Advanced Materials Research Vol. 910

Abstract: This paper analyses and selects the rheological mechanism and rheological analysis of the sand-gravel-fill dam, and combines with concrete-face sand-gravel-fill dam engineering practice, using three-dimensional nonlinear finite element methods to analyze the rheological effects on stress and deformation of the dam, using two calculation program of considering sand-gravel rheological effects or not. Then analyze and compare the results of the two calculation program, and systematically summarize the rheological effects on stress and deformation of the dam.

Abstract: Given the importance of the jib system which has direct impact on the comprehensive performance of portal crane, this article regards the Jib system as a whole. Detailed finite element model of the jib system was established and vibration modes were calculated based on the finite element method. This paper conducted a transient dynamic simulation and obtained dynamic response to the boom structure in the process of lifting rated weight at the maximum amplitude position. This research approach is not only very useful to obtain dynamic response and assess the fatigue life of the jib system in the design phase, but also to provide a theoretical basis for the design of portal crane.

Abstract: According to the progressive damage analysis based numerical characteristic length scheme presented by Zhang, a progressive damage model established by Liu is adopted here to calculate characteristic lengths for mechanical composite joints. Four groups of specimens with different lay-ups and geometries were designed and fabricated and static tensile experiments were carried out to verify the suitability of the numerical characteristic length model. Good agreements between the predicted ultimate failure loads of the specimens and experimental outcomes are obtained. In addition, the characteristic lengths calculated from the experimental ultimate failure loads are in accordance with that obtained from numerical ultimate failure loads, which give evidence of the feasibility and suitability of the numerical characteristic length model.

Abstract: The existing fire-extinguishing plants have a lot of problems. For example, the amount of extinguishant is very large, mix is uneven, extinguishant is easy to splash, harmful to the human, the system structure is complex, spray nozzle is demanding and so on. And the open literature sources on the marine fire hydrant are very few. Besides because of the difficulty of numerical simulation of two-phase flow, the research on numerical simulation of the marine fire hydrant is hardly any. In this thesis, a new-style marine fire hydrant is designed to be small volume, easy to use and low pressure lost. It blends the gas to water through its special structure. It regards the gas-water mixture as the extinguishant. In this way, the water flow can be soften, and reduce the splash. The extinguishant can overlay the burnable body uniformly. At last, reach the better extinguishant under the dual effect of the oxygen exclusion and cooling.

Abstract: In the article, proposing one kind of design plan about rotational speed measurement system design based CPLD. Various modules design has completed according to EDA tools and VHDL hardware description language. The feasibility of the speed measurement system design was verified based on the experiment. At present, the system has been successfully application in the fuel injection pump test-bed.

Abstract: This article through introduction tradition high frequency laboratory existence shortcoming and malpractice , Proposed the idea of Virtual instrument made for high-frequency laboratory ,then introduced the characteristic of LabVIEW (a development platform for virtual experiment),And proved the feasibility of using virtual machines have the discriminator through the simulation experiment .

Abstract: Despite of its remarkable active performances, brushless DC motors, which are widely used in mechanical engineering, have an obvious disadvantage in its high electromagnetic torque ripples. In the paper, a ripple suppression method based on predictive controls of stator currents is proposed according to analysis of causes electromagnetic torque ripples generate in commutation periods of brushless DC motors. First of all, a relative accurate prediction is acquired through DC motor on-line parameter corrections based on generalized predictive control algorithms. Then rolling optimizations make tracking errors and control qualities optimized for best control effects. And finally, minimum electromagnetic torque ripples are achieved. The simulation results show that torque ripples can be suppressed effectively with improved reliabilities by using the method proposed.

Abstract: In order to seek a better way of control in sewage treatment, a control system which consisted of water unit, sand unit, the oxidation ditch unit, precipitation unit and sludge dewatering unit was designed. The paper investigates various controllable parameters in sewage treatment system and the way of present common automation control. We designed manual control variable aeration program and two automatic control subroutine which included thickness grille and pumping station by using WIN 32 software. The program is designed in Siemens STEP 7 V5.5 software development platform and chose the 10 input contacts which are I0.0~I0.7, I1.0~I1.1 and 10 output contact which are Q1.0~Q1.1, Q0.0~Q0.7.This design achieves automatic control and improves the purifying efficiency on the premise of ensuring water quality.

Abstract: In order to achieve the automatic control of electrostatic precipitator (ESP) more efficiently and accurately, an ESP system combining hardware and software is designed. According to the requirement of the ESP system,the Electronic Design Automation (EDA) is introduced to the ESP control system and the system is divided into four modules.These sub-modules are designed and the simulation waveform of the system is ananalyzed,based on the Very-High-Speed Integrated Circuit Hardware Description Language (VHDL) programming language and Quartus software.The results show that the security, flexibility and reliabity of the system is improved by using EDA as the control ,which is a great value for generalization.

Abstract: In order to improve the efficiency of electrostatic precipitators, a control system of constant current source based on Single Chip Microcomputer (SCM) is designed. In the control process, we use the pulse signal from microcontroller P1 port as digital signals of the switch. By changing the number of contact closure control, we achieve steady flow output of different magnitude. By using closed-loop feedback control, we achieve constant monitoring of dust concentration and ensure it compliance with outlet concentration of national requirements. The results show that microcontroller control system has a strong anti-interference, high accuracy, ease of programming, etc. Used in the electrostatic precipitator, collection efficiency can be further improved.