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LS DYNA User Defined Failure Criterion

Submitted by Kapil.Nandwana on
LS DYNA
USER DEFINED
FAILURE CRITERION

Hi:

 I am simulating a projectile impact on a plate and using LS - DYNA for the same. 

I have to use Barlat's anistropic plasticity model with the Johnson Cook Failure Criterion.

Now, Although Barlat's Model is in built into LS DYNA, how do I implement JC Failure criterion ? Is there a feature of User defined failure criterion in DYNA ?

If not, Is implementing a UMAT consisting of Barlat's consitutive eqn and JC failure criterion the only other option ?

 

Thank You,

  

 

 

 

Openings Available: Ph.D. students in MEMS/Nanotechnology

Submitted by tonyjunhuang on
job

The Penn State Biofunctionalized Nano-Electro-Mechanical-Systems (BioNEMS) Laboratory (http://www.esm.psu.edu/huang/) is actively recruiting highly motivated, qualified Ph.D. students. 

 

We welcome students trained in the following fields: Mechanical Engineering; Electrical Engineering; Chemical Engineering; Chemistry; Biology; Optics; Material Science; Bioengineering; Physics.

Outstanding Scientists : New Delhi (India)_ CSIR

Submitted by Amit Pandey on
job
India
outstanding scientists

 

Oppurtunity for experience scientist and professors at

Council of Scientific & Industrial Research [CSIR]:

 http://www.csir.res.in/

http://www.nature.com/naturejobs/science/jobs/93864-Outstanding-Scienti…

You have a mission back home in India

Symmetry of Infinitesimal (linear) strain tensor

Submitted by Jayadeep U. B. on
education
strain tensor

Hello everyone,

 Why do we have the infinitesimal (linear) strain tensor to be symmetric? The reasons, which I have understood so far are:

1. It is defined to be symmetric so that it behaves like a tensor.

2. The stress tensor, which is its energy conjugate, is symmetric, and hence the skew-symmetric part has no contribution towards strain energy.

 Can anyone suggest more fundamental reason(s) for the symmetry of linear strain tensor, like the moment equlibrium leading to symmetry of the Cauchy stress tensor?

Thanks in advance,

Functionally graded materials

Submitted by mrityunjay on

Hi 

 I am a new entrant to this site. I am a Ph.D student working in the area mechanical behavior of fgm's.

Is there anyone to support and share the knowledge in the domain of theorotical modelling for damping behavior of fgm beam?

I need to know about different laws (exponential, sigmoidal etcs) on fgm's. any literature?

mrityunjay

Warning messages related to negative eigen values while using Abaqus Standard

Submitted by unsrohith on

Hi all,

 I am working on simulation of necking in a uniaxial tension test using sheet specimens of 1 mm sheet thickness. I have given stress strain data upto a plastic strain of 1 , I am using 4 elements in the thickness direction of the sheet.My job is able to complete but with lot of warning messages as follows:

1) The strain increment has exceeded fifty times the strain to cause first yield at 286 points

2) The system matrix has 174 negative eigenvalues.

ANSYS CONTACT Pair Problem

Submitted by hijazi on
research

I am doing analysis in ANSYS which requires the contact pair to be defined. I am unable to select an appropriate value of Pinball region, Penetration Tolerance and normal penalty stiffness. Does any body have an idea how to select the good values for better solution? If you have anykind of material related to contact pair kindly email me at hijazi.19 [at] gmail.com (hijazi[dot]19[at]gmail[dot]com)

 Thanks

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