Hello All, In the design of bolted joint preload is very important factor, which is basically axial 1

[GopalkrishnaPai]

Hello All,

In the design of bolted joint preload is very important factor, which is basically axial load on the bolt.

when the bolted joint assembly undergoes external loads (forces / moments), will induce axial load on the bolt.

I would like to know, what is the % of axial load on the due to external load on the bolt can be allowed or accepted during design /analysis.

I read in one of the article, that the axial load on the bolt due to external load should not be greater than 30% of preload.

Does any code says regarding the axial load on the bolts due to external load ..?

Can anyone help on the above point.

Kind Regards,
Pai

 

[BJI]

For now I am assuming this is a gasketed joint, with a ring gasket sitting inside the bolt circle, if not, please disregard the following. The change in load seen by the bolt depends on the mechanical interaction of the joint components. Without more detailed analysis, you have no idea how much this value is.

As an equivalent percentage of preload, there are no reliable rules of thumb IMO. The code (ASME VIII-1 and VIII-2) presents one method based on that from CC2901, which is suitable for assessing external loads (albeit quite conservative in the current form). This considers leakage and is based on the ASME PCC-1 Appendix O target bolt stress. Higher bolt loads would provide increased capacity for external loads without leakage.

 

[Tmoose]

"I read in one of the article.........."

Please provide more information about (magazine?) article.
A copy or link would be very useful getting everyone "on the same page."

Like BJI said, the nature of the bolted joint is key, and must not be ignored.

Would you get right to work on a project if your boss provided only the technical details in your original post?