# Decision criterion if bolted joints are loaded concentrically or eccentrically

When dimensioning bolts I have to decide if the applied load is concentrically or eccentrically to the bolt axis (according to VDI 2230 but I think in other approaches too). But how do I decide and justify my decision for concentrically or eccentrically load?

Yet I made my decision if the axial load of a specific bolt (the working load is proportionally related to the bolts in the bolted joint) is concentrically or eccentrically to the bolt axis. My worry is that this decision criterion is to rigorous and my dimensioning of the bolt leads (always) to an overdesigned bolt.

Are there more decision criterion to consider?

Now I give some parameters which might be relevant – but mind the following list is not complete:

• the material of the housing and cover (plastic or metal)
• the thickness of the housing and cover
• may be some parameters of a FEM simulation
• bend of the considered bolt ($$[N/mm^2]$$ or $$[°]$$)
• surfaces of the used materials
• the coating
• the roughness of material (caused by kind of production)
• and more parameters…

And what are the thresholds of these parameters to say the load is concentrically or eccentrically?

I’m expecting a statement like: When the parameter A fulfils the following, then you can say that the applied load on the bolt is concentrically.

I’m glad to hear from your experiences how you decide if a bolt is loaded concentrically or eccentrically.

Many thanks in advance.

• And if the bolt is loaded in shear or double shear? Feb 4, 2019 at 11:28
• @ Solar Mike: I'm not sure how to handle your comment. Is shear an other parameter which should be considered? Feb 4, 2019 at 12:27
• How do bolts get bent? Feb 4, 2019 at 13:10
• @ Solar Mike: Here you can see a sketch of a bended bolt researchgate.net/figure/… As you can see the load is eccentrically and therefore the bolt bends Feb 4, 2019 at 15:56
• So have a look at: coefs.uncc.edu/mwhelan3/files/2010/10/… Feb 4, 2019 at 16:01