A New Micromechanical Model to Study Transformation Plasticity in High-Carbon Steels

2019 ◽  
Author(s):  
Rohit Voothaluru ◽  
Vikram Bedekar ◽  
Praveen Pauskar
Keyword(s):  
Finite Element ◽  
Micromechanical Model ◽  
Inelastic Strain ◽  
Material Model ◽  
Carbon Steels ◽  
Transformation Plasticity ◽  
Element Approach ◽  
In Situ Neutron Diffraction ◽  
Constitutive Formulation

Abstract Hardened steels in engineering applications tend to have gradient microstructures with varying amounts of retained austenite alongside harder phases such as martensite or bainite. However, the metastable austenite can transform into martensite under mechanical loads, resulting in an inelastic strain within the material from the volumetric mismatch between FCC austenite and BCT martensite. In this work, a new constitutive formulation based upon the critical driving force for austenite transformation is presented. The model was implemented into a crystal plasticity formulation, and empirical data from in-situ neutron diffraction was used to determine the local micro-plasticity and transformation plasticity parameters. The results from finite element modeling also show that using a homogenized finite element approach could help to establish a material model that can capture the transformation plasticity within these materials with good accuracy.

Evaluating the Mechanical Behavior of 316 Stainless Steel at the Microscale Using Finite Element Modelling and In-Situ Neutron Scattering

2010 ◽  
Author(s):  
Dong-Feng Li ◽  
Noel P. O’Dowd ◽  
Catrin M. Davies ◽  
Shu-Yan Zhang
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Modelling ◽  
Mechanical Response ◽  
Fe Model ◽  
Lattice Strains ◽  
Crystallographic Slip ◽  
In Situ Neutron Diffraction ◽  
Elastic Lattice

In this study, the deformation behavior of an austenitic stainless steel is investigated at the microscale by means of in-situ neutron diffraction (ND) measurements in conjunction with finite-element (FE) simulations. Results are presented in terms of (elastic) lattice strains for selected grain (crystallite) families. The FE model is based on a crystallographic (slip system based) representation of the deformation at the microscale. The present study indicates that combined in-situ ND measurement and micromechanical modelling provides an enhanced understanding of the mechanical response at the microscale in engineering steels.

scholarly journals Micromechanical modeling of 8-harness satin weave glass fiber-reinforced composites

2016 ◽  
Vol 51 (5) ◽  
pp. 705-720 ◽  
Author(s):  
RS Choudhry ◽  
Kamran A Khan ◽  
Sohaib Z Khan ◽  
Muhammad A Khan ◽  
Abid Hassan
Keyword(s):  
Finite Element ◽  
Glass Fiber ◽  
Material Properties ◽  
Micromechanical Model ◽  
Unit Cell ◽  
Micromechanical Modeling ◽  
Void Content ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced

This study introduces a unit cell-based finite element micromechanical model that accounts for correct post cure fabric geometry, in situ material properties and void content within the composite to accurately predict the effective elastic orthotropic properties of 8-harness satin weave glass fiber-reinforced phenolic composites. The micromechanical model utilizes a correct post cure internal architecture of weave, which was obtained through X-ray microtomography tests. Moreover, it utilizes an analytical expression to update the input material properties to account for in situ effects of resin distribution within yarn (the yarn volume fraction) and void content on yarn and matrix properties. This is generally not considered in modeling approaches available in literature and in particular, it has not been demonstrated before for finite element micromechanics models of 8-harness satin weave composites. The unit cell method is used to obtain the effective responses by applying periodic boundary conditions. The outcome of the analysis based on the proposed model is validated through experiments. After validation, the micromechanical model was further utilized to predict the unknown effective properties of the same composite.

scholarly journals Implementing a micromechanical model into a finite element code to simulate the mechanical and microstructural response of arteries

2020 ◽  
Vol 19 (6) ◽  
pp. 2553-2566
Author(s):  
Daniele Bianchi ◽  
Claire Morin ◽  
Pierre Badel
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Micromechanical Model ◽  
Mechanical Tests ◽  
Material Behavior ◽  
The Finite Element Method ◽  
Experimental Findings ◽  
Constitutive Formulation ◽  
Constitutive Parameters ◽  
Computational Strategy

