Greetings to everyone,

Our team is currently working on the development of a VUMAT code in Abaqus for composite modelling using the Puck's failure theory as damage initiation criteria. Currently we manage to develop 6 different algorithms (4 on literature and 2 of our own) to find the fracture angle of any state of stress in an accurrate and efficient manner.

My question is related to the post damage behavior. Let's assume that a material point reach the Puck's failure initiation condition for an angle of -58° in matrix compression. It is clear that the material can resist further load in matrix tension and we need to degrade the stiffness matrix and so on. However, for this post damage stresses the fracture angle needs to be set to -58° or do we need to still look for the fracture angle? It is also known that the most critical angle depends on the state of stress and if we set constant from that point on are we understimating the damage?

If you need further instructions or the question is not clear enough please let me know. I'll be glad to share more details in case they are required.

Thanks in advance for your aid and support