scholarly journals Characterization of High-Strength Packaging Steels: Obtaining Material Data for Precise Finite Element Process Modelling

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1683
Author(s):  
Fabian Knieps ◽  
Benjamin Liebscher ◽  
Ioana Moldovan ◽  
Manuel Köhl ◽  
Johannes Lohmar
Keyword(s):  
Finite Element ◽  
Flow Curve ◽  
Material Selection ◽  
Biaxial Tension ◽  
Selection Process ◽  
High Strength ◽  
Tensile Tests ◽  
Bulge Test ◽  
Hardening Law ◽  
Stress States

The steadily increasing demand for downgauging to reduce costs in packaging steel applications requires the development of high-strength packaging steel grades to meet strength requirements. At the same time, the demand for a simulative, computer-aided layout of industrial forming processes is growing to reduce costs in tool constructions for downgauging manners. As part of this work, different high-strength packaging steels were characterized for use in a finite element based process layout and validated using application-oriented experiments. Due to a low hardening rate and the occurrence of Lüders bands, high-strength packaging steels show a low amount of elongation in tensile tests, while for other stress states higher degrees of deformation are possible. Thus, common extrapolation methods fail to reproduce the flow curve of high-strength packaging steels. Therefore, a new approach to extrapolate the flow curve of high-strength packaging steels is presented using the tensile test and bulge test data together with a combined Swift–Voce hardening law. Furthermore, it is shown that the use of complex anisotropic yield locus models such as Yld2000-2d is necessary for high-strength packaging steels in order to be able to precisely simulate application-oriented loads in between plane strain and biaxial tension in validation experiments. Finally, the benefit of a material selection process for packaging steel applications guided by finite element simulations based on precisely characterized material behaviour is demonstrated.

Development of a Pneumatic Bulge Test for High Temperatures and Controlled Strain Rates

2014 ◽  
Vol 1018 ◽  
pp. 245-252 ◽  
Author(s):  
Alexander Braun ◽  
Johannes Storz ◽  
Markus Bambach ◽  
Gerhard Hirt
Keyword(s):  
Finite Element ◽  
Hot Stamping ◽  
High Strength ◽  
Tensile Tests ◽  
Finite Element Simulations ◽  
Bulge Test ◽  
Strain Rates ◽  
Hot Gas ◽  
Pneumatic Bulge Test ◽  
Simulation Input

Due to new material concepts (e.g. boron-manganese steels), hot stamping of sheet metal parts has emerged in order to produce high strength components. Thereby, the design of hot stamping processes by means of finite element simulations requires information about the thermo-mechanical material behaviour up to high strain levels at various temperatures as simulation input. It is known that hot tensile tests are only evaluable until low strain levels. Therefore, a hot gas bulge test for temperatures in the range of 600 °C to 900 °C and strain rates up to 1/s is being developed. In order to design such a hot gas bulge test, the requirements (e.g. forming pressure) are estimated by finite element simulations. The result is a test bench, which already enables a pneumatic forming of specimens at room temperature and pressures up to 200 bar without any unexpected side effects.

Effects of Anisotropic Yield Functions on Prediction of Forming Limit Diagram for AHS Steel

2014 ◽  
Vol 622-623 ◽  
pp. 257-264
Author(s):  
Sansot Panich ◽  
Vitoon Uthaisangsuk
Keyword(s):  
Biaxial Tension ◽  
Yield Criterion ◽  
Forming Limit Diagram ◽  
High Strength ◽  
Forming Limit ◽  
Bulge Test ◽  
Yield Criteria ◽  
Hardening Law ◽  
Yield Functions ◽  
Work Hardening Coefficient

