Magneto-rheological visco-elastomer （MRVE） as a new smart material developed in recent years has several significant advantages over magneto-rheological liquid. The adjustability of structural dynamics to random env...Magneto-rheological visco-elastomer （MRVE） as a new smart material developed in recent years has several significant advantages over magneto-rheological liquid. The adjustability of structural dynamics to random environmental excitations is required in vibration control. MRVE can supply considerably adjustable damping and stiffness for structures, and the adjustment of dynamic properties is achieved only by applied magnetic fields with changeless structure design. Increasing researches on MRVE dy- namic properties, modeling, and vibration control application are presented. Recent advances in MRVE dynamic properties and structural vibration control application including composite structural vibration mitigation under uniform magnetic fields, vibration response characteristics improvement through harmonic parameter distribution, and optimal bounded parametric control design based on the dynamical programming principle are reviewed. Relevant main methods and results introduced are beneficial to understanding and researches on MRVE application and development.展开更多
The impact of a mountain ridge(MR)on the wind speed distribution and flow structures along a railway,under crosswinds beside a windbreak at attack angles of 90◦and 105◦,is studied in this paper.Based on the observed f...The impact of a mountain ridge(MR)on the wind speed distribution and flow structures along a railway,under crosswinds beside a windbreak at attack angles of 90◦and 105◦,is studied in this paper.Based on the observed flow field deterioration mechanism,mitigation measures are proposed and the corresponding effects are compared,from which the preferred mitigation scheme is determined.For the original MR,the wind speed coefficient U is larger than 1.2 in the range below the train height at both wind angles.With the implementation of the flow field mitigation measures,as the distance(L)increases from the MR to the windbreak,the wind speed decreases linearly for the 90◦wind angle and quadratically for the 105◦wind angle.When the mitigation measure with L/h=8.1(h is the train height)is adopted,the wind speed coefficient U fluctuates very slightly in the MR area,with−0.2<U<0.05 at both wind angles.Therefore,L/h=8.1 is recommended to protect the operation safety of trains travelling under strong crosswinds.展开更多
基金supported by the National Natural Science Foundation of China(11572279,11432012,and U1234210)the Zhejiang Provincial Natural Science Foundation of China(LY15A020001)the Hong Kong Polytechnic University Fund(1-BBY5)
文摘Magneto-rheological visco-elastomer （MRVE） as a new smart material developed in recent years has several significant advantages over magneto-rheological liquid. The adjustability of structural dynamics to random environmental excitations is required in vibration control. MRVE can supply considerably adjustable damping and stiffness for structures, and the adjustment of dynamic properties is achieved only by applied magnetic fields with changeless structure design. Increasing researches on MRVE dy- namic properties, modeling, and vibration control application are presented. Recent advances in MRVE dynamic properties and structural vibration control application including composite structural vibration mitigation under uniform magnetic fields, vibration response characteristics improvement through harmonic parameter distribution, and optimal bounded parametric control design based on the dynamical programming principle are reviewed. Relevant main methods and results introduced are beneficial to understanding and researches on MRVE application and development.
基金supported by a grant (RIF)from the Research Grants Council of the Hong Kong Special Ad-ministrative Region (SAR),China (Grant No.R-5020-18)the National Natural Science Foundation of China (Grant No.U1934209)+1 种基金support by the Innovation and Technology Commission of the Hong Kong SAR Government (Grant No.K-BBY1)The Hong Kong Polytechnic University’s Postdoc Matching Fund Scheme (Grant No.1-W16W).
文摘The impact of a mountain ridge(MR)on the wind speed distribution and flow structures along a railway,under crosswinds beside a windbreak at attack angles of 90◦and 105◦,is studied in this paper.Based on the observed flow field deterioration mechanism,mitigation measures are proposed and the corresponding effects are compared,from which the preferred mitigation scheme is determined.For the original MR,the wind speed coefficient U is larger than 1.2 in the range below the train height at both wind angles.With the implementation of the flow field mitigation measures,as the distance(L)increases from the MR to the windbreak,the wind speed decreases linearly for the 90◦wind angle and quadratically for the 105◦wind angle.When the mitigation measure with L/h=8.1(h is the train height)is adopted,the wind speed coefficient U fluctuates very slightly in the MR area,with−0.2<U<0.05 at both wind angles.Therefore,L/h=8.1 is recommended to protect the operation safety of trains travelling under strong crosswinds.
