Reviews the state of the fault diagnosis methods based on the brief introd uction the fault diagnosis theory was introduced.First,the fault dia gnosis methods are classified into f ive categories:expert system fault diagnosis;fuzzy fault diagnosis;fault tree fa ult diagnosis;neural network fault diagnosis and data fusion fault diagnosis.Then the step of every fault diagnosis methods is presented,the most importan t peculiarity and their limitations in each category are introduced and analyze d.Finally,further problems to be studied in this field and the developme nt trends are pointed out.

Survey of knowledge-based fault dia gnosis methods

Shaping Cutter Original Profile for Fine-module Ratchet Teeth Cutting

Increase of heat exchange in shell-and-pipe heat exchange devices allows to decrease cost, dimensions and weight of heat exchange equipment. The main directions in a field of increase of heat exchange are application of surface intensifiers on pipes of a heat exchange devices, in a case there is a need to increase heat exchange of a heat transfer agent inside pipes, and application of various types of baffles, in a case there is a need to increase casing heat exchange. The paper presents the results of the study of increase of heat exchange in a casing by means of segmental and helix baffles; circular baffles were not taken into account, because in that case mechanism of increase of heat exchange is the same with segmental baffles and has the same disadvantages, such as dead zones before and after the baffles. In the study we developed solid state models of heat exchanging devices with segmental and helix baffles created finite-element models, carried out numerical studies of heat exchange and fluid dynamics processes in shell-and-pipe heat exchange devices with segmental and spiral inserted baffles at various flow conditions of a heat transfer agent. Also, values of coefficients of heat transfer, heat flow, flow structure and pressure losses in pipes and casing at various flow conditions are obtained. Application of baffles allows to increase heat flow for a whole range of flow conditions. The biggest effect in absolute values of heat flow is achieved by means of implementation of helix baffles, however, it also leads to the biggest values of hydraulic losses. The main advantage of helix baffles is uniform distribution of a heat transfer agent in a casing and absence of dead zones, which are formed in a case of segmental baffles.

Simulation of Heat Transfer and Fluid Dynamics Processes in Shell-and-Pipe Heat Exchange Devices with Segmental and Helix Baffles in a Casing

Presented in this paper are the main factors of tooth profile modifications and its calculation formulas for type HXD1 electric locomotive′s drive pinion.It is indicated that the main factors of inequilateral tooth profile modifications are the locomotive weight acting on axle-neck through axle box bearing and axle bending caused by traction force.Comparing to the imported drive pinion tooth profile modification test data,more reasonable academic data for drive pinion tooth profile modification are obtained.

Tooth profile modifications of type HX_D1 electric locomotive′s drive pinion

The paper introduces a way to design and calculate the volume of mending teeth of gear as well as several methods of mending teeth of gear

The design and method of mending teeth of gear

According to the traditional tooth profile, modification process cannot meet the traction gear’s technical requirements of the high-speed locomotive. A new way for the tooth profile modification technology was provided in the paper. The slotting profile modification process was proposed, the formulating methods of the tooth profile modification K diagram was introduced, modification curve fit as the sections of involutes, the modification profile angles of slotting cutter corresponding sections of involutes was deduced using the profile angle error analysis theory and the tooth profile of modification slotting cutter precision was designed. The feasibility and advantages of modification slotting cutter were validated by examples, which indicates the widely use of this technology in high-speed locomotive traction gear.

Design Principle’s Research of Traction Gear’s Modification Slotting Cutter of High-Speed Locomotive

A numerical simulation for heat exchanger with continuous helical baffles was carried out. The study focuses on the effects of helix angle on heat transfer characteristics. The results show that both the shell-side heat transfer coefficient and pressure drop decrease with the increase of the helix angle at certain mass flow rate. The latter decreases more quickly than the former. The tangential velocity distribution on shell-side cross section is more uniform with continuous helical baffles than with segmental baffles. The axial velocity at certain radial position decreases as the helix angle increases in the inner region near the central dummy tube, whereas it increases as the helix angle increases in the outer region near the shell. The heat exchange quantity distribution in tubes at different radial positions is more uniform at larger helix angel.

Analyses on Effect of Helix Angle on the Continuous Helical Baffles Heat Exchanger

Relative to gear shaping and gear hob, using gear slotting produces herringbone gear which is used in nuclear power turbine speed redactor has more obvious technical and economic benefits, but profile angle error of slotting cutter causes profile error and base pitch deviation of herringbone gear. It will result in high-frequency noise which damages the tactical and technical performance of warship. By analyzed the wire cutting system of rack cutter used in MAAG type gear machining for herringbone gear, the mathematical model of error prediction for rack cutter profile angle was founded. On the base of model of error prediction, the principle of error control and the method of revision control are presented. Finally, the example of prediction and control is provided.

Prediction and Control for Profile Angle Error of Slotting Cutter of Herringbone Gear in Turbine Redactor

To effectively avoid the loss of useful information, in this paper, we extract feature information from the fault signal of rotating machinery in different aspects such as amplitude-domain, time-domain and time-frequency domain. Then for the multi-dimensional feature extraction is prone to the problem of “dimension disaster”, introduce the principles of FDR in data mining to determine the classification ability of each individual feature, and introduce the cross correlation coefficient to solve the problem that dealing with individual feature neglects the interrelationship between the features, and construct a new feature level data fusion algorithm. Finally, According to the characteristics of the HMM (Hidden Markov model), SVM (Support Vector Machine) and its hybrid model, we construct a new decision-level data fusion model.

Study of Data Fusion Method for Fault Diagnosis Based on FDR Feature Selection Algorithm and HMM/SVM Model

In view of the advantages of slotting modification processing and the difficulties in the design and manufacture of Modification Slotting Cutter, development for CAD / CAM system of modification slotting cutter’s design and manufacture for high-speed and heavy-loading gear has the following features:Firstly, the adaptive design of modification slotting cutter is implemented based on different modification target.Secondly,the precise design of modification slotting cutter is implemented by automatic regulating its section line position based on simulation results of the evaluation of the modification. Thirdly, the automatic regulation for fixture system and wire cutting process parameters of modification slotting cutter is implemented based on prediction model of slotting cutter’s pressure angle error, thereby reducing the design and manufacturing difficulty and to improve the precision as well as self-adaptability for modification slotting cutter.

Liang Bin Hu

Papers

Design Principle’s Research of Traction Gear’s Modification Slotting Cutter of High-Speed Locomotive

Analyses on Effect of Helix Angle on the Continuous Helical Baffles Heat Exchanger

Prediction and Control for Profile Angle Error of Slotting Cutter of Herringbone Gear in Turbine Redactor

Study of Data Fusion Method for Fault Diagnosis Based on FDR Feature Selection Algorithm and HMM/SVM Model

Development for CAD / CAM System of Modification Slotting Cutter’s Design and Manufacture for High-Speed and Heavy-Loading Gear