振动筛的故障诊断及动力学分析

发布时间：2018-08-29 20:24

【摘要】：对于大多机械设备,振动是一种有害现象,也是导致机械设备破坏或失效的直接原因,但对于振动筛而言,振动是有利的。通过振动筛可以完成物料的分离、脱水等工作,因此被广泛运用于各个工业领域。但因为振动筛工作环境恶劣、时间长、强度大,使得振动筛容易出现故障,易导致整个流水线停机,给企业造成很大的经济损失。但是目前对于振动筛故障诊断尚未有成熟的理论,因此,对于振动筛故障诊断的研究有着至关重要的意义和实用价值。在振动筛的故障诊断中,本文主要针对故障信号难以提取的问题进行研究。由于振动筛自身的冲击和振动比较大,使得故障信号经常被淹没,所以需要很好的提取故障信号。在振动筛运行中,发生的故障类型有很多,本文以滚动轴承故障为例,提取出故障信号,从而进行故障识别。本文分别对轴承正常时和发生故障时的振动筛的振动信号进行分析,使用MATLAB和ORIGIN软件对信号进行仿真,通过观察信号的特征,主要使用包络分析方法对信号进行处理,提取出故障信号,得到轴承的故障特征,从而识别出故障类型。通过包络分析对实际信号的分析和处理,取得了很好的效果,解决了振动筛故障信号难以提取的问题。本文在分析旋转机械滚动轴承的频谱特征的基础上,对振动筛自身结构特点进行分析,从而得到了振动筛轴承的故障频谱特征,发现其故障频谱特征相对旋转机械发生了变化,其外圈频谱存在调制,而内圈不存在调制,恰恰与旋转机械相反。这一点新发现对于振动筛轴承的故障诊断提供了理论支持和依据。因为振动筛的使用寿命与其运动特性有关,异常振动容易使筛体结构产生损伤从而影响它的使用寿命。故本文还对振动筛的运动特性进行分析和研究,利用ANSYS建立振动筛实体模型,通过模态分析与谐响应分析,得到了振动筛的各阶模态频率值及振型特点,研究了振动筛在各种频率偏心力的影响下结构所表现出的振动状态及应力集中区域,通过动力学分析的结果对结构损伤提供了辅助性帮助。
[Abstract]:For most mechanical equipment, vibration is a harmful phenomenon and a direct cause of mechanical equipment failure or failure, but vibration is advantageous to vibrating screen. The material separation and dehydration can be accomplished by vibrating screen, so it is widely used in various industrial fields. However, because of the bad working environment, long time and high intensity, the vibrating screen is prone to malfunction, which easily leads to the shutdown of the whole assembly line and causes a great economic loss to the enterprise. However, there is no mature theory for the fault diagnosis of vibrating screen, so it is of great significance and practical value to study the fault diagnosis of vibrating screen. In the fault diagnosis of vibrating screen, this paper mainly focuses on the problem that the fault signal is difficult to extract. Because the vibration and shock of the vibrating screen are large, the fault signal is often submerged, so it is necessary to extract the fault signal well. In the operation of vibrating screen, there are many kinds of faults. In this paper, the fault signal of rolling bearing is extracted for fault identification. In this paper, the vibration signal of the vibrating screen is analyzed when the bearing is normal and the fault occurs. The signal is simulated by MATLAB and ORIGIN software. By observing the characteristics of the signal, the envelope analysis method is mainly used to process the signal. The fault signals are extracted and the bearing fault characteristics are obtained, and the fault types are identified. Through the analysis and processing of the actual signal by envelope analysis, good results have been obtained, and the problem that the fault signal of vibrating screen is difficult to be extracted has been solved. Based on the analysis of the frequency spectrum characteristics of rolling bearings of rotary machinery, the structural characteristics of vibrating screen are analyzed, and the fault spectrum characteristics of vibrating screen bearings are obtained, and it is found that the fault spectrum characteristics of vibrating screen bearings have changed relative to the rotating machinery. The frequency spectrum of the outer loop is modulated, but the inner ring is not modulated, which is exactly opposite to the rotating machinery. This new discovery provides theoretical support and basis for fault diagnosis of vibrating screen bearings. Because the service life of the vibrating screen is related to its motion characteristics, abnormal vibration can easily cause damage to the structure of the screen and thus affect its service life. Therefore, the motion characteristics of vibrating screen are analyzed and studied in this paper. The solid model of vibrating screen is established by using ANSYS. Through modal analysis and harmonic response analysis, the modal frequency values and modal characteristics of vibration screen are obtained. The vibration state and stress concentration area of the vibrating screen under the influence of various frequency eccentricity forces are studied. The results of dynamic analysis provide auxiliary help to the damage of the structure.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH237.6;TH165.3

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