Advanced Materials Research Vols. 490-495

Abstract: Using MATLAB，the digital teaching software of Maxwell ’s speed distribution function is compiled. The software can deal with Maxwell speed distribution function in digital. This paper concerns mainly about the simulation of the speed distribution graph of the Maxwell speed distribution law and the speed distribution graph in different temperatures by using MATLAB Moreover, the three statistics is programmed and calculated

Abstract: As development of laser technology, the characteristic of laser atmospheric propagation is always hot spot in laser domain. Using theoretical models of laser atmospheric propagation, a simulation system is researched by implementing a scientific method of software development. This simulation system can simulate the radiate property of laser propagation in atmosphere, and demonstrate the course of laser propagation. This theoretical model of atmospheric propagation is based on Lambert-Beer law, combined with other classic theoretical model such as Rayleigh scattering and Mie scattering. Multiple scattering theories are used when simulating the laser propagation in smoke or fog. In calculation, the atmosphere is divided into layer. An appropriate model will be selected for calculation in each layer in order to enhance the stimulation precision. Lastly, the figure of light spot is drawn along with transmission space. Laser atmospheric propagation is demonstrated.

Abstract: To overcome the shortcomings of existing technology and achieve a type of shaft and sleeve assembly in navigate with high coaxial requirements, a novel coaxial positioning system is presented based on the flexible decoupling beams and micro-vision system. In order to meet the adjustments online and maintain posture of the shaft and sleeve, a flexible beams structure with pattern of “square lattice” is designed. Combined with micro motorized X-Y stage and clamps, the structure achieves exact coaxial positioning precision and station keeping function. The mechanics theory and finite element method are used to analysis and simulate the beams. The Hough algorithm is applied in the micro-vision system to realize the precise coaxial positioning of real-time detection and calculation. Experiments show that the coaxial positioning accuracy is better than 8μm, and the positioning device could guarantee the realization of positioning assembly in practical applications.

Abstract: Piezoelectric vibrator is the core of ambient energy harvesters utilizing piezoelectric effect. The developed piezoelectric vibrators are generally one degree of freedom (DOF) vibration systems with narrow resonant frequency bandwidth, which restricts the energy harvesting efficiency. This paper studies a design of two DOF piezoelectric vibrator consisted of two single DOF vibrators and a connecting spring to extend the resonant frequency bandwidth. By adjusting the structural parameters, two natural frequencies of the vibrator are set to adjacent values, so that it can maintain a high response rate over a wide frequency range near its two resonance points. Structural parameters for maximizing the power output of the vibrator are optimized by using ANSYS software. Contrastive analysis between a typical cantilevers array and the proposed vibrator is performed. The results show that the proposed vibrator has better broadband response and the design scheme is effective.

Abstract: To detect the damage of curl tube structure with more effect, the finite element method (FEM) and experimental modal analysis (EMA) were employeed to generate the modal flexibility of the curl tube. The modal flexibility was used to compute the modal flexibility-curvature by using the central difference method. Different degrees and locations of damage were simulated by additional quality in the intact curl tube to verify the modal flexibility-curvature and difference generated by both FEM and EMA. The results show that the modal flexibility of curl tube should have the direction. In addition, we conclude that the flexibility curvature’s difference in x and y plane can not be used for damage identification. But using the flexibility curvature’s difference of the z direction in the vertical plane, we can not only identified the multiple damage location, but also to analized degree for the extent of injury to the same location .

Abstract: In order to find the principal axes of inertia and calculate their moment of inertia to any plane homogeneous rigid body for calculating easily the moment of inertia to any axis of this rigid body, the principal axes could be found and their moment of inertia could be calculated automatically by using the reading-image of MATLAB to read the image messages about the flat surface of the rigid body and by the procedures which ware made according to the logic relation about the principal axis and the moment of inertia of the rigid body. Applying this method in a homogeneous cube, a result was acquired, error of which is small compared with the theoretical value. So this method is reliable, convenient and practical

Abstract: Product concept generation and concept design are major activities for obtaining an optimal concept in new product development (NPD). A customer requirements driving new product concept generation method is addressed in this paper. This study proposes a new method to generate product concept, through which NPD team acquire customers’ requirement and product attributes. The new method is based on integrating of Naïve Bayes cluster and rough set theory (RST). It takes marketing strategy, business strategy into consideration, which makes new product development more effective compared with the traditional method. We believe that the proposed method will have a positive significance on the future new product development

Abstract: With the development of petrochemical industry, the status of pressure vessel has become increasingly important, and higher requirements are introduced for the security of nozzle zone at the pressure bearing region of pressure vessel. In order to study the stress status of nozzle zone at the channel of pressure vessel, solid modeling for channel and straight pipe was performed with ANSYS software. Through finite element analysis and calculation, the stress concentration region of channel was determined and the reason was analyzed. In addition, the nozzle zones of the model before and after loading were compared. The result reveals that symmetrical stress concentration region lies at the junction of channel and pipe. The maximum stress is located at the inside of nozzle zone of channel and less than the yield stress of material.

Abstract: In order to choose a reasonable isolator component for engine mounting system and to isolate the engine’s vibration effectively, experiments were made on bracket vibration severity of a high power diesel engine. In the experiment, the engine worked at many working performance and used two kinds of isolator component such as rubber-isolator and wire net-isolator. The aims of the experiment were to find the effects of the main vibration excitation on the body; to master the rules of vibration with rotational speed and load; to understand the characteristic and rank of vibration severity when the engine used different isolator and to provide foundations for choosing an effective isolating component. Test showed that the wire-net isolator had better characteristics than that of the rubber isolator. The results have reference value in engine’s further design.

Abstract: Traditionally assembly cost models are established through static spreadsheet algorithms. However, there are some inherent problems in using spreadsheets for the estimation of manufacturing cost. Among these is the lack of accounting for dynamic effects caused by stochastic variation such as inventory fluctuation, downtimes, supply interruptions, and system failures. Therefore, a dynamic cost estimation model is proposed which can be seen as an integration method between spreadsheet modeling and the virtual plant concept, which maintained the accessibility and flexibility of the spreadsheet model, and did not require a significant increase in the effort level to build a simulation. However, it still includes the effects of interaction between machines, along with simulating random failures, maintenance dispatch and repair. A case study is also tested and the results verify that the methodology demonstrates the feasibility of dynamic cost model based on a number of improvements on static spreadsheet algorithms