A Simple Analogous Model for the Determination of Cyclic Plasticity Parameters of Thin Wires to Model Wire Drawing

2007 ◽  
Vol 129 (3) ◽  
pp. 488-495
Author(s):  
T. Schenk ◽  
T. Seifert ◽  
H. Brehm
Keyword(s):  
Tensile Tests ◽  
Wire Drawing ◽  
Cyclic Stress ◽  
Cyclic Plasticity ◽  
Integration Time ◽  
Model Parameters ◽  
Compression Tests ◽  
Thin Wires ◽  
Fe Simulations ◽  
Analogous Model

Cyclic stress-strain measurements have to be performed in order to determine the cyclic plasticity parameters of material models describing the Bauschinger effect. For thin wires, the performance of tensile tests is often not possible due to necking of the specimen on exceeding the yield stress, whereas compression tests are uncritical. This paper presents an approach to determine the cyclic plasticity parameters by performance of compression tests for wires before and after drawing. Here, a simple analogous model is used instead of finite-element (FE) simulations. This approach has been applied for two different integration time steps in order to evaluate their influence on the fit and the accuracy of the integration. It is shown that good accuracy can be obtained for the cyclic plasticity parameters. For FE simulations using larger integration time steps, large deviations have been noted. However, there the analogous model could also be adopted in order to find appropriate model parameters. In general, it is the intention of this paper to show that searching an analogous model can be a very time- and cost-saving task.

Tension-Compression Tests for Springback Prediction of AHS Steel Using the Yoshida-Uemori Model

2017 ◽  
Vol 728 ◽  
pp. 78-84
Author(s):  
Weerapong Julsri ◽  
Surasak Suranuntchai ◽  
Vitoon Uthaisangsuk
Keyword(s):  
Elastic Recovery ◽  
Kinematic Hardening ◽  
High Strength ◽  
Cyclic Stress ◽  
Model Parameters ◽  
Structural Components ◽  
Compression Tests ◽  
Complex Shapes ◽  
Automotive Parts ◽  
Springback Prediction

In sheet metal formingprocess of automotive parts, springback effect is crucial, in particular, foradvanced high strength (AHS) steels. Most structural components of new vehiclesshow very complex shapes that require multi–step forming procedures.Therefore, finite element (FE)simulation has been often used to describe plasticdeformation behavior and springback occurrence of formed metal sheets.Recently, the kinematic hardening Yoshida–Uemorimodel has showed great capability for predicting elastic recovery of material. In this work, the AHSsteel grade JSC780Y wasinvestigated, in which tension–compressiontests were carried out. From resulted cyclic stress–strainresponses, material parameters were identified using different fitting methods.Determined model parameters were firstly verified by using simulations of 1–elementmodel. The most appropriate parameter set was thenobtained. Finally, a Hat-Shape forming test was performed and springback waspredicted and compared with experimental results.

Critical Entropy Threshold: An Irreversible Thermodynamic Theory of Fatigue

2012 ◽  
Author(s):  
P. W. Whaley
Keyword(s):  
Fatigue Damage ◽  
Fatigue Testing ◽  
Tensile Tests ◽  
Cyclic Stress ◽  
Irreversible Thermodynamic ◽  
Fatigue Properties ◽  
Microplastic Deformation ◽  
Polycrystalline Materials ◽  
Model Parameters ◽  
Stress Strain

A theoretical model for material fatigue is described using irreversible thermodynamics to quantify fatigue damage by the generation of microplastic entropy. The microplastic entropy generated quantifies the microplastic deformation, commonly accepted as the mechanism of fatigue damage in polycrystalline materials. A stochastic model for microplastic deformation is utilized to calculate the expected values of tensile stress–strain, cyclic stress–strain, microplastic strain energy density and the microplastic entropy generated. When the cumulative microplastic entropy generated in cyclic loading exceeds the critical microplastic entropy threshold calculated from tensile tests, failure occurs. Calculated fatigue life with 99% tolerance limits (99% confidence) compares favorably to data for 6061-T6 aluminum rod and sheet specimens. Model parameters are determined from tensile tests and simple cyclic tests, decreasing the high cost of fatigue testing for parameter identification. This new theory has the potential to significantly decrease the cost of characterizing the fatigue properties of new materials.

scholarly journals An inverse analysis to identify the Johnson-Cook constitutive model parameters for cold wire drawing process

2020 ◽  
Vol 21 (5) ◽  
pp. 527
Author(s):  
Ashkan Mahmoud Aghdami ◽  
Behnam Davoodi
Keyword(s):  
Strain Rate ◽  
Objective Function ◽  
Inverse Analysis ◽  
Static Condition ◽  
Tensile Tests ◽  
Wire Drawing ◽  
Material Behavior ◽  
Model Parameters ◽  
Drawing Process ◽  
Cold Wire

