Free body diagram of a preloaded system with a gasket

[MechanicalEngineer]

Hello,Ive got a question and wondering if there is someone that could help me? I would really appreciate it!

I am studying for an exam that I am going to have in a couple of weeks and it has been going great besides that I have been stuck on a question about tension in a preloaded system with a bolt and gasket.

So, to the problem.

Let’s assume that there are two plats that don’t bend and between these two plats there is a bolt that have been going through a gasket so that the system in under pressure from a preloaded force. Now, the bolt is tightening even more so that pressure rises. The area of the gasket is 3A and the area in the bolt is A and the E-module is the same.

How should the free body diagram? I have the correct answer from an old exam but can’t understand why the free body diagram, shouldn’t the tension force from the bolt be to the opposite side of the tension force from the gasket? They have drawing the tension force of the preloaded bolt and gasket in the same direction.

There are two images that are linked, one is for the question and one is the answer from the exam.

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I really appreciate it!

(Sorry for the bad English)

 

[BvU]

Your links are way off

 

[berkeman]

Your links are way off

Thanks @BvU -- links have been deleted now.

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