【作者】 符朝兴；

【导师】 王秀伦；

【作者基本信息】 大连交通大学 ， 机械制造及其自动化， 2005， 博士

【摘要】 车辆的振动和噪声是影响汽车行驶舒适性的两个最主要的因素。随着车速的提高,路面不平度的激振力也不断加大。高频段的振动能量成为激发车身部件振动并辐射噪声的主要能源。为此,对悬架系统隔振的研究必须向更高的频率范围扩展。在车辆中,弹性元件的特性是影响车辆振动的主要因素,要研究车辆的高频振动,必须分析车辆各种隔振元件的高频传递特性,它是车辆振动研究的基础。论文尝试用冲击波动理论去分析车辆的高频振动,揭示车辆高频振动的一些现象,以提高车辆的振动控制能力。论文把车辆隔振元件作为具体的研究对象,也就是把理论研究直接面对实际产品,可以提高我国车辆产品的设计水平及竞争力。基于上述观点,进行下面的研究工作。 1、建立了车辆常用三种弹性元件的波动方程,提出求解其传递特性的方法,并推导出弹性波在三种弹性元件中的传递速度,对沿弹性元件传播的位移、速度、应力、应变和作用力的传递特性进行了探讨,分析了弹性单波沿弹性元件传播时的求解方法及波动干涉问题,对钢板弹簧横向振动三个波动方程的应用范围进行分析,利用直杆状模型推导了螺旋弹簧的波阻公式。探讨了三种弹性元件波动传递特性的异同。可以得出,螺旋弹簧的传递特性与长直弹性杆的传递特性相同,钢板弹簧弯曲波动方程不适合分析高频振动,其剪切波动方程及转动惯量波动方程可以描述高频振动,但应该注意应用范围,在实际车辆中螺旋弹簧与扭杆弹簧的剪切波动传递速度相差很大。 2、应用三种弹性元件的波动传递特性,探讨其单自由度系统受短波冲击的求解方法。并对它们的响应进行分析,探讨了弹簧刚度变化对其响应的影响。得出不同的模型对位移、速度的响应影响比较小,对加速度响应影响比较大。 3、应用古典振动理论及冲击波动理论,对三种弹性元件悬架车辆的振动进行模拟并对响应进行分析。提出用冲击波动力学分析车辆振动的理论依据,由此建立车辆的波阻力及变形力振动模型。通过冲击波影响弹簧的长度及其对应的质量,建立了弹簧惯性力及变形力车辆振动模型。综合多种因素,建立螺旋弹簧悬架车辆振动的波动理论模型,探讨了模型的求解方法,并对各种模型从理论和解法两个方面进行对比。仿真验证冲击波动理论模型与古典振动理论模型在低频段的一致性及弥补后者不能表达高频振动的缺陷。提出了在波动理论下弹簧多参数的应用方法及悬架高频响应的模拟方法。并以螺旋弹簧悬架为代表,对车辆振动的时域响应进行分析。 4、应用螺旋弹簧的波动传递特性,依据波动冲击理论建立车辆受冲击两自由度模型。在考虑弹性元件的具体结构的情况下,模拟车辆在不同频率冲击下的稳态响应。揭示了车辆地板及车桥在一些频带有过大响应的原因。 5、应用古典振动理论及冲击波动理论,分别对扭杆悬架车辆、螺旋弹簧悬架车辆及钢板弹簧悬架车辆的振动进行模拟,并根据实际情况,把三种悬架的具体模型转化为统一模型。在当前悬架设计理论的基础上,考虑弹性元件的波阻力及惯性力,对弹性元件进行重新设计,分析两种参数对车辆高频振动的影响。为车辆模拟方法的多样性及悬架设计考虑高频因素等车辆振动有关问题的解决提供参考。 6、进行车辆振动的实验,分别测量车桥及车辆弹性元件上方地板的频域振动情况。验证波动理论应用在车辆振动研究的正确性,验证把车辆高频振动理解为冲击振动的正确性,更多还原

【Abstract】 Vehicle vibration and noise are the two main factors that affecting the level of comfort when vehicle running. With the increasing of vehicle velocity, the impulse force of road unevenness also increases. The vibration energy in high frequency becomes the main energy source that excites vehicle body vibration and radiates noise. So the separate vibration research of suspension system must be developed with higher frequency. The characters of elastic components in vehicle are the main factors that affecting vehicle vibration, when researching the high frequency vibration of vehicle. We must analyze the transmission characters in high frequency of all separate vibration components, as it is the basis of vehicle vibration research. Impact wave theory is applied in this thesis to analyze the high frequency vibration and to discover some phenomena of the high frequency vibration of vehicle. It can promote the control ability technology of vehicle vibration. This thesis regards the vehicle vibration components as the concrete research object, which means orienting the theory research to the real product; it can improve the vehicle design level and competing ability in our country. Based on these viewpoints, the research work in this thesis is carried out as follows:1. Three elastic components wave equations are set up and a new method is put forward to find solution to the transmission character of helical spring. The elastic wave transmission velocity in the helical spring and the transmission characters of displacement, velocity, stress, strain and force of the spring transmission are researched. The solution of elastic single wave of helical spring and problems of wave interference are analyzed. The wave resistance equation of helical spring using straight spar model is developed. It can concludes that the transmission character of helical spring is equal to straight elastic pole, that the wave equation of steel spring is not suitable to high frequency vibration analysis, that it can describe moment inertia, but should pay attention to applying range, because the difference is very large between helical spring and twisting spring.2. The transmission character of helical spring is applied to discuss the solution to the l-Dof system impacted by short wave. The responses and the effect on the response when spring stiffness changed are analyzed and discussed.3. The classical vibration theory and impact wave theory are applied to simulate the helical spring suspension vehicle vibration and its response is analyzed. It puts forward the theoretical support of using the impact wave mechanics to analyze the vehicle vibration, develops the expression equation of the wave resistance of helical spring stress wave and sets up wave resistance force and deformed force vibration models of vehicle, it also sets up helical spring inertia force and deformed force vibration models of vehicle which based on the effect of the impact wave on the helical spring length and corresponding mass, sets up wave theory modeling of vehicle vibration of helical spring suspension by considering many factors, it also discusses the solutions to model and compares all the models in theory and solution. Simulation and test prove consistency of impact wave theory model and classical vibration theory model in low frequencydomain and satisfying the shortcomings of the latter which can not express high frequency vibration. It concludes the application method of helical spring parameters and the simulation method of high frequency response of suspension in wave theory.4. The transmission character of helical spring is applied and 2-Dof vehicle model is setup that impacted by wave according to wave impact theory. The response that impacted by short wave of variational stiffness helical spring suspension is researched. Stimulate vehicle response that impacted by different frequencies under the condition of considering concrete structure of helical spring, discover the reason that high frequency vibration of variational stiffness and its affection analysis.5. Classic vibration theory and impact wave theory are applied to stimulate the vehicle vibration of torsion bar suspension vehicle and helical spring suspension vehicle, transfer the two suspension models to uniform model and transfer the wave resistance force and inertia force of two elastic components to comparable equivalent parameters, analysis the affection of the two parameters on vehicle high frequency vibration. It can provide reference to the variety of stimulation method, suspension design and control vehicle vibration.6. Experimentation research on vibration of vehicle is carried out. Vehicle bridge and elastic components floor vibration are measured, which verify the correctness of wave dynamics and that translating high frequency vibration into impact vibration, and the definition of duration, and the application range of wave equation.更多还原