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ferroelectrics

Amir Abdollahi's picture

Three-dimensional simulation of crack propagation in ferroelectric polycrystals: Effect of combined toughening mechanisms

We simulate the fracture processes of ferroelectric polycrystals in
three dimensions using a phase-field model. In this model, the grain
boundaries, cracks and ferroelectric domain walls are represented in a
diffuse way by three phase-fields. We thereby avoid the difficulty of
tracking the interfaces in three dimensions. The resulting model can
capture complex interactions between the crack and the polycrystalline
and ferroelectric domain  microstructures. The simulation results show
the effect of the microstructures on the fracture response of the
material. Crack deflection, crack bridging, crack branching and
ferroelastic domain switching are observed to act as the main fracture
toughening mechanisms in ferroelectric polycrystals. Our fully 3-D

Amir Abdollahi's picture

Phase-field modeling of crack propagation in piezoelectric and ferroelectric materials

This is an accepted manuscript in Journal of the Mechanics and Physics of Solids

Title: Phase-field modeling of crack propagation in piezoelectric and ferroelectric materials with different electromechanical crack conditions

Authors: Amir Abdollahi and Irene Arias, Universitat Politecnica de Catalunya (UPC), Barcelona

 

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Amir Abdollahi's picture

Crack initiation patterns at electrode edges in multilayer ferroelectric actuators

This is the preprint of an article that will appear in Smart Materials and Structures (SMS)

Title: Crack initiation patterns at electrode edges in multilayer ferroelectric actuators

Authors: Amir Abdollahi and Irene Arias, Universitat Politecnica de Catalunya (UPC), Barcelona

 

Abstract:

Amir Abdollahi's picture

Numerical simulation of intergranular and transgranular crack propagation in ferroelectric polycrystals

This is the preprint of an article that will appear in International Journal of Fracture (IJF)

Title: Numerical simulation of intergranular and transgranular crack propagation in ferroelectric polycrystals

Authors: Amir Abdollahi and Irene Arias, Universitat Politecnica de Catalunya (UPC), Barcelona

 

 

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Looking for postdoctoral position: FEM, ferroelectrics, MEMS, computational electromagnetics.

I am looking for a postdoctoral position. I have expeience in finite element modeling and laboratory measurements of ultrasonic waves in ferroelectric and piezoelectric plates, piezoelectric transducers and actuators, MEMs. Also worked in the field of computational electromagnetics. Please look at the attached resume.

Amir Abdollahi's picture

Phase-field simulation of anisotropic crack propagation in ferroelectric single crystals

This is the preprint of an article that will appear in Modelling and Simulation in Materials Science and Engineering (MSMSE)

Title: Phase-field simulation of anisotropic crack propagation in ferroelectric single crystals: effect of microstructure on the fracture process

Authors: Amir Abdollahi and Irene Arias, Universitat Politecnica de Catalunya (UPC), Barcelona

 

 

Abstract:

Seeking a postdoctoral position in computational mechanics / applied physics / ultrasonic engineering

I am very interested in a postdoctoral position in computational mechanics, ultrasonics, applied physics, mechanical engineering, or electrical engineering. I am proficient in FEM, FDTD, Moments methods. Experienced in ultrasonic measurements that involve ferroelectric crystals, thin films, periodic structures.  Please see attached resume.

Arash_Yavari's picture

Finite-Temperature Atomic Structure of 180^o Ferroelectric Domain Walls in PbTiO_3

In this letter we obtain the finite-temperature structure
of 180^o domain walls in PbTiO_3 using a quasi-harmonic
lattice dynamics approach. We obtain the temperature dependence of
the atomic structure of domain walls from 0 K up to room
temperature. We also show that both Pb-centered and Ti-centered
180^o domain walls are thicker at room temperature; domain
wall thickness at T=300 K is about three times larger than that of
T=0 K. Our calculations show that Ti-centered domain walls have a

Wei Hong's picture

Electric-field-induced antiferroelectric to ferroelectric phase transition in a mechanically confined perovskite oxide

The electric-field-induced phase transition was investigated under mechanical confinements in bulk samples of an antiferroelectric perovskite oxide at room temperature. Profound impacts of mechanical confinements on the phase transition are observed due to the interplay of ferroelasticity and the volume expansion at the transition. The uniaxial compressive prestress delays while the radial compressive prestress suppresses it. The difference is rationalized with a phenomenological model of the phase transition accounting for the mechanical confinement.

Numerical phase modeling of BTO nanostructure using Landis' model with FEAP

  The difference to the common model used is the f,g terms. The 3D FEM formulation has been derived and a new fortran program is written. The derivative matrix is symmetric. But the calculation result does not converge. I have tried every means to get a converging result. But it doesn't work, the residual norm always increases.

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