机械固定结合面动态参数确定方法研究

发布时间：2018-02-16 15:14

本文关键词： 参数识别悬臂梁模型结合面动态特性　出处：《宁夏大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着先进制造业加工水平的不断提升,各个行业对机械设备的动态性能要求也越来越高。而机械结合面作为机械结构中一种固有的结构,其动态特性对整机的动态性能有着显著的影响。以机床为例,有资料表明,机床总刚度的60%-80%和总阻尼的90%都是来源于结合面。在进行机械结构的动态设计时,能否获得正确的结合面动态参数是建立准确机械结构动力学模型的关键所在。因此,结合面的动力学建模与参数识别一直都是值得研究的课题。基于这一关键问题,本文进行了如下研究：首先,系统的总结了当前有关机械结合面特性的研究工作,在此基础上设计了一种含有固定结合面的悬臂梁测试模型。然后,采用“理论建模与动态试验相结合”的方法来识别结合面的动力学参数。先根据悬臂梁结构建立其动力学模型,然后利用DASP模态测试系统对试件进行模态试验,并进行模态分析得到含有固定结合面悬臂梁结构的固有频率和阻尼比。最后通过系统的特征方程计算出结合面的刚度和阻尼系数并进行优化。接着,分析了悬臂梁模型在不同结合条件下,其结合面刚度系数与阻尼系数的变化规律。用三种不同尺寸的悬臂梁试件在不同的预紧力作用下,分别识别出其结合面的刚度与阻尼系数,并分析不同条件下对结合面特性参数的影响。最后,通过应用ANSYS有限元分析软件,分别在考虑结合面影响与不考虑结合面影响的两种状态下建立悬臂梁结构的有限元模型,并进行模态分析。以试验模态分析为基准,通过振型相似比较其固有频率的方法,充分证明了该识别方法是有效性。
[Abstract]:With the development of advanced manufacturing industry, the dynamic performance of mechanical equipment is required more and more. As an inherent structure of mechanical structure, the mechanical bonding surface is a kind of inherent structure. Taking machine tool as an example, it is shown that 60-80% of the total stiffness of the machine tool and 90% of the total damping are derived from the interface. Whether the correct dynamic parameters can be obtained is the key to the establishment of an accurate dynamic model of mechanical structure. Therefore, the dynamic modeling and parameter identification of the combined surface are always worthy of study. In this paper, the following studies are carried out: firstly, the current research work on mechanical bonding surface characteristics is systematically summarized, and a cantilever beam test model with fixed bonding surface is designed. Then, the dynamic parameters of the interface are identified by the method of "theoretical modeling and dynamic test". Firstly, the dynamic model of the cantilever beam structure is established, and then the modal test of the specimen is carried out by using the DASP modal test system. The natural frequencies and damping ratios of cantilever structures with fixed joints are obtained by modal analysis. Finally, the stiffness and damping coefficients of the joints are calculated and optimized by the characteristic equations of the system. Then, the variation law of stiffness coefficient and damping coefficient of cantilever beam model under different bonding conditions are analyzed. Three kinds of cantilever beam specimens with different sizes are used under different pretightening forces. The stiffness and damping coefficients of the bonding surface are identified respectively, and the effects of different conditions on the characteristic parameters of the bonding surface are analyzed. Finally, by using ANSYS finite element analysis software, The finite element model of cantilever beam structure is established under the condition of considering the influence of the bonding plane and the influence of the joint plane respectively, and the modal analysis is carried out. Based on the experimental modal analysis, the natural frequency of the cantilever beam structure is compared by the mode similarity. It is proved that the method is effective.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH113

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