Research on steel tube fatigue experiment technology based on Butterworth filter method

Duplex stainless steel tube is an important component of subsea umbilical, providing hydraulic, chemical and other injection channels for subsea production system equipment. Duplex stainless steel tube is transported by reel, which will produce plastic deformation and have large impact on its fatigue properties. There are lot of noisy during the test. Therefore, this paper studied the Butterworth filter method to process signals and the fatigue properties of duplex stainless steel tube after transport by reel, and get more accurate filtered signals, compares it with the S-N curve of small diameter steel tube in DNV-RP-C203 to analyze the fatigue properties of plastic deformed steel tube, and the results show that the fatigue properties of steel tube after transport by reel have slight attenuation.