Applied Mechanics and Materials Vols. 148-149

Abstract: Aiming at the requirements of high performance of optical communication systems, a new type of photonic crystal fiber (PCF) is proposed. This kind of PCF consists of hexagonal air holes in the inner cladding and octagonal air holes in the others layers. Two big elliptical air holes are embedded to enhance the birefringence. Numeral results show that this kind of PCF exhibits high birefringence with the level of 10-3 and high nonlinearity with the level of 10-2m-1w-1. In addition, two zero dispersion points are obtained after optimization, which will find application in dispersion compensation PCFs.

Abstract: In this paper, C80B car body is the research object to study the load-stress transfer relationship that has great influence on the car body structure. First of all, through the test data of line DaTong to Qin Huangdao, the load-time history of C80B car body’s load on center plate, load on draw gear, roll load and torsional load have been obtained, as well as the stress-time history of the body fatigue key parts have been obtained. And the load spectrum and stress spectrum have been made up. Then the finite element analysis of the car body is made. The load-stress transfer coefficient of fatigue key parts on car body could be obtained. Last the load and stress transfer relationship in detail considering the measured data has been analyzed.

Abstract: A reliability risk assessment model based on fuzzy FMEA was presented by using fuzzy comprehensive evaluation. Fuzzy matrixes were constructed according to the investigation data, in which occurrence probability ranking, effect severity ranking and detection difficulty ranking are all weighted analyzed. A fuzzy hierarchy analysis method was used to obtain the weight of each influence factor. In the model, the potential fault modes and the reasons can be analyzed and the preventive measures can be taken in prevention stage to avoid finding the problems after the products are put into production and market. It will provide new ideas and new methods to improve the operation security of the engine, to prevent and forecast failure, and to estimate and control the risk.

Abstract: The analysis on the physiological characteristics of the human body posture was carried out with the ergonomic principles from the perspective of human anatomy and physiology. The requirement for the structure and size of the passenger seat was discussed from the point of passenger comfort. Several design problems were analyzed with some recommendations for improvement.

Abstract: Zn-25Al coatings were prepared by cold spray on mild carbon steel Q235. The coatings were studied by potentiodynamic polarization test, corrosion potentials and electrochemical impedance spectrum in natural seawater. The results show that the Ecorr of Zn-25Al coating is -1.01V (SCE) and the Ecorr of Q235 is -0.65V (SCE) at the beginning of the immersion. Self-corrosion potential of Zn-25Al coating is lower than that of Q235. The coatings turn to activity anodic dissolution zone when the potential reaches -1.05V. The coatings changes to passivation zone after the potential reaches -1.01V and the current intensities increase slightly with the potential increasing quickly. Zn-25Al coatings can provide lower protection potential and promising current to protect Q235 from corrosion.

Abstract: Silk is an superior textile material. The cohesion is an important property of raw silk. The cohesion of raw silk is measured with the Duplan tester and raw silk cohesion automatic tester, respectively. The correlations between the cohesive times given by the Duplan tester and the diameter variations of raw silk after different times of abrasion are analyzed using grey relational analysis. The results shows that the diameter variation between ten-time abrasion and one-time abrasion has the highest correlation with the cohesive times, which shows good application prospects for the raw silk cohesion automatic tester when a ten-time abrasion is adopted.

Abstract: In this paper, we focus on the hardware design of control circuit based on shunt active power filter (APF). It described the AD transformation module, DSP data processing module, CPLD logic control module, man-machine interaction module and asynchronous communication module. As the core controller, TMS320C5416 digital signal processor (DSP) controls this peripheral assistant circuit to complete data acquisition, harmonic detection and output of control signal. Finally, we design the layout and routing of the control circuit.

Abstract: Expanded graphite (EG) was prepared by microwave irradiation and evaluated as adsorbent for the removal of disperse blue 2BLN (DB) from aqueous solution by the batch adsorption technique under different conditions of initial pH value, adsorbent dosage, initial dye concentration and contact time. The experimental data were analyzed considering pseudo-first-order, pseudo-second-order and intra-particle diffusion approaches. The adsorption kinetics at room temperature could be expressed by the pseudo second order model very well. The results indicate that the adsorption rate is fast enough and more than eighty percent of the adsorbed DB can be removed in the first 15 min at room temperature, which makes the process practical for industrial application.

Abstract: Scaling-rotation symmetry is combined by rotation symmetry and scaling symmetry, belongs to mechanical static structure symmetry, and widely exists in mechanical systems. Scaling-rotation symmetry plays an important role in realizing the technical, economic and social performances of mechanical products. Based on the concept system of rotation symmetry and the research on large numbers of instances, taking the directivity, the rotary type and the alternations of symmetry components, the types of symmetry benchmark, and the variable type of scaling as standards, the concept system of scaling-rotation symmetry was established. The concept system can provide a theoretical basis for the further research on the application of scaling-rotation symmetry in mechanical systems.

Abstract: Abstract: The 0.05%Eu3+ and 0.1%Sm3+ co-doped TiO2 composite nanoparticles have been prepared by sol-gel method and characterized by the techniques such as XRD and SEM/EDAX. The photocatalytic degradation of Methylene blue in aqueous solution was used as a probe reaction to evaluate their photocatalytic activity. The effects of process parameters like, solution pH and H2O2 concentration on the extent of photodegradation have been investigated.