Hi there! I am really new to Abaqus and I need to model a composite
laminated crash cone under impact to a flat solid wall (analytical
surface is used). I modelled a cone with a layers of conventional shell
elements with hashin failure criteria and surface-based cohesive
behaviour as interaction between layers representing the interface of
composite laminates. The model runs successfully but once I checked the
energy balance, the damage dissipation energy from the cohesive, it
turned out to be NEGATIVE (I think this is wrong).