【作者】 林敏；

【导师】 张湘伟；

【作者基本信息】 广东工业大学 ， 车辆工程， 2011， 博士

【摘要】 汽车行驶平顺性是体现汽车乘坐舒适程度的主要性能指标。当前评估汽车平顺性的方法主要有样车试验和数值仿真两种方法。样车试验的方法周期长,人力、财力投入大,已不适应现代汽车快速更新的特点；数值仿真的方法作为一种辅助甚至主要的方法就日益显得非常重要。数值仿真方法与样车试验方法相比,具有如下优点：不受试验条件的限制,避免一些随机因素的干扰,具有可比性；其次,能够同时针对现有汽车进行性能评价,又能对新产品的行驶平顺性预测。这样就能预先了解行驶平顺性存在的问题并及时解决,也能优化各参数间的匹配关系,改善行驶平顺性指标,缩短设计期限,降低生产造价,在设计初期就能够预测各部件对汽车行驶平顺性的影响。汽车行驶平顺性的建模与仿真在国内外都进行了大量的研究及其应用,直至今日,都是汽车界研究与探索的一个具有重要的研究方向。在整理和归纳有关研究方法的基础上,结合国家自然科学基金项目(10272033)“基于流形的力学过程虚拟技术力学理论及方法研究”,应用虚拟激励法对汽车行驶平顺性仿真进行了系统深入研究。本文的具体工作是：从研究开发与工程适用的角度出发,综述归纳了平稳随机振动虚拟激励法的基本理论,给出了较为严密的推导过程,并运用虚拟激励法的理论分析汽车平顺性。其次,应用平稳随机振动的虚拟激励法,进行了汽车行驶平顺性的仿真分析,验证了虚拟激励法求解有效性。通过与傅里叶方法分析结果的比较论证方法正确性,同时,通过计算效率的比较,验证了本文计算方法更高效。再者,应用有限元法思想和多体动力学的方法,提出了建立汽车振动结构数学模型的方法,组装总位移向量、总质量阵、总刚度阵和总阻尼阵。建立了汽车结构系统振动的数学模型,验证了本文方法的有效性。构造了一种结构系统卷积泛函,证明了该卷积泛函变分为零与系统振动平衡方程的等效性。基于变分理论,建立了时域数值方法的通用逐步递推公式,应用逐步递推公式,由稳定性分析和计算实例验证了时域数值方法的正确性与精度；建立了轿车九自由度结构系统振动模型,在应用新的单元类型的同时,进一步完善了汽车结构系统振动数学模型的建模方法。最后,在汽车整车实车实验所进行的平稳与非平稳的道路实验基础上,联合虚拟激励法、建模方法和数值方法,对乘用车的行驶平顺性,对平稳随机路面激励与非平稳随机激励路面进行了较为完整的仿真分析,验证了虚拟激励法在路面分析和汽车整车平顺性预测上的有效性和可行性。更多还原

【Abstract】 Ride of vehicle is the main performance index in reflecting if it’s comfortable when we by car. There are two methods to evaluate ride of vehicle-sample car testing and numerical simulation. It’s a long time for sample car to do a test, and much labor and money to be devoted make it not suited to today’s fast update request. So numerical simulation is becoming much more important to be a assistance or even a main method. Vehicle ride performance modeling and simulation has an irreplaceable important role:first of all, it is not affected by testing conditions, avoid some random factors, comparable; secondly, in view of the existing automobile capable of simultaneously presented performance evaluation, but also on the new products of ride performance prediction. It can advance understanding of ride performance problems and resolved in a timely manner, can also optimize the matching relationship of parameters, to improve ride comfort index, shorten the design period, reduce the production cost, in early design to predict components of vehicle ride performance influence.Vehicle ride performance modeling and simulation at home and abroad have done a lot of research and its application, however, can find a simple, rapid and accurate to meet the research requirement of automobile modeling and simulation method, has been the automobile research and exploration of a very important research direction.On the research direction of the basis, combined with the national research and development project(10272033):National Natural Science Foundation of China:Based on manifold mechanical process virtual technology mechanics theory and method research. Pseudo excitation method on automobile ride comfort simulation system in-depth study and research, and its application to passenger car ride comfort experiment verification.This article is specifically:From the engineering application point of view, expand the stationary random vibration pseudo excitation method the basic theory, gives a rigorous derivation process, ultimately rich and complete virtual excitation method theory.Secondly, in the stationary random vibration pseudo excitation method based on, the vehicle ride simulation analysis, verified the validity of the application of virtual excitation method for solving. Through the comparison of analysis results and FFT method proved correctness and FFT method, at the same time, through the computation efficiency comparison than FFT method calculation speed.Furthermore, based on the finite element method and multi-body dynamics method, put forward to build the vehicle vibration structure model, assembly displacement vector, mass matrix, stiffness matrix and the total damping matrix. Through the preparation of procedures for automatic assembly of the vehicle structure vibration mathematical model, to verify the effectiveness of the proposed modeling method. Through the preparation of element analysis, overall analysis and restriction analysis of the program module, is simple and efficient structure system mathematical model of automobile vibration. At the same time, construct a kind of structure system convolutional functional, prove that the convolution variational zero and the system vibration equation equivalence. Furthermore, based on the variational theory, established a time-domain numerical method for general gradual recursion formula, application of gradual recursion formula, the stability analysis and numerical results show the time-domain numerical method accuracy and precision; the establishment of the cars nine degree of freedom vibration model, the application of new unit types at the same time, further improve the vehicle structure vibration mathematical modeling method.Finally, in automobile vehicle experiment conducted by the stationary and non-stationary Road on the basis of experiments, the pseudo excitation method, the modeling method and numerical method, for passenger car ride comfort, to stationary random road excitation and non stationary random excitation pavement of a more complete analysis, pseudo excitation method is proved in the surface analysis and the whole vehicle ride comfort prediction provides accurate and efficient analysis method.更多还原