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.

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.

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.

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 Material Model for the Orthotropic and Viscous Behavior of Separators in Lithium-Ion Batteries under High Mechanical Loads

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4585
Author(s):  
Marian Bulla ◽  
Stefan Kolling ◽  
Elham Sahraei
Keyword(s):  
Mechanical Behavior ◽  
Lithium Ion ◽  
Material Model ◽  
Tensile Tests ◽  
Element Analysis ◽  
Rate Dependent ◽  
Novel Material ◽  
Li Ion ◽  
Role Based ◽  
Drive Systems

The present study is focused on the development of a material model where the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material is considered. The increasing need to reduce the climate-damaging exhaust gases in the automotive industry leads to an increasing usage of electric powered drive systems using Lithium-ion (Li-ion) batteries. For the safety and crashworthiness investigations, a deeper understanding of the mechanical behavior under high and dynamic loads is needed. In order to prevent internal short circuits and thermal runaways within a Li-ion battery, the separator plays a crucial role. Based on results of material tests, a novel material model for finite element analysis (FEA) is developed using the explicit solver Altair Radioss. Based on this model, the visco-elastic-orthotropic, as well as the visco-plastic-orthotropic, behavior until failure can be modeled. Finally, a FE simulation model of the separator material is performed, using the results of different tensile tests conducted at three different velocities, 0.1 mm·s−1, 1.0 mm·s−1 and 10.0 mm·s−1 and different orientations of the specimen. The purpose is to predict the anisotropic, rate-dependent stiffness behavior of separator materials in order to improve FE simulations of the mechanical behavior of batteries and therefore reduce the development time of electrically powered vehicles and consumer goods. The present novel material model in combination with a well-suited failure criterion, which considers the different states of stress and anisotropic-visco-dependent failure limits, can be applied for crashworthiness FE analysis. The model succeeded in predicting anisotropic, visco-elastic orthotropic and visco-plastic orthotropic stiffness behavior up to failure.

Prediction of Cutting Force in Bone Cutting Using Finite Element Analysis

2021 ◽  
Author(s):  
Varatharajan Prasannavenkadesan ◽  
Ponnusamy Pandithevan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cutting Force ◽  
Material Model ◽  
Tensile Tests ◽  
Bovine Bone ◽  
Element Analysis ◽  
Cutting Processes ◽  
Parameter Values ◽  
First Time

Abstract In orthopedic surgery, bone cutting is an indispensable procedure followed by the surgeons to treat the fractured and fragmented bones. Because of the unsuitable parameter values used in the cutting processes, micro crack, fragmentation, and thermal osteonecrosis of bone are observed. Therefore, prediction of suitable cutting force is essential to subtract the bone without any adverse effect. In this study, the Cowper-Symonds model for bovine bone was developed for the first time. Then the developed model was coupled with the finite element analysis to predict the cutting force. To determine the model constants, tensile tests with different strain rates (10−5/s, 10−4/s, 10−3/s, and 1/s) were conducted on the cortical bone specimens. The developed material model was implemented in the bone cutting simulation and validated with the experiments.

scholarly journals Experiment and finite element analysis of U-profile subjected to dynamic loading

2018 ◽  
Vol 183 ◽  
pp. 02056
Author(s):  
Martin Rund ◽  
Martin Mašek ◽  
Jan Džugan ◽  
Pavel Konopík ◽  
Jiøí Janovec
Keyword(s):  
Dynamic Loading ◽  
Fem Simulation ◽  
Field Measurements ◽  
Material Model ◽  
Tensile Tests ◽  
Ductile Damage ◽  
Experimental Investigations ◽  
Loading Conditions ◽  
Element Analysis ◽  
Dynamic Loading Conditions

The presented study deals with the FEM simulation of dynamic behaviour of U-profile crash under three point bent loading conditions verified by experimental investigations. The material ductile damage behaviour under wide strain rate region covering 0.001 – 1 000 s-1 was experimentally determined with the use of standard and micro tensile tests (M-TT). DIC systems were used for strain field measurements under quasi-static and dynamic loading conditions. Based on these experimental data, material model considering ductile damage was established in Abaqus/Explicit code. Additionally, also metallographic investigations were performed for the fracture behaviour description.

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.

