No material is around pretension bolt

At bolt hole I set a bolt to contact freeze with the bolt hole.

 

then set the pretension on the bolt, like the photo.

 

 

 

and this just a part of loading condition of all model.

 

I want to ask why my topology result pretension at here didn't need any material.

 

I have seen the result of pretension, bolts are subjected pretension and aslo have contact force.

 

 

This is my result then reduce 10% material