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Mesh sensitivity in stress based failure criterion

Submitted by Gouse on
failure
softening

Hi,

 I want to simulate filaure in cement mortar. I am using Rankine criterion for detecting failure. For propagating damage i want to soften element. Here can I suddenly reduce the stiffness of the element to a negligible value as soon as it reaches specified failure criterion. I read in some book about mesh sensitivity in stress based failure criterion but i could not understand.Can some body expalin what is its consequence of suddenly reducing stiffness of element to a negligible value. How mesh will effect.

With Best Regards

Gouse

 

Initial Stresses by Subroutine SIGINI

Submitted by kashoo on

I am trying to simulate indentation process on stressed material. Problem is whenever I try to introduce initial stresses from SIGINI subroutine in axisymmetric model, to balance stresses, original stress field changes. When I do this in 3D model it works fine but for axisymmetric model as I cant introduce displacement control constraint at edge of axisymmetric, stresses relax towards the side of axisymmetric constraint.

Any idea or example of maintaining resdiual stresses in axisymmetric model thorugh SIGINI?

Terminology for discrete approaches to modelling fracture

Submitted by grassl on
research

It appears to me that there is more and more research done on discrete approaches to modelling fracture.

Especially for brittle or quasi-brittle materials these methods are undergoing a revival.

I am not sure why this is the case. I am also not in the position to judge if this revival is useful.

I just had recently a look at some of these models and I found these discrete models to be suitable

for description of fracture in heterogeneous materials, where cracks appear at many different positions.



Mechanobiology post-doctoral position, Oxford, UK

Submitted by Mark S Thompson on
job
micromechanics
mechanobiology
tendon

A postdoctoral research position is available immediately at the Mechanobiology Group, Nuffield Department of Orthopaedics, Rheumatologyand Musculoskeletal Sciences at the University of Oxford to study tendon mechanobiology and repair following injury or pathology. This is an exciting opportunity to join a multi-disciplinary team drawn from the Botnar Research Centre, the Oxford Institute of Biomedical Engineering and the John Radcliffe Hospital to work at the forefront of strategically important musculoskeletal research.

In situ observation of dislocation nucleation and escape in a submicrometre Al single crystal

Submitted by Daniel Kiener on
research
nanomechanics; plasticity; dislocation dynamics; in-situ TEM

Dear colleagues,

Experimental nanomechanics is a frequently discussed topic on imechanica, see e.g. the very active monthly topics by Xiaodong Li, Julia Greer and Wei Cai.

Continuing on this, I would like to draw your attention to a paper we recently published:

"In situ observation of dislocation nucleation and escape in a submicrometre aluminium single crystal" by Sang Ho Oh, Marc Legros, Daniel Kiener & Gerhard Dehm (http://www.nature.com/nmat/journal/v8/n2/abs/nmat2370.html).

Howard Stone elected to the National Academy of Engineering

Submitted by Anonymous (not verified) on
mechanician

Howard A. Stone, of Harvard University, is elected to the National Academy of Engineering, for the development of fundamental concepts and novel applications in microfluidics and for improving the understanding of small-scale, viscous-flow phenomena.  Here is the full list of members elected in 2009.

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