Finite Element Modeling of Deformation Behavior of Steel Specimens under Various Loading Scenarios

2015 ◽  
Vol 651-653 ◽  
pp. 969-974 ◽  
Author(s):  
Dilip Banerjee ◽  
Mark Iadicola ◽  
Adam Creuziger ◽  
Tim Foecke
Keyword(s):  
Finite Element ◽  
Deformation Behavior ◽  
Stress Measurement ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Strain Paths

Lightweighting materials (e.g., advanced high strength steels, aluminum alloys etc.) are increasingly being used by automotive companies as sheet metal components. However, accurate material models are needed for wider adoption. These constitutive material data are often developed by applying biaxial strain paths with cross-shaped (cruciform) specimens. Optimizing the design of specimens is a major goal in which finite element (FE) analysis can play a major role. However, verification of FE models is necessary. Calibrating models against uniaxial tensile tests is a logical first step. In the present study, reliable stress-strain data up to failure are developed by using digital image correlation (DIC) technique for strain measurement and X-ray techniques and/or force data for stress measurement. Such data are used to model the deformation behavior in uniaxial and biaxial tensile specimens. Model predictions of strains and displacements are compared with experimental data. The role of imperfections on necking behavior in FE modeling results of uniaxial tests is discussed. Computed results of deformation, strain profile, and von Mises plastic strain agree with measured values along critical paths in the cruciform specimens. Such a calibrated FE model can be used to obtain an optimum cruciform specimen design.

Predicting Edge Cracks on Shear-Cut High-Strength Steels by Modified Uniaxial Tensile Tests

2016 ◽  
Vol 703 ◽  
pp. 49-55 ◽  
Author(s):  
Martin Feistle ◽  
Isabella Pätzold ◽  
Roland Golle ◽  
Wolfram Volk
Keyword(s):  
Tensile Test ◽  
Measurement Method ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Forming Process ◽  
Contact Measurement ◽  
Edge Cracks ◽  
Near Future

During the forming of high-strength steels, edge cracks occur unexpectedly on sheared edges e.g. during collar forming. A non-contact measurement method based on the well-known tensile test was developed. It allows the investigation of the formation of edge cracks under tensile loads and determining general criteria to predict the formation of edge cracks during a specific forming process. The criteria are validated experimentally by means of the collar-forming test. In conjunction with the proposed line-fit-method these criteria can be implemented easily in FEM software in the near future for the prediction of edge cracks.

scholarly journals The Evaluation of Laser Weldability of the Third-Generation Advanced High Strength Steel

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1051 ◽  
Author(s):  
António B. Pereira ◽  
Rafael O. Santos ◽  
Bruno S. Carvalho ◽  
Marilena C. Butuc ◽  
Gabriela Vincze ◽  
...  
Keyword(s):  
Automotive Industry ◽  
Greenhouse Gas Emission ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Weld Bead ◽  
Uniaxial Tensile ◽  
Third Generation ◽  
Advanced High Strength Steels

To meet the demands of vehicular safety and greenhouse gas emission reduction, the automotive industry is increasingly using advanced high strength steels (AHSS) in the production of the components. With the development of the new generation of AHSS, it is essential to study their behavior towards manufacturing processes used in the automotive industry. For this purpose, the welding capability of newly developed third-generation Gen3 980T steel was investigated using the Nd:YAG (Neodymium:Yittrium Aluminum Garnet) laser-welding with different parameter conditions. The analysis was made by uniaxial tensile tests, micro-hardness, Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The criteria used to evaluate the quality of the weld were the distance between the fracture and the weld bead and the surface finish. A relationship between the quality of the weld and the energy density was observed, expressed by a partial penetration for values below the optimal, and by irregularities in the weld bead and a high number of spatters for the values above the optimal.

scholarly journals Reduction of Residual Stress for High-Strength Low-Alloy Steel Strip Based on Finite Element Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Zengshuai Qiu ◽  
Anrui He ◽  
Jian Shao ◽  
Xiaoming Xia
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Boundary Conditions ◽  
Alloy Steel ◽  
Steel Strip ◽  
High Strength ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Fe Model ◽  
Low Alloy Steel

Intensive cooling technology is widely utilized in the production of high-strength hot-rolled steel strip. However, intensive cooling at high cooling rate may cause stress heterogeneity on a steel strip, which further generates great residual stress and influences steel strip shape. In this study, a three-dimensional finite element (FE) model of high-strength low-alloy steel strip on the run-out table coupled with heat transfer, phase transformation, and strain/stress is developed by ABAQUS software. To enhance modeling precision, several experiments are conducted, such as uniaxial tensile test at multiple temperatures, dynamic continuous cooling transformation, and scanning electron microscopy, to determine the material properties and boundary conditions of the FE model. Four new models are established based on this model to reduce the residual stress of strip by modifying the initial and boundary conditions. Results show that reducing the initial transverse temperature difference is the most effective in reducing residual stress, followed by sparse cooling, edge masking, and posterior cooling.