Johnson-Cook constitutive equation was utilized to model the 10100 copper and AA 1100 aluminum wires at the cold wire drawing process. Initial Johnson cook parameters were determined through quasi-static tensile tests at different strain rates. Analytical and finite element with VUHARD subroutine solutions were implemented to calculate the drawing forces using the Johnson cook parameters. Wire drawing experiments were carried out at different drawing conditions with two areal reductions and four drawing speeds with the strain rate ranged from 37 s−1 to 115 s−1 and wire drawing forces were measured using a load cell connected to the drawing die. Results showed that the Johnson cook model with parameters determined from a quasi-static condition was not able to predict the material behavior at the wire drawing process with a moderate strain rate. In order to modify the initial JC parameters an inverse analysis approach was adopted. An objective function was defined based on analytical and experimental drawing forces differences with respect to JC parameters. Using the Newton–Raphson method, new JC parameters were identified by minimizing the objective function. Updated Johnson cook parameters showed much more correlation with experimental results.

Automated Parameter Determination of Advanced Constitutive Models

2005 ◽  
Author(s):  
Syed M. Rahman ◽  
Tasnim Hassan ◽  
S. Ranji Ranjithan
Keyword(s):  
Heuristic Search ◽  
Constitutive Models ◽  
Cyclic Stress ◽  
Cyclic Plasticity ◽  
Parameter Determination ◽  
Model Parameters ◽  
Optimization Approach ◽  
Analysis And Design ◽  
Chaboche Model

Parameter determination of advanced cyclic plasticity models which are developed for simulation of cyclic stress-strain and ratcheting responses is complex. This is mainly because of the large number of model parameters which are interdependent and three or more experimental responses are used in parameter determination. Hence the manual trial and error approach becomes quite tedious and time consuming for determining a reasonable set of parameters. Moreover, manual parameter determination for an advanced plasticity model requires in-depth knowledge of the model and experience with its parameter determination. These are few of the primary reasons for advanced cyclic plasticity models not being widely used for analysis and design of fatigue critical structures. These problems could be overcome through developing an automated parameter optimization system using heuristic search technique (e.g. genetic algorithm). This paper discusses the development of such an automatic parameter determination scheme for improved Chaboche model developed by Bari and Hassan [4]. A new stepped GA optimization approach which is found to be more efficient over the conventional GA approach in terms of fitness quality and optimization time is presented.

scholarly journals Design and characterization of concrete masonry parts and structural concrete using repurposed plastics as aggregate

2019 ◽  
Vol 28 (1) ◽  
pp. 81-88
Author(s):  
Miguel A. González-Montijo ◽  
Hildélix Soto-Toro ◽  
Cristian Rivera-Pérez ◽  
Silvia Esteves-Klomsingh ◽  
Oscar Marcelo Suárez
Keyword(s):  
Structural Strength ◽  
Construction Materials ◽  
Tensile Tests ◽  
Compression Tests ◽  
Conventional Concrete ◽  
Structural Capacity ◽  
Plastic Type ◽  
Concrete Mix ◽  
Scientists And Engineers

AbstractHistorically known for being one of the major pollutants in the world, the construction industry, always in constant advancement and development, is currently evolving towards more environmentally friendly technologies and methods. Scientists and engineers seek to develop and implement green alternatives to conventional construction materials. One of these alternatives is to introduce an abundant, hard to recycle, material that could serve as a partial aggregate replacement in masonry bricks or even in a more conventional concrete mixture. The present work studied the use of 3 different types of repurposed plastics with different constitutions and particle size distribution. Accordingly, several brick and concrete mix designs were developed to determine the practicality of using these plastics as partial aggregate replacements. After establishing proper working material ratios for each brick and concrete mix, compression tests as well as tensile tests for the concrete mixes helped determine the structural capacity of both applications. Presented results proved that structural strength can indeed be reached in a masonry unit, using up to a 43% in volume of plastic. Furthermore, a workable structural strength for concrete can be achieved at fourteen days of curing, using up to a 50% aggregate replacement. A straightforward cost assessment for brick production was produced as well as various empirical observations and recommendations concerning the feasibility of each repurposed plastic type examined.

