Hi, i have tried to make an accurate Nonlinear-Static thread (M12x1,75) simulation: the Torque-Load has always only max. 4% different to the analitical calculation,
but the stress distribution looks a bit weird. The "nut" is fixed and the bolt head has a 0,1 rad Cylindrical prescribed displacement with initial contact.
I´ve thought maybe the mesh, but after tried every settings (node to surface-surface to surface, standard-curveture,mesh method, mesh fineness,
mesh Tolerance, 4 and 16 points, decrease step size) the result was always the same, this wavy pattern with 10 min and max positions.
The model also do not contain any form that can cause any problem like this, with cylindrical head the result is also the same and when i simply
pull the head to simulate the load everething looks as should without the pattern and the stress distribution looks correct.
Maybe someone has an idea how and what should i modify?