铸铁表面接触的粘弹性性质试验研究

发布时间：2018-01-01 07:20

本文关键词：铸铁表面接触的粘弹性性质试验研究　出处：《西安理工大学学报》2017年03期 　论文类型：期刊论文

【摘要】：通过试验研究了铸铁表面法向接触的动力学性质,发现接触层的变形响应幅值一直存在蠕变和恢复特性,接触层的变形响应相对于激振力的滞后角也有类似特性,接触层的刚度和阻尼与接触历史有关。通过考察接触层在阶跃激励下的变形响应规律,发现阶跃响应曲线可以分为瞬时的弹性变形和持续时间较长的粘性变形两部分,粘性变形随时间的变化关系符合衰减指数规律。此外,还发现阶跃响应中粘性变形约占总变形的30%,在激振力幅值为22.7kPa~295kPa,预紧力为0.45 MPa~1.68MPa之间时,该比值基本保持恒定。通过考察接触层在简谐激励下的变形响应,发现接触层的变形幅值在法向载荷作用下存在逐渐减小的趋势,即接触刚度在法向载荷作用下不断提高,在载荷减小或者卸载后,经过一段时间后再次加载,发现接触振动的幅值有一定程度的恢复,即接触刚度有降低的趋势。通过分析简谐激振力信号和变形响应信号的相位还发现,接触层阻尼有随着载荷作用时间增大的趋势,载荷减小或者卸载后,经过一段时间后再次加载,发现接触阻尼会减小,接触层的振动幅值和滞后的相位都表现出明显的粘弹性性质。
[Abstract]:The dynamic properties of normal contact on the surface of cast iron have been studied. It is found that the deformation response amplitude of the contact layer has creep and recovery characteristics all the time. The stiffness and damping of the contact layer are related to the contact history. The deformation response of the contact layer under step excitation is investigated. It is found that the step response curve can be divided into two parts: instantaneous elastic deformation and viscous deformation with longer duration. The relationship between viscous deformation and time conforms to the law of attenuation exponent. It is also found that viscous deformation accounts for about 30 of the total deformation in step response, when the amplitude of exciting force is 22.7kPa295kPaand the pretightening force is 0.45 MPa~1.68MPa. By investigating the deformation response of contact layer under harmonic excitation, it is found that the deformation amplitude of contact layer decreases gradually under normal load. That is to say, the contact stiffness increases continuously under the normal load, and after the load is reduced or unloaded, after a period of time, it is found that the amplitude of contact vibration has a certain degree of recovery. By analyzing the phase of the harmonic excitation force signal and the deformation response signal, it is found that the contact layer damping increases with the loading time, and the load decreases or unloads. After reloading for a period of time, it is found that the contact damping decreases and the vibration amplitude of the contact layer and the phase of the hysteresis show obvious viscoelastic properties.
【作者单位】：西安职业技术学院电子信息工程系;西安理工大学机械与精密仪器工程学院;西安理工大学印刷包装与数字媒体学院;
【基金】：国家自然科学基金资助项目(51675422) 陕西省科技厅科技统筹创新工程重点实验室资助项目(2014SZS10-P05)
【分类号】：O343
【正文快照】： 机械系统是由各种零件组合起来的,零件之间相互接触的表面薄层区域称为接触层。这些在微观上是粗糙的接触面使得机械系统的性质不但与零件本身有关,还与零件之间的接触性质有关。在机床的结构设计和制造过程中,机床精度的稳定性、可靠性,都与接触层有密切关系。机械接触层的性

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