Cohesive Element Examples using MD-Nastran

This message is in response to Kauser Imtiaz regarding sample models using cohesive elements for MD-Nastran. Yes, there are several good examples already available (and more coming all the time).

In the MD-Nastran R3 User's Guide, there are examples showing applications of the new technology. This is part of the MD-Nastran Documentation installation. Chapter 20 is Composite Fracture and Delamination. It is an example using SOL400 with both VCCT and Cohesive Element approaches for delamination in a composite specimen with a face sheet. The sample files that go along with this problem are: nug_20v.dat for VCCT and nug_20d.dat for Delamination (cohesive) elements.

MARC and SOL600 also have some nice examples. In the new features PPT file: marcwhatsnews2008r1.ppt
that comes in:
C:\MSC.Software\Marc\2008r1\mentat2008r1\doc\marcwhatsnews2008r1.ppt
on pp. 73-76 you will see some examples of adding Cohesive interface elements "on the fly", meaning during the solution. They are not created initially in the model. p.76 shows the same NASA Test specimen that I described from the MD-Nastran R3 User's Guide Chapter 20 with an animation.

Another good example is in the MARC User's Guide, Chapter 2.20. This file is marc_ug.pdf and is found in:
C:\MSC.Software\Marc\2008r1\mentat2008r1\examples\marc_ug\marc_ug.pdf
Chapter 2.20 is the delamination of a thick composite layered structure with a circular defect. Input files that go along with this model are in:
C:\MSC.Software\Marc\2008r1\mentat2008r1\examples\marc_ug\s2\c2.20

I can get these files to you directly if you have any trouble locating them. All would be available after installing the MD-Nastran Edition for Stanford also with the documentation.

I also sent a direct reply to Kauser by E-Mail on June 18, 2009. Happy to talk with you anytime about these applications.

Kim Parnell