How to understand stress region due to the bolt pre-laod? 1

[Henry26]

Hello guys,

How do you interpret this region? Is it reliable?
I used non-linear contact between parts. I'm confused because this region is bigger than Yield Stress, but I know that this region will not break. My doubt isn't about stress at bolt, but the region that bolt abuts the part.
See attachment:

Thanks in advance,
Henry.

 

[rb1957]

it's a rather nice colour picture. it doesn't tell me much about mesh density or stress ... it is just a colour picture.

it looks like you've got a bolt in a slot, so you could hand calc what's happening on the two contact areas. if you need to provide more support to the bolt head, then add a thick washer.

another day in paradise, or is paradise one day closer ?

 

[corus]

Presumably the area under the bolt head will be under compression whilst the bolt head will be in tension. The area under the bolt head won't break but distort if the stresses are above yield. Try plotting the maximum and minimum principal stresses rather than Von Mises to understand the stress distribution better.

 

[Henry26]

Thank you for answers,

Considering that this region has refined mesh, has complete assemply (including washer) and it's made out on steel (easy to find on the market), in practical I know this region will deform plastically, but I also know it will not break by fatigue or others way. I just know that others regions with less stress will break first, but I can't understand why, once the stress is much less.

 

[Bopeco]

There is no washer under the bolt head, that would help to distribute the load on a bigger surface.
The region under the bolt has compression so fatigue will harder occur as the cracks will be closed.

The rest of the structure have very low stress values so it's not a surprise it won't break