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.

Ductile Tearing Simulation of Circumferential Cracked Pipe Under Cyclic Loading Using Damage Criteria Determined by Monotonic Pipe Test Data

2018 ◽  
Author(s):  
Jin-Ha Hwang ◽  
Gyo-Geun Youn ◽  
Naoki Miura ◽  
Yun-Jae Kim
Keyword(s):  
Fracture Toughness ◽  
Cyclic Loading ◽  
Ductile Fracture ◽  
Test Data ◽  
Strain Energy ◽  
Fracture Strain ◽  
Damage Model ◽  
Fracture Toughness Test ◽  
Ductile Tearing ◽  
Damage Criteria

To evaluate the structural integrity of nuclear power plant piping, it is important to predict ductile tearing of circumferential cracked pipe from the view point of Leak-Before-Break concept under seismic conditions. CRIEPI (Central Research Institute of Electric Power Industry) conducted fracture test on Japanese carbon steel (STS410) circumferential through-wall cracked pipes under monotonic or cyclic bending load in room temperature. Cyclic loading test conducted variable experimental conditions considering effect of stress ratio and amplitude. In the previous study, monotonic fracture pipe test was simulated by modified stress-strain ductile damage model determined by C(T) specimen fracture toughness test. And, ductile fracture of pipe under cyclic loading simulated using damage criteria based on fracture strain energy from C(T) specimen test data. In this study, monotonic pipe test result is applied to determination of damage model based on fracture strain energy, using finite element analysis, without C(T) specimen fracture toughness test. Ductile fracture of pipe under variable cyclic loading conditions simulates using determined fracture energy damage model from monotonic pipe test.

Energy-based numerical modeling of the strain rate effect on fracture toughness of SA508 Gr. 1a

2017 ◽  
Vol 52 (3) ◽  
pp. 177-189 ◽  
Author(s):  
Hyun-Suk Nam ◽  
Yun-Jae Kim ◽  
Jin-Weon Kim ◽  
Jong-Sung Kim
Keyword(s):  
Fracture Toughness ◽  
Strain Rate ◽  
Damage Model ◽  
Type Model ◽  
Fracture Toughness Test ◽  
Ductile Tearing ◽  
Rate Dependent ◽  
Energy Concept ◽  
Axial Fracture ◽  
Dynamic Loading Conditions

This article presents an energy-based method to simulate ductile tearing under dynamic loading conditions. The strain rate–dependent material properties are characterized by the Johnson–Cook-type model. The damage model is defined based on the multi-axial fracture strain energy concept. The proposed damage model is applied to simulate the fracture toughness test of SA508 Gr. 1a under four different test speeds. Simulated results show a good overall agreement with the experimental results.

Quasi-static indentation characteristics of sandwich composites with hybrid facesheets: Experimental and numerical approach

2021 ◽  
pp. 109963622199387
Author(s):  
Subramani Anbazhagan ◽  
Periyasamy Manikandan ◽  
Gin B Chai ◽  
Sunil C Joshi
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
Volume Fraction ◽  
Numerical Models ◽  
Damage Model ◽  
Sandwich Panels ◽  
Numerical Approach ◽  
Metal Composite ◽  
Numerical Predictions ◽  
Static Indentation

The load response, energy absorption, different damage mechanisms and failure modes of sandwich panels subjected to complete perforation by quasi-static indentation and the insights gleaned are presented in this paper. The experimental campaign was carried out on samples made of different type of facesheets: Aluminium, glass fibre-reinforced plastic and metal-composite hybrid (combined aluminium and GFRP) with two different core heights. Reliable numerical models were developed with appropriate constitutive material and damage model for facesheets and honeycomb core to complement the experimental observations. Good agreement between experimental results and numerical predictions in terms of force-displacement response and perforation damage ensure the fidelity of the developed numerical model. Effects of facesheet type, core height, energy absorbed by the constituent layers, damage evolution history are briefly discussed. It was observed that the energy absorption of sandwich panels and peak indentation force resisted by the top and bottom facesheet are strongly dependent on its metal-volume fraction, whilst unaffected with the height of the core. Recommendations for developing computationally efficient numerical models were provided.

J-R Curve Prediction of Pre-Strained Stainless Steel 316 Material Using FE Damage Analysis Method

2018 ◽  
Author(s):  
Jun-Min Seo ◽  
Ji-Soo Kim ◽  
Yun-Jae Kim
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Damage Model ◽  
Damage Analysis ◽  
Fracture Toughness Test ◽  
Toughness Test ◽  
Cold Worked ◽  
Axial Fracture ◽  
Stainless Steel 316 ◽  
Strain Model

In this study, a method to predict J-R curve of SUS316 material using FE damage analysis is proposed. As experimental data, tensile and fracture toughness test results of cold worked SUS316 are used. The damage model used in this study is multi-axial fracture strain model and the model is determined by simulating the tensile and fracture toughness test according to the procedure in R6 code [1]. A pre-strain constant is newly introduced to consider pre-strain damage caused by the pre-strain, and the damage for various degrees of pre-strain are calculated. As a result, the predicted J-R curves using FE damage model show good agreement with the experimental data.

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.

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.

A novel model of Z-pin insertion in prepreg based on fracture mechanics

2021 ◽  
pp. 095440542110144
Author(s):  
Guobiao Ji ◽  
Liang Cheng ◽  
Shaohua Fei ◽  
Jiangxiong Li ◽  
Yinglin Ke
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Analytical Model ◽  
Model Parameters ◽  
Force Model ◽  
Fe Model ◽  
Cohesive Elements ◽  
Fe Method ◽  
Insertion Force ◽  
Mechanics Model

Through-thickness reinforcement is a promising solution to the problem of delamination susceptibility in laminated composites. Modeling Z-pin–prepreg interaction is essential for accurate robotics-assisted Z-pin insertion. In this paper, a novel Z-pin insertion force model combining the classical cohesive finite element (FE) method with a dynamic analytical fracture mechanics model is proposed. The velocity-dependent cohesive elements, in which the fracture toughness is provided by the analytical model, are implemented in Z-pin insertion FE model to predict the crack initiation and propagation. Then Z-pin insertion experiments are performed on prepreg sample with metallic Z-pins at different velocities to identify the analytical model parameters and validate the simulation predictions offered by the model. Dynamics of Z-pin interaction with inhomogeneous prepreg is described and the effects of insertion velocity on prepreg contact force are studied. Results show that the force model agrees well with experiments and the fracture toughness rises with the increasing Z-pin insertion velocity.

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.

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