Reducing stiffness

Dear all

I am running a model of composite joint to failure. I would like anyone to help me in reducing the stiffness of the model. The model is being very stiff compared to the real structure. I am aware of the fact that FEM models are usually stiffer than the real structure, however my model is too stiff compared to the real structure.

I am using viscosity to lead to convergence and I am using implicit analysis in my simulation. My model also has bolt pre-load, contact and friction in the simulation. I would like anyone to suggest ways to reduce the stiffness of the model. Please give ideas, how can I reduce the stiffness of the model. Thanking you in advance.

Kind regards

Maajid