In this study, experimental and numerical analyses of Forming Limit Diagram (FLD) for Advanced High Strength (AHS) steel grade 980 were performed. Forming limit curve was first determined by means of the Nakazima stretch-forming test. Then, analytical calculations of the FLD based on the Marciniak-Kuczynski (M-K) model were carried out. Different yield criteria, namely, Hill’48 (r-value and stress-based), Yld89 (r-value and stress-based) and Barlat2000 (Yld2000-2d) were investigated. The strain hardening law according to Swift was applied. To identify parameters of each model, uniaxial tension, balanced bi-axial bulge test and in-plane biaxial tension test were performed. As a result, predicted plastic flow stresses and plastic anisotropies of the AHS steel by various directions were evaluated. In addition, effects of the anisotropic yield functions, strain rate sensitivities, imperfection values and work hardening coefficient on the predicted FLD were studied and discussed. It was found that the FLD based on the Yld2000-2d yield criterion was in better agreement with the experimental curve. Accuracy of the FLD predictions based on the M-K theory, especially in the biaxial state of stress, significantly depended on the applied yield criteria, for which yield stresses and r-values of different loading directions were required.

scholarly journals Material selection and design analysis of multi-purpose disposable safety syringe

2018 ◽  
Vol 7 (4.13) ◽  
pp. 214-220
Author(s):  
Mohd Nasri Ishak ◽  
Abd Rahim Abu Talib ◽  
Mohammad Yazdi Harmin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Selection ◽  
Selection Process ◽  
Design Analysis ◽  
Element Analysis ◽  
Safety Feature ◽  
The Finite Element Analysis ◽  
Current Design ◽  
Selection For

Current design of safety syringes requires two handed operation and additional processes which is not similar to the normal syringes. Due to this concern, a new design of safety syringe is introduced in order to produce a safety syringe which allows a single-handed operation and similar to the operation of a normal syringes. This paper presents the material selection process and design analysis of a newly devel-oped multi-purpose disposable safety syringe. Based on the design analysis, the force which needed to dismantle the nozzle is found to be 20 N and this value is practical for the end users. The finite element analysis had also shown that the design concept is safe and has safety feature for the user to use. In addition, copolymer is proven as the best material selection for safety syringe production.

Analysis of the Hydraulic Bulge Test with FEA Concerning the Accuracy of the Determined Flow Curves

2009 ◽  
Vol 410-411 ◽  
pp. 439-447 ◽  
Author(s):  
Alper Güner ◽  
Alexander Brosius ◽  
A. Erman Tekkaya
Keyword(s):  
Flow Curve ◽  
Material Flow ◽  
High Strength ◽  
Bulge Test ◽  
Flow Curves ◽  
Element Analysis ◽  
Hydraulic Bulge ◽  
The Finite Element Analysis ◽  
Curve Determination ◽  
Set Up

This work covers the finite element analysis of geometric and process parameters in hydraulic bulge tests in terms of the accuracy of the evaluated flow curve. The important parameters are identified and varied to cover the whole range of possible uses. The effects of these parameters are analyzed for three representative materials: aluminium, mid-strength steel, and high-strength steel. The flow curves of the materials for each set of parameters are calculated by using the results of the simulations and the membrane theory. It is seen that even with simulation results, it is not always possible to obtain the input flow curve, especially towards the end of the test. The dimensions of the sheet and the tooling affect the plastic strain development and geometry of the bulge, leading to errors in computed flow curves. In order to observe the effect of the material flow from the flange on the determined yield stresses, the function and position of the drawbeads are also examined. These parameters, together with the method used to calculate the radius of the bulge, determine the accuracy of the calculated flow curve. Guidelines for an accurate flow curve determination regarding the test set-up and calculation methods are given.

The Effect of Solution Heat Treatment and Natural Ageing on the Yield Characteristics of a 2024-O Aluminium Alloy

2000 ◽  
Author(s):  
M. T. J. Ashbridge ◽  
A. G. Leacock ◽  
K. R. Gilmour ◽  
M. F. O’Donnell ◽  
D. McDonnell
Keyword(s):  
Heat Treatment ◽  
Finite Element ◽  
Solution Heat Treatment ◽  
Large Scale ◽  
Biaxial Tension ◽  
Yield Criterion ◽  
Deformation Behaviour ◽  
Material Model ◽  
Tensile Tests ◽  
Age Hardening

