考虑温度影响的拉杆转子固有特性研究

发布时间：2018-06-20 19:10

本文选题：拉杆转子 + 分形接触理论　；参考：《陕西科技大学》2017年硕士论文

【摘要】：以材料表面的微观特性分析为起点,运用粗糙表面的分形接触理论,建立了轮盘面接触模型,从理论上对拉杆转子的接触刚度问题作了进一步深入研究。通过MATLAB软件编程计算了拉杆转子的法向和切向接触刚度,得到不同预紧力和粗糙度下的刚度变化曲线。将一系列刚度值添加到轮盘的接触模型中,并对拉杆转子进行了有限元模态分析;计算了滑动轴承的动力特性系数,对拉杆转子-轴承系统做了有限元模态分析,研究了刚性支撑和滑动轴承支撑下拉杆转子固有特性受预紧力的影响,以及改变转子转速影响滑动轴承动力特性系数的变化规律并分析滑动轴承性能改变对拉杆转子固有特性的影响;最后分析了温度对法向和切向接触刚度以及温度对拉杆转子-轴承系统固有频率的改变。分析发现接触刚度主要与预紧力和表面粗糙度有关,且随着预紧力增大,接触刚度值开始时增长较快,之后会逐渐变缓,并趋于一个定值,轮盘接触表面越光滑的接触刚度值越大,固有频率的变化规律也是如此;随着拉杆转子转速的升高,滑动轴承的刚度系数和阻尼系数均呈下降趋势,拉杆转子的固有频率在刚性支撑下要大于滑动轴承支撑的情况;滑动轴承支撑下拉杆转子固有频率的变化是按照正向涡动频率随转速的提高而增大,反向涡动频率随着转速的提高而减小;随着温度的升高,转子的材料性能会发生变化,使得拉杆转子的接触刚度下降,其固有频率也随之变小。为了验证所建模型的正确有效性,通过锤击实验测试了拉杆转子的固有特性,得到了模型转子的幅频特性曲线。具体内容是对模型拉杆转子的每根拉杆单独进行了预紧力标定,拟合出拉杆预紧力随拧紧力矩变化的曲线,组装并调试了拉杆转子实验台,完成了不同转速和预紧力下拉杆转子的锤击响应实验。分析结果与实验测试得到数据的一致性可以说明本文构建的模型和使用的方法能够准确体现拉杆转子的力学特性并正确分析其动力学问题。
[Abstract]:Based on the analysis of the microcosmic characteristics of the material surface and the fractal contact theory of rough surface, the contact model of wheel and disk surface is established. The contact stiffness of the rod rotor is further studied theoretically. The normal and tangential contact stiffness of the rod rotor is calculated by MATLAB software, and the stiffness variation curves under different pretightening forces and roughness are obtained. A series of stiffness values are added to the contact model of the wheel plate, and the finite element modal analysis of the pull rod rotor is carried out, the dynamic characteristic coefficient of the sliding bearing is calculated, and the finite element modal analysis of the pull rod rotor-bearing system is done. In this paper, the influence of pretension force on the inherent characteristics of the pull rod rotor supported by rigid support and sliding bearing is studied. The influence of rotor speed on the dynamic characteristic coefficient of sliding bearing is analyzed, and the influence of the change of bearing performance on the natural characteristic of pull rod rotor is analyzed. Finally, the change of normal and tangential contact stiffness of temperature and the natural frequency of pull rod rotor bearing system are analyzed. It is found that the contact stiffness is mainly related to the pretension force and the surface roughness, and with the increase of the pretension force, the contact stiffness value increases rapidly at the beginning, then becomes slower and tends to a fixed value. With the increase of rotor speed, the stiffness coefficient and damping coefficient of sliding bearing decrease with the increase of rotor speed. The natural frequency of the rod rotor under rigid support is larger than that of the sliding bearing support, and the natural frequency of the pull rod rotor under the sliding bearing support increases with the increase of the rotational speed. The reverse vortex frequency decreases with the increase of rotational speed, and with the increase of temperature, the material performance of the rotor changes, which makes the contact stiffness of the rod rotor decrease and its natural frequency become smaller. In order to verify the validity of the model, the inherent characteristics of the pull rod rotor are tested by hammering experiments, and the amplitude-frequency characteristic curves of the model rotor are obtained. The specific content is that the pretension force of each rod of the model rod rotor is calibrated separately, the curve of the tension force changing with the tightening moment is fitted, and the test bench of the pull rod rotor is assembled and debugged. The hammering response of the rod rotor under different rotational speeds and pre-tightening forces has been completed. The consistency between the analysis results and the experimental data shows that the model and the methods used in this paper can accurately reflect the mechanical characteristics of the rod rotor and correctly analyze its dynamic problems.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH113

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