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ahmedettaf's picture

Can you "chop" a mechanical wave?

In this paper we highlight several interesting phenomena that may emerge from coupling simple elastic systems like 1d bars. While in compostes we usually focus on wave propagation normal to the stratification direction (composite layers are coupled in series), here we show that extreme attenuation at multiple frequencies may emerge in linear systems that are coupled transversaly. We also introduce a simple device that act as a chopper for mechanical signals.

http://www.nature.com/articles/s41598-017-16364-8

Poisson Contraction and Fiber Kinematics in Tissue: Insight from Collagen Network Simulations

Connective tissue mechanics is highly non-linear, exhibits a strong Poisson effect and is associated with significant collagen fiber re-arrangement. Although the general features of the stress-strain behavior in tension and compression and under uniaxial, biaxial and shear loading have been discussed extensively, especially from the macroscopic perspective, the Poisson effect and the kinematics of filaments have received less attention. In general, the relationship between the microscopic fiber network mechanics and the macroscopic experimental observations remains poorly defined.

About periodic BC for large mesh in ABAQUS

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Hi all,

Perfectly matched layers

Hello,

 

I am looking for a practical reference/example on how to implement the perfectly matched layers for mechanical problems in a Finite Element code. I want to model a plate where it is surrounded by the PML from all sides, like a piece of earth crust surrounded by the land. The sources which I see for PML, are mostly in the area of electromagnetics.

 

Your inputs are appreciated.

Setareh

zhan-sheng guo's picture

Stress induced by diffusion, curvature, and reversible electrochemical reaction in bilayer lithium-ion battery electrode plates

In this paper, a new reaction-diffusion model, coupling the reversible electrochemical reaction, Lithium (Li) diffusion, and bending, is proposed to investigate the curvature, neutral axis movement, and stress in bilayer electrode. Bending curvature and stress, for the first time, are analytically and numerically investigated relate to both the diffusion and the reversible electrochemical reaction. The results reveal that the reversible electrochemical reaction retards the lithiation process, leading to the slowing down of diffusion process.

Fan Xu's picture

Photo-controlled patterned wrinkling of liquid crystalline polymer films on compliant substrates

Photo-chromic liquid crystalline polymer (LCP) is a type of smart materials which are sensitive to light. Here we harness its photo-mechanical response to flexibly control surface patterning, through modeling a film involving homeotropic nematic liquid crystals with director perpendicular to the polymer film attached on a compliant substrate. Theoretical and numerical analyses were conducted to explore the surface instability of such film/substrate systems under both uniform and non-uniform illuminations by ultraviolet (UV) light, respectively.

Guoyong Mao's picture

Morphology of voltage-triggered ordered wrinkles of a dielectric elastomer sheet

Wrinkles have attracted a lot of attention in the fields of material science and engineering applications. And dielectric elastomer is a potential smart material which has advantages including large deformation, light weight, high energy density, quick response and et al. We try to use DE to make a wrinkle structure which is quick response and reversible easily.

Yongle Sun's picture

Dynamic compressive behaviour of cellular materials: a review of phenomenon, mechanism and modelling

Dynamic compressive behaviour of cellular materials is crucial to their applications in energy absorption, ballistic mitigation and blast/impact protection. The recent research progress in this subject has led to an improved understanding of the experimental, analytical and numerical observations. This review focuses on the aspects ofphenomena, mechanisms and modelling on the concerned subject.

Matt Pharr's picture

Lab-on-Skin: A Review of Flexible and Stretchable Electronics for Wearable Health Monitoring

Skin is the largest organ of the human body, and it offers a diagnostic interface rich with vital biological signals from the inner organs, blood vessels, muscles, and dermis/epidermis. Soft, flexible, and stretchable electronic devices provide a novel platform to interface with soft tissues for robotic feedback and control, regenerative medicine, and continuous health monitoring.

ABAQUS EXPLICIT DYNAMICS

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Multiple scattering theory for polycrystalline materials

This work is a natural extension of the author’s previous work: “Multiple scattering theory for heterogeneous elastic continua with strong property fluctuation: theoretical fundamentals and applications” (arXiv:1706.09137 [physics.geo-ph]), which established the foundation for developing multiple scattering model for heterogeneous elastic continua with either weak or strong fluctuations in mass density and elastic stiffness. Polycrystalline material is another type of heterogeneous materials that widely exists in nature and extensively used in industry.

Multiple scattering theory for heterogeneous elastic continua with strong property fluctuation: theoretical fundamentals and applications

Scattering of elastic waves in heterogeneous media has become one of the most important problems in the field of wave propagation due to its broad applications in seismology, natural resource exploration, ultrasonic nondestructive evaluation and biomedical ultrasound. Nevertheless, it is one of the most challenging problems because of the complicated medium inhomogeneity and the complexity of the elastodynamic equations.

Ph.D. Student Positions in Computational Materials Science and Mechanics

Several Ph.D. student positions are available in Professor El-Azab’s group with the School of Materials Engineering, Purdue University. The group performs advanced theoretical and computational research in the areas of mesoscale plasticity and dislocation dynamics, radiation effects in materials, microstructure evolution, phase field method development, and computational methods for materials science and mechanics. Applicants with MS in mechanical, aerospace, or materials engineering, with background in microstructure science, continuum mechanics and elasticity, numerical methods or computational techniques such as finite element method are highly preferred. Knowledge of at least one advanced programming language such as Fortran or C++ is required. Exceptional applicants with BS degree will also be considered. The openings are for spring 2018, summer 2018 and fall 2018. Applicants must meet Purdue University and School of Materials Engineering admission criteria. For inquiry please send email to Professor El-Azab (aelazab@purdue.edu).

Piezoelectric Stack Modelling in ABAQUS

How does one model a piezoelectric stack Actuator in ABAQUS?

Sundaraelangovan selvam's picture

In 1D wave propagation problem, how to find the curl of a given source function?

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I am trying to solve 1-D wave equation by calculating potentials ϕ

Amit Acharya's picture

On Weingarten-Volterra defects

Amit Acharya

The kinematic theory of Weingarten-Volterra line defects is revisited, both at small and finite deformations. Existing results are clarified and corrected as needed, and new results are obtained. The primary focus is to understand the relationship between the disclination strength and Burgers vector of deformations containing a Weingarten-Volterra defect corresponding to different cut-surfaces.

Antonio Papangelo's picture

Discussion of “Measuring and Understanding Contact Area at the Nanoscale: A Review” by Tevis D. B. Jacobs and Ashlie Martini

M. Ciavarella(1) and A. Papangelo(2)

(1) Politecnico di BARI, Center of Excellence in Computational Mechanics, Deparment of Mechanics, Mathematics and Management. Viale Gentile 182. 70125 Bari (Italy)

(2) Hamburg University of Technology, Department of Mechanical Engineering, Am Schwarzenberg-Campus 1, 21073 Hamburg, Germany

michele.ciavarella@poliba.it, antonio.papangelo@poliba.it

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