Joined: 25 Nov 2013
Location: Houston, TX
|Posted: Mon Jul 27, 2015 4:24 pm
We have been using the elastic-plastic methods in the ASME pressure vessel code (Section VIII, Div 2) and things were going swimmingly until we came to the ratcheting. The code requires you run 3 load cycles, and at the end the analysis show no plastic strain or a convergence of the plastic strain. There is also a requirement that you have an elastic core in the load bearing portion of the model, and we meet this, but have some small local plastic effects we can't get to settle down. The local strains occur on a bolt hole, so I feel this is a problem with how I model the bolts/bolthole and not with the design (bolts modeled as line body), but am having difficulty proving it. Does anyone have experience with this type of analysis and have any comments?
Trendsetter Vulcan Offshore