Advanced Materials Research Vols. 1025-1026

Abstract: The fatigue life of autofrettaged thick-walled cylinders with a radial cross-bore is investigated by applying inelastic finite element analysis with cyclic pressure loading. A non-linear kinematic hardening model considering bauschinger effect is used for determining cyclic plastic strain ranges in fatigue evaluations. A macro is written in ANSYS to calculate the equivalent alternating stress intensity, based on the ASME Boiler and Pressure Vessel Code. For a specific cyclic load level, a distinct optimum autofrettage pressure is identified by plotting autofrettage pressure against the equivalent alternating stress intensity and the number of cycles from design fatigue data. The optimum autofrettage pressure was found in the range of 80.5%-92.5% of limit pressure. The hydrotest had little influence on the fatigue life when the thick-walled cylinder was autofrettaged with an optimum autofrettage pressure.

Abstract: The issue of damage to data distribution mechanisms is an overlooked theme today. However, it is very important to devote attention to this problem, since data distribution mechanisms are important carriers of diverse information. It is necessary to protect data distribution mechanisms, and armoured tubes are used for this purpose. Armoured tubes are used in particular where there is a danger of damage to data distribution mechanisms caused by mechanical strain. However, their use is not restricted only to protection against mechanical strain, but also includes protection of conductors against potential sabotage. They can very often be seen in massive or level crossing contacts. Testing of armoured tubes was performed due to the detection of potential deficiencies of such protection.

Abstract: Brick is one of the most common masonry units used as building material. Due to the demand, different types of waste have been investigated to be incorporated into the bricks. Many types of sludge have been incorporated in fired clay brick for an example marble sludge, stone sludge, water sludge, sewage sludge and ceramic sludge. The utilization of these waste materials in fired clay bricks usually has positive effects on the properties such as lightweight bricks with improved shrinkage, porosity, and strength. Therefore, the objective of this study is to incorporate different percentages of mosaic sludge and investigate heavy metals leachability from the mosaic sludge brick. Heavy metals leachability was conducted by using toxicity characteristic leaching procedure (TCLP). Physical and mechanical properties were also determined which are compressive strength, shrinkage, density and initial rate of suction. From the results obtained, it shows that fired clay brick with 5% of mosaic sludge obtained the best result with highest compressive strength and low initial rate of suction (18.76N/mm² and 10.08 g/mm²) respectively. Nevertheless, all the other properties for all bricks incorporated with different percentages of mosaic sludge were also complied with the BS 3921:1985 standard. The results also demonstrated that the leachability of potential heavy metals in mosaic brick were complied with USEPA (1996) and EPAV (2005a) regulatory limit. In conclusion, mosaic sludge could be an alternative low cost material for fired clay brick as well as providing a disposal method for mosaic sludge waste.

Abstract: Water jet impingement on a flat target surface can be seen in cooling and cleaning applications, where the flow velocity, static and dynamic pressures are the three main parameters to be considered. Although the jet impingement is a basic free-surface liquid flow, the understanding of flow characteristics after the impingement is essentially needed to elucidate the flow behaviors and its influences to some specific processes. Therefore, the aim of this study is to investigate the flow characteristics of water jet impingement on a solid surface through the computational fluid dynamics and experiments. An obstacle with different thickness was added into the target surface, representing the uneven morphology of workpiece surface to be cooled or cleaned. The parameters considered were the jet impact angle and obstacle thickness, and the water layer formed radially from the stagnation point was observed and analyzed. According to the results, there was a good agreement between the numerical and experimental findings. The jet impact angle was found to remarkably affect all the performance characteristics examined in this study. The water flow characteristics were found to be changed after the flow impinged and passed over the obstacle. In addition, the static and dynamic pressures caused by the impingement were also presented and discussed.

Abstract: With the world’s energy crisis aggravation, the wind turbine technology is undergoing a rapid and continual development all over the world. At present, the increase of the single-system capacity is becoming a major trend of the development of the wind turbine technology, however, how to design a cooling system to keep the whole turbine working in a allowable temperature environment is a critical problem. In this paper, a cooling system of a 3MW wind-driven generator is given and numerical simulation is conducted at 100% load, and then an improvement structure is proposed according to the calculation results. The results show that the windings and stator teeth can be cooled down effectively by the improving method. The improving cooling system removes the over-temperature problem of high temperature zone and allows the temperature of the generator to be less than the limit of 120°C as required.

Abstract: A ground test method of the heat exchanger in intake is proposed using simplified method. A theoretical analysis was carried out to investigate its influences on the performance of heat exchanger. The results show that the performance of heat exchanger keeps invariable with the density of gas if the temperature and mass flow rate remain the same. The error caused by substituting total pressure of free stream for inlet entrance was analyzed and the results show that for subsonic inlet the experimental error is relatively small and the experimental error increasing rapidly as flight Mach number exceed 1.2 and flight altitude has little impact on the experimental error while the error increasing slightly with flight altitude.

Abstract: A new designed 1000MW generator stator was planned to be transported by DQ₄₅ Schnabel car with end shield mode. In order to ensure the safety of transportation, three design schemes of end shield were proposed。In this paper, refined finite element models were established including frame of stator with different end shield, and nonlinear finite element analyses according to load condition of transportation on railway were performed subsequently. The numerical results indicated that load condition of structure could be improved significantly by using the third proposed end shield with tension bar, and the safety of transportation could be guaranteed. At last, the numerical results of the third scheme were compared with test data, and the reliability of finite element models was confirmed.

Abstract: Ice accretion on 3D complex configuration is studied by numerical methods. The flow field is obtained by using Fluent 6.0 with a S-A turbulence model. Droplet trajectories and impingement characteristics are obtained by using the Eulerian approach. Ice shape is calculated based on the improved Messinger model with a new runback distribution scheme. By applying the method presented in this paper, ice accretion on NACA0012 is computed and the results are in good agreement with the available experiment data. It preliminarily shows that the improved method in this paper is feasible, Meanwhile, ice accretion on a four-element wing is studied. According to the analysis of the calculated result, the method presented in the paper can correctly simulate the ice accretion on 3D complex configuration.

Abstract: This research is to develop the automatic machine for sorting colored objects with conveyor belt. It was designed to classify colored objects such as red, green, blue and other colors by using fiber optic sensor. The microcontroller is automatically used to move the material objects along with the conveyor belt into the containers on the tray. The microcontroller is automatically used to move the materials along with the conveyor belt, and then fell into the defined containers on the tray. The fiber optic was used for the object detection to read the amount of the intensity of light that hits the object then reflected back to the sensor, after that converted into an electrical signal to the microcontroller to control the stepper motor in order to choose containers and color of objects to match each other. Design and experiments of this research can be used as a basis for practiced mechatronics engineering laboratory. In addition, the machine can be used as a model for related industries of colored sorting. From the result, it can be shown that the sorting machine classified the colored objects as red, green, blue and other color with high accuracy. The average time of the test objects is 9.96, 13.47, 16.58 and 9.04 seconds for objects as red, green, blue and other colors respectively.

Abstract: The article considers the analysis of the bellows fatigue strength carried out using the Ansys software package. The results of the research into the fatigue crack life and fatigue safety factor of a bellow valve are given.The reliability evaluation of the bellow valve working under the high-frequency load has been given by the authors.