FEMAP NASTRAN Cracktip element 1

[Brick6]

Hi there,

I'm currently looking into cracking of a plate. I know the NASTRAN solver has these CRAC2D and CRAC3D elements which are used to determine Ki and Kii etc. I'm starting a simple investigation with just a quater of a plate, but cannot find where to specify the CRAC2D element to my mesh in FEMAP. I cannot find any tutorial on how to implement this in FEMAP. Does anybody know how to use this or got some documentation on this?

Thanks in advance,

Cheers

Brick

 

[jbrackin]

The CRAC2D and CRAC3D elements are not supported by Femap at the current time. You could create the crac tip element and its property input manually with a text editor and include it in the bulk data via "start text". Then you would see the output by looking in the f06 file. This would require manually creating the nodes required in Femap, then making the element input in a text editor to connect them as described in the Nastran documentation. If you decide to try this, then one very important requirement is to make the element square, a distorted element will give bad answers. You could find sample input deck in the TPL directory of the Nastran installation.

 

[rb1957]

it might be easier to get a post-processor, that'll take your nastran output and calculate a J-integral

Quando Omni Flunkus Moritati

 

[Brick6]

Thanks guys,

I tried modelling with the 'start text' option, but this is very inefficient. Do you know any post-processor or script which can calculate the J-integral from NASTRAN output files?

It would help me a lot!

 

[rb1957]

a google for "nastran j-intgral" found ...

http://www.mscsoftware.com/support/...ocumentation/nastran_2007r1_release_guide.pdf

Quando Omni Flunkus Moritati

 

[Brick6]

Oh, I forgot to mention you that I'm using NX Nastran and not the MSC version. I already came across the msc documentation, nevertheless NX does not have the J-integral included. I was therefore wondering if somebody knew if it is possible to do J-integral calculations using VBA or another script.