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Cyclic Bidirectional loading in ABAQUS

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I'm modeling a column under Constant Axial load (Y-axis) and Cyclic bidirectional loading (X & Z-axes). Does anyone have experience how to apply Cyclic bidirectional loading in ABAQUS? See the attached picture.

peppezurlo's picture

Catastrophic thinning of dielectric elastomers

Consider a thin dielectric plate with conducting faces: when will it break if a voltage is applied? If it is rigid it will break once its dielectric strength is overcome by the voltage. But what if it is highly stretchable, like the elastomers used for soft actuators, stretchable electronics, or energy harvesters? The precise answer to that question is not known. 

A novel class of highly efficient and accurate time-integrators in nonlinear computational mechanics

A new class of time-integrators is presented for strongly nonlinear dynamical systems. These algorithms are far superior to the currently common time integrators in computational efficiency and accuracy. These three algorithms are based on a local variational iteration method applied over a finite interval of time. By using Chebyshev polynomials as trial functions and Dirac–Delta functions as the test functions over the finite time interval, the three algorithms are developed into three different discrete time-integrators through the collocation method.

Piezoresistivity modeling with Ansys

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Dear Colleagues,  I am working with ANSYS PDL to model a piezoresistive cement-based material; the material is assumed to be isotropic and the piezoresistive strain matrix [m] has to be determined, details are specified in the attachment. I would be pleased if you would provide your expert insight on the following questions.  1. In piezoresistive strain matrix [m], what do components X, Y, XY, YZ and XZ mean physically? How are these quantities determined?

Alejandro Ortiz-Bernardin's picture

Consistent and stable meshfree Galerkin methods using the virtual element decomposition

Paper Accepted for Publication in International Journal for Numerical Methods in Engineering

Consistent and stable meshfree Galerkin methods using the virtual element decomposition

A. Ortiz-Bernardin, A. Russo, N. Sukumar

 

Abstract

Mike Ciavarella's picture

moving singularities (crack analogues) in fretting fatigue

    The stress concentration induced by fretting fatigue was studied with a simple "Crack Analogue" model (CA) by the MIT group of Suresh in the late 1990's, which was then "improved" by the present author to take into account simply both contact loads and bulk stresses loads, and even the case of finite stress concentration in the so-called "Crack Like Notch Analogue" (CLNA) model.

Amit Acharya's picture

Fracture and singularities of the mass-density gradient field

To appear in Journal of Elasticity

A continuum mechanical theory of fracture without singular fields is proposed. The primary
contribution is the rationalization of the structure of a `law of motion' for crack-tips, essentially
as a kinematical consequence and involving topological characteristics. Questions of compatibility
arising from the kinematics of the model are explored. The thermodynamic driving force
for crack-tip motion in solids of arbitrary constitution is a natural consequence of the model.
The governing equations represent a new class of pattern-forming equations.

mohsenzaeem's picture

Effects of SiC, SiO2and CNTs nanoadditives on the properties of porous alumina-zirconia ceramics produced by a hybrid freeze casting-space holder method

Highly porous alumina-zirconia ceramics were produced by adding space-holder materials during freeze casting. To increase the strength of porous ceramics, different amounts of nanoadditives (silicon carbide-SiC, silica-SiO2, and multi-wall carbon nanotubes-CNTs) were added. Space-holder materials were removed by preheating, and solid samples were produced by sintering. Up to 68% porosity was achieved when 40% space-holder was added to the solid load of slurry. Wall thicknesses between pores were more uniform and thinner when nanoadditives were added.

