便携式滚动轴承故障智能诊断系统的设计

设计了一种便携式滚动轴承故障智能诊断系统，对系统的工作原理、硬件结构及软件技术进行了详细的描述。该诊断系统除具有“便携式”的特征外，还具有操作简便，测试、诊断与分析自动化、智能化等特点，适用于生产现场对滚动轴承故障进行快速、自动地诊断。     

The influence of surface roughness and the contact pressure distribution on friction in rolling/sliding contacts

A numerical contact model is used to study the influence of surface roughness and the pressure distribution on the frictional behaviour in rolling/sliding contacts. Double-crowned roller surfaces are measured and used as input for the contact analysis. The contact pressure distribution is calculated for dry static contacts and the results are compared with friction measurements in a lubricated rolling/sliding contact made with a rough friction test rig. The mean pressure is suggested as a parameter that can be used to predict the influence of surface roughness on the friction coefficient in such contacts. The results show two important properties of the friction coefficient for the friction regime studied in this paper: (1) there is a linear decrease in friction coefficient as a function of the slide-to-roll ratio, and (2) the friction coefficient increases linearly with increasing mean contact pressure up to a maximum limit above which the friction coefficient is constant. The absolute deviation of experimental results from the derived theory is for most cases within 0.005.     

Improvement of tribological performance of steel by solid lubricant shot-peening in dry rolling/sliding contact wear tests

The effect of shot-peening treatment with the particulate MoS₂ solid lubricant on the wear resistance of steel in the dry rolling/sliding contact wear tests was investigated. The duplex shot-peening treatment with ceramic balls and the particulate MoS₂ solid lubricant provided excellent wear resistance under a severe loading and sliding condition because the uniform and minute surface roughness given by shot-peening treatment with ceramic balls could keep shot-peened MoS₂ particles with a low friction coefficient on the sample surface. Furthermore, the sample surface was covered with shot-peened MoS₂ particles by a MoS₂ layer formed during the rolling/sliding contact wear test.     

A Self-Tuning PI control system design for the flatness of hot strip in finishing mill processes

A novel flatness sensing system which is called the Flatness Sensing Inter-stand Looper (FlatSIL) system is suggested and a self-tuning PI control system using the FlatSIL is designed for improving the flatness of hot strip in finishing mill processes. The FlatSIL system measures the tension along the direction of the strip width by using segmented rolls, and the tension profile is approximated through the tension of each segmented roll. The flatness control system is operated by using the tension profile. The proposed flatness control system as far as the tension profile-measuring device works for the full strip length during the strip rolling in finishing mills. The generalized minimum variance self-tuning (GMV S-T) PI control method is applied to control the flatness of hot strip which has a design parameter as weighting factor for updating the PI gains. Optimizing the design parameter in the GMV S-T PI controller, the Robbins-Monro algorithm is used. It is shown by the computer simulation and experiment that the proposed GMV S-T PI flatness control system has better performance than the fixed PI flatness control system.     

铝材冷轧变形区油膜形成机理及影响因素

通过计算分析与轧制实验，探讨了名材冷轧变形区油膜形成机理及影响因素结果表明：流劝动力学成膜机理主要依赖于润滑剂粘度和轧制速度，特别是润滑剂粘度较氏时，轧制速度必须达到一定值，否则无法形成有效的油膜，而机械夹带作为低粘，低速条件下变形区主要成膜机理，其膜厚度依赖于轧辊与轧件粗糙度和夹带系数ｍ，０．１〈ｍ〈０．５，且随润滑剂粘度提高而增大。     

特细长轴球头端面的加工

提出了一种用摩擦打磨和搓削相结合加工特细长轴球头端面的新方法。并设计了搓削加工中的设备。该球头端面加工方法易于操作，加工效率高，成本低。     

3D Analysis of cold rolling using a constitutive model for interface friction

Full three-dimensional numerical analyses are carried out for the cold rolling of plates of finite width, to study the effect of the width spread during rolling. The contact and friction between roll and plate is modeled in terms of an interface constitutive model that accounts for the friction forces in the rolling direction as well as those in the transverse direction that give resistance to the width spread. At low normal pressures Coulomb friction is represented while at high normal pressure a yield stress limitation of the maximum tangential stress is incorporated, and slip as well as no slip is accounted for. Finite strain elasto-plasticity is applied for the plate material, using mostly isotropic hardening or in a few cases kinematic hardening to represent the effect of a rounded vertex on the yield surface. In addition, for a given plate thickness and degree of reduction the effect of different values of the roll radius and the effect of different values of the plate width are analysed.     

Elucidating white-etching matter through high-strain rate tensile testing

A form of damage in bearing steels subjected to rolling contact fatigue is the formation of localised regions of white material just below the contact surface. These ‘white-etching regions’ are strikingly visible signs of damage during metallographic examination. One mechanism proposed to explain their formation is adiabatic shear localisation. Experiments are reported here using high-strain rate (250?s^?1) tensile testing to show that this is not the case.     

A hybrid fault diagnosis approach based on mixed-domain state features for rotating machinery

To make further improvement in the diagnosis accuracy and efficiency, a mixed-domain state features data based hybrid fault diagnosis approach, which systematically blends both the statistical analysis approach and the artificial intelligence technology, is proposed in this work for rolling element bearings. For simplifying the fault diagnosis problems, the execution of the proposed method is divided into three steps, i.e., fault preliminary detection, fault type recognition and fault degree identification. In the first step, a preliminary judgment about the health status of the equipment can be evaluated by the statistical analysis method based on the permutation entropy theory. If fault exists, the following two processes based on the artificial intelligence approach are performed to further recognize the fault type and then identify the fault degree. For the two subsequent steps, mixed-domain state features containing time-domain, frequency-domain and multi-scale features are extracted to represent the fault peculiarity under different working conditions. As a powerful time-frequency analysis method, the fast EEMD method was employed to obtain multi-scale features. Furthermore, due to the information redundancy and the submergence of original feature space, a novel manifold learning method (modified LGPCA) is introduced to realize the low-dimensional representations for high-dimensional feature space. Finally, two cases with 12 working conditions respectively have been employed to evaluate the performance of the proposed method, where vibration signals were measured from an experimental bench of rolling element bearing. The analysis results showed the effectiveness and the superiority of the proposed method of which the diagnosis thought is more suitable for practical application.