Abstract Recent advances in computational technology have allowed engineers to conduct previously impractical analyses, particularly with the development of the Finite Element Method (FEM). In turn, this has led the sheet metal forming industry into an economy drive, with an increasing necessity for ‘first time’ forming operations and reduced scrap rates. The successful prediction of large-scale plastic deformation in a sheet component relies on the accuracy of the material model used, especially when anisotropic materials are considered. Some stretch formed or deep drawn forms are geometrically complex and may require several draws with inter-stage anneals and/or solution heat treatments to achieve full form, and the varying material properties create significant difficulties in the modelling of these forming processes. Current orthotropic yield criteria do not allow for any sense of time dependency and although the atomic effects of solution heat treatment and precipitation hardening are well understood, the macroscopic effects of deformation behaviour are not. A test program was developed to investigate the effects of an increasing age hardening time on an aerospace Alclad 2024-O material after a solution heat treatment. With access to industrial heat treatment equipment, extensive tensile tests were conducted at varying age hardening times and a test rig was manufactured to obtain balanced biaxial tension data. Through the subsequent analysis, a method of predicting the data needed to generate a materials model suitable for FEA was developed, based on a modified version of Hill’s 1990 non-quadratic yield criterion. This was used to generate yield loci for the various age hardening times and compared with the loci generated with the predicted loci. Evaluation of the accuracy of the new criterion, and hence the predictive method, was achieved through its implementation in a finite element code used to model a punch-stretch test. Modelled surface strains were then compared with those measured strains determined during an empirical validation test programme. With the knowledge that the analysis came from data predicted from a minimum of empirical tests, the predicted results were found to be in good agreement with the experimental values.

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.

Finite Element Simulation of Crack Compliance Experiments to Measure Residual Stresses in Thick-Walled Cylinders

2003 ◽  
Vol 125 (3) ◽  
pp. 305-308 ◽  
Author(s):  
R. R. de Swardt
Keyword(s):  
Finite Element ◽  
Hoop Stress ◽  
High Strength ◽  
Finite Element Models ◽  
Fe Model ◽  
Element Simulation ◽  
Highly Nonlinear ◽  
Strain Stress ◽  
Reverse Yielding ◽  
Stress States

A comparative study to map the residual strain/stress states through the walls of autofrettaged thick-walled high-strength steel cylinders has been conducted with neutron diffraction, Sachs boring, and the compliance methods. Test samples with different wall thickness ratios were prepared to have significant amounts of reverse yielding due to the Bauschinger effect. In an effort to explain observed differences in the hoop stress results, the crack compliance experiment was simulated with finite elements. Several residual stress fields were introduced in the finite element models. A theoretical finite element (FE) model, which is capable of accurately modeling the highly nonlinear reverse yielding of the material, was able to accurately predict the crack compliance strain measurements.

Design of an Experimental Device for Biaxial Tension Tests Used in a Uniaxial Test Machine

2013 ◽  
Vol 554-557 ◽  
pp. 174-181
Author(s):  
Heng Kuang Tsai ◽  
Yi Wei Lin ◽  
Fuh Kuo Chen ◽  
Shi Wei Wang
Keyword(s):  
Finite Element ◽  
High Strength Steel ◽  
Biaxial Tension ◽  
High Strength ◽  
Finite Element Simulations ◽  
Advanced High Strength Steel ◽  
Steel Sheets ◽  
Biaxial Stretching ◽  
Tension Tests ◽  
Sliding Mechanism

