FFS-III failure criteria for corrosion metal loss

[usecheijk]

I have a doubt about MAWOP calculation in FFS-III burst analyisis of pipelines under internal pressure, considering corrosion metal loss.

Most of MAWOP FEA calculations reported in the literature considers full yielding of the remanent material in metal loss zone as failure criteria. Thus, the Von Mises equivalent stress is compared with a flow stress and defining a MAWOP according to this.

In some analysis yield stress or the ultimate stress are selected as flow stress. However, in my opinion, using Sflow=Sys is very conservative and Sflow=Sult is very non-conservative criteria. Why not use Sflow=1/2(Sy+Sult), for example, as intermidiate failure criteria?.

Thanks!

 

[DSB123]

If you want to go against the Code then you have the prerogative to do so!!! However when something goes wrong then I hope you can justify why you ignored the Code. Code limits are there for a reason!!!