Study on Coupling Resonance of Alignment and Flatness of Old Road
In order to trace the main source of the driving comfort problem on the old road,the linear parameters and flatness are incorporated into the dynamic equation which is based on the force analysis,and the human-vehicle-road dynamic model is established.Based on the domestic and international study results,the vibration perception and comfort evaluation criteria are selected and the study is carried out by using grid calculation.Firstly,taking the 120 km/h vehicle speed as an example,the dynamic indicators such as weighted acceleration under 3 working conditions of flatness,alignment and coupling resonance are calculated respectively.The dynamic calculation results are analyzed to determine the range of coupling resonance area,and the coupling resonance evaluation indicator is established.After analyzing the weighted acceleration RMS,peak value and its expansion coefficient calculation results,combined with the classification of coupling resonance types,the control factors,morphology,characteristics and influencing range of coupling resonance are summarized.Secondly,the initial angle,wavelength,amplitude,main parameter change of speed and weighted acceleration RMS of flatness control type affecting driving comfort are calculated,and the range of initial angle affecting weighted acceleration root mean square is calculated.The relationship between wavelength change and weighted acceleration RMS under each representative vehicle speed condition is improved.The linear and multiple parabolic function relationships of amplitude,vehicle speed and weighted acceleration RMS are determined by regression.Finally,the relationship between the radius of the vertical curve and the RMS of the weighted acceleration and its expansion coefficient under the condition of mutual interference coupling resonance is studied,and the two are parabolic functions.The result shows that(1)it is shown that the main control factors of coupling resonance affecting driving comfort are the frequency and amplitude of flatness;(2)as the speed decreasing,the wavelength that affects driving comfort is getting shorter and shorter,and the range is getting smaller and smaller;(3)the larger the radius of the vertical curve,the smaller the coupling resonance.
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