2 例.求图示体系的频率、振型 已知:k1=k2=k:m1=m2 El 解:「k1x1+k12X2-mO02X1=0 El k21X1+k22-m2O2X2=0 k m,O 2 0 n, rh k1=k+k2=2kk2=k21=-kk2=k 618 2k-mo k 0 k k-mo 0.618 (2k--m)k-02m)-k2=0 1.618 0.618 O1=0.618k/mc2=1.618k/m 1X, 211.618X20.618解: 例.求图示体系的频率、振型. 已知: ; . k1 = k2 = k m1 = m2 = m 0 2 21 22 2 12 2 11 1 = − −   k k m k m k m1 2 k EI1 =  EI1 =  1 k m2 0 1 2 k11X1 + k12X2 −m1  X = 0 2 2 k21X1 + k22X2 − m2  X = k k k 2k 11 = 1 + 2 = k = k = −k 12 21 k = k 22 0 2 2 2 = − − − −   k k m k m k (2 )( ) 0 2 2 2 k − m k − m − k = 1 = 0.618 k / m 2 =1.618 k / m 0.618 1 ; 1.618 1 2 2 1 2 2 1 1 1 = = − X X X X         = 1.618 1 X 1         − = 0.618 1 X 2 1 1.618 1 0.618 X1 X2