Hello everyone,

I am currently modelling a composite bolted joint in Abaqus and I’m seeing significant discrepancies in peak load when compared to my experimental results. The adherends are modelled using shell elements with a composite layup, and I’m using Hashin damage initiation for failure prediction.

For both the unidirectional and multidirectional composite specimens, my simulation under‑predicts the experimental peak load by approximately 50% and 30%, respectively. Interestingly, I have validated the same modelling workflow against other published experiments, and in those cases, my results matched the reported values closely.

The main difference between the successful validation cases and my current model is the material property dataset. In the present experiment, only E1 and tensile strength were provided. I calculated the remaining orthotropic material parameters (E2, G12, G23, ν12, etc.) based on typical relationships. I have also tried tuning these parameters within reasonable bounds, but this only produced minor improvements and did not close the gap.

Has anyone experienced similar sensitivity of Hashin‑based damage predictions to calculated or estimated material properties? Could I be missing a certain detail that might cause such large deviations?

Any insights or suggestions would be greatly appreciated. 

I have attached the geometry below.