Global-Local Characterization and Numerical Modeling of TWB Laser Welded Joints

2017 ◽  
Author(s):  
F. Nalli ◽  
P. Russo Spena ◽  
L. Cortese ◽  
D. Reiterer
Keyword(s):  
Local Level ◽  
High Strength Steels ◽  
High Strength ◽  
Image Correlation ◽  
Correlation Technique ◽  
Fe Model ◽  
Base Metals ◽  
Displacement Fields ◽  
Advanced High Strength Steels ◽  
Tailor Welded Blanks

Sheet forming of tailor welded blanks (TWBs) of advanced high strength steels is complex because of the notable differences in mechanical properties, and hence in formability, of base metals, heat affected zones and weld seam. In this work, an accurate characterization of the mechanical behavior of these regions in TWBs made of a DP and TRIP steel was carried out. Micro-samples, machined from base metals and fusion zone were employed to retrieve the local constitutive laws up to fracture. At the same time, macro-samples, extracted throughout the welded joint were tested to assess the weldment overall behavior. Along with global load-displacement data, strain and displacement fields of the joint were evaluated, using a Digital Image Correlation technique. An FE simulation of the entire joint was setup, using the previously identified material properties. In a comparison between the FE model and experiments, good results were obtained both at a global and local level, up to fracture.

scholarly journals Finite element model and experimental studies on rubber-cord composite

2007 ◽  
Vol 29 (4) ◽  
pp. 551-561 ◽  
Author(s):  
Tran Huu Nam
Keyword(s):  
Finite Element ◽  
Experimental Studies ◽  
Element Model ◽  
Tensile Tests ◽  
Rubber Matrix ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Material Behaviour ◽  
Mechanical Responses ◽  
Cyclic Tension

The rubber-cord composite (CRC) which is created of rubber matrix reinforced with textile cords is used for many applications such as pneumatic membranes, automobile tires, pneumatic air-springs, hydraulic hoses and many others. The CRC is characterized by strongly anisotropic material behaviour and can simultaneously undergo large elastic deformations. In this paper a finite element (FE) model was developed and applied to study the mechanical responses of CRC. This model consists of 8-node hexahedral brick elements describing rubber matrix and 3-D spar elements for modeling of textile cords. The experimental studies in uniaxial and cyclic tension were performed. The material constants of textile cords were fitted to experimentally measured data by approach technique using linear and bilinear elastic models. The simulations of uniaxial tensile tests using proposed FE model were carried out. The numerical results of simulations were compared to experimental ones in order to verify the accurateness of the FE model. The obtained results indicated that the proposed FE model can be applied for the modeling and simulation of mechanical behaviour of CRC.

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.

Influence of the contact with friction on the deformation behavior of advanced high strength steels in the Nakajima test

2021 ◽  
pp. 030932472110212
Author(s):  
Mohammad Mehdi Kasaei ◽  
Marta C Oliveira
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Rate ◽  
Contact Pressure ◽  
Deformation Behaviour ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels ◽  
Deformation Mechanics ◽  
Nakajima Test

This work presents a new understanding on the deformation mechanics involved in the Nakajima test, which is commonly used to determine the forming limit curve of sheet metals, and is focused on the interaction between the friction conditions and the deformation behaviour of a dual phase steel. The methodology is based on the finite element analysis of the Nakajima test, considering different values of the classic Coulomb friction coefficient, including a pressure-dependent model. The validity of the finite element model is examined through a comparison with experimental data. The results show that friction affects the location and strain path of the necking point by changing the strain rate distribution in the specimen. The strain localization alters the contact status from slip to stick at a portion of the contact area from the pole to the necking zone. This leads to the sharp increase of the strain rate at the necking point, as the punch rises further. The influence of the pressure-dependent friction coefficient on the deformation behaviour is very small, due to the uniform distribution of the contact pressure in the Nakajima test. Moreover, the low contact pressure range attained cannot properly replicate real contact condition in sheet metal forming processes of advanced high strength steels.

Investigations on the Mechanical Properties and Formability of Friction Stir Welded Tailored Blanks

2007 ◽  
Vol 344 ◽  
pp. 143-150 ◽  
Author(s):  
Gianluca Buffa ◽  
Livan Fratini ◽  
Marion Merklein ◽  
Detlev Staud
Keyword(s):  
Mechanical Properties ◽  
Stress Condition ◽  
Research Effort ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Sheet Stamping ◽  
Wide Range

Tight competition characterizing automotive industries in the last decades has determined a strong research effort aimed to improve utilized processes and materials in sheet stamping. As far as the latter are regarded light weight alloys, high strength steels and tailored blanks have been increasingly utilized with the aim to reduce parts weight and fuel consumptions. In the paper the mechanical properties and formability of tailored welded blanks made of a precipitation hardenable aluminum alloy but with different sheet thicknesses, have been investigated: both laser welding and friction stir welding have been developed to obtain the tailored blanks. For both welding operations a wide range of the thickness ratios has been considered. The formability of the obtained blanks has been characterized through tensile tests and cup deep drawing tests, in order to show the formability in dependency of the stress condition; what is more mechanical and metallurgical investigations have been made on the welded joints.

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