Comparison of Three Methods for Material Hardening Parameter Identification under Cyclic Tension-Compression Loadings: Roll Levelling Case Study

2015 ◽  
Vol 651-653 ◽  
pp. 957-962 ◽  
Author(s):  
Elena Silvestre ◽  
Eneko Sáenz de Argandoña ◽  
Lander Galdos ◽  
Joseba Mendiguren
Keyword(s):  
Parameter Identification ◽  
Kinematic Hardening ◽  
High Strength Steels ◽  
High Strength ◽  
Material Model ◽  
Forming Process ◽  
Element Analysis ◽  
Transient Behaviour ◽  
Cyclic Tension ◽  
Hardening Parameter

The roll levelling is a forming process used to remove the residual stresses and imperfections of metal strips by means of plastic deformations. The process is especially important to avoid final geometrical errors when coils are cold formed or when thick plates are cut by laser. In the last years, and due to the appearance of high strength materials such as Ultra High Strength Steels, machine design engineers are demanding a reliable tool for the dimensioning of the levelling facilities. In response to this demand, Finite Element Analysis is becoming an important technique able to lead engineers towards facilities optimization through a deeper understanding of the process.In this scenario, the accuracy and quality of the simulation results are highly dependent on the accuracy of the implemented material model. During roll levelling process, the sheet metal is subjected to cyclic tensile-compressive deformations, therefore a proper constitutive. model which considers the phenomena that occurs during cyclic loadings, such as the Bauschinger effec, work hardeningt and the transient behaviour, is needed. The prediction of all these phenomena which affect the final shape of the product are linked to the hardening rule.In the present paper, the roll levelling simulation of a DP1000 steel is performed using a combined isotropic-kinematic hardening formulation introduced by Chaboche and Lemaitre since its simplicity and its ability to predict the Bauschinger effect. The model has been fitted to the experimental curves obtained from a cyclic tension-compression test, which has been performed by means of a special tool developed to avoid the buckling of the specimen during compressive loadings. The model has been fitted using three different material hardening parameter identification methodologies which have been compared.

Testing and Modeling of Roll Levelling Process

2014 ◽  
Vol 611-612 ◽  
pp. 1753-1762 ◽  
Author(s):  
Elena Silvestre ◽  
Eneko Sáenz de Argandoña ◽  
Lander Galdos ◽  
Joseba Mendiguren
Keyword(s):  
Finite Element ◽  
High Strength Steels ◽  
Beam Theory ◽  
High Strength ◽  
Theoretical Models ◽  
Element Model ◽  
Forming Process ◽  
Element Analysis ◽  
Design Engineers ◽  
Ultra High Strength Steels

Roll levelling is a forming process used to remove the residual stresses and imperfections of metal strips by means of plastic deformations. During the process the metal fibres are subjected to cyclic tension-compression deformations leading to achieve flat product. The process is especially important to avoid final geometrical errors when coils are cold formed or when thick plates are cut by laser. In the last years, and due to the appearance of high strength materials such as Ultra High Strength Steels, machine design engineers are demanding a reliable tool for the dimensioning of the levelling facilities. In response to this demand, Finite Element Analysis and Analytical methods are becoming an important technique able to lead engineers towards facilities optimization through a deeper understanding of the process. Aiming to this study two different models have been developed to analyze the roll levelling operations: an analytical model and a finite element model. The FE-analysis was done using 2D-modelling assuming plane strain conditions. Differing settings, leveller configuration and materials were investigated. The one-dimensional analytical levelling model is based on classical beam theory to calculate the induced strain distribution through the strip, and hence the evolving elastic/plastic stress distribution. Both models provide a useful guide to process-sensitivities and are able to identify causes of poor leveller performance. The theoretical models have been verified by a levelling experimental prototype with 13 rolls at laboratory.

Springback Investigation in Roll Forming of a V-Section

2014 ◽  
Vol 553 ◽  
pp. 643-648 ◽  
Author(s):  
Akbar Abvabi ◽  
Joseba Mendiguren ◽  
Bernard F. Rolfe ◽  
Matthias Weiss
Keyword(s):  
Elastic Modulus ◽  
Continuous Process ◽  
High Strength Steels ◽  
Shell Element ◽  
High Strength ◽  
Material Model ◽  
The Body ◽  
Roll Forming ◽  
Forming Process ◽  
Advanced High Strength Steels

To have fuel efficient vehicles with a lightweight structure, the use of High Strength Steels (HSS) and Advanced High Strength Steels (AHSS) in the body of automobiles is increasing. Roll forming is used widely to form AHSS materials. Roll forming is a continuous process in which a flat strip is shaped to the desired profile by passing through numerous sets of rolls. Formability and springback are two major concerns in the roll forming of AHSS materials. Previous studies have shown that the elastic modulus (Young’s modulus) of AHSS materials can change when the material undergoes plastic deformation and the main goal of this study is to numerically investigate the effect of a change in elastic modulus during forming on springback in roll forming. Experimental loading-unloading tests have been performed to obtain the material properties of TRIP 700 steel and incorporate those in the material model used in the numerical simulation of the roll forming process. The finite element simulations were carried out using MSC-Marc and two different element types, a shell element and a solid-shell element, were investigated. The results show that the elastic modulus diminution due to plastic strain increases the springback angle by about 60% in the simple V-section roll forming analyzed in this study.

