Issue 29

W. Guodong, Frattura ed Integrità Strutturale, 29 (2014) 376-384; DOI: 10.3221/IGF-ESIS.29.33 376 The research for mechanics stimulation method of nonlinear random vibration based on statistical linear theory Wang Guodong Chongqing water resources and electric engineering college Chongqing, 402160, China 673843103@qq.com A BSTRACT . Earthquake disasters have brought great harm to people's life safety and economic property. Its effect on fabric mainly focus on random effects currently, the general pseudo excitation method could solve the inefficiency calculation problem of linear random earthquake. However it could not take the nonlinear problem factors into account for calculation. In this paper, we suggest that a nonlinear structural incentive method should be improved based on statistical linearity to calculate and solve absolute displacement value. Through the analysis and research for cases, we calculate the displacement, speed, random vibration spectrum of bridge’s accelerated speed, as well as the influencing situation of axial force. The results indicate that such perfect incentive method could not only perform nonlinear structure analysis , but also to be very accurate and high effective. Such method could reasonably avoid the displacement decomposition and solution of the pseudo- static model ， thus it will be widely applied in common software. K EYWORDS . Structure; Incentive method; Nonlinear random vibration; Axial force. I NTRODUCTION n recent years, earthquake disasters occurred frequently in our country, it has brought more and more loss to people. The prevention and control efforts that we have taken for earthquake disasters have been enlarged in China. However the seismic theory has been gradually advanced, and transformed from static force into dynamic force, and transferred from established pattern into random one. Now we should explore the transforming mechanism from linearity to nonlinearity. The effect of earthquake on structure mainly focuses on the random effects of seismic oscillation currently. The earthquake input process is generally assumed to be stationary stochastic process. When the actual earthquake occurs, its effect is small in early times, while it would be magnified in following period, afterwards it will be of attenuation gradually. Thus the earthquake input process should be considered as non-stationary random process .Accordingly, the effect of earthquake on structure could make construction be in linear elastic stage originally. As earthquake effect increases, the structure will enters into nonlinear phase gradually, and begins to have plastic accumulation. When plasticity accumulation reaches certain stage, the structure will be destroyed for it could not resist seismic action. In the seismic process, how architectural structure operates under the load of earthquake is the standard of measuring anti-seismic effect. In the original seismic experience, applying proper method into designing building structure is an approach suitable to actual circumstance. Nowadays, the widely applied method in China includes response spectrum method, response spectrum method and vibration method. But these methods are relatively fixed, and could not be flexibly applied into the seismic construction of actual building, thus a set of more scientific and reasonable method was born. As it could adopt to the approach of earthquake’s random excitation, it is called random vibration method. It takes I