Papers by Author: Ming Qiu

Abstract: The effects of acrylamide modified liner on bonding properties and tribological properties of self-lubricating spherical plain bearings were explored by used of Instron5944 electronic universal testing machine and homemade spherical plain bearings friction and wear tester. The results showed that the bonding properties of bearings modified by acrylamide modified liner were much more improved than those of the unmodified bearings; Self-lubricating spherical plain bearing friction and wear properties and oscillating frequency obvious correlational dependence. With the increase of the oscillation frequency, the friction coefficient and the wear loss increased, while the friction temperature rose. The friction coefficient, wear loss and friction temperature of bearings modified were much more improved than those of the unmodified bearings. It showed that the liners after modification treatment can improve the tribological properties of self-lubricating spherical plain bearings.

Abstract: Based on information-poor theory, this paper expounds the variable uncertainty, the function polytrope, and the chaotic characteristics of rolling bearing performances, and reveals the nonlinear dynamic characteristics of rolling bearing performances. This can provide a new method of evolvement of characteristics of rolling bearing performances, and offer a train of thought for breaking through the system of the statistical theory which is chronically adopted to evaluate bearing performances, and for opening up a new field of poor information analysis.

Abstract: For costly and dangerous experiments, growing attention has been paid to the study of the performance and reliability of rolling bearings with poor information. The existing reliability theory relying on the classical statistical theory and Bayesian theory will become ineffective if the probability distribution is unknown. In view of this, the developments of studies on forecasting methods for the performance and reliability of rolling bearings with poor information are summarized in this article.

Abstract: Geothermal energy provides the renewable energy sector with an opportunity to produce base load power, whilst meeting current government objectives of many countries in relation to greenhouse gas emission and renewable energy portfolio standards. The utilization of geothermal power develops well in many developed countries, such as America, Japan, France, Italy, Iceland, etc. But it is still at an early stage in China. The development of alternative energy such as geothermal energy is as a basic national policy. It is also an important issue for China how to make good use of geothermal resource currently. In this paper, according to the distribution, we introduce the development and utilization of Chinese geothermal resources.

Abstract: In this paper, some experiments was implemented for analyzing the affecting factors on allowable contact stress of four-point-contact slewing rings with single row including the hardening depth, hardness and the osculation between the steel ball and the raceway. Firstly, the common material 42CrMo was chosen and heat-treated with some process of heat treatment for getting different hardening depth. And then, the indentation tests were conducted with the test-rig, followed by the data process. Finally, some conclusions can be obtained by comparing and analyzing the data. It concludes that when the hardening depth beyond 0.3 and the hardness is not lower than 57HRC, a better allowable contact stress can be got, besides, the better osculation 0.52 is better for the load capacity.

Abstract: Experiments were carried out to investigate the tribological properties of spherical plain bearings with copper grid composite liners filled PTFE under two contact pressures(40MPa,60MPa), four oscillating frequencies (1.2Hz, 1.8Hz, 2.4Hz, 3.0Hz) and two swinging conditions. With the help of SEM, EDS and Three-dimensional morphology profiler, the wear mechanism was analyzed. The results indicate the coefficients and wear depths under tilt swinging condition are higher than those of swivel swinging. While the friction temperature show the contrary trend. The research discovers that the friction temperature has a great influence on tribological properties of spherical plain bearings. The analysis demonstrates that the main wear mechanisms are the adhesive and abrasive wear under the two swinging conditions and extrusive wear exist also.

Abstract: The friction and wear behaviors of three kinds of spherical plain bearings with PTFE fabric composite liners were investigated by a high oscillating frequency and heavy load tribo-tester. Dry sliding tests were carried out at different oscillating frequencies. With the help of SEM and EDS, the differences of worn surfaces of the three spherical bearings were investigated. The results indicate that the fiber woven with PTFE effects the friction and wear characteristics of bearing, the tribological properties of bearing with Kevlar/PTFE fiber woven liner is the best in the three kinds of bearing. The abrasive wear are appeared on the surface of wore liners of bearingⅠ,while bearingⅡappeared normal wear, bearing III showed serious adhesive wear and abrasive wear.

Abstract: The friction and wear behaviors of three kinds of spherical plain bearings with PTFE woven liners were investigated by a high oscillating frequency and heavy load tribo-tester. Dry sliding tests were carried out at an oscillating frequency of 1.2Hz and four different loads. With the help of SEM and EDS, the differences of worn surfaces of the three kinds were investigated. The results indicate that the wear depth and friction temperature for the three kinds of bearings show increasing trend with the increasing of load, while the friction coefficient is the opposite. The comprehensive performance of bearing II is the best in the whole course of experiment, while the bearing III is the worst. The adhesive and abrasive wear mechanisms are appeared on the surface of liners. The quality of boning influences the tribological property of the spherical plain bearing.

Abstract: The working principle and performance characteristics of a self-made oscillation tribo-tester were introduced. Under different oscillation frequency and pressure conditions, the friction coefficient and linear wear of spherical plain bearings with polytetrafluoroethylene (PTFE) woven liner were investigated. By using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), the wear mechanism of the spherical plain bearing was analyzed. The results indicate that with the oscillation frequency increases, the friction coefficient of spherical plain bearings decreased while the wear loss increased. In the high frequency of 4.8Hz, the reduction ranges of the friction coefficient is not obvious with the contact pressure increased, but the effect of contact pressure on the wear of the spherical plain bearing is great. During the experiment, adhesive wear, abrasive wear and spalling wear took place on the surfaces of woven liners.

Abstract: Based on the FEM and the relative software ANSYS, the analysis of slewing bearings with negative clearance was presented. In this paper, the stress distribution of slewing bearings under condition of different loads has been studied. The clearance has been changed by altering the ball diameter, thus the relationship between the contact stress of the inner/outer raceway and balls and the clearance has been received. Subsequently, compared to the calculation results based on some theoretical models from others, the reliability of the FEM can be verified