【作者】 赵德敏；

【导师】 张琪昌；

【作者基本信息】 天津大学 ， 工程力学， 2007， 硕士

【摘要】 本论文分两部分,第一部分是关于座椅的动态舒适性研究,第二部分关于窄带随机动力系统研究。研究车辆人-椅振动规律对改善乘员的乘座舒适性具有重要的意义。将磁流变阻尼器用于座椅悬架系统,磁流变阻尼器采用改进的Bingham模型,利用非线性振动理论和数据仿真方法对两自由度人-椅模型进行了理论分析,理论结果和数值计算结果基本吻合。研究了影响磁流变阻尼器特性的物理参数对系统主共振响应的影响,得到较为理想的减振效果的磁流变阻尼器参数模型,为车辆座椅的振动控制提供了理论依据。将确定性系统的研究方法用于非线性随机系统,可以为随机系统的研究开拓新的思路。目前大多数非线性随机系统的成果属于宽带随机激励的系统,然而现实中很多系统是窄带随机参激系统,对于这类系统,有效地解析方法还很少。复规范形法是研究确定性系统非常有效且应用广泛的方法,因此探索用复规范形法研究窄带随机参数激励振动有很重要的理论和现实意义。本文首次将复规范形法用于窄带随机系统,研究了Duffing, Rayleigh, and Van der pol方程在谐和与窄带随机参数激励联合作用下的主共振响应和稳定性。并用数值法验证了方程的理论分析结果的正确性,理论方法和数值方法都表明随随机扰动强度的增加,系统的稳态解从定周期运动变为一拟周期运动,本文还用数值法计算了平凡解的最大Liapunov指数曲面,并且用多尺度法进一步验证了复规范形法用于窄带随机过程的有效性。更多还原

【Abstract】 The paper includes mainly two parts. The first one is dynamical ride comfortbility investigation of vehical seat, and the second one is investigation of narrow-band random dynamics systems.Investigate vehicle seat-person vibration discipline is important for improving ride comfortability of vehicle occupants. Magnetorheological fluid (MRF) damper is used in seat suspension system. The modified Bingham model is adopted for MRF damper. The nonlinar vibratation theory and numerical simulation method are applied to the two freedom seat-person model. The analytical solutions are basically conformed to the numerical solutions. The physical parameters of the MRF damper‘s effection on the system is also obtained. It can provide theory basic for control system.The methods of deterministic dynamics systems applied to non-linear stochastic dynamics systems can exploit new ways for stochastic dynamics systems. Now many achievements of stochastic dynamics systems belong to systems of broad-band random excitations, but in realism many systems are narrow-band random parameter excited dynamics systems. For these systerms, only few theoretic methods are applided. The complex normal form method is a effective method and has been widely used in the analysis of deterministic systems. So it is important to apply complex normal form method to investigation of narrow-band random parameter excited dynamics systems.The paper applies complex normal form method to narrow-band random parameter excited dynamics systems. The principal resonance and stability of the Duffing Rayleigh and Van der pol oscillator under combined harmonic and narrow-band random parameteric excited are obtained. The theoretical analyses are verified by numerical results. The theoretic results and numerical results are all show that when the intensity of the random excitation increases, the nontrivial steady state solution may change from a limit cycle to a diffused limit cycle. The largest Liapunov exponent three-dimensional surface is also abtained by numerical method. The complex normal form method is also verified by multiple scales in the systerm.更多还原