高频冲击下挖掘机动臂和斗杆动态特性及疲劳寿命研究

【作者】 谭明敏；

【导师】 杨务滋；

【作者基本信息】 中南大学 ， 车辆工程， 2011， 硕士

【摘要】 挖掘机式冲击器是随着液压挖掘机的快速发展而出现的一种工程机械设备,它不仅拥有挖掘机的良好的机动性,还能充分发挥冲击器自身的功能。这使得它在采矿、路面建设、铁路建设等领域发挥了巨大的作用。但现有的挖掘式冲击器都是由挖掘机改装而来的,而挖掘机工作装置最初的设计是以铲斗挖掘为主要功能,装上冲击器后,其工作状况为高频冲击振动,因此需对工作装置进行动态特性分析,了解其固有频率和动力响应,从而能够验证其结构能否成功地克服共振与受迫振动引起的有害效果。本文以某公司生产的LK3000的挖掘机式冲击器为例,对其工作装置在高频冲击工作状态下的动态特性进行分析,包括模态分析和谐响应分析,主要研究工作如下：(1)首先对冲击机械和其工作原理进行了简单的概述,分析了国内外挖掘机和冲击器的研究现状,提出了本课题的研究主题,即动臂和斗杆在高频冲击作用下的动态响应和疲劳寿命研究。(2)根据动力学理论,对工作装置进行了动力学分析,研究了矩形脉冲和周期冲击载荷下工作装置的动态响应,提出了提高结构动刚度的相关措施。(3)利用ANSYS软件对动臂和斗杆工作装置进行了模态和谐响应分析,得到了动臂和斗杆的固有频率和主振型图,以及在固有频率下谐响应峰值曲线,并对动臂和斗杆的疲劳寿命进行了研究。(4)开展了斗杆动态特性的实验研究,实验结果验证了有限元分析结果的正确性。本文通过分析挖掘机式冲击器工作装置在高频冲击下的动态特性,为挖掘机和冲击器的功率匹配提供一定的依据,并为其优化设计提供理论基础,对工作性能、使用寿命的提高具有很重要的意义。更多还原

【Abstract】 The excavator-impactor is a new construction machinery equipment as the rapid development of hydraulic excavator.lt not only has good flexibility, excavator can make full use of impactor’s funnction.This makes it in mining, road construction, railway construction etc playing a large role.But in the currently, most of the excavator-impactors were modified by excavators, while excavator’s working devices mainly design for scooping at first,after installing the impactor, the working environment is turnning to high frequency vibration, and thus it must to analysis the working device’s dynamic characteristic, understanding the dynamic characteristics,and getting the natural frequency and dynamic response, so as to verify the structure can successfully overcome the resonance,fatigue, and other harmful effects caused by forced vibration or not.Taking the LK3000 excavator-impactor for example, analysis the working device’s dynamic characteristics at high frequency impact work condition, including modal analysis and harmonic responses analysis, the main contents of this paper are listed as follow:(1)Firstly,the paper gives a brief overview to the impact mechanical and its working principle,and expounds the excavator and impact studies in present situation home and abroad, then proposes the theme of this paper, namely, stuaying the dynamic characteristic of main arm and bucket arm in the high frequency impact and fatigue life.(2)This chapter describes dynamics’relevant theoretical knowledge, and analyses the working devices’dynamic,then works out the dynamic response to the periodic impact load and the rectangular pulse,lastly, puts forward the measures to improve structure stiffness.(3)Using ANSYS software to analysis working devices’modal and harmonic responses, gets their inherent frequency and main mode in natural frequency,unserstands the harmonic peak curve at the inherent frequency,then figures out their fatigue life for the dangerous zone(4) Carrying out experimental research to bucket arm’s dynamic characteristics,the result verifies the correctness of the finite element analysis results.Through analysing excavator-impact’s working device dynamic characteristic at high frequency,offers the basic theory to match excavator and impactor, and the optimization design, it is important to better their performance, and longer their fatigue life.更多还原