We can use either WAVE input line or GNTRF input line for fatigue’s wave response run. The results from both methods vary where GNTRF input line generate lower joint fatigue life. Does it mean that using Wave input line for fatigue wave response run is more conservative? Which one is preferable method to be used considering the joint fatigue life obtained from both methods are different?
GNTRF will be a better method to generate wave loads on structures as it will save you plenty of time. Both GNTRF and WAVE LOADS should give the same results. The difference of results may come from your input data. Make sure you have the same waves for both lines so you will get the same results.