Dear Daniel, to describe the interaction between filler particles and matrix in the course of crack developing you can use micromechanical model of cogesive zone. Really, as you note, the complexity of this problem is caused by changing of properties of composite material in different points of crack path. Using mentioned above micromechanical model in FEM analysis allows take into account this circumstance.

Before I try to help you, what is the software used? Ansys or others?

Hussein Farroukh I am using abaqus.

I have attached images showing the cohesive material properties that I have assigned for the epoxy. Please bear in mind I am a complete novice and inputted them in pa instead of Gpa.

Please if you or anybody could Identify where I have gone wrong it would be an incredible help.

Daniel Orubo , Can you share the errors that occur after the run? The interaction is defined as cohesive behavior properties? The quality of the mesh was checked with no poor element?

Hussein Farroukh the only error I’m facing is that the model job results are unable to converge.

Daniel Orubo , Firstly, I think there is no problem with the material definition, but there is more than one reason: The interaction will be defined as having cohesive behavioral properties The quality of mesh will be good, with no poor elements- Reduce the time step of your explicit model- And finally, check the accuracy of your boundary conditions with the used system unit.

Hussein Farroukh when you say there is no problem with the material properties, do you mean that they are all in line with each other, for example my E/Enn is much larger compared to my nominal stresses.

Also how can I check accuracy of my boundary conditions with the used system