Abstract A computational strategy based on the finite element method for simulating the mechanical response of arterial tissues is herein proposed. The adopted constitutive formulation accounts for rotations of the adventitial collagen fibers and introduces parameters which are directly measurable or well established. Moreover, the refined constitutive model is readily utilized in finite element analyses, enabling the simulation of mechanical tests to reveal the influence of microstructural and histological features on macroscopic material behavior. Employing constitutive parameters supported by histological examinations, the results herein validate the model’s ability to predict the micro- and macroscopic mechanical behavior, closely matching previously observed experimental findings. Finally, the capabilities of the adopted constitutive description are shown investigating the influence of some collagen disorders on the macroscopic mechanical response of the arterial tissues.

scholarly journals Microstructural Modeling of Rheological Mechanical Response for Asphalt Mixture Using an Image-Based Finite Element Approach

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2041 ◽  
Author(s):  
Wenke Huang ◽  
Hao Wang ◽  
Yingmei Yin ◽  
Xiaoning Zhang ◽  
Jie Yuan
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Micromechanical Model ◽  
Asphalt Mixture ◽  
Simulation Software ◽  
Fe Model ◽  
Finite Element Approach ◽  
X Ray ◽  
Element Approach ◽  
Asphalt Mortar

In this paper, an image-based micromechanical model for an asphalt mixture’s rheological mechanical response is introduced. Detailed information on finite element (FE) modeling based on X-ray computed tomography (X-ray CT) is presented. An improved morphological multiscale algorithm was developed to segment the adhesive coarse aggregate images. A classification method to recognize the different classifications of the elemental area for a confining pressure purpose is proposed in this study. Then, the numerical viscoelastic constitutive formulation of asphalt mortar in an FE code was implemented using the simulation software ABAQUS user material subroutine (UMAT). To avoid complex experiments in determining the time-dependent Poisson’s ratio directly, numerous attempts were made to indirectly obtain all material properties in the viscoelastic constitutive model. Finally, the image-based FE model incorporated with the viscoelastic asphalt mortar phase and elastic aggregates was used for triaxial compressive test simulations, and a triaxial creep experiment under different working conditions was conducted to identify and validate the proposed finite element approach. The numerical simulation and experimental results indicate that the three-dimensional microstructural numerical model established can effectively analyze the material’s rheological mechanical response under the effect of triaxial load within the linear viscoelastic range.

Faulting, fracturing and in situ stress prediction in the Ahnet Basin, Algeria — a finite element approach

2000 ◽  
Vol 320 (3-4) ◽  
pp. 311-329 ◽  
Author(s):  
Fred Beekman ◽  
Madjid Badsi ◽  
Jan-Diederik van Wees
Keyword(s):  
Finite Element ◽  
In Situ Stress ◽  
Finite Element Approach ◽  
Stress Prediction ◽  
Element Approach

scholarly journals A tridimensional finite element approach to model a tunnel with shotcrete and precast concrete

2016 ◽  
Vol 9 (3) ◽  
pp. 403-413 ◽  
Author(s):  
P. V. Fiore ◽  
D. B. Maghous ◽  
A. Campos Filho
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Analytical Solution ◽  
Precast Concrete ◽  
Measured Data ◽  
Concrete Lining ◽  
Finite Element Approach ◽  
Element Approach ◽  
Elastic Lining

ABSTRACT This paper describes a numerical simulation with 3D finite elements of a tunnel. The viscoplastic law of Perzyna represents the rockmass behavior. The concrete, shotcrete or precast, is modeled as a viscoelastic material through the Maxwell and Kelvin chain models. Finite element simulations are performed by incorporating subroutines for viscoelastic concrete models in the ANSYS code. The method to simulate tunnel excavations is by activating and deactivating elements in sequential steps. In the first part of the paper two validations are performed. The analytical solution and the deformation achieved on the stabilization in the ANSYS code are compared with an unlined tunnel. A lined tunnel, with an elastic and viscoplastic rockmass combined with an elastic lining, is compared with the results of the GEOMEC91 code. In the second part, it is compared the same tunnel with two different concrete lining for two chain models. Finally, it is modeled the Kielder experimental tunnel, which in situ measured data is available.

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