Here you will find the UDL source code for an example of the cohesion contact model proposed by Johnson, Kendall and Roberts*:
http://www.dem-solutions.com/support/fi ... 010_10.zip
The model differs from the linear cohesion model by approximating the bridging of the fluid around the two particles in contact. There is a PDF included in the ZIP file which gives more detail.
Please take a look at the code for your own project and remember to come back and post up any modifications or code snippets which will help other users along the way. Feel free to use this forum for asking questions about this contact model.
DEM Solutions Team.