【作者】 黎杰；

【导师】 潘亦苏；

【作者基本信息】 西南交通大学 ， 信息化制造工程， 2010， 硕士

【摘要】 柴油机是汽车、机车、拖拉机、工程机械、船舶等的基本动力装置。自二十世纪五十年代以来,随着科学技术的迅猛发展,以柴油机为动力的各种装置保有量的日益增加,人们对柴油机的要求越来越高。而发动机的主要承载零件的性能优劣直接影响着发动机的可靠性和寿命。随着发动机强化指标的不断提高,其工作部件的工作条件更加复杂。在多种周期性变化载荷的作用下,如何在设计过程中保证各部件具有足够的疲劳强度和刚度及良好的动静态力学特性成为柴油机设计的关键性问题,而曲轴做为柴油机中最关键的部件,保证其安全性和稳定性一直是柴油机研发工作中的重点。本文旨在探索一条可以较为精确分析柴油机曲轴工作时动力学响应的方法。本文选取某16缸柴油机作为研究对象,结合有限元软件ANSYS和多体动力学软件ADAMS构建了柴油机的虚拟样机模型(包括全刚性体模型、曲轴为柔性和机体曲轴都为柔性的刚柔耦合模型)。对比研究了三个模型下曲轴主轴颈和曲柄销承载曲线的异同,并得到曲轴和机体的柔性化对主轴颈的载荷时间历程曲线有较大的影响的结论。本文进一步对曲轴的扭振特性进行了研究,利用柴油机的多体动力学模型计算出了各工作转速的扭振角周期变化曲线,并进行了谐次分解。计算结果表明本文研究的柴油机一阶扭转固有频率较高,靠近一阶扭转频率的谐次都是高阶谐次,因此工作转速内的扭转振幅并不会危害到曲轴的安全性。通过上述工作及其结果与分析可见虚拟样机技术确实能够比较准确和方便的预测实际发动机的动力学性能。在发动机研发过程中能节约研发成本、提高研发效率以及提升产品性能。更多还原

【Abstract】 Diesel is the basic power device of car,locomotive,tractor,construction machinery,ships, etc. Since the twentieth century, the fifties, along with the rapid development of science and the increasing of devices powered by internal combustion engines,people have more and more demindings on the improving of diesel.The performance of main parts of engine directly affects the reliability and life of the engine.With the continuous improving of strength norm, the working conditions of the working parts become more complex.Under a variety of Cyclical changing loads.the key issue is how to ensure that the parts of the engine can have sufficient fatigue strength,stiffness,dynamic properties and static mechanical properties during the designing of diesel engine. As the most critical components of diesel,how to ensure the safe and stability of the crankshaft is always the point of diesel engine research. This paper aims to explore a more precise way to analysis the dynamic response of the crankshaft.This paper selects a 16-cylinder diesel as research object and builds the virtual prototype of the diesel using software ADAMS and ANSYS(including the full rigid body model and two rigid flexible coupling models).The comparative study of the loading curve of the crankshaft journals and crank pins of the three models can prove that the flexibility of the crankshaft and block causes great influence. Further this paper studys the torsional vibration characteristics of the crankshaft. The rigid flexible coupling dynamic model of the engine is used to calculate the vibration angle curve changing with time and the harmonic analysis is done.The conclusion is that the first torsional vibration frequency is so high that only the frequency of high-order harmonic can approach it.The torsional vibration amplitude of the working condition cann’t effect the safety of the diesel.Through the work mentioned before and its results it can be seen that virtual prototyping technology can really be convenient and accurate to predict the dynamic performance of the actual engine. It can save development costs, improve efficiency and enhance product performance during the engine designing.更多还原