Consistent linearized tangent moduli for hyperelastic materials... is it always a positive definite matrix?
In order to obtain numerical solution of problemsthat involves a hyperelastic material model, we use what is known as incremental/iterative solution techniques of Newthon's type. The basic idea is to contruct a discrete system of nonlinear equation, KU=F, and solving it using a Newton's method or a modified version of it. As we know, its lead to a systematic linearization of the internal force vector and by the chain rule to the linearization of the material model.
Picking a node within a 3D Solid Volume
hi all,
I have a solid 3D part made of concrete. I would need
the results of a few points inside the concrete. However, I realised it
was not easy to pick them when doing a Set because the nodes are hidden
(they are not on the surface. I have 1) partition my model exactly at
the points when I need to pick 2) i name the points as datum points.
Using the CAE interface, how can i pick this nodes? I have attached a pic for better understanding. Can anyone please advise?
Thank you.
Project Tuva (Feynman's lecture series)
Here is an interesting link I came across while searching for the Feynman lectures -- Project Tuva.
http://research.microsoft.com/apps/tools/tuva/
It provides each of Prof. Feynman's seven lectures delivered at Cornell as a part of the Messenger lecture series. This format of posting lectures by Microsoft is absolutely amazing. I hope more such lectures especially videos of keynote lectures in leading conferences and congresses can be made available online.
-Arun
modelling cyclic plasticity in abaqus
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I have to model cyclic plasticity in ABAQUS. The method to use ( this is as per ASME Boiler and Pressure Vessel code) involves only a single loading ( rather the load range has o be applied) and using a stabilized cyclic stress strain data expresssed in Ramberg Osgood format. The parameters for Ramberg Osgood are specified in the equation to be used fpr stabilized cyclic stress strain curve.
Implementing the same in ABAQUS, gives me the following possibilities :
Problem with fortran code for solving large strain 2D elastic problem by FEM using Updated Lagrangian Framework
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I am using my own fortran code to solve a large strain 2D elastic problem using FEM in Updated Lagrangian framework and I am using incremental formulation. It works well for 2D pull of a square block with 2 elements and I've compared the results with a commercial FEA package. But while solving bending of a cantilever beam the results starts to blow up and the elements distort abruptly after certain time step. This happens only when the load or the displacement given at the free end of the beam is large otherwise it works fine.
In-surface Buckling of Silicon Nanowires on Elastomeric Substrates
Buckling of thin layers or aligned arrays of stiff materials on elastomeric substrates has many important applications, such as stretchable electronics, precision metrology and flexible optoelectronics. These systems show one common phenomenon, the stiff thin layers buckle normal to the substrate surface (out-of-surface buckling). By contrast, we recently reported for the first time that silicon nanowires (SiNWs) on elastomeric substrates buckle only within the substrate surface, i.e. in-surface buckling. Experimental process to obtain buckled SiNWs is described.
Food for Thought: A Few Recent arXiv Papers
Since my research touches on the basics of QM, I have developed this habit of visiting arXiv.org every now and then. Last week or so, at arXiv.org, I found a couple of interesting articles on physics in general. I would like to share these with you.
Postdoctoral Scholar Position in Modeling Li-Ion Batteries
A postdoctoral research position in the modeling of failure mechanisms for lithium ion batteries is available immediately at the Richard G. Lugar Center for Renewable Energy in Indiana University-Purdue University Indianapolis (IUPUI). The candidate will work on the study of failure mechanisms of lithium ion batteries which are related to lithium ion diffusion, heat generation and transfer, chemical reaction, and stress development inside the battery.
Research Engineer Position in Computational Mechanics at KAUST
A research engineer position is available in the Composite and Heterogeneous Materials Modeling and Simulation Laboratory (COHMAS) at King Abdullah Univeristy of Science and Technology (KAUST).
This position will be mainly engaged in two kind of activities:
1) Act as the Lab manager from the computational and simulation side, and support students, post-docs and researchers in the group in developing applications and usinghigh performance computing facilities;