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Mesh sensitivity in stress based failure criterion

Submitted by Gouse on

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

 

VUMAT and ALE in ABAQUS

Submitted by xiaoxinke on

Hi all,

     Here I encoutered a error in ABAQUS when I include ALE with VUMAT. When ALE was not included with VUMAT, my job can work well while with the combination of VUMAT and ALE, the job cann't work any more due to a "Signal 8" error. And if I use a built-in material model and at the same time ALE, a job can work. Furthermore, element failure is considered in all of the cases.

    Anyone can give some suggetion? Thanks in advance!

Xinke

Puzzle: What caused this failure?

Submitted by Biswajit Banerjee on

Here's a puzzle for our readers.  The following image is of the surface of a failed joint followed by a picture of the joint (not the same one but a similar one) before joining.  What material is it? What caused the failure?  All manner of speculation is welcome.



Failed joint



Unfailed joint

The Fourth International Conference on Forensic Engineering

Submitted by Javi Rua on

The Fourth International Conference on Forensic Engineering

From Failure to Understanding



2nd – 4th December 2008

Institution of Civil Engineers

London, UK

Research Positions in Modeling of Solids and Structures

Submitted by Emilio P. Calius on

Please see attachment for details of Computational Mechanics researcher openings at Industrial Research (www.irl.cri.nz), a Crown Research Institute in beautiful New Zealand.

The role involves the application of advanced modeling and simulation methods to research on solids and structures, with an emphasis on complex systems such as composites and meta-materials, or solids with multiple defects and discontinuities.

The position is research oriented but also provides opportunities to consult with industry on commercial projects.

Candidates with expertise in theory and computation of elastic wave propagation, the mechanical behavior of composites, structural dynamics, or acoustics are encouraged to apply.

Multi-Axial Failure Models for Fiber-Reinforced Composites

Submitted by Ashkan Vaziri on

The increasing use of fiber-reinforced composites accentuates the need for developing multi-axial fatigue failure models for these materials. In this article (attached), we proposed several multiaxial fatigue failure models for fiber-reinforced composites considering the contribution of mean and cyclic normal stress/strain and shear stress/strain at the plane of failure and examined their capability for predicting the fatigue life of the E-glass/epoxy composite materials.

Griffith controversy

Submitted by Konstantin Volokh on

Using the Griffith energy method for analysis of cavitation under hydrostatic tension we conclude that the critical tension tends to infinity when the cavity radius approaches zero (IJSS, 2006, doi: 10.1016/j.ijsolstr.2006.12.022). The conclusion is physically meaningless, of course. Moreover, if we assume that the failure process occurs at the edge of the cavity then the critical tension should be length-independent for small but finite cavities while the Griffith analysis always exhibits length-dependence. The main Griffith idea - introduction of the surface energy - is controversial because it sets up the characteristic length, say, surface energy over volume energy. By no means is this approach in peace with the length-independent classical continuum mechanics.

CFRAC 2007 International Conference on Computational Fracture and Failure of Materials and Structures

Submitted by Nicolas MOES on

If you are interested by the computational aspects of fracture and failure of materials and structures,there is a dedicated conference for you : CFRAC 2007, which will be held in Nantes, France, 11-13 June 2007. It is an thematic conference of the European Community in Computational Methods in Applied Sciences (ECCOMAS). The for abstract is now closed. This conference wil involve a certian number