Transferability of the Gurson Damage Model Parameters with Charpy and Tensile Tests with Different Constrain Level

2009 ◽  
Vol 65 ◽  
pp. 19-31
Author(s):  
Ruben Cuamatzi-Melendez ◽  
J.R. Yates
Keyword(s):  
Strain Rate ◽  
Damage Model ◽  
Rolling Direction ◽  
Fracture Initiation ◽  
Tensile Tests ◽  
Model Parameters ◽  
Gurson Model ◽  
Finite Element Program ◽  
Element Program ◽  
Gurson's Model

Little work has been published concerning the transferability of Gurson’s ductile damage model parameters in specimens tested at different strain rates and in the rolling direction of a Grade A ship plate steel. In order to investigate the transferability of the damage model parameters of Gurson’s model, tensile specimens with different constraint level and impact Charpy specimens were simulated to investigate the effect of the strain rate on the damage model parameters of Gurson model. The simulations were performed with the finite element program ABAQUS Explicit [1]. ABAQUS Explicit is ideally suited for the solution of complex nonlinear dynamic and quasi–static problems [2], especially those involving impact and other highly discontinuous events. ABAQUS Explicit supports not only stress–displacement analyses but also fully coupled transient dynamic temperature, displacement, acoustic and coupled acoustic–structural analyses. This makes the program very suitable for modelling fracture initiation and propagation. In ABAQUS Explicit, the element deletion technique is provided, so the damaged or dead elements are removed from the analysis once the failure criterion is locally reached. This simulates crack growth through the microstructure. It was found that the variation of the strain rate affects slightly the value of the damage model parameters of Gurson model.

scholarly journals A Flow Stress Model of 300M Steel for Isothermal Tension

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 252
Author(s):  
Rongchuang Chen ◽  
Shiyang Zhang ◽  
Xianlong Liu ◽  
Fei Feng
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Tensile Deformation ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Model Parameters ◽  
Average Deviation ◽  
Cross Sectional ◽  
300M Steel

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.

Experimental and Numerical Investigation of Texture Development during Hot Rolling of Magnesium Alloy AZ31

2007 ◽  
Vol 539-543 ◽  
pp. 3448-3453 ◽  
Author(s):  
C. Schmidt ◽  
Rudolf Kawalla ◽  
Tom Walde ◽  
Hermann Riedel ◽  
A. Prakash ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Hot Rolling ◽  
Rolling Texture ◽  
Rolling Process ◽  
Model Parameters ◽  
Compression Tests ◽  
Basal Texture ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31 ◽  
Softening Behavior

Due to the deformation mechanisms and the typical basal texture rolled magnesium sheets show a significant asymmetry of flow stress in tension and compression. In order to avoid this undesired behavior it is necessary to achieve non-basal texture during rolling, or at least, to reduce the intensity of the basal texture component. The reduction of the anisotropy caused by the basal texture is very important for subsequent forming processes. This project aims at optimizing the hot rolling process with special consideration of texture effects. The development of the model is carried out in close cooperation with the experimental work on magnesium alloy AZ31 .The experimental results are required for the determination of model parameters and for the verification of the model. Deformation-induced texture is described by the visco-plastic self-consistent (VPSC) model of Lebensohn and Tomé. The combination of deformation and recrystallization texture models is applied to hot compression tests on AZ31, and it is found, that the model describes the observed texture and hardening/softening behavior well. In some cases rotation recrystallization occurs in AZ31 which appears to be a possibility to reduce the undesired basal rolling texture.

scholarly journals Parametric study on the behaviour of bagasse ash-calcium carbide residue stabilized soil

2018 ◽  
Vol 195 ◽  
pp. 03015
Author(s):  
John Tri Hatmoko ◽  
Hendra Suryadharma
Keyword(s):  
Calcium Carbide ◽  
Friction Angle ◽  
Tensile Tests ◽  
Peak Strength ◽  
Compression Tests ◽  
Exchange Reactions ◽  
Short Term ◽  
Calcium Carbide Residue ◽  
Stabilized Soil ◽  
Strength And Stiffness

A series of experiments including unconfined compression tests, three-axial tests, compaction tests, and split tensile tests were undertaken to investigate the influence of compaction parameters on the behaviour of bagasse ash-calcium carbide residue stabilized soil. A preliminary study on soil with the addition of 4%, 6%, 8%, 10%, and 12% calcium carbide residue established that the lime fixation point (LFP) was 4%. Then 9% bagasse ash was added to soil with 4% calcium carbide residue, and the cation exchanges and pozzolanic reactions were investigated. The addition of calcium carbide residue to bagasse ash stabilized soil caused short-term changes due to cation exchange reactions, including an increase in the friction angle and cohesion in the stabilized soil. In addition, due to the short-term reaction, the maximum stiffness in three-axial tests occurred in the samples moulded with less than their optimum moisture content (OMC), whereas the peak strength occurred in the samples moulded at their OMC. After a 28-day curing period, pozzolanic reactions improved significantly the three-axial peak strength and stiffness of the stabilized soil, and the maximum three-axial shear strength and stiffness occurred in the samples prepared below their OMC.

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