“At the beginning of this year,Chinese President Xi Jinping attended the World Economic Forum where he pointed out that the Paris Agreement is a hard-won achievement which is in keeping with the underlying trend of g...“At the beginning of this year,Chinese President Xi Jinping attended the World Economic Forum where he pointed out that the Paris Agreement is a hard-won achievement which is in keeping with the underlying trend of global development.All signatories should stick to it instead of walking away from it as this is a responsibility we must assume for future generations.展开更多
Bearings in a gas turbine engine are the key connecting components transmitting force and motion between rotors and thin-walled flexible casing.The bearing stiffness and damping of squeeze film damper(SFD)nearby beari...Bearings in a gas turbine engine are the key connecting components transmitting force and motion between rotors and thin-walled flexible casing.The bearing stiffness and damping of squeeze film damper(SFD)nearby bearings are easily affected by many factors,such as assembly process,load condition and temperature variation,resulting in uncertainties.The uncertainties may influence the response of the measuring point on the casing.Hence,it is difficult to carry out the fault diagnosis,whole machine balancing and other related works.In this paper,a double integral quantitative evaluation method is proposed to simultaneously analyze the influence of two uncertain dynamic coefficients on the response amplitude and phase of casing measuring points.Meanwhile,the coupling influence of stiffness and damping accompanied by dramatic changes with rotational speeds are essentially discussed.As an example,a typical engine bearing-casing system with complex dynamic characteristics is analyzed.The impact of uncertain dynamic coefficients on the unbalance response is quantitatively evaluated.展开更多
文摘“At the beginning of this year,Chinese President Xi Jinping attended the World Economic Forum where he pointed out that the Paris Agreement is a hard-won achievement which is in keeping with the underlying trend of global development.All signatories should stick to it instead of walking away from it as this is a responsibility we must assume for future generations.
基金co-supported by the Young Scientists Fund of the National Natural Science Foundation of China(No.51905025)the Joint Funds of the National Natural Science Foundation of China(No.U1708257)the Fundamental Research Funds for the Central Universities(No.JD1911)。
文摘Bearings in a gas turbine engine are the key connecting components transmitting force and motion between rotors and thin-walled flexible casing.The bearing stiffness and damping of squeeze film damper(SFD)nearby bearings are easily affected by many factors,such as assembly process,load condition and temperature variation,resulting in uncertainties.The uncertainties may influence the response of the measuring point on the casing.Hence,it is difficult to carry out the fault diagnosis,whole machine balancing and other related works.In this paper,a double integral quantitative evaluation method is proposed to simultaneously analyze the influence of two uncertain dynamic coefficients on the response amplitude and phase of casing measuring points.Meanwhile,the coupling influence of stiffness and damping accompanied by dramatic changes with rotational speeds are essentially discussed.As an example,a typical engine bearing-casing system with complex dynamic characteristics is analyzed.The impact of uncertain dynamic coefficients on the unbalance response is quantitatively evaluated.