FastBEM Fracture 2-D available for download

The fast boundary element program used in the recent paper:

Y. J. Liu, Y. X. Li, and W. Xie, "Modeling of multiple crack propagation in 2-D elastic solids by the fast multipole boundary element method,"  Engineering Fracture Mechanics, 172, 1-16 (2017)

Faxin Li's picture

A breakthrough in Guided Wave – Excitation of shear-horizontal (SH) wave is not a problem any longer

Excitation of non-dispersive shear-horizontal (SH) waves in plates is always a challenge. Recently, we successfully excited single-mode SH0 wave in plates using a face-shear (d24) mode piezoelectric transducer. Meanwhile, the d24 mode transducer can selectively receive SH0 wave and filter Lamb waves. This work was published as a Letter in the IOP journal Smart Materials and Structures (http://dx.doi.org/10.1088/0964-1726/25/11/11LT01).

Fatemeh Ahmadpoor's picture

A perspective on the statistical mechanics of 2D materials

2D materials are fascinating for numerous reasons. Their geometrical and mechanical characteristics along with other associated physical properties have opened up fascinating new application avenues ranging from electronics, energy harvesting, biological systems among others. Due to the 2D nature of these materials, they are known for their unusual flexibility and the ability to sustain large curvature deformations. Further, they undergo noticeable thermal fluctuations at room temperature.

bardia's picture

PhD/masters position in Mechanical Department at University of Hawaii at Manoa

A PhD/masters position is available in AMMI Lab at University of Hawaii at Manoa in the field of surgical robotics. Interested and outstanding candidates should visit my website at http://uhatmanoa.wixsite.com/ammi. Information about general admission process could be found on http://uhatmanoa.wixsite.com/ammi/prospective-students.

Ajeet Kumar's picture

Unusual couplings in elastic tubes - negative poisson effect and overwinding on being stretched

We demonstrate intersting extension-torsion-inflation coupling in intrinsically twisted chiral tubes. In particular, we show that by tuning its intrinsic twist and the material constants, such tubes can show negative poison effect on being stretched. Similarly, such tubes can overwind initially when stretched - the same unusual behavior has been reported earlier when a DNA molecule is stretched.

zichen's picture

Edge effect of strained bilayer nanofilms for tunable multistability and actuation

Inspired by the need to develop reconfigurable materials at the micro- and nano- scales that are capable of exhibiting more than one stable configuration, we employed both theoretical and computational models supported by experiments to study the multistable behavior of a Si/Cr microclaw and uncover the mechanical principles involved.

trisha_sain's picture

Phd positions in Michigan Technological University

PhD positions are available from Fall 2017, in Michigan Technological University, in Mechanical Engineering-Engineering Mechanics Department. The candidates are to work in the computational modeling of multiphysics behavior of polymer materials, high rate fracture response of gel like tissue mimicking materials or Design of microarchitectured polymer composites for improved functionality. Interested candidates can email their CV with relevant information at -tsain[AT]mtu.edu

Candidates with background in continuum mechanics, finite elements and materials modeling are preferred.

Timothy Morrissey's picture

A Transparent, Self-Healing, Highly Stretchable Ionic Conductor

Self-healing materials can repair damage caused by mechanical wear, thereby extending lifetime of devices. Here, a transparent, self-healing, highly stretchable ionic conductor is presented that autonomously heals after experiencing severe mechanical damage.

A Transparent, Self-Healing, Highly Stretchable Ionic Conductor

Christopher Provatidis's picture

CAD-based precursors of IsoGeometric Analysis

Article title: CAD-based collocation eigenanalysis of 2-D elastic structures
Journal title: Computers and Structures
Author: Dr. C Provatidis
Final version published online: 18-Dec-2016
DOI information: 10.1016/j.compstruc.2016.11.

Bin Liu's picture

The widely used tensile stiffness ratio is not a correct measure of anisotropy degree

In our recent paper, some interesting conclusions are found when we attempt to establish a standardized compliance matrices for general anisotropic materials. The abstract is as follows.

UMAT for isotropic hardening

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Hello,

I'm new here and I'm not sure if this a right place to ask a question or not.

I'm trying to practice writing UMAT code and I just finished the (Coding for isotropic Mises plasticity) from the the attached document. I'm trying to check validity of this code with simple model: what kind of this simple model? how can I do that? 

 

Please help me with this problem

Regards,

Qusay

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