Hi all,
I am looking to use the fringe component to determine which elements in my model have exceeded a certain strain. I will be using the THuMS model to analyze the brain's reaction to impact. Being that the brain is modelled as a viscoelastic, I wouldn't expect a large amount of plastic strain in the impacts I will be modelling. However, the injury criterion I will be using (Cumulative Strain Damage Measure) seeks the volume of the brain which has exceeded a defined strain limit, typically 15%.
I have figured out how to use the fringe component to show damaged (max principal strain > 15%) and undamaged elements for each given state, where a damaged element is red and an undamaged element is green, but I am struggling to find a way to make the data accumulate from beginning to end, ie., once an element becomes damaged, it will not return to an undamaged state.
Any help would be greatly appreciated!
Hi @rybask1,
Very cool! I’m familiar with CSDM and have studied it in the past. I’ve ran across the same issue in PrePost and could not find a way to do this, but I’ll keep thinking on ideas.
The main way I found to study CSDM is through scripting in Matlab. You could make *Set_Solid for different parts of the brain (or entire parts of the brain if you don’t care about individual parts) and add this to *Database_history_solid_set. Make sure you have *Database_extent_binary and STRFLG=1 active to output strain of the elements.
Here are some guidelines for outputting information from solid elements if you need it:
https://www.dynasupport.com/howtos/element/solid-output
But if you want to visualize your results, you may be able to set the range of the fringe in Prepost to show everything below 15% to be blue and everything above to be red. Maybe try setting the minimum strain to 0.15 and max to 0.1501. Something like this may be what you are looking for.
Thanks a bunch! I got the fringe component looking how I want for individual timesteps by setting the minimum to 0 and the maximum to .30 and switching the settings to use only 2 colors, similar to what you described. This makes the limit (where the color changes from red to blue) 0.15.
I could definitely use a Matlab script, along with the history file, to extract the necessary data to calculate the CSDM value, but I was hoping for a fringe component color contour of the final, accumulated state. I appreciate the input regardless!
Did your Matlab script analyze the filtered strain vs time data for each element of the brain and report elements whose maximum strain was greater than .15?
@rybask1 Yeah but I did that back in grad school so I no longer have access to the script unfortunately.