Reply To: LS Prepost to calculate J integral

[longt8]

Hello jday Thank you very much for your quick response!
This time I import the d3plot and the keyword input file to LS-PrePost before proceeding to Applications>Tools>Jintegral.


I did it in following steps:
(1) selected the nodes on the crack edge
(2) selected the crack surface node(white dot) where I only selected one node on the 1/4 ellipse surface.
(3) selected the Vector in X direction as the crack open direction1/4 ellipse surface.

Now I have 3 questions:
Question 1 for step(2): the "crack surface node", for this case do I need to select the ellipse surface shown above or the bottom surface plane on the bottom? Is it correct to only pick only one node?
Question 2 for step(3) : If the sample is pull in Y direction, the crack opening direction here is in X?
The crack propagate direction is in X so I am confused with the crack open direction(actually I think it should Y, but the J-integral will become negative) define in the interface.
Question 3 for dimension : dyna is dimensionless, so why the J-integral is N/mm? How the system select the unite with out user defined it. I can adjust it?

Note:
For this 1/8model, I give the symmetric BC:
(1)XZ plane on the bottom
(2)YZ plane on the left
(3)XY on the back.
Finally, I give the displacement on top for XZ plane in Y direction to simulate the a plate with a ellipse hole in the center.

Thank you!
Best Teng