The Use of Genetic Algorithms to Calibrate Johnson–Cook Strength and Failure Parameters of AISI/SAE 1018 Steel

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
M. F. Buchely ◽  
X. Wang ◽  
D. C. Van Aken ◽  
R. J. O'Malley ◽  
S. Lekakh ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Best Practice ◽  
Damage Mechanism ◽  
Tensile Tests ◽  
Model Parameters ◽  
Plastic Behavior ◽  
Optimization Strategy ◽  
Element Analysis ◽  
Failure Models ◽  
The Impact

Johnson–Cook (JC) strength and failure models have been widely used in finite element analysis (FEA) to solve a variety of thermo-mechanical problems. There are many techniques to determine the required JC parameters; however, a best practice to obtain the most reliable JC parameters has not yet been proposed. In this paper, a genetic-algorithm-based optimization strategy is proposed to calibrate the JC strength and failure model parameters of AISI/SAE 1018 steel. Experimental data were obtained from tensile tests performed for different specimen geometries at varying strain rates and temperatures. FEA was performed for each tensile test. A genetic algorithm was used to determine the optimum JC parameters that best fit the experimental force-displacement data. Calibrated JC parameters were implemented in FEA to simulate the impact tests of standard V-notch Charpy bars to verify the damage mechanism in the material. Considering good agreement of the experimental and FEA results, the current strategy is suggested for calibration proposes in other kind of materials in which plastic behavior could be represented by the JC strength and failure models.

scholarly journals Simulation of thermal cycle aging process on fiber-reinforced polymers by extended finite element method

2017 ◽  
Vol 52 (14) ◽  
pp. 1947-1958 ◽  
Author(s):  
Sergio González ◽  
Gianluca Laera ◽  
Sotiris Koussios ◽  
Jaime Domínguez ◽  
Fernando A Lasagni
Keyword(s):  
Finite Element ◽  
Degradation Process ◽  
Damage Mechanism ◽  
Fiber Reinforced Polymers ◽  
Model Parameters ◽  
Suitable Model ◽  
Fiber Reinforced ◽  
Aging Effects ◽  
Extended Finite Element ◽  
Element Analysis

The simulation of long life behavior and environmental aging effects on composite materials are subjects of investigation for future aerospace applications (i.e. supersonic commercial aircrafts). Temperature variation in addition to matrix oxidation involves material degradation and loss of mechanical properties. Crack initiation and growth is the main damage mechanism. In this paper, an extended finite element analysis is proposed to simulate damage on carbon fiber reinforced polymer as a consequence of thermal fatigue between −50℃ and 150℃ under atmospheres with different oxygen content. The interphase effect on the degradation process is analyzed at a microscale level. Finally, results are correlated with the experimental data in terms of material stiffness and, hence, the most suitable model parameters are selected.

The Precise Determination of the Johnson–Cook Material and Damage Model Parameters and Mechanical Properties of an Aluminum 7068-T651 Alloy

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
B. Bal ◽  
K. K. Karaveli ◽  
B. Cetin ◽  
B. Gumus
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Physical Simulation ◽  
Damage Model ◽  
Rolling Direction ◽  
Stress Triaxiality ◽  
Material Model ◽  
Tensile Tests ◽  
Model Parameters ◽  
Element Analysis

Al 7068-T651 alloy is one of the recently developed materials used mostly in the defense industry due to its high strength, toughness, and low weight compared to steels. The aim of this study is to identify the Johnson–Cook (J–C) material model parameters, the accurate Johnson–Cook (J–C) damage parameters, D1, D2, and D3 of the Al 7068-T651 alloy for finite element analysis-based simulation techniques, together with other damage parameters, D4 and D5. In order to determine D1, D2, and D3, tensile tests were conducted on notched and smooth specimens at medium strain rate, 100 s−1, and tests were repeated seven times to ensure the consistency of the results both in the rolling direction and perpendicular to the rolling direction. To determine D4 and D5 further, tensile tests were conducted on specimens at high strain rate (102 s−1) and temperature (300 °C) by means of the Gleeble thermal–mechanical physical simulation system. The final areas of fractured specimens were calculated through optical microscopy. The effects of stress triaxiality factor, rolling direction, strain rate, and temperature on the mechanical properties of the Al 7068-T651 alloy were also investigated. Damage parameters were calculated via the Levenberg–Marquardt optimization method. From all the aforementioned experimental work, J–C material model parameters were determined. In this article, J–C damage model constants, based on maximum and minimum equivalent strain values, were also reported which can be utilized for the simulation of different applications.

