Modelling of bolted connections in Abaqus

[BATUHAN]

Hi Dears,

I try to model double bolted lap connection using Abaqus. I am using two methods. The first solid equivalent model (solid element for plates and bolts) and the second is the simplified model ( shell element for plate, beam element for bolt shank and multipoint constraints for washer)
When the bolt diameter equals to bolt hole in models, model runs but the initial stiffness is much higher than experimental results). When the bolt hole is larger than the bolt diameter, model cant converge ad I got error too many attempts made for this increment.
I tried to assign springs, which have very low stiffness, between hole and bolt but it did not work.

Please may you help me how to solve this problem?

 

[FEA way]

If it’s static analysis then you have to make sure that all rigid body motions are eliminated. There are several ways to handle this, like the use of automatic stabilization in step settings. However, if you want to keep the bolts loose throughout the analysis, it might be difficult to achieve convergence and I would rather try with dynamic quasi-static simulation.