scholarly journals Multi-Scale Analyses and Modeling of Metallic Nano-Layers

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 450
Author(s):  
Zara Moleinia ◽  
David Bahr
Keyword(s):  
Experimental Data ◽  
Constitutive Model ◽  
Crystal Plasticity ◽  
Single Layer ◽  
Adaptive Boosting ◽  
Multi Scale ◽  
Nano Scale ◽  
Boosting Technique ◽  
Constitutive Parameters ◽  
Computational Processes

The current work centers on multi-scale approaches to simulate and predict metallic nano-layers’ thermomechanical responses in crystal plasticity large deformation finite element platforms. The study is divided into two major scales: nano- and homogenized levels where Cu/Nb nano-layers are designated as case studies. At the nano-scale, a size-dependent constitutive model based on entropic kinetics is developed. A deep-learning adaptive boosting technique named single layer calibration is established to acquire associated constitutive parameters through a single process applicable to a broad range of setups entirely different from those of the calibration. The model is validated through experimental data with solid agreement followed by the behavioral predictions of multiple cases regarding size, loading pattern, layer type, and geometrical combination effects for which the performances are discussed. At the homogenized scale, founded on statistical analyses of microcanonical ensembles, a homogenized crystal plasticity-based constitutive model is developed with the aim of expediting while retaining the accuracy of computational processes. Accordingly, effective constitutive functionals are realized where the associated constants are obtained via metaheuristic genetic algorithms. The model is favorably verified with nano-scale data while accelerating the computational processes by several orders of magnitude. Ultimately, a temperature-dependent homogenized constitutive model is developed where the effective constitutive functionals along with the associated constants are determined. The model is validated by experimental data with which multiple demonstrations of temperature effects are assessed and analyzed.

Prediction of Ridging by 3-Dimensional Texture in Ferritic Stainless Steels

2014 ◽  
Vol 622-623 ◽  
pp. 72-76
Author(s):  
Yang Jin Chung ◽  
Deok Chan Ahn ◽  
Frédéric Barlat ◽  
Myoung Gyu Lee
Keyword(s):  
Crystal Plasticity ◽  
Stainless Steels ◽  
Rolling Direction ◽  
Single Layer ◽  
Experimental Result ◽  
Dimensional Structure ◽  
Ferritic Stainless Steels ◽  
3 Dimensional ◽  
Crystal Plasticity Fem ◽  
Constitutive Parameters

Experimental and numerical investigations of the ridging in ferritic stainless steels were presented in this paper. Two kinds of ferritic stainless steels exhibiting different levels of ridging were selected as model materials. The measured roughness of the uniaxially elongated specimens up to 15% in rolling direction (RD) was compared to the prediction using a rate-dependent crystal plasticity FEM (CPFEM). Initial textures of the two materials on 5 equi-spaced sequential RD planes were obtained by EBSD measurement. The initial textures were utilized as input data for the constitutive parameters of the crystal plasticity. Measured respective single planar textures were collected all together so that the 5-layer textures complete 3-dimensional structure and they were mapped onto the FE mesh. Ridging profiles predicted by the CPFEM using both every single layer texture and multilayer texture were compared to the experimental results. Predicted ridging profile of a material exhibiting weak ridging by using 5-layer EBSD mapping was in good agreement with the experimental result. On the other hand, prediction by using only single layer texture was efficient to estimate the ridging in a material exhibiting severe ridging due to the elongated cluster of analogous orientations along RD.

UNCERTAINTY ANALYSIS OF A ONE-DIMENSIONAL CONSTITUTIVE MODEL FOR SHAPE MEMORY ALLOY THERMOMECHANICAL DESCRIPTION

2014 ◽  
Vol 06 (06) ◽  
pp. 1450067 ◽  
Author(s):  
SERGIO A. OLIVEIRA ◽  
MARCELO A. SAVI ◽  
ILMAR F. SANTOS
Keyword(s):  
Experimental Data ◽  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Uncertainty Analysis ◽  
Numerical Simulations ◽  
Shape Memory ◽  
Tensile Tests ◽  
One Dimensional ◽  
Uncertainty Range ◽  
Constitutive Parameters

The use of shape memory alloys (SMAs) in engineering applications has increased the interest of the accuracy analysis of their thermomechanical description. This work presents an uncertainty analysis related to experimental tensile tests conducted with shape memory alloy wires. Experimental data are compared with numerical simulations obtained from a constitutive model with internal constraints employed to describe the thermomechanical behavior of SMAs. The idea is to evaluate if the numerical simulations are within the uncertainty range of the experimental data. Parametric analysis is also developed showing the most sensitive constitutive parameters that contribute to the uncertainty. This analysis provides the contribution of each parameter establishing the accuracy of the constitutive equations.

