Fatigue screening per Div 2, 5.5.2 and Table 5.8

[jtseng123]

Dear all,

I have a lug supported fully insulated vessel. Operating at 100F for 10 days, then go to regeneration at 500F for 2 days, then idle for 8 days. So a full cycle is 20 days. Very easy to calculate how many cycles for 30 years. But our client is saying I need to consider Table 5.8 for temperature difference by adding thousands of cycles. That means this vessel will need to perform FEA fatigue analysis.
Is our client correct to apply Table 5.8 ?

 

[TGS4]

What Method in 5.5.2 are you using? Of course you need to consider the temperature difference - the focus is on the adjacent points temperature difference. Why would you think that you wouldn't have to consider it?

You may need to perform a transient thermal analysis (often in an FEA) to calculate this.