Key Engineering Materials Vols. 419-420

Abstract: The technologies of expert system, ontology modeling and reasoning are studied and applied in this paper. A framework of ontology-based expert system for equipment selection and matching in fully mechanized caving face is built up. The OWL(Web Ontology Language) based equipment knowledge base is set up, and the redundant test is made in the protégé environment. The equipment selection and matching rules are built up by using SWRL(Semantic Web Rule Language). By using JAVA language, the output of equipment selection expert system is optimized based on the theory of Analytic Hierarchy Process. At last, the functions of the expert system are achieved under JESS(Java Expert System Shell) environment. Practical application shows that the equipments selected and matched by ontology-based expert system are more realistic.

Abstract: It is important to study system vibration characteristics for improving product quality and ensuring safety operation of units. In this paper, some dynamics of rotor systems are studied in large centrifugal compressor. The models of diaphragm coupling and tilting pad bearing are established by appropriate simplification. The finite element model of rotors with bearing and coupling is set up by taking interrelation of these subsystems into account. The unbalance responses of journal are computed based on the relative standard. The effect of bearing parameters (length-diameter ratio, clearance ratio and lubricating oil number) to journal vibration of rotor systems is analyzed. Finally test results and theoretical results are compared and errors are analyzed. The research results will provide theoretical basis for improving the bearing design of compressor rotor systems.

Abstract: The Freeform Extrusion Fabrication (FEF) is a Solid Freeform Fabrication process, which fabricates 3D ceramic green parts by extruding an aqueous ceramic paste of high solids loading. The extrusion velocity is a very important parameter and should be better understood. In this paper, experiments were carried out to investigate extrusion velocity in FEF extrusion process of aqueous alumina paste. It is found that the extrusion velocity has a corresponding relationship with extrusion force. The extrusion run can be divided into 4 stages: compaction stage, transient stage, steady stage and stop stage. The step ram velocity input was applied in FEF process and improved the extrusion velocity profiles in transient stage.

Abstract: In this paper, a new type of shaft end torque loadling device is studied for the closed power flow test system of the high-power marine reducer, and it illustrates the structure of the load device, makes the principle of analysis and power calculation of the loading device; and analyses the test system power flow conditions and anti-way self-locking of the installation, Finally, the loading devices of the test system is designed to the order of 100000 magnitude reducer, verify the feasibility of this loading method.

Abstract: To solve the permutation flowshop problem more effectively, a novel artificial immune particle swarm optimization (PSO) algorithm has been proposed. The new algorithm combined the biology immune system theory with particle swarm algorithm by the following phases. Firstly, the scheduling objective and constrain condition were served as antibodies while solutions was served as antigens. Secondly, the particles were encoded as workpiece processing sequence. Furthermore, a concentration selection strategy was adopted to maintain the particle diversity. Finally, comparing with genetic algorithm and PSO, case results showed that immune PSO algorithm not only optimized results and convergence velocity but also had a small fluctuation.

Abstract: The quality of man-machine interface (MMI) directly affects efficiency, safety and comfort of the man-machine system. Therefore, it is significant to study an appropriate evaluation technology for MMI. The method of grey relational analysis based on interval numbers is put forward in the field of MMI evaluation in this paper, based on human thinking having the grey and fuzzy characteristic. In this method, interval numbers are employed as a mean to reflect the rating of indexes instead of real numbers, which offer uncertain information. By judging the correlative degree between the evaluation criterion and the design schemes, the optimal scheme can be found. Based on the proposed method, a novel subjective evaluation model of MMI is set up and applied in the subjective evaluation on the digital control system console of the power plant. Results of the evaluation example prove that the proposed method for MMI evaluation is reasonable and applicable.

Abstract: In order to solve the thermal deformation of the hydrostatic thrust bearing in the heavy equipment, a simulation research concerning temperature field of multi-pad hydrostatic thrust bearing having circular cavities was described. The Finite Volume Method of Fluent has been used to compute three-dimensional temperature field of gap fluid between the rotation worktable and base. This study theoretically analyzes the influence of cavity radius and cavity depth on the bearing temperature performance according to computational fluid dynamics and lubricating theory. It has revealed its temperature distribution law. The simulation results indicate that an improved characteristic can be gotten from a circular cavity hydrostatic thrust bearing, oil cavity temperature decreases by gradually with cavity radius enhancing, oil cavity temperature decreases by gradually with cavity depth. Through this method, the safety of a hydrostatic thrust bearing having circular cavities multi-pad can be forecasted, and the optimal design of such products can be achieved, so it can provide reasonable data for design and lubrication and experience and thermal deformation computation for hydrostatic thrust bearing in the heavy equipment.

Abstract: Optical 3D measurement systems are used in a lot of applications, for instance for quality control and reverse engineering. A structured light active optical 3D measurement method are very often based on projection sinusoidal fringe pattern on the object. The key element of such a shape measurement method is how to generate sinusoidal fringe pattern. The purpose of this paper is to review the method of generation sinusoidal fringe pattern and contrast the two chief method from the specific viewpoint based phase measurement profilmetry. Experiment verification of the performance of each generation method is provided and finally some suggestions on generation method for phase measurement profilometry applications is offered.

Abstract: The abnormal noise was found in a marine planetary gearbox during the experiment. Then, the load test of the gearbox was done on a gearbox test rig and the vibration signal was measured and collected. The fault of the gearbox was analyzed by the time domain and frequency domain analysis. The trouble part was diagnosed and treated. The method used in this paper combined the theory analysis with engineering application. Simultaneously, it has provided a properly feasible method and valuable reference for the fault diagnosis of planetary gearbox.

Abstract: Finite element method is an approximate computational method which is widely used and continuously developed. Variational principles are the foundation of finite element method. In this paper, the generalized variational principles of quasi-static electro-magneto-thermo-elasticity are established using variational integral method. And these variational principles can be degenerated to be variational principles of simple coupling properties materials, which offer theoretical support for finite element method of coupling problems of electro-magneto-thermo-elastic.