Accurate Prediction of Springback in Forming of BIW Parts

2012 ◽  
Vol 165 ◽  
pp. 93-97
Author(s):  
Nagur Aziz Kamal Bashah ◽  
Ahmad Zakaria ◽  
Khairul Za’im Kamarulzaman ◽  
Achmed Mobin ◽  
Mohd Safuan Mohd Abdul Lazat ◽  
...  
Keyword(s):  
Neural Network ◽  
High Strength Steels ◽  
High Strength ◽  
Material Model ◽  
Part Geometry ◽  
Constitutive Material Model ◽  
The Neural Network ◽  
Automotive Parts ◽  
Constitutive Material ◽  
Different Levels

The use of High Strength Steels (HSS) for automotive parts improves car performance in terms of structural strength and weight reduction. However it poses major challenges to manufacturing since HSS is prone to springback. Springback causes deviation in part geometry from its intended design thus giving problem to its subsequent assembly process. In this paper, three models for predicting springback were evaluated. First model is based on the Multiple Regression (MR) technique. Second model utilized Hill Orthotropic constitutive material model and the last model employed a neural network predictive model. All the models were evaluated by using tool surface and stamped part historical data that are obtained from three selected springback prone automotive BIW parts representing three different levels of springback severity namely high, medium and small. The results on the low springback part show that the neural network model outperforms the other approaches.

scholarly journals Heat Treatment Design for a QP Steel: Effect of Partitioning Temperature

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1136
Author(s):  
Marcel Carpio ◽  
Jessica Calvo ◽  
Omar García ◽  
Juan Pablo Pedraza ◽  
José María Cabrera
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Quenching Temperature ◽  
Advanced High Strength Steels ◽  
New Family ◽  
Automotive Parts ◽  
Fresh Martensite ◽  
Industry Needs

Designing a new family of advanced high-strength steels (AHSSs) to develop automotive parts that cover early industry needs is the aim of many investigations. One of the candidates in the 3rd family of AHSS are the quenching and partitioning (QP) steels. These steels display an excellent relationship between strength and formability, making them able to fulfill the requirements of safety, while reducing automobile weight to enhance the performance during service. The main attribute of QP steels is the TRIP effect that retained austenite possesses, which allows a significant energy absorption during deformation. The present study is focused on evaluating some process parameters, especially the partitioning temperature, in the microstructures and mechanical properties attained during a QP process. An experimental steel (0.2C-3.5Mn-1.5Si (wt%)) was selected and heated according to the theoretical optimum quenching temperature. For this purpose, heat treatments in a quenching dilatometry and further microstructural and mechanical characterization were carried out by SEM, XRD, EBSD, and hardness and tensile tests, respectively. The samples showed a significant increment in the retained austenite at an increasing partitioning temperature, but with strong penalization on the final ductility due to the large amount of fresh martensite obtained as well.

scholarly journals Identification of the LLDPE Constitutive Material Model for Energy Absorption in Impact Applications

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1537
Author(s):  
Luděk Hynčík ◽  
Petra Kochová ◽  
Jan Špička ◽  
Tomasz Bońkowski ◽  
Robert Cimrman ◽  
...  
Keyword(s):  
Strain Rate ◽  
Material Model ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Stress Strain ◽  
Rate Dependent ◽  
Constitutive Material Model ◽  
Principal Directions ◽  
Constitutive Material

Current industrial trends bring new challenges in energy absorbing systems. Polymer materials as the traditional packaging materials seem to be promising due to their low weight, structure, and production price. Based on the review, the linear low-density polyethylene (LLDPE) material was identified as the most promising material for absorbing impact energy. The current paper addresses the identification of the material parameters and the development of a constitutive material model to be used in future designs by virtual prototyping. The paper deals with the experimental measurement of the stress-strain relations of linear low-density polyethylene under static and dynamic loading. The quasi-static measurement was realized in two perpendicular principal directions and was supplemented by a test measurement in the 45° direction, i.e., exactly between the principal directions. The quasi-static stress-strain curves were analyzed as an initial step for dynamic strain rate-dependent material behavior. The dynamic response was tested in a drop tower using a spherical impactor hitting a flat material multi-layered specimen at two different energy levels. The strain rate-dependent material model was identified by optimizing the static material response obtained in the dynamic experiments. The material model was validated by the virtual reconstruction of the experiments and by comparing the numerical results to the experimental ones.