Simulation of the round insert face milling process of AISI 316LN stainless steel with machining-based plastic behavior modeling

2020 ◽  
pp. 095440542095884
Author(s):  
Do Young Kim ◽  
Dong Min Kim ◽  
OBum Kwon ◽  
Hyung Wook Park
Keyword(s):  
Genetic Algorithm ◽  
Stainless Steel ◽  
Cutting Force ◽  
Metal Cutting ◽  
Face Milling ◽  
Model Parameters ◽  
Plastic Behavior ◽  
Force Prediction ◽  
316Ln Stainless Steel ◽  
Constitutive Material Model

A proper plastic behavioral model is required to simulate metal cutting. Here, we model the plastic behavior of AISI 316LN stainless steel during face milling. We used a numerical approach to derive a plasticity model appropriate for machining; a two-dimensional cutting force prediction and a genetic algorithm were conducted for that. The force prediction was performed considering a geometrical relationship between the work material and cutting tool. We used the Johnson-Cook (JC) constitutive material model, and initial model parameters were obtained via tension testing at low strain rates (0.001–1 s−1). The genetic algorithm optimized the model parameters; the predictive accuracy with respect to cutting force was high in the model with optimized parameters. We used the optimized JC model for finite element analysis and simulated face milling with a round insert. We measured the cutting forces to validate our modeling approach; the simulated and measured principal forces were in good agreement (error rate ≤ 3.9% under all machining conditions). Our model improved the accuracy of plastic behavior prediction by 93.0% versus the original model. The high accuracy was retained even when the machining environment changed.

scholarly journals Finite Element Analysis and Experiment of the Bruise Behavior of Carrot under Impact Loading

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 471
Author(s):  
Xudong Xia ◽  
Zhanhong Xu ◽  
Chennan Yu ◽  
Qiaojun Zhou ◽  
Jianneng Chen
Keyword(s):  
Finite Element ◽  
Impact Force ◽  
Simulation Analysis ◽  
Damage Mechanism ◽  
Separation Mechanism ◽  
Element Analysis ◽  
Damage Prediction ◽  
The Impact ◽  
Damage Impact ◽  
Pendulum Experiment

Root–stem separating is one of the most important processes in carrot harvesting, but it is easy to cause damage due to the impact. In order to reduce the damage of carrot harvesting and provide the basis for the design of the separation mechanism, the damage mechanism of carrot was studied by the finite element method (FEM) and pendulum experiment in this study. Through the simulation analysis and the pendulum experiment, it was found that the critical damage impact force was 45.2 N and 43.1 N, respectively. Comparing the two results, the critical impact force of the carrot was basically the same, with an error of 4.87%. In conclusion, the FEM was reliable for the carrot damage prediction, and the critical impact force could be used for the design of a carrot harvesting mechanism.

Improvement of the Inverse Finite Element Analysis Approach for Tensile and Toughness Predictions by Means of Small Punch Technique

2021 ◽  
Author(s):  
Dirk Kulawinski ◽  
Kevin Iding ◽  
Robin Schornstein ◽  
Dasgin Özdemir-Weingart ◽  
Peter Dumstorff
Keyword(s):  
Fracture Toughness ◽  
Damage Model ◽  
Material Model ◽  
Tensile Tests ◽  
Optimization Process ◽  
Model Parameters ◽  
Element Analysis ◽  
Characteristic Values ◽  
Turbine Shaft ◽  
Inverse Finite Element Analysis

Abstract This paper focuses on the inverse FEA to calculate the SPT tests and the prediction of the tensile and fracture toughness behavior. For the description of the SPT tests via FEA the hardening rule of Ramberg-Osgood and the damage model of Gursson-Tvergaard-Needleman (GTN) were used. The inverse FEA optimization process cannot provide a unique solution for the 12 parameters included in the material model. This results from a dependency between some parameters, which leads to the same solution in the optimization. Hence a novel description of the dependent parameters was developed and implemented within the optimization process. Therefore, an enhanced inverse FEA approach was proposed which provides a fast converging solu- tion for determination of the material model parameters. Within this study the forged turbine shaft material EN: 27NiCrMoV15-6 was investigated. For comparison purposes SPT tests as well as tensile tests and fracture toughness tests were carried out. In the case of the tensile properties the test and simulation show coincidence in the curve as well as the characteristic values. For the toughness behavior the characteristic value of the test was met by the simulation.

