行人SMD模型参数对人群-结构耦合动力特性的影响

Influences of pedestrian SMD model parameters on dynamic characteristics of crowd-structure interaction

分析行人单自由度弹簧-质量-阻尼器系统中模型参数的随机特性,建立步行人群-结构耦合自由振动方程,采用复模态法求解得到结构的固有频率和阻尼比。研究行人频率、阻尼比和弹性质量对结构基频和阻尼比变化率的影响;应用Monte-Carlo仿真,得到不同频率结构在不同的人群与结构质量比下的基频和阻尼比的95%及5%分位点。分析表明,当空载结构与行人的频率比约为1.1时,结构基频和阻尼比的变化率最大;空载结构基频离行人频率范围较近时,质量比增大会使结构基频和阻尼比的随机散布增大。

Model parameters ' change characteristics of a pedestrian single-DOF spring-mass-damper( SMD)system were investigated. The coupled free vibration equation of a walking crowd-structure system was established. The structure natural frequencies and damping ratios were derived with the complex mode method. The influences of pedestrian model's natural frequency,damping ratio and elastic mass on change rates of the structure fundamental frequency and damping ratio were studied,respectively. Using Monte-Carlo simulation,a series of meaningful results were obtained under different mass ratios of crowd to structure. The results indicated that change rates of the structure's fundamental frequency and damping ratio are the maximum when the ratio of the structure fundamental frequency( no crowd) to pedestrian one is about 1. 1; when the structure fundamental frequency( no crowd) is close to the allowed range of pedestrian model's natural frequency,the increase in mass ratio of crowd to structure causes the random distribution of the structure's fundamental frequency and damping ratio to expand.