Applied Mechanics and Materials Vols. 105-107

Abstract: Scaling exists commonly and its harm is huge. Because of this, design an amplitude-modulating electromagnetic field generator. The drive signal is obtained by amplitude modulation and power amplification. Generate two sine signals by the wien bridge and make the two signals through the MC1496 multiplier, the carrier’s amplitude changes with the modulator’s rule. And the frequency of carrier and modulator could be changed with the adjustment of the Oscillation resistance. Then, make use of D class amplifier TDA8920BTH to enlarge the power of modulated signal. At last, load the drive signal on a ferrite of magnetic coil to gain an electromagnetic field whose strength is modulated. Differ from the ordinary form of winding pipe with wire line, this design is making the magnetic coil close to a pipe. That’s more convenient for installing and removing. Of course, the concrete effect of descaling is needed to test by further experiments.

Abstract: Wavelet Neural Network (WNN) integration modeling based on Rough Set (RS) is studied. An integration modeling algorithm named RS-WNN, which first introduces a heuristic attribute reduction recursion algorithm to determine the optimum decision attributes and then conducts WNN modeling, is proposed. This method is adopted to more effectively eliminate the redundant attributes, lower the structure complexity of WNN, which reduce the time of training and improve the generalization ability of WNN. The result of the experiment shows this method is superior and efficient.

Abstract: This paper is devoted to the numerical simulation of heat transfer in fluids. We develop a numerical formulation based on isogeometric analysis that permits straightforward construction of higher order smooth NURBS approximation. Firstly, we introduce the partial differential equation (PDE) which servers as basis for the whole paper. Then, we introduce Lagrange multiplier method to deal with essentional boundary contions accroding to the nature of NURBS basis function. After getting the Equivalent integral equation, the isogeometric solving format is established based on the idea of isoparametric which is the necessary fundamentals of Isogeometric Analysis. We also discuss the programming algorithm of isogeometric analysis based on Matlab. Finally, a numerical example in two dimensions is presented that illustrate the effectiveness and robustness of our approach.

Abstract: Crack propagation is the main reason which leads to the invalidity of the metal components. A set of detecting equipment based on the acoustic emission method was designed, and it was mainly composed of acoustic emission sensor, signal operating circuits and signal acquisition system. Specimens of 16MnR material were manufactured and the static axial tension test of them was carried on. Acoustic emission signals from the specimen were detected by acoustic emission equipment by using piezoelectric ceramic sensor. Signal datum were acquired and operated by the acquisition system, as well as the acquisition program written for it. The final results has demonstrated that acoustic emission equipment designed for the test performed well in acquiring the signals induced by the metal crack propagation.

Abstract: Due to the development in the construction and building industry in recent years, numerous methods for safer, easier and more economical design of structures have been studied.Because of the high bi-axial bending capacity and high compressive strength of hollow structural sections, these sections are considered as a popular alternative by designers. Supporting the panel zone demands in the columns and occurring the moment hinge at the ends of beam are too available in column with hollow section. One of the major problems in the way of using these sections is lack of appropriate load path to connect beams to them, which ends up using through-plates. Through-plates are plates that pass through column and beams connect to them at their webs. Consequently these plates should have sufficient stiffness in order to provide enough strength. This paper proceeds to study the buckling behavior of through-plates in moment beam to column connections under gravity loads.

Abstract: Corona discharge is a kind of self maintained discharges that occurs in the extremely uneven electric field which often happens in the industrial and daily living environments. In this paper, we study the characteristics of corona discharge, especially the ones in the time domain and frequency domain of negative corona discharge. Based on the analyzed characteristics mentioned above, we design and optimize a kind of patch antennas, which has the advantages of small volume compared to the traditional one used to receive the signals generated by corona discharge. This new antenna can be used in the field of security inspection on high voltage transmission lines applied in the industrial applications.

Abstract: How to make the dispatch plan of (Ready-mix concrete) RMC trucks more effective and more efficient is an important issue for the RMC companies. Up to now, only a few researches have been done to solve this problem and almost none of them consider the situation of several RMC plants supplying several job sites. This paper presents a new model, which uses Genetic Algorithms (GAs) to optimize the dispatch plan for several RMC plants supplying several job sites, and use Short Message Service (SMS) technique to monitor the process of going on or to deal with something emergency.

Abstract: It is nearly impossible to carry out prototype experiments of large deployable space antennas because of their large dimensions. To solve this problem, a performance prediction approach is proposed in this paper. The prototype’s working performance is predicted by the scale model of the large deployable antenna. Based on this method, the natural frequency of the ring tension truss deployable antenna working in space is studied. The effect of the structural parameter distortion is taken into consideration by similarity criteria, and a similarity experimental formula of structural natural frequency is obtained. Four finite element models are established to validate the correction of the prediction method. The simulation results show that it’s valid for the prediction method to analyze the prototype in space, and it can be applied to promote the design, and performance prediction of the large deployable antennas.

Abstract: The properties of flue gas desulphurization (FGD) gypsum were analysized by Thermo-gravimetry/differential scanning calorimetry (TG/DSC), technical performance analysis, optical microscope and Scanning electron microscope (SEM). Mechanical properties of FGD gypsum-steel slag powder cementitious material were researched. The results revealed that FGD gypsum have similar moisture content, major component CaSO₄ ·2H₂O with natural gypsum, and has better technical performance than natural gypsum. The results of optical microscope and SEM of the FGD gypsum hydration support this further. When the dosage of steel slag powder is 15%, containing activator ,better mechanical properties can be obtained. Key words: FGD gypsum, Property, Cementitious material

Abstract: Using traditional strip method to predict longitudinal motion of hybrid monohull, the results are very different from test results, it can not reflect the effect of built-up appendage by reason of ignoring viscous force. This paper calculated the hydrodynamic coefficients of the hybrid monohull with two correction methods, one considering the viscous effect with lateral flow theory, the other calculating the correction coefficients based on RANS equation by using FLUENT software, and then predicted the longitudinal motion by STF method. By comparing the predicted results with the model test results, it shows that, both of two correction methods can reflect the effect of built-up appendage, and can be used for predicting the longitudinal motion of hybrid monohull, the accuracy of the latter is obviously better than former, it has good value in engineering application.