Variation of Beremin Model Parameters With Temperature by Monte Carlo Simulation

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
K. Bhattacharyya ◽  
S. Acharyya ◽  
S. Dhar ◽  
J. Chattopadhyay
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Master Curve ◽  
Model Parameters ◽  
Three Point Bending ◽  
Brittle Transition ◽  
Different Temperatures ◽  
Ductile To Brittle Transition ◽  
Vessel Material ◽  
Reactor Pressure

In this work, variation of the Beremin parameters with temperature for reactor pressure vessel material 20MnMoNi55 steel is studied. Beremin model is used, including the effect of plastic strain as originally formulated in the Beremin model. A set of six tests are performed at a temperature of −110 °C in order to determine reference temperature (T0) and master curve for the entire ductile-to-brittle transition (DBT) region as per the ASTM Standard E1921. Monte Carlo simulation is employed to produce a large number of 1 T three-point bending specimen (TPB) fracture toughness data randomly drawn from the scatter band obtained from the master curve, at different temperatures of interest in the brittle dominated portion of DBT region to determine Beremin model parameters variation with temperatures.

On the Use of the Notch Master Curve for Apparent Fracture Toughness Predictions of Notched Ferritic Steels Operating Within the Ductile-to-Brittle Transition Zone

2015 ◽  
Author(s):  
Sergio Cicero ◽  
Tiberio Garcia ◽  
Virginia Madrazo
Keyword(s):  
Fracture Toughness ◽  
Transition Zone ◽  
Fracture Resistance ◽  
Master Curve ◽  
Ferritic Steels ◽  
Brittle Transition ◽  
Apparent Fracture Toughness ◽  
Different Temperatures ◽  
Fracture Tests ◽  
Ductile To Brittle Transition

This paper presents the Notch-Master Curve as a model for the prediction of the apparent fracture toughness of ferritic steels in notched conditions and operating at temperatures corresponding to their ductile-to-brittle transition zone. The Notch-Master Curve combines the Master Curve of the material in cracked conditions and the notch corrections provided by the Theory of Critical Distances. In order to validate the model, the fracture resistance results obtained in fracture tests performed on notched CT and SENB specimens are presented. The results gathered here cover four ferritic steels (S275JR, S355J2, S460M and S690Q), three different notch radii (0.25 mm, 0.50 mm and 2.0 mm) and three different temperatures within the corresponding ductile-to-brittle transition zone. The results demonstrate that the Notch Master Curve provides good predictions of the fracture resistance in notched conditions for the four materials analyzed.

scholarly journals Modelling the Constraint Effect on Reference Temperature with Finite Element Parameters for Reactor Pressure Vessel Material 20MnMoNi55 Steel

2020 ◽  
Vol 70 (3) ◽  
pp. 323-328
Author(s):  
Kushal Bhattacharyya ◽  
Sanjib K. Acharyya ◽  
Sankar Dhar ◽  
Jayanta Chattopadhyay
Keyword(s):  
Finite Element ◽  
Reference Temperature ◽  
Three Point Bending ◽  
Average Value ◽  
T Stress ◽  
Series Of Experiments ◽  
Ductile To Brittle Transition ◽  
Vessel Material ◽  
Different Thickness ◽  
Reactor Pressure

A series of experiments were performed in the ductile to brittle transition region on three-point bending specimens of different thicknesses and a/W ratio of 20MnMoNi55 steel. master curve and reference temperature (T0) are obtained as per ASTM E1921-02 with different thickness and a/W ratio of the specimen and a variation of T0 is obtained, which indicates constant dependent on T0. Mathematic models are formulated to correlate T0 with Q-stress, T-stress and Triaxiality ratio to count for the constraint loss. Both the average value and also the maximum value of the finite element parameters are considered to predict T0 at different constraint label and compared with the experimental results.

scholarly journals Investigating of Strain Effect on Cleavage Fracture for Reactor Pressure Vessel Material

2021 ◽  
Author(s):  
Kushal Bhattacharyya
Keyword(s):  
Cleavage Fracture ◽  
Master Curve ◽  
Strain Effect ◽  
Strain Diagram ◽  
Huge Number ◽  
Element Analysis ◽  
Different Temperatures ◽  
Clear Plastic ◽  
Vessel Material ◽  
Reactor Pressure

Failure mechanism of 20MnMoNi55 steel in the lower self of ductile to brittle transition (DBT) region is considered as brittle fracture but it has been observed from the experimental analysis of stress-strain diagram that clear plastic deformation is shown by the material before failure. Therefore, strain correction is implemented in the cleavage fracture model proposed by different researchers in the lower self of the DBT region with the help of finite element analysis. To avoid a huge number of experiments being performed, Monte Carlo simulation is used to generate a huge number of random data at different temperatures in the lower self of the DBT region for calibration of the cleavage parameters with the help of the master curve methodology. Fracture toughness calculated after strain correction through different models are validated with experimental results for the different probability of failures.