In the present study, a set of novel clamping apparatus that could deliver biaxial stretching motions with the use of a uniaxial tensile testing machine was designed and manufactured. The conversion of uniaxial motion into biaxial stretching motions is achieved by a sliding mechanism that consists of two blocks sliding in two mutually perpendicular grooves, respectively. During the biaxial tension test, a cross-shaped specimen sitting in the grooves are stretched by the two blocks driven by a pulling rod. The different stress ratios could be obtained by adjusting the groove surface shape and the lengths of specimen wings. In the clamping apparatus design stage, the finite element simulations were performed to examine the validity of the sliding mechanism and the frictional force generated between the sliding blocks and the grooves. The coefficient of friction was determined afterwards from the comparison of the pulling forces obtained in the experiments with those calculated by the finite element simulations. In addition, the optimum geometry and dimension of the cross-shaped specimen used in the biaxial tension tests were investigated by the finite element analysis as well. The slotted specimen proposed by Kuwabara et al. was taken as the basic design. A sufficiently large area in the central region of specimen where the principal stress directions aligned with the groove direction was obtained for gluing the strain gauges to the specimen for the biaxial stretching tests. The number of slots and associated slot widths were also examined to optimize the shape of the specimens. The proposed clamping apparatus was manufactured and the biaxial tension tests were conducted with cross-shaped specimens made of advanced high strength steel sheets. The validity of the designed clamping apparatus used for biaxial tension tests was confirmed and the congruence of various yield criteria applied to the advanced high strength steel sheets subjected to biaxial stress states was discussed.

scholarly journals Systematic Design Approach to the Development of High-Strength, Locally Adapted Structures with the Aid of the Finite Element Design (FED) Method

2010 ◽  
Vol 137 ◽  
pp. 413-450
Author(s):  
Armin Lohrengel ◽  
Volker Wesling ◽  
Günter Schäfer ◽  
Antonia Schram ◽  
Sara Bessling ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Selection ◽  
High Strength ◽  
Material Design ◽  
Design Approach ◽  
Systematic Design ◽  
Design Engineers ◽  
Functional Orientation ◽  
Local Properties ◽  
Single Material

Design engineers can choose from a large variety of materials in order to fulfill a certain function. In those fields of application with a lower level of complexity, it is often sufficient to manufacture the entire component in a “monolithic” manner from one single material. Concurrent, partly contradictory and, most probably, local requirements that must be fulfilled by a component often make material selection more difficult. As a consequence, it is often necessary to use several different materials with a local and functional orientation, which is a part of the multi-material design strategy. The potential of different materials can be used most effectively if this information is made available to the design engineers as early on in the design process as possible. The aim of the SFB 675 sub-project C7, therefore, is the development of a systematic design approach (Finite Element Design, FED) that focuses on finite component elements. As a result, the potential of the optimization of local properties is taken into consideration, and the interaction between the materials, production processes, and design can all be described.

scholarly journals Experimental and numerical investigation of the effect of holes on the springback in cold roll forming of UHSS

2021 ◽  
Author(s):  
Zhi-min Liu ◽  
Pan Zhang ◽  
xiaoli liu ◽  
ming zhang ◽  
qiang ma ◽  
...  
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Finite Element Model ◽  
High Strength ◽  
Element Model ◽  
Tensile Tests ◽  
Roll Forming ◽  
Cold Roll Forming ◽  
Cold Roll ◽  
Forming Precision

Abstract Ultra-high strength steel (UHSS) pre-notched sections are getting growing popularity in the automotive industry with the development of automotive lightweight. However, the springback of UHSS products is large, and the existence of holes also has an effect on the springback. Accurate prediction of springback of UHSS pre-notched products in cold roll forming ( CRF ) is a key issue to be solved. In this paper, the effect of holes on the springback of UHSS in CRF is discussed by simulation and experiment. The finite element model of pre-notched car threshold was constructed, and its accuracy was validated by continuous CRF experiment. The mathematical model of variable elastic modulus determined by tensile tests of martensite (MS) 1300 was applied in finite element model. The accuracy of springback was improved by 15% in the hole region by using variable elastic modulus . Several forming schemes were designed to research the effect of different features on the springback in the hole region. The results show that the existence of holes reduces the springback and the effect is different at different positions of the car threshold. The springback in the hole region decreases with the increase of the number of stands, the strip thickness and the hole diameter, and with the decrease of the distance between stands and the distance between holes. This study provides a help for reducing the influence of holes on the springback and improving the forming precision of pre-notched sections in the actual production of CRF.

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