Hi all, I am referencing a Timber-Concrete Composite modelling paper and tried to replicate the model by myself. However, I could not get the same result shown in the paper. I have tried different ways to adjust my simulation, yet I am still nowhere closer to the paper's result. I would like to seek help here and would be grateful if anyone could help.

My model is a symmetrical model that only simulated half of the beam specimen to save computational cost. Displacement loading is used. My simulation has several problems and details can be find in the PDF uploaded.

Out of the problems listed in the PDF, the most important is stress overestimation in both the CLT part and concrete slab. I have double check my material properties and tested different support boundary condition settings, interaction between layers and changing the loading point constraint from "rigid body" to "coupling" without coupling DOF 3 & 4 with the reference point. Yet, all these did not help.

I therefore would like to know what could potentially be the reason behind the overestimation of stress distribution in my model. Thanks!