Comparison Between Two Experimental Procedures for Cyclic Plastic Characterization of High Strength Steel Sheets

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
G. B. Broggiato ◽  
F. Campana ◽  
L. Cortese ◽  
E. Mancini
Keyword(s):  
Sheet Metal ◽  
High Strength Steel ◽  
Kinematic Hardening ◽  
High Strength Steels ◽  
High Strength ◽  
Bending Test ◽  
Compression Tests ◽  
Element Analysis ◽  
Constitutive Parameters ◽  
Springback Prediction

In finite element analysis of sheet metal forming the use of combined isotropic-kinematic hardening models is advisable to improve stamping simulation and springback prediction. This choice becomes compulsory to model recent materials such as high strength steels. Cyclic tests are strictly required to evaluate the parameters of these constitutive models. However, for sheet metal specimens, in case of simple axial tension-compression tests, buckling occurrence during compression represents a serious drawback. This is the reason why alternative set-ups have been devised. In this paper, two experimental arrangements (a cyclic laterally constrained tension-compression test and a three-point fully reversed bending test) are compared so as to point out the advantages and the disadvantages of their application in tuning the well-known Chaboche’s hardening model. In particular, for tension-compression tests, a new clamping device was specifically designed to inhibit compressive instability. Four high strength steel grades were tested: two dual phases (DP), one transformation induced plasticity (TRIP) and one high strength low alloy material (HSLA). Then, the Chaboche’s model was calibrated through inverse identification methods or by means of analytical expressions when possible. The proposed testing procedure proved to be successful in all investigated materials. The achieved constitutive parameters, obtained independently from the two experimental techniques, were found to be consistent. Their accuracy was also been assessed by applying the parameter set obtained from one test to simulate the other one, and vice versa. Clues on what method provides the better transferability are given.

Investigation on the Numerical Simulation of Hot Stamping of Advanced High Strength Steels

2011 ◽  
Vol 189-193 ◽  
pp. 2144-2147 ◽  
Author(s):  
Li Min Wang ◽  
Tian Rui Zhou ◽  
Li Juan Wang ◽  
Xiao Ling Yang
Keyword(s):  
Finite Element ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Material Model ◽  
Element Analysis ◽  
Advanced High Strength Steels ◽  
Element Simulation ◽  
The Finite Element Analysis ◽  
Set Up

Hot stamping represents an innovative manufacturing process for forming of advanced high strength steels, implying a sheet at austenite temperature being rapidly cooled down and formed into a die at the same time (quenching). This affords the opportunity to manufacture components with complex geometric shapes, high strength and a minimum of springback which currently find applications as crash relevant components in the automotive industry. With regard to the numerical modeling of the process, the knowledge of thermal and thermo-mechanical properties of the material is required. The material model under hot stamping condition of advanced high strength steel should be set up. The Finite Element Analysis is an essential precondition for a good process design including all process parameters. This paper presents the finite element simulation of a hot stamping process and describes a number of procedures for the simulation of hot stamping. In addition, the development direction is pointed out at the end of this paper.

Finite Element Analysis of Reinforcement Rocker Part Made from JAC780Y Steel Sheets

2021 ◽  
Vol 877 ◽  
pp. 83-89
Author(s):  
Aeksuwat Nakwattanaset ◽  
Surasak Suranuntchai
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
High Strength Steel ◽  
High Strength ◽  
Material Model ◽  
Advanced High Strength Steel ◽  
Forming Process ◽  
Element Analysis ◽  
Steel Sheets ◽  
Springback Prediction

The manufacturing industries for automotive parts aim to develop technologies for reducing vehicle weight in order to decrease fuel consumption. However, passive safety function for drivers and passengers must not be impaired or should be even improved. Therefore, advanced high strength steel sheet plays more and more important role in designing automotive components. Nowadays, prediction of formability for sheet metal stamping has high capability more than the past. The major challenge is springback prediction. Moreover, it assists in the tooling design to correctly compensate for springback. Especially in automotive production, springback effects have been generally exhibited distinct after forming process of the high strength steel sheets. The springback effect occurred in the deformed state of metal parts must be taken into account by designing any sheet metal panels. Then, the purpose of the present research is to investigate the springback phenomenon of an automotive part named Reinforcement Rocker RL made from an advanced high strength steel grade JAC780Y, after stamping. In addition, the tools design has been carried out. Finite Element (FE) program known as DYNAFORM (based on LS-DYNA solver), has been applied to analyze and improve the springback effect on such forming part. An anisotropic material model according to type 36 (MAT_036 3-PARAMETER_BARAT) was applied. The results obtained from simulations were compared with required parts in each section. Then, the die surface from compensation in 2nd step forming was modified to use. Finally, the simulation part was verified with the real stamping part. It was found that the finite element simulation showed high capability for prediction and compensation of springback in high strength steel sheets forming.