scholarly journals Thermodynamic compatibility conditions of a new class of hysteretic materials

2021 ◽  
Author(s):  
Salvatore Sessa
Keyword(s):  
Constitutive Model ◽  
Dynamic Analysis ◽  
Closed Form ◽  
Iterative Procedure ◽  
Displacement Amplitude ◽  
Compatibility Conditions ◽  
Algebraic Functions ◽  
New Class ◽  
Thermodynamic Compatibility ◽  
Constitutive Parameters

AbstractThe thermodynamic compatibility defined by the Drucker postulate applied to a phenomenological hysteretic material, belonging to a recently formulated class, is hereby investigated. Such a constitutive model is defined by means of a set of algebraic functions so that it does not require any iterative procedure to compute the response and its tangent operator. In this sense, the model is particularly feasible for dynamic analysis of structures. Moreover, its peculiar formulation permits the computation of thermodynamic compatibility conditions in closed form. It will be shown that, in general, the fulfillment of the Drucker postulate for arbitrary displacement ranges requires strong limitations of the constitutive parameters. Nevertheless, it is possible to determine a displacement compatibility range for arbitrary sets of parameters so that the Drucker postulate is fulfilled as long as the displacement amplitude does not exceed the computed threshold. Numerical applications are provided to test the computed compatibility conditions.

Multi-scale model of a top-fired steam methane reforming reactor and validation with industrial experimental data

2022 ◽  
Vol 428 ◽  
pp. 131492
Author(s):  
Valeria Tacchino ◽  
Paola Costamagna ◽  
Silvia Rosellini ◽  
Valter Mantelli ◽  
Alberto Servida
Keyword(s):  
Experimental Data ◽  
Scale Model ◽  
Methane Reforming ◽  
Steam Methane Reforming ◽  
Multi Scale ◽  
Steam Methane

Microstructure and Mechanical Properties of Multi-Scale Titanium Diboride Matrix Nanocomposite Ceramic Tool Materials

2010 ◽  
Vol 431-432 ◽  
pp. 523-526
Author(s):  
Han Lian Liu ◽  
Chuan Zhen Huang ◽  
Shou Rong Xiao ◽  
Hui Wang ◽  
Ming Hong
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Transgranular Fracture ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Micro Scale ◽  
Multi Scale ◽  
Nano Scale ◽  
Matrix Nanocomposite

Under the liquid-phase hot-pressing technique, the multi-scale titanium diboride matrix nanocomposite ceramic tool materials were fabricated by adding both micro-scale and nano-scale TiN particles into TiB2 with Ni and Mo as sintering aids. The effect of content of nano-scale TiN and sintering temperature on the microstructure and mechanical properties was studied. The result showed that flexural strength and fracture toughness of the composites increased first, and then decreased with an increase of the content of nano-scale TiN, while the Vickers hardness decreased with an increase of the content of nano-scale TiN. The optimal mechanical properties were flexural strength 742 MPa, fracture toughness 6.5 MPa•m1/2 and Vickers hardness 17GPa respectively. The intergranular and transgranular fracture mode were observed in the composites. The metal phase can cause ductility toughening and crack bridging, while crack deflection and transgranular fracture mode could be brought by micro-scale TiN and nano-scale TiN respectively.

A Cyclic Plasticity Modeling for Uniaxial and Multiaxial Ratcheting Simulation of Austenitic Steel

2012 ◽  
Author(s):  
Salim Meziani ◽  
Lynda Djimli
Keyword(s):  
Experimental Data ◽  
Stainless Steel ◽  
Constitutive Model ◽  
Data Base ◽  
Good Choice ◽  
Cyclic Plasticity ◽  
Strain History ◽  
Material Parameters ◽  
Plastic Shakedown

The first objective of this paper investigates the influence of the previous strain history on ratcheting of the 304 L stainless steel on ambient temperature. The identification is done using the Chaboche constitutive model. New tests were performed where different strain-controlled histories have been applied prior to ratcheting tests. It is demonstrated that under the same conditions, one can observe ratcheting, plastic shakedown or elasticity according to the prior strain-controlled history. The second objective points out the correlation between the experimental data base devoted to the identification of the material parameters and the quality of the predictions in cyclic plasticity. The results suggest that the choice of the tests should be closely linked to the capabilities of the model. In particular, the presence of non proportional strain-controlled tests in the data base may be not a good choice if the model itself is not able to represent explicitly such a character.

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