Key Engineering Materials Vols. 656-657

Abstract: This paper describes mechanical design of automatic target-scoring machine. Automatic target-scoring system use array of laser beams to define coordination of bullet through. The mechanical design accord to modular easy to installation, repairand upgrades. The system includes:emitter module, detector module, adjustment mechanism, andmechanical frame. All modules were design by CAD-CAM and machinedby CNC machines to high accuracy In additionfor accuracy using adjustment mechanisms to adjust modules.

Abstract: In this paper, design, fabrication and characterization of a double-sided in-plane lateral comb-drive actuator fabricated by a plaster-based 3D-printer is described. The design is based on MEMS (Micro Electro-mechanical Systems) design concept. The movable part of the actuator consists of a (10x52.5) mm rectangular plate, and the end sides have depression areas in order to fit a (0.5x21.3) mm beam-shaped hinges. In the remaining sides of the plate, 18 comb fingers (0.5x10) mm are set at each opposite side. The stationary part of the actuator consists of 17 comb fingers with the same dimension to that of the stationary ones, and they are set at both sides of a frame and interdigitated with the movable comb fingers on the same plane. The gap between the movable and stationary comb fingers is 1.0mm. The structure thickness is 1.5mm. Such a structure, which both sides are provided with an in-plane interdigitated comb fingers, is called double-sided in-plane lateral comb-drive actuator. This actuator has been fabricated by using a plaster-based 3D-printer. Since plaster composite is an electrical insulating material, the structure has been suitably masked and the upper and lateral surfaces have been metallized thereafter by Au ion sputtering for the actuator electrodes formation. The hybrid fusion of 3D-printing manufacturing technology and MEMS-based design concept has been recently proposed by the authors and named as SMEMS (Sub-milli Electro-mechanical Systems), since the smallest possible fabrication size is in the order of sub-millimeters. The advantage of SMEMS technology is the quick and easy fabrication of 3D structures from 3D-CAD data. Furthermore, SMEMS is completely environment-clean since any hazardous chemicals or gases are used. The actuator has been driven by differential voltages, where both sides are biased at a voltage of 100V, and a 200 Vpp and its 180°shifted sinusoidal voltages are applied at each side. The actuator laterally moved by 96.8μm (full width) at a resonance frequency of 72Hz, and the mechanical quality factor has been estimated to be about 10.

Abstract: Metal pipes have a long history as fluid conduits, and are commonly joined with components such as elbows to form bent transport paths. However, with the increasing demands for economy and energy saving, pipes with reduced joints and thinner walls are desired. The number of joints can be reduced by a drawing and bending process that forms a bend section at any position in the pipe. However, this approach incurs problems such as wrinkling and flattening, especially under conditions of large bending angle, decreased bending radius, and thin pipe walls. In this research, applying vibrations to the mandrel was trialed as an approach for controlling the wrinkle depth and flattening. First, processing experiments were performed on thin walled pipes (wall thickness = 0.5 mm; outer diameter = 14 mm). The change of flattening and the number and depths of wrinkles were investigated in the presence and absence of vibrations. Next, simulations were performed using the commercial nonlinear finite element software. Through these simulations, the flatness and appearance of wrinkles were analyzed by modeling the behavior and distribution of stresses and strains in the processing process. The application of vibration to the mandrel appears to be a promising approach for controlling the wrinkling and flattening problems during pipe processing.

Abstract: the purpose of this research was to develop a new micro-anode-guided electroplating (MAGE) system equipped by an image-guided positioning controller, to fabricate two-dimensional microstructures. From real-time image, the relative positions of the micro-anode and the microstructures tip can be located and maintained. When the relative position is adjusted, the deposition direction of the microstructures can be controllable and microstructures with different geometries can be fabricated. Moreover, the results of experiment can be explained by the distribution of electro field strength simulated by Comsol Multiphysics 4.2.

Abstract: A new average flow model to analyze the lubrication characteristics of mechanical seals with parallel sealing faces is proposed. The present model determines the flow factors considering the side leakage under the operating condition equivalent to that in the mechanical seal. The correction factor for the expected hydrodynamic pressure generated by the relative motion of rough surfaces is also defined. The results are compared with those based on the Patir’s average flow model and show that the present model can be effective for the analysis of the lubrication characteristics of mechanical seals with parallel sealing faces.