scholarly journals Emergence of the neural network for reading in five-year-old beginning readers of different levels of pre-literacy abilities: An fMRI study

NeuroImage ◽  
2011 ◽  
Vol 57 (3) ◽  
pp. 704-713 ◽  
Author(s):  
Yoshiko Yamada ◽  
Courtney Stevens ◽  
Mark Dow ◽  
Beth A. Harn ◽  
David J. Chard ◽  
...  
Keyword(s):  
Neural Network ◽  
Beginning Readers ◽  
The Neural Network ◽  
Fmri Study ◽  
Different Levels

scholarly journals Study on modified Johnson-Cook constitutive material model to predict the dynamic behavior Mg-1Al-4Y alloy

2020 ◽  
Vol 7 (2) ◽  
pp. 026522
Author(s):  
Jinhui Wang ◽  
Xiaoguang Yuan ◽  
Peipeng Jin ◽  
Hongbin Ma ◽  
Bo Shi ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Material Model ◽  
Constitutive Material Model ◽  
Constitutive Material

Evaluation of Formability Under Different Deformation Modes for TWIP900 Steel

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Suleyman Kilic ◽  
Fahrettin Ozturk
Keyword(s):  
Twip Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Material Model ◽  
Deformation Analysis ◽  
Advanced High Strength Steels ◽  
Element Simulation ◽  
Springback Prediction ◽  
Deformation Modes ◽  
Prediction Capability

Automotive manufacturers always seek high strength and high formability materials for automotive bodies. Advanced high strength steels (AHSS) are excellent candidates for this purpose. These steels generally show a reasonable degree of formability, in addition to their high strength. One particular type is the twinning-induced plasticity (TWIP) steel, which is a high manganese austenite steel, and represents a second generation in AHSS. In this study, comprehensive deformation analysis of TWIP900CR steel including tensile, bending, Erichsen, and deep drawing of cylindrical cups tests is made. Finite element simulation of U and V shaped bending processes is also performed. Results indicate that the TWIP steel has good mechanical properties and high formability. However, springback is quite significant. The coining force should be considered in order to reduce the amount of springback. For springback prediction, it is found that the Yld2000-2d material model has better prediction capability than the Hill48 model.

SIMS Analysis of Deuterium Absorption and Diffusion in Austenitic Fe-Mn-C Steels

2012 ◽  
Vol 323-325 ◽  
pp. 477-483 ◽  
Author(s):  
T. Dieudonné ◽  
Loïc Marchetti ◽  
François Jomard ◽  
M. Wery ◽  
J. Chêne ◽  
...  
Keyword(s):  
Short Circuit ◽  
Strong Dependence ◽  
High Strength Steels ◽  
High Strength ◽  
Austenitic Steels ◽  
Alloy Chemistry ◽  
Aqueous Environments ◽  
Diffusion Phenomena ◽  
Automotive Parts ◽  
Ultra High Strength Steels

Austenitic Fe-Mn-C steels are Ultra High Strength Steels which may be used for the production of deep drawn automotive parts containing extremely high residual stress and strain levels. In consequence, hydrogen absorption occurring during the corrosion process in aqueous environments may enhance the sensitivity of these steels to different kinds of hydrogen-induced damage, in particular Stress Corrosion Cracking (SCC). In order to predict and prevent SCC, it is important to study the behaviour of hydrogen in these austenitic steels exposed to aqueous environments and in particular the dependence on the alloy chemistry and microstructure. SIMS profiles of deuterium introduced by cathodic charging in selected specimens were used to characterize the diffusion of hydrogen in these steels. This allowed to be studied the role of chemical composition and microstructure on the kinetics of H absorption at room temperature. The competition between bulk matrix diffusion and short-circuit diffusion phenomena along grain boundaries was investigated. The results show a strong dependence of H diffusion and distribution on the alloy chemistry and grain size.

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