《汽车理论》课程教学课件（英文讲稿）第6章 汽车平顺性 Ride Performance 6.3 Simplify of Automobile Vibration System and Vibration of Single Mass System（汽车振动系统的简化及单质量系统的振动）

Attenuation vibration inf luenced by 阻尼比对衰减振动的影响（2）·系数:damping factor,减幅（减振）d=Ae-nVi-2H=enTd=Ae-n(i+)A2元2元2元Measured SbynT =n=n0.y-y-s0experiment试验方法测阻尼2元(≤ 个=d 个)Ind :比(Zeta)/1-521(d →?)V1+4元2/ln2d

Attenuation vibration inf luenced by  1 2 damping factor, A d A  : 减幅（减振）系数 Measured ξ by experiment 试验方法测阻尼 比ζ （Zeta） 2 2 1 ( ?) 1 4 / ln d d       2 2 ln ( ) 1 d d        1 2 1 1 1 2 1 1 ( ) 1 2 0 2 2 2 2 2 1 1 nt nT n r t T n A Ae d T n e e A Ae n                               

3.Frequency response characteristics of single mass system单质量系统的频率响应特性m,+Cz+ Kz = Cq+ Kq艺+2nz+のz= 2ng+のqFourier transformationz(t)→z(f)一time domain时域= frequency domain频率域Fourier transformation time domain differentiation theorem傅变时域微分定理：F[f(t)]= F(の)LO(jo)" F(o)(dt)

3.Frequency response characteristics of single mass system 单质量系统的频率响应特性 2 2 2 0 0 2 2 m z Cz Kz Cq Kq z nz z nq q             Fourier transformation time domain differentiation th ( ) ( ) ( ) ( eorem ) ( ) ( ) n n n F f t F d f t F j F dt            傅变时域微分定理： Fourier transformation ( ) ( ) time domain frequency domain z t z f  时域 频率域

3.Frequency response characteristics of single mass system单质量系统的频率响应特性艺+2nz +のz =2ng+のqFouriertransformationdifferential eguation对运动微分方程傅变(jの) z(の) + 2n(jの) z(の) +0z(の) = 2n(jo) q(の) +0q()[(α -0°)+ j2noz(0)=[α + j2no ]q(0)F[f(t)]=F(α)の + j2noz(0)(0 -)+ j2noq(の)dF(jo)" F(の)(dt)

2 2 0 0 z nz z nq q     2 2    ( ) ( )  ( ) ( ) ( ) ( ) n n n F f t F d f t F j F dt            3.Frequency response characteristics of single mass system 单质量系统的频率响应特性 2 0 2 2 0 ( ) 2 ( ) ( ) 2 z j n q j n              Fourier transformation 2 1 2 1 2 0 0 2 2 2 0 0 differential eguation (j ) ( ) 2 ( ) ( ) ( ) 2 ( ) ( ) ( ) 2 ( ) 2 ( ) z n j z z n j q q j n z j n q                                   对运动微分方程傅变

3.Frequency response characteristics of single mass system单质量系统的频率响应特性z(の)output输出z(t)Fouriertransformationinput输入q(t)(q(0)Transfer characteristicsFourier transformation of outputz(の)传递特性,频响函数q(の)Fourier transformation of inputscopefrequencycharacteristics幅频特性：V(α) +(2no)2z()q(の)/(o -)? +(2n0)0 + j2noz(の)(o-の)+ j2nq(の)

Fourier transformation Transfer characteristics Fourier transformation of output ( ) Fourier transformation of in output ( ) ( ) input ( ) pu ) ) t ( ( z t z t q z q q                 传递特性, 输出 输入 频响函数 3.Frequency response characteristics of single mass system 单质量系统的频率响应特性 2 2 2 0 2 2 2 2 0 ( ) ( ) (2 ) ( ) ( ) (2 scope frequency characteristics ) z n q n            幅频特性: 2 0 2 2 0 ( ) 2 ( ) ( ) 2 z j n q j n           