【作者】 杨波；

【导师】 薛冬新；

【作者基本信息】 大连理工大学 ， 动力机械及工程， 2015， 硕士

【摘要】 内燃机作为一种重要的动力机械,对现代社会的发展起着很大的作用。研究内燃机的动态响应特性对于开发新型内燃机来是一项重要的研究内容。其动态响应对于内燃机的的振动噪声,结构强度,疲劳寿命都是有着很重大的影响。而机体作为内燃机结构中占很大比例的一部分,同时也是内燃机中其他零部件的重要支撑,其动态响应特性显得也尤为重要。本文以企业机车开发的新型柴油机直列8缸机8L265为基础,计算新型柴油机机体的动态响应。以有限元思想,模态分析理论方法为指导,建立机体的有限元模型和多体动力学模型,合理简化条件,并对其进行了机体的自由模态分析和约束模型分析,了解机体结构自身固有动态特性；建立以曲轴活塞连杆系统为主的多体动力学模型,计算分析了主要的激励载荷的时域变化曲线；在之前模拟计算的基础上,对机体在主要激励载荷的作用下的瞬态动力学进行分析,提取其振动和应力的动态响应信号,并且做进一步的时频和频谱分析,进一步研究其动态响应特性,识别出柴油机机体表面各个方向的振动信号的主要频率成分；最终提出以降低机体振动幅值,动态应力以及降低应力频率为目标的改善机体动态响应的方法,并做相应的比较,得出相对最优的方案。更多还原

【Abstract】 The internal combustion engine, as a major power machinery, plays an important role in the modern society. The research on the dynamic response characteristics of the internal combustion engine is an important content for the development of new engine. It has great influence on the vibration, noise, structural strength and fatigue life and other performance of internal combustion engine. And the engine block accounts for a large proposition in the whole engine. Also, it is the important support of other parts of engine.In this paper, based on the model of new inline 8 cylinder engine developed by the CNR, it does the calculation of the dynamics response of engine block. Under the guidance of finite element analysis (FEA) and the modal analysis theory, it establishes the FEM model and multi body dynamic model (MBD). Then the free modes and constraint modes are simulated to know about the inherent dynamic characteristics of the engine block. Establishing the multi-body dynamics model of the crankshaft, connecting rod and piston system, the curve of the main load in the time domain is researched. After the simulation calculation presented already, the transient dynamics of engine block is on the studying under the main load, including gas pressure, piston side force and bearing load. Then get the dynamic response of the vibration and stress signal and do further analysis of time-frequency analysis and spectrum analysis. This is to identify the main frequency of vibration signals of engine block surface in every direction. At last, the approach of reducing the vibration amplitude, the dynamic stress and force frequency as a goal is put forward to make the optimization.更多还原