Finite Element Modeling of the Ferroelectroelastic Material Behavior in Consideration of Domain Wall Motions

2005 ◽  
Vol 881 ◽  
Author(s):  
Albrecht C. Liskowsky ◽  
Artem S. Semenov ◽  
Herbert Balke ◽  
Robert M. McMeeking
Keyword(s):  
Finite Element ◽  
Representative Volume Element ◽  
Element Model ◽  
Ferroelectric Materials ◽  
Material Point ◽  
Volume Element ◽  
Material Behavior ◽  
Internal Variables ◽  
Gauss Point ◽  
Representative Volume

AbstractA simulation of the nonlinear electromechanical macroscopic behavior of ferroelectric materials by means of the finite element method is presented. A material point is depicted by a representative volume element, for which homogeneous boundary conditions are valid. The evolution of integral averages over the representative volume element is to homogenize the results. For this homogenization we favor a finite element model in which each Gauss point represents exactly one single crystal. Their number of internal variables is limited to the lattice orientation and the volume fractions of the domains. The former are randomly distributed in space. It is possible to calculate the material behavior for arbitrary coupled and nonlinear electromechanical loading cases, but the model is not effective for the solution of boundary value problems for entire bodies.

Crystal Plasticity Simulation of the Bauschinger Effect of Polycrystalline AA7075 through a Texture-Based Representative Volume Element Model

2014 ◽  
Vol 553 ◽  
pp. 22-27
Author(s):  
Ling Li ◽  
Lu Ming Shen ◽  
Gwénaëlle Proust
Keyword(s):  
Finite Element ◽  
Representative Volume Element ◽  
Crystal Plasticity ◽  
Bauschinger Effect ◽  
Voronoi Tessellation ◽  
Strain Curve ◽  
Element Model ◽  
Volume Element ◽  
Model Parameters ◽  
Representative Volume

A texture-based representative volume element (TBRVE) model is developed for the three-dimensional crystal plasticity (CP) finite element simulations of the Bauschinger effect (BE) of polycrystalline aluminium alloy 7075 (AA7075). In the simulations, the grain morphology is created using the Voronoi tessellation method with the material texture systematically discretised from experiment. A modified CP constitutive model, which takes into account the backstress, is used to simulate the BE during cyclic loading. The model parameters are calibrated using the first cycle stress-strain curve and used to predict the mechanical response to the cyclic saturation of AA7075. The results indicate that the proposed TBRVE CP finite element model can effectively capture the BE at the grain level.

Crystal plasticity modeling of grain refinement in aluminum tubes during tube cyclic expansion-extrusion

2016 ◽  
Vol 232 (6) ◽  
pp. 481-494 ◽  
Author(s):  
A Babaei ◽  
MM Mashhadi ◽  
F Mehri Sofiani
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Representative Volume Element ◽  
Crystal Plasticity ◽  
Element Model ◽  
Volume Element ◽  
Deformation History ◽  
Crystal Plasticity Finite Element ◽  
Representative Volume ◽  
History Of

In the present study, a crystal plasticity finite element model was developed for simulating the microstructure evolution and grain refinement during tube cyclic expansion-extrusion as a severe plastic deformation method for tubular materials. A new approach was proposed for extracting the real deformation history of a representative volume element during severe plastic deformation methods. The deformation history of a representative volume element during four cycles of tube cyclic expansion-extrusion was extracted by the proposed approach. Then, in a crystal plasticity finite element model, the deformation history was applied to a two-dimensional polycrystalline representative volume element with randomly assigned crystalline orientations. The intergranular interactions between grains and the intragranular orientation gradients were successfully simulated by the crystal plasticity finite element model. The distribution of misorientation angles, the evolution of grain boundaries, and the achieved average grain size after different cycles of tube cyclic expansion-extrusion were investigated by the crystal plasticity finite element model. On the other hand, ultrafine grained aluminum tubes were processed by four cycles of tube cyclic expansion-extrusion and the grain size of the processed tubes was studied by scanning electron microscopy observations and X-ray diffraction analyses. The experimental and predicted (by crystal plasticity finite element model) average grain sizes were compared.

scholarly journals Effect of Fiber Geometry and Representative Volume Element on Elastic and Thermal Properties of Unidirectional Fiber-Reinforced Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Siva Bhaskara Rao Devireddy ◽  
Sandhyarani Biswas
Keyword(s):  
Thermal Conductivity ◽  
Finite Element ◽  
Thermal Properties ◽  
Elastic Modulus ◽  
Cross Section ◽  
Representative Volume Element ◽  
Material Properties ◽  
Volume Element ◽  
Unidirectional Fiber ◽  
Representative Volume

