ASMA BPVC VIII DIV 3 KD-231 (plastic collapse)

[SiggiN]

Hi all!

I'm have problem understanding when the global plastic collapse criteria is met. I was hoping someone could comment on my understanding described below:

Background:
I'm calculating a component according to API 17 TR 8, 5.4.2 Global Plastic collapse, which is closely linked (exactly the same?) to BPVC VIII DIV 3 KD-231

My understanding:
There are two ways this criteria can be met:

1) Apply the load factors from table 1 to the relevant loads (pressure, preload, etc.), if convergence is achieved the criteria is met, and no further action is required

The tricky part:
2) "factoring the component plastic collapse load by the applicable load factors", my understanding in this case is if the analysis failes one will divide the plastic collapse load by the load facotrs and compare the result with the RWP

i.e:

Step 1) Assume an arbitrary load (e.g. 100MPa) that will cause plastic collapse

Step 2) Say the analysis fails at 80% load, the plastic collapse load is 100MPa*0.8= 80MPa

Step 3) I would divide this load by the load factors: e.g. 80MPa/1.8 = 44MPa

Step 4) This load shall be greater than the RWP of the component


Criteria API 17 TR 8:

Load Factors: