Vibration fatigue is one of the main failure modes of blade.The vibration fatigue life of blade is scattered caused by manufacture error,material property dispersion and external excitation randomness.A new vibration ...Vibration fatigue is one of the main failure modes of blade.The vibration fatigue life of blade is scattered caused by manufacture error,material property dispersion and external excitation randomness.A new vibration fatigue probabilistic life prediction model(VFPLPM)and a prediction method are proposed in this paper.Firstly,as one-dimensional volumetric method(ODVM)only considers the principle calculation direction,a three-dimensional space vector volumetric method(TSVVM)is proposed to improve fatigue life prediction accuracy for actual threedimensional engineering structure.Secondly,based on the two volumetric methods(ODVM and TSVVM),the material C-P-S-N fatigue curve model(CFCM)and the maximum entropy quantile function model(MEQFM),VFPLPM is established to predict the vibration fatigue probabilistic life of blade.The VFPLPM is combined with maximum stress method(MSM),ODVM and TSVVM to estimate vibration fatigue probabilistic life of blade simulator by finite element simulation,and is verified by vibration fatigue test.The results show that all of the three methods can predict the vibration fatigue probabilistic life of blade simulator well.VFPLPM &TSVVM method has the highest computational accuracy for considering stress gradient effect not only in the principle calculation direction but also in other space vector directions.展开更多
Objective： To study the anti-fatigue effects of salidroside in mice. Methods： Totally 120 normal male Kunming mice were randomized into 5 groups （4 salidroside intervention groups and the control group） based on b...Objective： To study the anti-fatigue effects of salidroside in mice. Methods： Totally 120 normal male Kunming mice were randomized into 5 groups （4 salidroside intervention groups and the control group） based on body weight. The control group was given distilled water and the 4 intervention groups were given various doses of salidroside （60, 180, 360, 720 mg/kg） for 15 consecutive days, respectively. The levels of lactate, serum urea nitrogen, muscle and liver glycogen, the longest swimming time and hemoglobin were determined before and after swimming test. Results： Different doses of salidroside significantly lengthened the swimming time and increased the contents of hemoglobin and muscle and liver glycogen, while reducing that of lactate in blood significantly compared with control group, especially in the 180 mg/kg salidroside group. Conclusion： Salidroside has noticeable anti-fatigue effect on mice. These effects were dose-dependent, and the strongest effect on most biomarkers was seen with an intermediate dose.展开更多
As a kind of clean and renewable energy,tidal current energy is becoming increasingly popular all over the world with the shortage of energy and environmental problems becoming more and more severe.A floating tidal cu...As a kind of clean and renewable energy,tidal current energy is becoming increasingly popular all over the world with the shortage of energy and environmental problems becoming more and more severe.A floating tidal current power station is a typical type of tidal current power transformers which can sustain the loads of wind,waves,and current,and even the extreme situation of a typhoon.Therefore,the mooring system must be reliable enough to keep the station operating normally and to survive in extreme situations.The power station examined in this paper was installed at a depth of 40 m.A 44 mm-diameter R4-RQ4 chain was chosen,with a 2 147 kN minimum break strength and 50 kN pretension.Common studless link chain was used in this paper.Based on the Miner fatigue cumulative damage rule,S-N curves of chains,and MOSES software,a highly reliable mooring system was designed and analyzed.The calculation results show that the mooring system designed is reliable throughout a 10-year period.It can completely meet the design requirements of American Petroleum institution（API）.Therefore,the presented research is significant for advancing the design of this kind of power station.展开更多
基金supported by the Aviation Science Foundation of China(No.20150252003)
文摘Vibration fatigue is one of the main failure modes of blade.The vibration fatigue life of blade is scattered caused by manufacture error,material property dispersion and external excitation randomness.A new vibration fatigue probabilistic life prediction model(VFPLPM)and a prediction method are proposed in this paper.Firstly,as one-dimensional volumetric method(ODVM)only considers the principle calculation direction,a three-dimensional space vector volumetric method(TSVVM)is proposed to improve fatigue life prediction accuracy for actual threedimensional engineering structure.Secondly,based on the two volumetric methods(ODVM and TSVVM),the material C-P-S-N fatigue curve model(CFCM)and the maximum entropy quantile function model(MEQFM),VFPLPM is established to predict the vibration fatigue probabilistic life of blade.The VFPLPM is combined with maximum stress method(MSM),ODVM and TSVVM to estimate vibration fatigue probabilistic life of blade simulator by finite element simulation,and is verified by vibration fatigue test.The results show that all of the three methods can predict the vibration fatigue probabilistic life of blade simulator well.VFPLPM &TSVVM method has the highest computational accuracy for considering stress gradient effect not only in the principle calculation direction but also in other space vector directions.
基金the Foundation of the Gym Sport Bureau of Shanghai (04JT017)
文摘Objective： To study the anti-fatigue effects of salidroside in mice. Methods： Totally 120 normal male Kunming mice were randomized into 5 groups （4 salidroside intervention groups and the control group） based on body weight. The control group was given distilled water and the 4 intervention groups were given various doses of salidroside （60, 180, 360, 720 mg/kg） for 15 consecutive days, respectively. The levels of lactate, serum urea nitrogen, muscle and liver glycogen, the longest swimming time and hemoglobin were determined before and after swimming test. Results： Different doses of salidroside significantly lengthened the swimming time and increased the contents of hemoglobin and muscle and liver glycogen, while reducing that of lactate in blood significantly compared with control group, especially in the 180 mg/kg salidroside group. Conclusion： Salidroside has noticeable anti-fatigue effect on mice. These effects were dose-dependent, and the strongest effect on most biomarkers was seen with an intermediate dose.
基金Supported by the National "863" Program (Grant No.2007AA05Z450)the National S&T Program (Grant No.2008BAA15B04)+2 种基金2010 Ocean Special Funds (Grant No. ZJME2010GC01, No. ZJME2010CY01)Fundamental Research Funds for the Central Universities (GK2010260106)"111 Project" Foundation (Grant No. B07019) from State Administration of Foreign Experts Affairs of China and Ministry of Education of China
文摘As a kind of clean and renewable energy,tidal current energy is becoming increasingly popular all over the world with the shortage of energy and environmental problems becoming more and more severe.A floating tidal current power station is a typical type of tidal current power transformers which can sustain the loads of wind,waves,and current,and even the extreme situation of a typhoon.Therefore,the mooring system must be reliable enough to keep the station operating normally and to survive in extreme situations.The power station examined in this paper was installed at a depth of 40 m.A 44 mm-diameter R4-RQ4 chain was chosen,with a 2 147 kN minimum break strength and 50 kN pretension.Common studless link chain was used in this paper.Based on the Miner fatigue cumulative damage rule,S-N curves of chains,and MOSES software,a highly reliable mooring system was designed and analyzed.The calculation results show that the mooring system designed is reliable throughout a 10-year period.It can completely meet the design requirements of American Petroleum institution（API）.Therefore,the presented research is significant for advancing the design of this kind of power station.
