacturing costs, increased environmental friendliness, and improved dimensional consistency. In order to take advantage of these benefits, however, designers need to overcome the reduced formability of TWBs and be able to accurately predict unique characteristics related to TWB forming early in the design process. In this paper, an analytical model to predict the weld line movement and forming height for a uniform binder force, TWB forming application is presented. Comparison to numerical simulation results demonstrates the accuracy of this methodology. The analytical model provides designers a valuable tool to determine the location of steps on the die surface to accommodate the weld line movement and the potential forming height for a TWB forming with a uniform binder force. The methodology presented here has the potential to be extended to analyze a non-uniform binder force forming of TWBs.

Formability Enhancement for Tailor-Welded Blanks Using Blank Holding Force Control

2003 ◽  
Vol 125 (3) ◽  
pp. 461-467 ◽  
Author(s):  
Sijun He ◽  
Xin Wu ◽  
S. Jack Hu
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Strain Distribution ◽  
Weld Line ◽  
Finite Element Simulations ◽  
Stress Strain ◽  
Tailor Welded Blanks ◽  
Blank Holding Force ◽  
Weld Line Movement ◽  
Line Movement

Tailor-welded blanks (TWB) are widely used for stamped auto body panels because of their great benefits in weight and cost reduction. However, the weld line in a tailor-welded blank causes serious concerns in formability because of material discontinuity and additional inhomogeneous stress/strain distribution. This paper proposes a blank holding force (BHF) control strategy to control the weld line movement, distribute the deformation more uniformly and thereby improve TWB formability. The control methodology is developed based on a simplified 2-D sectional analytical model that estimates the stress/strain distribution and the BHFs required for each side of the flange with dissimilar materials. The model can be further extended to 3-D analysis by superimposing the 2-D sectional analysis results around the entire binder ring and thus determining the required BHF for the whole panel. Finite element simulations are performed to study the effects of forming parameters on the weld line movement. Experiments have been conducted to verify the analytical model and partial finite element simulations. Both analysis and experiments demonstrated that a lower BHF should be applied on the thicker blank side to allow more metal to flow-in for obtaining more uniform strain distribution. The proposed BHF control is proven to be a good approach to enhancing TWB formability.

Comparison between laser beam and gas tungsten arc tailored welded blanks via deep drawing

2020 ◽  
pp. 095440542096239
Author(s):  
Ahmad Aminzadeh ◽  
Ali Parvizi ◽  
Rasoul Safdarian ◽  
Davood Rahmatabadi
Keyword(s):  
Laser Beam ◽  
Base Metal ◽  
Deep Drawing ◽  
Weld Zone ◽  
Weld Line ◽  
Gas Tungsten Arc ◽  
Tailor Welded Blanks ◽  
Gas Tungsten ◽  
Weld Line Movement ◽  
Line Movement

This paper aims at analyzing the deformation behavior of tailor welded blanks (TWBs), manufactured by laser beam welding (LBW) and gas tungsten arc welding (GTAW), through the deep drawing process. Dissimilar and similar steels with different thicknesses were used in the production of tailor welded blanks. The Nd: YAG laser welding method with nitrogen (N2) as the shielding gas was used to join TWBs. The effects of some significant process factors, namely welding speed, blank holder forces (BHF), material properties of base metals, dry/lubricated condition and laser spot size was experimentally investigated on the weld line movement and drawing depth. Results indicated that using LBW with optimum parameters for the production of dissimilar TWBs caused the control of failure in the weaker base metal. Results showed that the sound welds were produced in similar TWBs with a thickness ratio of 2 when using GTAW, but the weld quality was poor when using LBW. Moreover, it is observed that the critical stresses were taken place outside of the weld zone and rupture due to the high heat input of laser and metallurgical changes of the base metal that occur in the pre-softening zone. In addition, the weld line movement occurred as a result of plastic strain change of the weld joint that caused failure-prone zone creation as well as the adverse wrinkling.

Comparison of Analytical Model to Experimental and Numerical Simulations Results for Tailor Welded Blank Forming

2006 ◽  
Vol 129 (1) ◽  
pp. 211-215 ◽  
Author(s):  
Matt Bravar ◽  
Neil Krishnan ◽  
Brad Kinsey
Keyword(s):  
Numerical Simulation ◽  
Plane Strain ◽  
Analytical Model ◽  
Weld Line ◽  
Forming Process ◽  
Tailor Welded Blanks ◽  
Industrial Utilization ◽  
Tailor Welded Blank ◽  
Weld Line Movement ◽  
Plane Strain Assumption

Tailor welded blanks (TWBs) offer several notable benefits including decreased part weight, reduced manufacturing costs, and improved dimensional consistency. However the reduced formability and other characteristics of the forming process associated with TWBs has hindered the industrial utilization of this blank type for all possible applications. One concern with TWB forming is that weld line movement occurs, which alters the final location of the various materials in the TWB combination. In this technical brief, an analytical model to predict the initial weld line placement necessary to satisfy the desired, final weld line location and strain at the weld line is used. Results from this model are compared to an experimental, symmetric steel TWB case and a 3D numerical simulation, nonsymmetric aluminum TWB case. This analytical model is an extension of one previously presented, but eliminates a plane strain assumption that is unrealistic for most sheet metal forming applications. Good agreement between the analytical model, experimental, and numerical simulation results with respect to initial weld line location was obtained for both cases. Results for the model with a plane strain assumption are also provided, demonstrating the importance of eliminating this assumption.

Formability of Tailor-Welded Blanks for Steel with Different Thickness and Materials

2011 ◽  
Vol 704-705 ◽  
pp. 1504-1511
Author(s):  
Yun Tao Li ◽  
Juan Ye ◽  
Ji Shun Song ◽  
Jian Zhang ◽  
Guang Da Liu
Keyword(s):  
Plastic Deformation ◽  
Tensile Test ◽  
Welded Joint ◽  
Tensile Axis ◽  
Weld Line ◽  
Fracture Morphology ◽  
Tailor Welded Blanks ◽  
Base Materials ◽  
Manufacturing Technologies ◽  
Different Thickness

With the demands of environmental protection and energy conservation, increasing resources and improving environment, TWB (Tailor Weld Blank) as one of green re-manufacturing technologies will be a guiding orientation in industry. In this study, microstructure of welded joint、tensile test、fracture surface、cupping test of the TWB were carried out. Results show that the microstructure of weld is acicular ferrite and plate pearlite. The microstructure of HAZ beside SAPH440 is pearlite and grain ferrite, and the microstructure of HAZ beside DP600 is numbly pearlite and plate ferrite. The results of tensile test show that the shape of the materials after drawing is not easy to be rebounded, plastic deformation of the blanks is excellent, and the SEM of fracture morphology shows that the fracture is ductile and cleavage when the weld line parallels tensile axis. When the weld perpendicular to tensile axial, the deformation of the TWB is uneven, the plastic deformation is poor and the fracture is typical ductile rupture. The research results of the cupping test suggest that the bulging formability of the TWB is worse than that of base materials, and the bigger proportion of the thin blank in the TWB, the better bulging formability of the TWB. Introduction

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