The bow structure of FPSO moored by the single mooring system is rather complicated. There are many potential hot spots in connection parts of structures between the mooring support frame and the forecastle. Mooring f...The bow structure of FPSO moored by the single mooring system is rather complicated. There are many potential hot spots in connection parts of structures between the mooring support frame and the forecastle. Mooring forces, which are induced by wave excitation and transferred by the YOKE and the mooring support frame, may cause fatigue damage to the bow structure. Different from direct wave-in duced-forces, the mooring force consists of wave frequency force (WF) and 2nd dr aft low frequency force (LF) [3] , which are represented by two sets of short-term distribution respectively. Based on two sets of short-term distribution of moor ing forces obtained by the model test, the fatigue damage of the bow structure of FPSO is analyzed, with emphasis on two points. One is the procedure and position selection for fatigue check, and the other is the application of new formulae for the calculation of accumulative fatigue damage caused by two sets of short-term distribution of hot spot stress range. From the results distingui shed features of fatigue damage to the FPSO’s bow structure can be observed.展开更多
The well-known tradeoff between strength and ductility is a key issue in the large-scale engineering application of steel materials to resist fatigue due to earthquakes and other vibrational excitations.The steel prod...The well-known tradeoff between strength and ductility is a key issue in the large-scale engineering application of steel materials to resist fatigue due to earthquakes and other vibrational excitations.The steel production industry provides a vast range of technologies to achieve the desired performances.Through experimental research,it was found that FeCrNi-based high-ductility steel(HD-S)can demonstrate remarkable hysteresis behavior due to extensive deformation capacity of strain-hardening until the ultimate fracture,compared to industrially manufactured high-strength steel(HS-S)with the level of 1 GPa in yield strength.The balance between strength and ductility can be realized by slightly adding the percentage of Ni by 5%to achieve a ductile hysteresis behavior.Moreover,the HD-S specimens exhibit greater resistance to low-cycle fatigue with large plastic amplitude.By developing a new damage evolution law based on instantaneous damage differential during nonstationary fatigue history,the fatigue life of materials is extended into the inelastic hinges of flexural beams/origami components.The proposed approach enables the fatigue design of steel structural components with desirable disaster-prevention capacities for complex steel structures.展开更多
文摘The bow structure of FPSO moored by the single mooring system is rather complicated. There are many potential hot spots in connection parts of structures between the mooring support frame and the forecastle. Mooring forces, which are induced by wave excitation and transferred by the YOKE and the mooring support frame, may cause fatigue damage to the bow structure. Different from direct wave-in duced-forces, the mooring force consists of wave frequency force (WF) and 2nd dr aft low frequency force (LF) [3] , which are represented by two sets of short-term distribution respectively. Based on two sets of short-term distribution of moor ing forces obtained by the model test, the fatigue damage of the bow structure of FPSO is analyzed, with emphasis on two points. One is the procedure and position selection for fatigue check, and the other is the application of new formulae for the calculation of accumulative fatigue damage caused by two sets of short-term distribution of hot spot stress range. From the results distingui shed features of fatigue damage to the FPSO’s bow structure can be observed.
基金supported by the National Key R&D Program of China under Grant No.2022YFB2602700the National Natural Science Fund for Excellent Young Scientists Fund Program,the Fundamental Research Funds for the Central Universities(Grant No.2022CDJKYJH052)the Support Plan for Returned Overseas Scholars of Chongqing(cx2020022).
文摘The well-known tradeoff between strength and ductility is a key issue in the large-scale engineering application of steel materials to resist fatigue due to earthquakes and other vibrational excitations.The steel production industry provides a vast range of technologies to achieve the desired performances.Through experimental research,it was found that FeCrNi-based high-ductility steel(HD-S)can demonstrate remarkable hysteresis behavior due to extensive deformation capacity of strain-hardening until the ultimate fracture,compared to industrially manufactured high-strength steel(HS-S)with the level of 1 GPa in yield strength.The balance between strength and ductility can be realized by slightly adding the percentage of Ni by 5%to achieve a ductile hysteresis behavior.Moreover,the HD-S specimens exhibit greater resistance to low-cycle fatigue with large plastic amplitude.By developing a new damage evolution law based on instantaneous damage differential during nonstationary fatigue history,the fatigue life of materials is extended into the inelastic hinges of flexural beams/origami components.The proposed approach enables the fatigue design of steel structural components with desirable disaster-prevention capacities for complex steel structures.