An analytic procedure for determination of fracture toughness of paper materials

2012 ◽  
Vol 27 (2) ◽  
pp. 352-360 ◽  
Author(s):  
Petri Mäkelä ◽  
Christer Fellers
Keyword(s):  
Fracture Toughness ◽  
Closed Form ◽  
Test Data ◽  
Material Model ◽  
Fracture Toughness Test ◽  
Element Analysis ◽  
Analytic Procedure ◽  
Analytic Expressions ◽  
Commercial Paper

Abstract The aim of the present work was to develop an analytic procedure for determination of the fracture toughness of paper materials based on laboratory material test data. Isotropic deformation theory of plasticity was used to model the tensile material behaviour of six different commercial paper grades. Closed-form analytic expressions for calibrating the material model based on tensile test data were developed. The analytically calibrated material model was shown to predict the non-linear tensile stress-strain behaviour of the investigated paper grades excellently. A closed-form analytic expression for determination of fracture toughness was developed based on the used material model and J-integral theory. The fracture toughness of the investigated paper grades was determined analytically based on laboratory fracture toughness test data. The suggested analytic procedure for determination of the fracture toughness was shown to be in excellent agreement with determinations of fracture toughness based on finite element analysis.

Rousselier Parameter Calibration for Esshete Weld Metal

2015 ◽  
Author(s):  
Sutham Arun ◽  
Andrew H. Sherry ◽  
Mohammad Sheikh ◽  
Mike C. Smith
Keyword(s):  
Fracture Toughness ◽  
Numerical Models ◽  
Damage Model ◽  
Mesh Size ◽  
Model Parameters ◽  
Fracture Toughness Test ◽  
Parameter Calibration ◽  
Numerical Predictions ◽  
Industrial Grade ◽  
Weld Material

This paper describes an investigation concerning calibration of the Rousselier ductile damage model parameters for an industrial grade weld material (Esshete 1250). Parameters such as σ1 and the mesh size (Lc) were calibrated using numerical models of tensile and fracture toughness test specimens (smooth round bar and side-grooved compact-tension (CT) types) and adopting the Rousselier damage model as a constitutive relation. The process of parameter calibration was investigated by comparing the numerical load-displacement, crack initiation and growth predictions with experimental data measured using the two test geometries. It was found that it was not possible to obtain a single set of parameters which provided a good agreement between numerical predictions and experimental behaviour for both smooth tensile bar and CT specimen due to the difference in the failure mechanism of these specimens. Therefore, experimental J-R curve data determined from unload-compliance CT laboratory specimen fracture toughness tests of Esshete weld material were used to determine the values of these two parameters. The calibration results showed that the values of σ1 affect the change of the slope of J-R curve, whereas an increase in Lc elevates the crack growth resistance. The ductile fracture behaviour of the weld material is best simulated using the value of Lc = 50 μm and σ1 = 506 MPa. A detailed description of the numerical approach and calibration steps undertaken are provided.

Inverse Finite Element Analysis of the Indentation Response of Human Cervical Tissue

2013 ◽  
Author(s):  
Kristin Myers ◽  
Wang Yao ◽  
Kyoko Yoshida ◽  
Joy Vink ◽  
Noelia Zork ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Viscoelastic Material ◽  
Material Model ◽  
Spherical Indentation ◽  
Cervical Tissue ◽  
Tissue Slices ◽  
Element Analysis ◽  
Material Parameters ◽  
Inverse Finite Element Analysis

The mechanical function of the cervix is crucial during pregnancy when it is required to resist the compressive and tensile forces generated from the growing fetus. Pathologies of the cervical extracellular matrix (ECM), premature cervical remodeling, and alterations of cervical material properties have been implicated in placing women at high-risk for preterm birth (PTB). To understand the mechanical role of the cervix during pregnancy and to potentially identify etiologies for PTB, the overall goal of our group is to quantify ECM-material property relationships in normal and diseased human cervical tissue. In this study we present an inverse finite element analysis (IFEA) that optimizes material parameters of a viscoelastic material model to fit the stress-relaxation response of excised tissue slices to spherical indentation. Here we detail our IFEA methodology, report viscoelastic material parameters for cervical tissue slices from nonpregnant (NP) and pregnant (PG) hysterectomy patients, and report slice-by-slice data for whole cervical tissue specimens.

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