Hello John, it is really helpful to receive your reply.

Can you explain a little bit about “wrap contact scoping around the edges”?I don’t really get this. The bolt gets contact with the bolt hole. My understanding is the frictional contact should be created between the bolt surface and bolt hole inner surface. How can I get the contact scoped to the edges? Please refer to the following figures which show how I created the frictional contacts. The bolt shank surface have two seperate frictional contacts with the left part of the surrounding material as well as the right part of the surrounding material, respectively.  THe reason why the material were separated into left and right parts is I have to create the Cohesive zone model in between the interface. The settings are also shown.

I can’t find the “combined” detection method in the settings. Will it only appear after the contact scoping is changed to edges?

The last question, to drop the midside nodes, do you imply the element order? I will change it to linear element.

Appreciate your reply and professional advice!

Kind regards.