Applied Mechanics and Materials Vols. 130-134

Abstract: Background subtraction is a typical method for moving objects detection. The Gaussian mixture model is one of widely used method to model the background. However, in challenge environments, quick lighting changes, noises and shake of background can influence the detection of moving objects significantly. To solve this problem, an improved Gaussian Mixture Model is proposed in this paper. In the proposed algorithm, Objects are divided into three categories, foreground, background and middle-ground. The proposed algorithm is a segmented process. Moving objects including foreground and middle-ground are extracted firstly; then foreground is segmented from middle-ground. In this way almost middle-ground are filtered, so we can obtain a clear foreground objects. Experimental results show that the proposed algorithm can detect moving objects much more precisely, and it is robust to lighting changes and shadows.

Abstract: This paper presents a system developed for online monitoring of various aging effects, such as fatigue, creep and fatigue–creep interaction. An appropriate life prediction methodology has been used to address the various aspects of creep, fatigue and creep fatigue interaction, creep and fatigue crack growth. The system converts the plant transients to temperature and stress responses using the analytical models modified by FEM. The fatigue usage factor is computed using the rainflow cycle counting algorithm. The creep damage index is evaluated from the computed temperature and stress histories and the material creep rupture curve. This system has already been installed at Henan Jiaozuo power plant in china for monitoring the fatigue and creep degradation.

Abstract: Focusing on a particular assembly line balancing problem of which the task time is a stochastic variable, a stochastic model is established, which aimed at maximization of assembly line balancing rate, completed probability and smoothness index. Simultaneously, an improved particle swarm optimization algorithm is proposed to solve this problem and a reasonable chromosome coding method which effectively prevent to generate infeasible solution is designed. For this reason, the algorithm convergence rate could be improved. At last, rear axle assembly line balancing designs of an automotive part company is taken to test validity of algorithm. Availability of the algorithm is verified by this example.

Abstract: This paper presents an analysis of field reliability and maintenance performance for a heavy engineering vehicle operating in a steel mill. Based on the field repair reports of the vehicle, the statistical characteristics of reliability and maintenance performance are evaluated and the evolution trend of mean time between failures (MTBF) and availability are analyzed. The effect of the preventive maintenance (PM) interval on availability is evaluated and a possibly adequate PM interval is obtained. The analysis method presented in this paper is useful for analyzing and evaluating the reliability of complex repairable systems.

Abstract: Spline is an important component to ensure transmission and connection in the mechanical design. But species and parameters of the spline are different according to the different national standards. In order to meet the user requirements, this paper developed spline rapid design function on VC2005 platforms with UDF method based on Pro/E platform that applies Pro/E secondary development kit Pro/TOOLKIT, uses Access database，and realizes selection design function of the spline type and parameter for China Standard, American standard, Germany standard etc.. Through practical application, the requirement of spline rapid design function in Pro/E is satisfied.

Abstract: In order to improve complex shape piston productivity computer integrated manufacturing system (CIMS) technology is presented. Design elements need to be taken into account in CIMS technology, which are geometry, material choice, and rationalization of components (reducing assemblies) and cost. In design freedom phrase, this new design freedom will place much more responsibility on the designer to think about the exact requirements of a part – with the unlimited geometry capability designers will therefore need to be much more imaginative to make full use of the new manufacturing processes. New design paradigm is presented and mechanical designers will be able to manufacture any complexity of product they require. Effect of graded materials on product design is considered and 2D and 3D of piston are carried out. CAD issues and assembly constraints of complex shape piston of diesel engine are discussed. It gives new method to design and produce complex shape piston of diesel engine.

Abstract: The original equipment manufacturing mode of the multi-species, multi-process and multi-unit is the main mode in Zhejiang manufacturing industry, the workshop layout affect directly the production efficiency and cost. The paper analyzed the impact factors of discrete operations workshop layout, established the Multi-Agent mathematical model of discrete operations workshop layout by using Multi-Agent theory, put forward the objective function of the workshop layout, and carried out empirical study by typical enterprises. By analyzing raw data of ZJ manufacturing enterprise, brought forward two layout programs based on mathematical model of Multi-Agent, evaluated the benefits and chose the better one of the two programs according to the objective function. The results after the implementation showed that the logistics measuring pitch of the program after selection is small, and the workshop area utilization is higher, and the equipment cost is reasonable. The model and optimization technology of discrete operations workshop layout based on Multi-Agent theory has important practical significance and good feasibility.

Abstract: This paper have completed the structural design of the GF3.5 25/500, and the cover of the high pressure vessel, flange, the body of the high pressure vessel was stress check, security check, the last combination of pressure tests, air tightness test, Commissioning completion of the three major test the final design.

Abstract: Jatropha curcas from Panzhihua area was used to explore the optimal process of screw-pressing. And the result shows the optimal process parameters are as follows: the water content of kernel is 3%; the ratio of kernel to shell is 8:2; the temperature of the mixture of kernel and shell entering the pressing chamber is 100°C; the temperature of the pressing chamber is 170°C; and the corresponding oil yield is 87.8958%.

Abstract: Focused on environment parameters information of large dead-time and inertia, in this paper, the multi-parameters monitoring system of low-power wireless communication technology based on ZigBee CC2430 was designed. System uses a star topology network. By placing network nodes in monitoring area, the monitoring center collects monitoring information to achieve data analysis and management. The realization mathod of wireless nodes and data transmission and communications is presented. Experimental result shows that the performance of this system is quite stable and could be widely used for automatic monitoring in other environment places.