Papers by Author: Xiao Mei Liu

Abstract: After data preprocessing,the autoregressive(AR) bispectrum diagonal slices were figured and fractal box dimensions were calculated. The results show that the box dimensions are different in evidence under different conditions. So the fault pattern recognitions of the relief valve are effective by the method of using fractal box dimension of AR bispectrum diagonal slices, it provides a simple and accurate method for fault diagnosis of the relief valve.

Abstract: A generalized element which has the behaviors both of dashpot and spring is utilized to describe the visco-elasticity of a type of MR (Magneto-Rheological) Damper. A fractional derivative equation of motion which needs 4 parameters is developed to consider the nonlinear characteristics of the MR Damping system. It is demonstrated that the controlling current affects the order of the fractional system significantly, the increasing of the currents lead to the increasing of systemic order, strengthen the influence of viscosity remarkably and weaken the influence of inertia simultaneously. Nonlinear characteristics for shearing thin MRF damping system are also studied.

Abstract: In this paper, Pulse electrochemical finishing (PECF) and pulse electrochemical compound finishing (PECCF) are introduced. The main technical parameters, including in intereletrode gap, current density, compositions of steel materials and pulse parameters on the resulting surface finish were studied. PECF and PECCF on different surface including plane and shafts surface are done. Well-pleasing experimental results is gained. Results indicate that PECF and PECCF can lead to both good smoothing efficiency and surface finish simultaneity at low costs.

Abstract: In this paper, electrochemical finishing（ECF） is presented. Compared with conventional finishing technology, the characterization of surface topography machined by ECF and its effect on the performance, including friction coefficient, original wear and tear, precision durability, fatigue strength, contact stiffness, corrosion resistance and adhesiveness are analyzed and studied. Experimental results have testified that ECF can observably improve surface quality of parts and finally improve its physical mechanical performances and lifetime to a large extent.