scholarly journals An Experimental and Computational Study on the Orthotropic Failure of Separators for Lithium-Ion Batteries

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4399
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei
Keyword(s):  
Failure Criterion ◽  
Computational Study ◽  
Short Circuit ◽  
Lithium Ion ◽  
Local Strain ◽  
Damage Mechanism ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Element Analysis ◽  
Deformation And Failure

In the present study, the mechanical properties of a dry-processed polyethylene (PE) separator are investigated in terms of deformation and failure limits. The focus is set on the anisotropic mechanical behavior of this material. A deeper understanding of the damage mechanism is important for further safety and crashworthiness investigations and predictions of damage before failure. It has been found that separator integrity is one of the crucial parts in preventing internal short circuit and thermal runaway in lithium-ion (Li-ion) batteries. Based on uniaxial tensile tests with local strain measurement, a novel failure criterion for finite element analysis (FEA), using the explicit FEA solver Altair Radioss, has been developed to predict the effect of high mechanical loads with respect to triaxiality, large plastic strain and orthotropy. Finally, a simulation model of a PE separator was developed combining the novel failure criterion with Hill’s yield surface and a Swift–Voce hardening rule. The model succeeded in predicting the anisotropic response of the PE separator due to deformation and failure. The proposed failure model can also be combined with other constitutive material laws.

Improvement of the Inverse Finite Element Analysis Approach for Tensile and Toughness Predictions by Means of Small Punch Technique

2020 ◽  
Author(s):  
Dirk Kulawinski ◽  
Kevin Iding ◽  
Robin Schornstein ◽  
Dasgin Özdemir-Weingart ◽  
Peter Dumstorff
Keyword(s):  
Fracture Toughness ◽  
Damage Model ◽  
Material Model ◽  
Tensile Tests ◽  
Optimization Process ◽  
Model Parameters ◽  
Element Analysis ◽  
Characteristic Values ◽  
Turbine Shaft ◽  
Inverse Finite Element Analysis

Abstract This paper focuses on the inverse FEA to calculate the SPT tests and the prediction of the tensile and fracture toughness behavior. For the description of the SPT tests via FEA the hardening rule of Ramberg-Osgood and the damage model of Gursson-Tvergaard-Needleman (GTN) were used. The inverse FEA optimization process cannot provide a unique solution for the 12 parameters included in the material model. This results from a dependency between some parameters, which leads to the same solution in the optimization. Hence a novel description of the dependent parameters was developed and implemented within the optimization process. Therefore, an enhanced inverse FEA approach was proposed which provides a fast converging solution for determination of the material model parameters. Within this study the forged turbine shaft material EN: 27NiCrMoV15-6 was investigated. For comparison purposes SPT tests as well as tensile tests and fracture toughness tests were carried out. In the case of the tensile properties the test and simulation show coincidence in the curve as well as the characteristic values. For the toughness behavior the characteristic value of the test was met by the simulation.

Estimating OLED Display Device Lifetime from pixel and screen brightness and its application

2019 ◽  
Vol 2019 (1) ◽  
pp. 331-338 ◽  
Author(s):  
Jérémie Gerhardt ◽  
Michael E. Miller ◽  
Hyunjin Yoo ◽  
Tara Akhavan
Keyword(s):  
Image Processing ◽  
Power Consumption ◽  
Model Parameters ◽  
Display Device ◽  
Image Processing Algorithm ◽  
Pixel Value ◽  
Device Lifetime ◽  
The Impact ◽  
Oled Display

In this paper we discuss a model to estimate the power consumption and lifetime (LT) of an OLED display based on its pixel value and the brightness setting of the screen (scbr). This model is used to illustrate the effect of OLED aging on display color characteristics. Model parameters are based on power consumption measurement of a given display for a number of pixel and scbr combinations. OLED LT is often given for the most stressful display operating situation, i.e. white image at maximum scbr, but having the ability to predict the LT for other configurations can be meaningful to estimate the impact and quality of new image processing algorithms. After explaining our model we present a use case to illustrate how we use it to evaluate the impact of an image processing algorithm for brightness adaptation.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

Sign in / Sign up

Export Citation Format

Share Document