An Investigation of Springback in Sheet Metal Forming of High Strength Steels

2014 ◽  
Vol 693 ◽  
pp. 370-375
Author(s):  
Jan Slota ◽  
Miroslav Jurcisin ◽  
Emil Spišák ◽  
Tomas Sleziak
Keyword(s):  
Sheet Metal ◽  
Kinematic Hardening ◽  
High Strength Steels ◽  
Strain Curve ◽  
High Strength ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Compression Phase ◽  
Cyclic Tension ◽  
Definition Of

Redistribution of residual stresses in a stamped sheet metal leads to the springback phenomenon. Springback phenomenon is well predicted for some mild steel materials, but not for steels with higher strengths. Nowadays, one of the most used tools to stamping optimization is usage of numerical simulations. In this paper was investigated sheet metal behavior under cyclic tension-compression test. Special fixture which serves as a buckling prevention of sheet metal in the compression phase of measuring stress-strain curve was designed. Obtained stress-strain curve was used to the definition of kinematic hardening model in numerical simulation. This model was verified with the real experiment in deep drawing process.

Numerical Modeling and Analytical Investigation of Autofrettage Process on the Fluid End Module of Fracture Pumps

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Mahdi Kiani ◽  
Roger Walker ◽  
Saman Babaeidarabad
Keyword(s):  
Residual Stresses ◽  
Kinematic Hardening ◽  
Analytical Formula ◽  
Strain Analysis ◽  
Material Model ◽  
Analytical Investigation ◽  
Stress Strain ◽  
Element Analysis ◽  
Hardening Material ◽  
Strain Evolution

One of the most important components in the hydraulic fracturing is a type of positive-displacement-reciprocating-pumps known as a fracture pump. The fluid end module of the pump is prone to failure due to unconventional drilling impacts of the fracking. The basis of the fluid end module can be attributed to cross bores. Stress concentration locations appear at the bores intersections and as a result of cyclic pressures failures occur. Autofrettage is one of the common technologies to enhance the fatigue resistance of the fluid end module through imposing the compressive residual stresses. However, evaluating the stress–strain evolution during the autofrettage and approximating the residual stresses are vital factors. Fluid end module geometry is complex and there is no straightforward analytical solution for prediction of the residual stresses induced by autofrettage. Finite element analysis (FEA) can be applied to simulate the autofrettage and investigate the stress–strain evolution and residual stress fields. Therefore, a nonlinear kinematic hardening material model was developed and calibrated to simulate the autofrettage process on a typical commercial triplex fluid end module. Moreover, the results were compared to a linear kinematic hardening model and a 6–12% difference between two models was observed for compressive residual hoop stress at different cross bore corners. However, implementing nonlinear FEA for solving the complicated problems is computationally expensive and time-consuming. Thus, the comparison between nonlinear FEA and a proposed analytical formula based on the notch strain analysis for a cross bore was performed and the accuracy of the analytical model was evaluated.

Fully Coupled Finite Element Analysis of an Automatic Multi-Stage Cold Forging Process

2020 ◽  
Vol 311 ◽  
pp. 88-93
Author(s):  
Jong Bok Byun ◽  
Hyun Joon Lee ◽  
Jong Bok Park ◽  
Il Dong Seo ◽  
Man Soo Joun
Keyword(s):  
High Strength ◽  
Material Model ◽  
Die Design ◽  
Cold Forging ◽  
Complete Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Forging Process ◽  
Multi Stage ◽  
Analysis Scheme

In this paper, non-isothermal analysis of an automatic multi-stage cold forging process of a ball-stud is conducted using a new material model which is a closed form function of strain, temperature and strain rate covering low and warm temperatures for high-strength stainless steel SUS304. An assembled die structural analysis scheme is employed for revealing the detailed die stresses, which is of great importance for process and die design for metal forming of the materials with high strengths. Die elastic deformation is dealt with to predict final geometries of material with higher accuracy. A complete analysis model is proposed to be used for optimal design of process and die designs in automatic multi-stage cold forging of high-strength materials.

Characterization of Heat Transfer Coefficients of Tool Materials and Tool Coatings for Hot Stamping of Boron-Manganese Steels

2010 ◽  
Vol 438 ◽  
pp. 81-88 ◽  
Author(s):  
Michael Wieland ◽  
Marion Merklein
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Tool Steels ◽  
Transfer Coefficients ◽  
Element Analysis ◽  
Coated Tool

One characteristic of hot stamping of ultra high strength steels is the high wear rate of the used tools which leads to shorter tool life. Coatings improving wear resistance can increase the lifetime of the used tools but process relevant data such as the heat transfer capability of coated tool steels are missing. Within this paper the heat transfer capabilities of coated tool steels for the hot stamping processes are determined. Therefore different coating systems based on AlCrN are applied on the tool steels and the pressure dependent heat transfer coefficient is determined using process relevant conditions. As semi-finished blank the hot stamping steel 22MnB5 with an aluminum-silicon pre-coating is used. With respect to a finite element analysis of the forming operation of the hot stamping process the heat transfer coefficient represents an important input data for the process layout.

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