Hi Everyone,

I have an assembly parts that mated together. the bolt connector is defined to hold them together. There are 4 parts that been bolted together which is washer (solid element), Sleeve (shell element), Frame tube (shell element) and connector (solid element).the shell element is defined with thin and middle to surface offset.

the geometry itself already been validated using clearance verification and no gap between each of the mated parts.

local contact (no penetration) is defined for each part by surface to surface contact. the default setting of 10% gap to consider contact and 1% to stabilize the area if the gap remain unchanged. the global contact is set as default as bonded.

both end is defined as fixed which no translation and rotation.

bolt connector is defined with advance bolt series option since the assembly has more than 2 parts.

the issues that haunting me is

1) I am getting a unrealistic high stress at the sleeve(shell) and washer parts when using mixed mesh element. Also, the stress distribution at the sleeve and washer is not as expected. However, when all those parts is converted to solid elements the "Abnormal bolt pretension is detected" is disappeared. the results and stress distribution seems more realistic with solid element mesh compared to mixed mesh (solid and shell). Since the sleeve and frame tube is a circular with 4mm thickness , by theory it is more precise to treat these parts as shell. So I wanted to produce study with mixed mesh element.

after try a few options suggested on the internet I am still not able to solve this issue.

any experts able to guide on the setup to find what is wrong with y setup.

attached is the simulation setup file for review.

#FEA