adding element

[Ng Theng Pin]

may i know can i adding the element during the analysis is running? and how i can do it\....

example:
when the stress value at element AA greater the threshold, i would like to add the element at the element AA so that can reduce the the stress value...

thank you...

[lumpwood]

I'm not sure its possible to add a new element when an analysis is running. However you could create a 'ghost mesh' of empty elements and fill them with material as the analysis progresses, based on some criterion. Alternatively you could halt the analysis, modify the mesh and restart the analysis, the usefulness of that approach will depend on how many times you need to add elements.

[Ng Theng Pin]

hi... lumpwood.. ist ghost mesh using in ANSYS.... how about in abaqus, because im using abaqus now... thanx...

[lumpwood]

Yes this is applicable for Abaqus too, 'ghost mesh' is just a slang term, you won't see it in the manual . There is no subroutine for adding elements once an analysis is running. If you want to modify stresses in an element it is much easier to just modify the material constitutive behaviour through USDFLD or UMAT subroutines than adding new elements.

[Ng Theng Pin]

hi.... how can i create ghost mesh in the model? any example that i can refer..... thank you

[lumpwood]

Have a look here: http://www.adamreeve.co.nz/publications/Reeve2009.pdf

[IceBreaker]

I guess there might be a way of flipping material ablation using UMESHMOTION into material growth, which, in effect, should do what is required.