The Weibull Stress Model for Predicting Cleavage Fracture in the Ductile-to-Brittle Transition Region

2008 ◽  
Author(s):  
Xiaosheng Gao ◽  
Jason P. Petti ◽  
Robert H. Dodds
Keyword(s):  
Fracture Toughness ◽  
Transition Region ◽  
Cleavage Fracture ◽  
Model Parameters ◽  
Ferritic Steels ◽  
Stress Model ◽  
Brittle Transition ◽  
Ductile To Brittle Transition ◽  
Constraint Effects ◽  
Weibull Stress

Transgranular cleavage fracture in the ductile-to-brittle transition region of ferritic steels often leads to spectacular and catastrophic failures of engineering structures. Due to the strongly stochastic effects of metallurgical scale inhomogenieties together with the nonlinear mechanical response from plastic deformation, the measured fracture toughness data exhibit a large degree of scatter and a strong dependence on constraint. This has stimulated an increasing amount of research over the past two decades, among which the Weibull stress model originally proposed by the Beremin group has gained much popularity. This model is based on weakest link statistics and provides a framework to quantify the relationship between macro and microscale driving forces for cleavage fracture. It has been successfully applied to predict constraint effects on cleavage fracture and on the scatter of macroscopic fracture toughness values. This paper provides a brief review of the research conducted by the authors in recent years to extend the engineering applicability of the Weibull stress model to predict cleavage fracture in ferritic steels. These recent efforts have introduced a threshold value in the Weibull stress model, introduced more robust calibration methods for determination of model parameters, predicted experimentally observed constraint effects, demonstrated temperature and loading rate effects on the model parameters, and expanded the original Beremin model to include the effects of microcrack nucleation.

Analysing the Notch Effect Within the Ductile-to-Brittle Transition Zone of S275JR Steel

2013 ◽  
Author(s):  
Sergio Cicero ◽  
Tiberio García ◽  
Virginia Madrazo ◽  
Jorge Cuervo ◽  
Estela Ruiz ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Bearing Capacity ◽  
Transition Zone ◽  
Master Curve ◽  
Notch Effect ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Brittle Transition ◽  
Apparent Fracture Toughness ◽  
Ductile To Brittle Transition

This paper analyses the notch effect in ferritic-pearlitic steel S275JR in a range of temperatures within the material Ductile-to-Brittle Transition Zone (DBTZ). The notch effect is evaluated in terms of load-bearing capacity, apparent fracture toughness (modeled here using the Theory of Critical Distances) and fracture micromechanisms. The concept of Master Curve in notched conditions is also presented. To this end, experimental results obtained in S275JR notched specimens are presented, together with Scanning Electron Microscopy (SEM) fractographies. The analysis is performed at −50 °C, −30 °C and −10 °C, the material Transition Temperature (T0) being −26.1 °C, with the notch radii ranging from 0 mm (crack-type defects) up to 2.0 mm. The results show how the lower the temperature the larger the notch effect, and also that the evolution of both the load bearing capacity and the apparent fracture toughness is directly related to the evolution of fracture micromechanisms. Moreover, the proposed Master Curve in notched conditions has provided good predictions of the experimental results.

scholarly journals MONTE CARLO SIMULATION OF ISING MODEL ON DIRECTED BARABASI–ALBERT NETWORK

2005 ◽  
Vol 16 (04) ◽  
pp. 585-589 ◽  
Author(s):  
MUNEER A. SUMOUR ◽  
M. M. SHABAT
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Ising Model ◽  
Monte Carlo Simulations ◽  
Characteristic Time ◽  
Spontaneous Magnetization ◽  
Zero Temperature ◽  
Different Temperatures ◽  
Large Systems ◽  
Ising Spins

The existence of spontaneous magnetization of Ising spins on directed Barabasi–Albert networks is investigated with seven neighbors, by using Monte Carlo simulations. In large systems, we see the magnetization for different temperatures T to decay after a characteristic time τ(T), which is extrapolated to diverge at zero temperature.

scholarly journals AXIAL AND OFF-AXIAL DYNAMIC TRANSITIONS IN UNIAXIALLY ANISOTROPIC HEISENBERG FERROMAGNET: A COMPARISON

2003 ◽  
Vol 14 (01) ◽  
pp. 49-59 ◽  
Author(s):  
MUKTISH ACHARYYA
Keyword(s):  
Magnetic Field ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Order Parameter ◽  
Heisenberg Ferromagnet ◽  
Axial Field ◽  
Ising Ferromagnet ◽  
High Anisotropy ◽  
Different Temperatures ◽  
Dynamic Transitions

Uniaxially anisotropic Heisenberg ferromagnet, in the presence of a magnetic field varying sinusoidally in time, is studied by Monte Carlo simulation. The axial (field applied only along the direction of anisotropy) and off-axial (field applied only along the direction which is perpendicular to the direction of anisotropy) dynamic transitions are studied. By studying the distribution of the dynamic order parameter component, it is observed that the axial transition is discontinuous for low anisotropy and becomes continuous in high anisotropy. The off-axial transition is found to be continuous for all values of anisotropy. In the infinite anisotropy limit, both types of transitions are compared with that observed in an Ising ferromagnet for the same value of the field and frequency. The infinitely anisotropic axial transition and dynamic transition in the Ising ferromagnet occur at different temperatures, whereas the infinitely anisotropic off-axial transition and the equilibrium ferro-para transition in the Ising model occur at the same temperature.

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