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3d bolt compression with contact

mvass

Dear all,

Lately I am having some problems solving a problem that might seem 'trivial', however I am still having problems getting some meaningful results. As seen from the files attached, the problem consists of two aluminium plates connected with a steel bolt and a bushing. There is a press fit of 0,2mm (if I remember well) between the bushing and the two plates. The upper plate has one of its sides fixed and a compressive force of 90 kN is acted on the lower plate. Although I have simulated the contact* between all components (plates, bolt, bushing) and ran a quassi static NL analysis, I keep getting extremely high stresses at the area seen on the attached picture. It is probably some mistake with the contact there but I cannot find it.

Please have a look on the attached .hm file. There are no contacts defined to allow you to use your own approach to the problem. You can use any of the latest HM versions to setup the problem.

Thank you in advance for your kind assistance.

*: a number of approaches used: friction, no friction, slide, freeze etc.

<?xml version="1.0" encoding="UTF-8"?>

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PrasannaK

Hi,

How many contacts did you define?

I think there should be 6 contacts.

PFA a model file for reference (with contacts created).

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mvass

Dear PrasannaK,

thank you for kindly replying to my question. I'll have a look on your file later this afternoon, however I must say that I have made some progress myself yesterday: I had to define a 'freeze' contact between the two plates, because the axial movement (slide contact, with friction), was causing the 'hot spot' on the bushing that I mentioned in my previous post. I am not however sure if that approach is physically correct. As to the contacts, I count the following: bushing-plate 1, bushing-plate 2, plate 1 - plate 2, bolt - bushing. If you also include the bolt's head, then it is bolt head-bushing, bolt head-plate 1, so yes that makes 6 contact surfaces in total.

Let me check your file and I'll contact you again.

Thank you for taking the time to check my model!

mvass

Dear PrasannaK,

I had a quick look on your approach. It seems that the contact properties defined need some serious adjustments, because if you run the model as per the updated file, the lower plate performs a large rotating motion. I'll have a further look and let you know, although as mentioned before I think I can solve the problem by: a) creating a 'freeze' contact between the two plates and simulating the bolt with 1D beam element connected with RBEs to the bushing and plates.