The aim of present work is focused on the evaluation of elastic and thermal properties of unidirectional fiber-reinforced polymer composites with different volume fractions of fiber up to 0.7 using micromechanical approach. Two ways for calculating the material properties, that is, analytical and numerical approaches, were presented. In numerical approach, finite element analysis was used to evaluate the elastic modulus and thermal conductivity of composite from the constituent material properties. The finite element model based on three-dimensional micromechanical representative volume element (RVE) with a square and hexagonal packing geometry was implemented by using finite element code ANSYS. Circular cross section of fiber and square cross section of fiber were considered to develop RVE. The periodic boundary conditions are applied to the RVE to calculate elastic modulus of composite. The steady state heat transfer simulations were performed in thermal analysis to calculate thermal conductivity of composite. In analytical approach, the elastic modulus is calculated by rule of mixture, Halpin-Tsai model, and periodic microstructure. Thermal conductivity is calculated analytically by using rule of mixture, the Chawla model, and the Hashin model. The material properties obtained using finite element techniques were compared with different analytical methods and good agreement was achieved. The results are affected by a number of parameters such as volume fraction of the fibers, geometry of fiber, and RVE.

Representative Volume Element for Mechanical Properties of Carbon Nanotube Nanocomposites Using Stochastic Finite Element Analysis

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Seyed Hamid Reza Sanei ◽  
Randall Doles
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Representative Volume Element ◽  
Volume Element ◽  
Length Scale ◽  
Stochastic Finite Element ◽  
Element Analysis ◽  
Representative Volume ◽  
Element Approach ◽  
Stochastic Finite Element Analysis

Abstract The aim of this study is to present a representative volume element (RVE) for nanocomposites with different microstructural features using a stochastic finite element approach. To that end, computer-simulated microstructures of nanocomposites were generated to include a variety of uncertainty present in geometry, orientation, and distribution of carbon nanotubes. Microstructures were converted into finite element models based on an image-based approach for the determination of elastic properties. For each microstructure type, 50 realizations of synthetic microstructures were generated to capture the variability as well as the average values. Computer-simulated microstructures were generated at different length scales to determine the change in mechanical properties as a function of length scale. A representative volume element is defined at a length scale beyond which no change in variability is observed. The results show that there is no universal RVE applicable to all properties and microstructures; however, the RVE size is highly dependent on microstructural features. Microstructures with agglomeration tend to require larger RVE. Similarly, random microstructures require larger RVE when compared with aligned microstructures.

Representative volume element-based simulation of multiple solid particles erosion of a compressor blade considering temperature effect

2019 ◽  
Vol 234 (8) ◽  
pp. 1173-1184
Author(s):  
Bijan Mohammadi ◽  
AmirSajjad Khoddami
Keyword(s):  
Finite Element ◽  
Solid Particle ◽  
Representative Volume Element ◽  
Erosion Rate ◽  
Compressor Blade ◽  
Volume Element ◽  
Solid Particles ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Representative Volume

Solid particle erosion is one of the main failure mechanisms of a compressor blade. Thus, characterization of this damage mode is very important in life assessment of the compressor. Since experimental study of solid particle erosion needs special methods and equipment, it is necessary to develop erosion computer models. This study presents a coupled temperature–displacement finite element model to investigate damage of a compressor blade due to multiple solid particles erosion. To decrease the computational cost, a representative volume element technique is introduced to simulate simultaneous impact of multiple particles. Blade has been made of Ti-6Al-4V, a ductile titanium-based alloy, which is impacted by alumina particles. Erosion finite element modeling is assumed as a micro-scale impact problem and Johnson–Cook constitutive equations are used to describe Ti-6Al-4V erosive behavior. In regard to a wide variation range in thermal conditions all over the compressor, it is divided into three parts (first stages, middle stages, and last stages) in which each part has an average temperature. Effective parameters on erosive behavior of the blade alloy, such as impact angle, particles velocity, and particles size are studied in these three temperatures. Results show that middle stages are the most critical sites of the compressor in terms of erosion damage. An exponential relation is observed between erosion rate and particles velocity. The dependency of erosion rate on size of particles at high temperatures is indispensable.

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