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Teng zhang's picture

Predicting fracture energies and crack-tip fields of soft tough materials

Soft materials including elastomers and gels are pervasive in biological systems and technological applications. Whereas it is known that intrinsic fracture energies of soft materials are relatively low, how the intrinsic fracture energy cooperates with mechanical dissipation in process zone to give high fracture toughness of soft materials is not well understood. In addition, it is still challenging to predict fracture energies and crack-tip strain fields of soft tough materials.

SHPB testing: speed of plastic waves in short cylinders

Dear iMechanica community,

I came across a problem in plasticity for which I am unable to find a reference in the literature and kindly ask your advice.

azadpoor's picture

Additive Manufacturing (3D printing) lab at TU Delft

After several years of research in the area of additive manufacturing, biofabrication, and additively manufactured biomaterials and implants, I finally put up the first version of the website of my lab. I will gradually improve the website, but there is already links to all publications coming out of my lab in the general area of AM.

 

How to contact between solid elements after cohesive elements failed?

      Hi, I have used langrangian framwork proposed by Needleman in 1994 to model materials' failure under compression. In this model cohesive elements were inserted along solid elements boundary.

keyhani's picture

For some educational purposes, I need a 2D Dislocation Dynamics Matlab Code.

For some educational purposes, I need a 2D Dislocation Dynamics Matlab Code. Where can I get it?

Simpleware case study: 3D FE Model of the Diabetic Neuropathic Foot

Diabetic foot represents a complication of diabetes that can lead to foot ulcers and other serious conditions. 3D Finite Element (FE) analysis enables dynamic characterisation of different loads within the foot.

Amir Abdollahi's picture

Constructive and Destructive Interplay between Piezoelectricity and Flexoelectricity in Flexural Sensors and Actuators

Flexoelectricity is an electromechanical effect coupling polarization to strain gradients. It fundamentally differs from piezoelectricity because of its size-dependence and symmetry. Flexoelectricity is generally perceived as a small effect noticeable only at the nanoscale. Since ferroelectric ceramics have a particularly high flexoelectric coefficient, however, it may play a significant role as piezoelectric transducers shrink to the sub-micrometer scale.

New research on unstructured tetrahedral meshes in fracture mechanics

Dear all,

I would like to draw your attention to our recently published research on the simulation of high accuracy fracture growth:

Parallelizing ABAQUS UEL?

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Does anybody know how to parallelize a user-defined element and make it work with the automatic parallelizing feature in ABAQUS? Any information related to this will be greatly appreciated ...

mortezaamjadi's picture

Ultra-stretchable and skin-mountable strain sensors using carbon nanotubes–Ecoflex nanocomposites

Super-stretchable, skin-mountable, and ultra-soft strain sensors are presented by using carbon nanotube percolation networksilicone rubber nanocomposite thin films. The applicability of the
strain sensors as epidermal electronic systems, in which mechanical compliance like human skin and high stretchability (e > 100%) are required, has been explored. The sensitivity of the strain

Xiaoding Wei's picture

"Imperfection" in graphene oxide invites surprising properties in a mechano-chemical way

In an article published in the August 20 issue of Nature Communications, we report a mechanochemical phenomenon in graphene oxide membranes, covalent epoxide-to-ether functional group transformations that deviate from epoxide ring-opening reactions, discovered through nanomechanical experiments and density functional-based tight binding calculations.

ahmedettaf's picture

Stick-slip instabilities in sheared granular flow: The role of friction and acoustic vibrations

We propose a theory of shear flow in dense granular materials. A key ingredient of the theory is an effective temperature that determines how the material responds to external driving forces such as shear stresses and vibrations. We show that, within our model, friction between grains produces stick-slip behavior at intermediate shear rates, even if the material is rate-strengthening at larger rates. In addition, externally generated acoustic vibrations alter the stick-slip amplitude, or suppress stick-slip altogether, depending on the pressure and shear rate.

Kejie Zhao's picture

Strengthening high-stacking-fault-energy metals via parallelogram nanotwins

A variety of questions remain open in the new form of nanotwins in Ni, welcome any comments! 

Solution-Dependent State Variables Defined in Subroutine FRIC Cannot be Displayed in ABAQUS Visualization Module

Hi,

 

I am now using ABAQUS subroutine FRIC to define some solution-dependent state variables, and I am currently able to check these values throung writing them into a TXT file in the subroutine. However, I cannot find these SDVs displayed in the ABAQUS visualization module although I have already specify them in the Field/History output manager.

 

I will be appreciate if anyone could give me some advice on this.

 

Thanks a lot,

Yi 

plastic energy density in an element

Hi every body,

I  did an orthogonal cutting simulation and I want to calculate the plastic deformation energy density distribution underneath the tool tip during cutting.

Anyone can give me more informations about this?

Thanks

 

Arash_Yavari's picture

On the Compatibility Equations of Nonlinear and Linear Elasticity in the Presence of Boundary Conditions

We use Hodge-type orthogonal decompositions for studying the compatibility equations of the displacement gradient and the linear strain with prescribed boundary displacements. We show that the displacement gradient is compatible if and only if for any equilibrated virtual first-Piola Kirchhoff stress tensor field, the virtual work done by the displacement gradient is equal to the virtual work done by the prescribed boundary displacements. This condition is very similar to the classical compatibility equations for the linear strain.

refine brick / voxel mesh

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Hello,

Discretising geometries with a brick (voxel) mesh of constant element size is very simple and quick.  However, sometimes there are locally small features which would benefit from a more refined discretisation... In my case, the geometry (a textile reinforcement) is complex and tet meshes get very large very quickly – and are slow to generate. Hence, bricks are a simple way forward.

Here are some geometry examples: http://texgen.sourceforge.net/index.php/Main_Page

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