Recent content by Winnower

Is there some confusion regarding units here? I don't think rhov2 is a pressure, it is a measure of energy density and has units of energy/unit-volume (J/m3) not Pascals. The Norsok "limit" of rhov2<=200000 is, I think, to limit a piping systems exposure to high turbulence flow which can set up...

Thanks all for your responses, BJI, I'm doing high cycle fatigue for piping systems on an FPSO, so it's the piping that is cycling and we are considering the hogging and sagging of the hull, the operating pressure cycling around the process value, the temperature cycling around the process...

Thanks for your reply DriveMeNuts, I guess we don't know what the orientation of the crack will be so a multi orientational, oblique, "3D" approach would probably be desirable. Isn't that what the CAESAR II max stress intensity gives us? My understanding is that fatigue cracks initiate at a...

Hi, is anyone familiar with using PD5500 for high cycle fatigue analysis in piping system according to DNV-RP-D101? I am running various load cases using CAESAR II to identify the different stress ranges in my piping according to the rain flow method as required but: CAESAR II outputs two...

Ok I have had a look at this again and I think I can rephrase the questions. 1) When CAESAR produces a fatigue stress report for the FAT case can anyone confirm that, for the B31.3 piping code the "code stress" listed is based on the "Max Stress Intensity" and that this is the stress that...

Hi, It sounds like you need to model the "end conditions" for your system. If the system ends with a flange going into a skid then I guess you need to model the flange pair and an appropriate amount of piping beyond that. To find out what the loads are at the flange pair you can use a "connect...

Hi, I’m looking for some clarification on a point. I have read around this topic quite extensively and think I have gleaned the knowledge I require but I have not found an explicit answer to my query without getting too bogged down in the theory. The query is: which stress we should use from...

  Hi, I’m looking for some clarification on a point. I have a query as to which stress we should use from CAESAR “stresses extended” output for our input to DNV/PD5500 high cycle fatigue analysis.   I am not using the CAESAR ASME high cycle fatigue module so the stress values in question are...

Thanks again Littleinch, I understand your concerns with the strength of the rolled cladding. They are my concerns too. I will perhaps conduct some tests to look at exactly how stiff the cladding is and what loads it can take. Yes, continuous support would be the correct way to model this...

Thanks again Littleinch, I understand your concerns with the strength of the rolled cladding. They are my concerns too. I will perhaps conduct some tests to look at exactly how stiff the cladding is and what loads it can take. Yes, continuous support would be the correct way to model this...

Thanks for your comments Littleinch, Apologies for my delayed reply, I have been away for some factory acceptance testing of some of our components so I did not have a chance to respond. I don't think that polyurethane and polyethylene would stand the temperatures I am dealing with, the lines...

Hi, I am currently struggling with pipe stress and pipe support of some 1" or less pipes and tubes. The lines are hot, some 500c (low allowable stresses), and the wind loads are high. The lines are insulated and traced and the overall diameter of the pipe, tracing, insulation and cladding is...