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Development of a plastic injection molding training system using Petri nets and virtual reality
Ma Bin, Guo Zhi-ying, Zhou Hua-min
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3 ): 4-.
https://doi.org/10.1631/jzus.2006.A0302
In this study, Virtual Reality (VR)-based plastic injection molding training system (VPIMTS), which can be modeled as an integrated system with a task planning module, an intelligent instruction module, a simulation module, and virtual environment (VE) module, was developed. Presented in this paper are an architecture of VPIMTS, a practical knowledge modelling approach for modelling the training scenarios of the system by using Petri nets formalism and key techniques (FEM, injection molding procedure modelling) which have been developed independently. The utilization of the Petri net model realized the environment where the trainee can behave freely, and also made it possible to equip the system with the function of showing the next action of the trainee whenever he wants. The overall system is a powerful approach for highly improving the trainee’s comprehension and injection molding study-efficiency by building digital, intelligent, knowledgeable, and visual aids.
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Using sequential analysis procedures to rank the influencing factors of public work’s quality
Yang Chau-ping
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3 ): 9-.
https://doi.org/10.1631/jzus.2006.A0330
In order to improve the efficiency in management of public work projects, screening and controlling influencing factors affecting the quality of a public work project is essential. This study synthesized 9 influential categories including 91 factors related to quality management of public works in Taiwan using a sequential analysis procedure. According to the Borda-values of influencing factors obtained from a first stage questionnaire, the number of primary factors selected by the responsible entities and the design-supervisory entities were 44 and 45 respectively. A Fuzzy Analytic Hierarchy Process (FAHP) was used to prioritize and rank these factors. The top five factors ranked by the responsible entities were (1) introduction of the earned value analysis, (2) working efficiency, (3) environmental laws and regulations, (4) price-index fluctuation, and (5) on-site safety management. The top five factors ranked by the design-supervisory entities were (1) man power, (2) laws and regulations, (3) price-index fluctuation, (4) traffic conditions, and (5) faulty design.
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Method and application of wavelet shrinkage denoising based on genetic algorithm
Ma Qi-ming, Wang Xuan-yin, Du Shuan-ping
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3 ): 14-.
https://doi.org/10.1631/jzus.2006.A0361
Genetic algorithm (GA) based on wavelet transform threshold shrinkage (WTS) and translation-invariant threshold shrinkage (TIS) is introduced into the method of noise reduction, where parameters used in WTS and TIS, such as wavelet function, decomposition levels, hard or soft threshold and threshold can be selected automatically. This paper ends by comparing two noise reduction methods on the basis of their denoising performances, computation time, etc. The effectiveness of these methods introduced in this paper is validated by the results of analysis of the simulated and real signals.
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Mechanical design and locomotion control of a homogenous lattice modular self-reconfigurable robot
Xia Ping, Zhu Xin-jian, Fei Yan-qiong
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3 ): 15-.
https://doi.org/10.1631/jzus.2006.A0368
In this paper, we propose a novel, 3D, like cubic shape, modular self-reconfigurable (MSR) robot named M-Cubes. Its key mechanical components are analyzed in detail. By communicating with the neighboring modules, each unit employs its automatic lock device composed of a pin and a hole on each connection plane which can connect or disconnect with neighboring modules. The M-Cubes system consisting of many identical modules cooperates to change their connection, and then the whole structure transforms into arbitrary structure. Furthermore, we describe its locomotion control based on the driving function and the adjacency matrix which is effective for solving the computationally difficult problem and optimizing the system motion path during the self-reconfiguration process. Finally, a simulation experiment using java 3D technology, proved the new method for controlling modular robot is robust and useful.
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Floating-roof steel tanks under harmonic settlement: FE parametric study and design criterion
Zhao Yang, Cao Qing-shuai, Xie Xin-yu
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3 ): 20-.
https://doi.org/10.1631/jzus.2006.A0398
Large vertical steel tanks for fluid storage are usually constructed on soft foundations, so it is not surprising that the tank wall will settle unevenly with the settlement of the foundation, thus inducing deformations and stresses in the tank. This work investigates the linear static behavior of floating-roof tanks under harmonic settlement through finite element (FE) analyses. The influences of the radius-to-thickness ratio, the height-to-radius ratio and the wind girder stiffness on the structural behavior are first analyzed. Comparisons between the circumferential stresses in the wind girder and the vertical stresses in the tank bottom are then made. The displacement and the stress along the tank height are also discussed, and the concept of tank division along its height is presented. Finally, a design approximation for the radial displacement at the tank top is developed based on FE results, and a settlement criterion based on the top radial displacement is proposed which can be used in practical design.
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Advanced aerostatic analysis of long-span suspension bridges
Zhang Xin-jun
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3 ): 23-.
https://doi.org/10.1631/jzus.2006.A0424
As the span length of suspension bridges increases, the diameter of cables and thus the wind load acting on them, the nonlinear wind-structure interaction and the wind speed spatial non-uniformity all increase consequently, which may have unnegligible influence on the aerostatic behavior of long-span suspension bridges. In this work, a method of advanced aerostatic analysis is presented firstly by considering the geometric nonlinearity, the nonlinear wind-structures and wind speed spatial non-uniformity. By taking the Runyang Bridge over the Yangtze River as example, effects of the nonlinear wind-structure interaction, wind speed spatial non-uniformity, and the cable’s wind load on the aerostatic behavior of the bridge are investigated analytically. The results showed that these factors all have important influence on the aerostatic behavior, and should be considered in the aerostatic analysis of long and particularly super long-span suspension bridges.
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Characterization of DC magnetron sputtering deposited thin films of TiN for SBN/MgO/TiN/Si structural waveguide
Xu Xuan-qian, Ye Hui, Zou Tong
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3 ): 30-.
https://doi.org/10.1631/jzus.2006.A0472
Optimal parameters for depositing Titanium nitride (TiN) thin films by DC reactive magnetron sputtering were determined. TiN thin films were deposited on Si (100) substrates by DC reactive magnetron sputtering, at different temperatures, different electrical current values, and different N2/Ar ratios. Structural characteristics of TiN thin films were measured by X-ray diffraction (XRD); surface morphology of the thin films was characterized using an atomic force microscope (AFM). The electric resistivity of the TiN films was measured by a four-point probe. In the result, temperature is 500 °C, electrical current value is 1.6 A, pure N2 is the reacting gas, TiN thin film has the preferred (200) orientation, resistance is small enough for its use as bottom electrodes.
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Behavior of preloaded RC beams strengthened with CFRP laminates
Zhang Ai-hui, Jin Wei-liang, Li Gui-bing
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2006, 7(3): 436-444.
https://doi.org/10.1631/jzus.2006.A0436
Eighteen reinforced concrete beams, including 16 beams strengthened with CFRP laminate at different levels of preload and 2 control beams, were tested to investigate the influence of preload level on flexural behavior of CFRP-strengthened RC beam. The experimental parameters include rebar ratios, number of plies of CFRP laminates and preload level at the time of strengthening. Theoretical analysis was also carried out to explain the experimental phenomena and results. The experimental and theoretical results indicated that the preload level has more influence on the stiffness and deflection of the strengthened beam, both at post-cracking and post-yielding stage, than that on the yielding and ultimate flexural strength of the strengthened beam. The main failure mode of CFRP-strengthened beam is the intermediate crack-induced debonding of CFRP laminates, provided that the development length of CFRP laminates and shear capacity of the beam are sufficient.
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30 articles
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