Abstract: Jack-up platform jacking system which undertakes the weight of the platform and working load is very important during the lifting, and its performance exerts a direct influence on the safety and application effect of the whole platform. The super-modulus pinion and rack of jack-up platform jacking system are most likely to damage by fracture and fatigue pitting, which are due to the hostile environments. As a result of dynamic load, the analysis of dynamic contact has important engineering significance in an actual project. For strengthening the carrying capacity of pinion and shortening the design period, the research of carrying capacity factors is very meaningful. In this paper, the changing of stresses on the pinion and rack are gained by FEM, and main parameters that influence the carrying capacity of the pinion in a jacking system are analyzed according to the calculation method in GB standard. The study results shows the contact stresses and bending stress are higher throughout the meshing process, which implies the dangerous position of the pinion. In single meshing period, the trend of bending stress in the compression side of pinion and rack is opposite, while the bending stress in the tension side of both rack and pinion are minimum near the pitch circle. The carrying capacity of pinion can be strengthened by changing the main parameters, such as tooth width, normal modulus, pressure angle, modification coefficient, but the influence degree of each parameter is different.

Abstract: A multi-curvature Fresnel concentrator is proposed in this study for a concentrated photovoltaic system (CPV) to suppress aberrations. Unlike a conventional Fresnel concentrator with a single curvature, the proposed one integrates several Fresnel concentrators with individual curvatures. An embodiment is designed for a PMMA concentrator comprising four curvatures. The simulated efficiency of the embodiment is 86.4%. The tolerance analyses and the fabrication considerations of the CPV are provided and discussed.

Abstract: The safety system is defined in BS/EN764-7(2002) (Safety systems for unfired pressure equipment) European Standard which is equipped with pressure releasing means (e.g, safety valve, reliefe valve, rapture disk). However, this safety system is not adequately functional as a safety system because the pressure releasing means cannot ensure the security for safe-side failures or degradation characteristics. In view of this, this paper presentation an interlock system applicable to pneumatic driving systems based on the safety (confirmation) principle. This system in the Safety-related parts (system) without giving (harm) the effects of hazardous side of error to stop the run of the load by the power source shut off from the possibility of hazardous side of error, it is practical there is no contradiction in ISO12100, ISO13849 international standard. The interlock system discussion about the suitability of the safety system defined in BS/EN764-7. As a result, the consideration for ensuring the reliability in “Safety of the control” by BS/EN764-7 is requested by adopting the safety system of the interlock system.

Abstract: As wedge cam contour’s conventional equation of small roller centering three-jaw jig calculated by classic method is complex and difficult to be used for processing directly, a numerical calculation method for the wedge cam contour is proposed. Firstly, structure and working principle of centering small roller jig is introduced. Secondly, a new numerical calculation method sampling for wedge cam contour using equal step is presented, which can be obtained sampling points expression by numerical calculation model. Then,these samples points assignment will be fitting and interpolation in accordance with quadratic polynomial curve. The equation of quadratic polynomial interpolation on these sampling points these sampling will be obtained, which can be directly applied to NC programming. At last, through comparing fitted quadratic polynomial curve calculated by the numerical method with the theoretical curve calculated by classic method, it is found that the comparison tolerance is much smaller than conventional processing tolerance which is produced by using the theoretical curve for processing. The comparison tolerance is analyzed, refining the sampling step length and using piecewise fitting and interpolation loop calculation method is proposed,which can further improve numerical calculation accuracy to satisfy the requirement of higher and higher positioning. Therefore, it can be concluded that the numerical calculation method can effectively solve the difficult processing problem of wedge cam contour, which will produce better economic benefits.

Abstract: In this paper, we propose a shielding system for impulse ground penetrating radar applications (GPR). The structure of shielding system is designed for our real impulse GPR application at 200 MHz central frequency for improving the deep penetration. The shielding system makes high quality of signal transmission from transmitter antenna to receiver antenna for impulse GPR system. It not only makes lowest T/R antenna coupling, high performance of antennas, preventing external noise but also reduces unnecessary air radiation which damages to the health of GPR user. A commercial absorbing material with a short thickness of 40mm is used to reduce the reflection of upper side of antenna in the cavity of shielding system. The design procedure is derived and its performance is explained. Shielding system is designed, simulated and optimized successfully in CST 2013 software. And it is fabricated with a good measurement results.