Applied Mechanics and Materials Vol. 421

Abstract: For an unmanned aerial vehicle, in order to study the aerodynamic characteristics of the large aspect ratio wing during the deployment process with variable sweep angles, the scaled model was tested in the wind tunnel at different angles of attack with various sweep angles of wing. Experimental results indicate that the aerodynamic configuration satisfies the cruise design requirements, providing favorable longitudinal and lateral-directional stability. Fuselage of multi-plane combination brings beneficial effect for lift. Analysis have been made on the cases including wing flow separation which lead to the step of lift curve, and the existence of longitudinal unstable range during wing unfolding, which make the foundation for next optimum of configuration. The work described in this paper can be applied in the design of unmanned aerial vehicles, missiles and other research areas.

Abstract: The tendency for coiled tubing grow in diameter and thin in wall under a combination loading of internal pressure and cyclic bending. The deformation mechanisms are described. The results show that the trends in coiled tubing deformation behavior are according with the context of theory: when the internal pressure exists, the tubing grew in the diameter; except for neutral point, the tubing thin in wall and the position in tensile is much thinner than in pressure; by the time of cycle increasing. The tubing grew in diameter and ovality, thin in wall.

Abstract: This study used linear regression analysis model to explore chilled water system of central air conditioning for energy saving of cooling water pump based on frequency conversion control of pumped. Research and analysis is divided two phases, the first phase is recording approach temperature and load rate (PLR; Partial Load Ratio) of cooling tower in variable frequency operational mode, then using linear regression analysis model to built the power consumption equation (KW/RT) of cooling water pump. Second phase will be to non-variable frequency operation modes to establish the same relationship equation, and then will be used the first phase record data that its wet bulb temperature and cooling towers PLR limits are in accordance with the second phase of the same range conditions, you can explore the power consumption difference of cooling water pump in variable frequency and non-variable frequency operational mode.Through this research and analysis, was informed that power consumption model error rate of less than 1%, also informed that variable frequency operational mode than non-variable frequency operational mode can save 782.8 kW (19.64%) in the quadratic regression analysis results. In three times regression analysis results can be saved 919.38 kW (22.3%). Accordingly, the present research findings and theoretical models can be used as cooling water pump energy saving, also can serve as the theoretical basis for other energy saving.

Abstract: According to the test requirements of elevator safety devices, a set of elevator tower was designed and manufactured. There are two wells, one is used to ascending test, and the other is used to descending test. The lifting devices are composed of electric hoist and trolley, and can move along the track on the top of tower in order to change test well. The guide bracket is hanged on the lifting hook of hoist and slides on the track with guide shoes. There are two hooks in release mechanism and controlled by electric control system and manual button separately. The loading mechanism implements hoisting and walking movements through silk pole and pulley system.

Abstract: In this study, an elastic-plastic finite element model is used to simulate the thermal affected bone (TAZ) during bone drilling process under the condition of constant applied drilling force. Various drilling times and measurement depths are investigated to explore the size of TAZ and stress distributions within the bone. The results indicate that the maximum TAZ occurs at the interface of cortical bone and cancellous bone. The maximum diameter of TAZ is found to be 3.5 mm in this study.

Abstract: The stoppage and lifetime of high speed motorized spindle was related to many influence. A total of 31 statistical lifetime data of imported motorized spindles in cylinder head production line were presented, according to these data, and the average cut operation lifetime could reach 8277 hours, and the 8000 hours of average design precision lifetime was validated. It was found that the main influencing factors of motorized spindle lifetime in initial stage were the original manufacturing defects, also in precision lifetime stage and fatigue lifetime stage, the main influencing factors were the service conditions which exceeded design allowable conditions and own unique structural characteristics of motorized spindle respectively. according to 7 data and GM(1,1) grey theory, the precision lifetime prediction model of motorized spindle was built and the. model error was tested. The reliability of prediction model is validated by 2 inchoate reality observation data which relative differences were 0.57% and 2.03% respectively.

Abstract: According to physiological and psychological characteristics of adults, this paper proposed sled design based on ergonomics. The paper respectively provided human research, analysis and design for two aspects directly related to ergonomics, handlebar and seat, in order to make product safer, more comfortable and effective to meet consumers demands.

Abstract: The objective of this study is to reduce a number of defects in Hard Disk Drive (HDD) manufacturing due to spiral scratch on media by applying DMAIC steps of Six Sigma approach. The spiral scratch is firstly identified as the significant loss with 6.03% defective rate. Secondly, the paddle to disk space, top cover edge sharpness, pitch static attribute and number of load/unload cycle are found to be the key process input variables (KPIV). The experiment based on four KPIVs is then designed following Box Behnken design. With the results from the experiment, the response surface method is applied to determine the optimal setting for these four KPIVs with respect to the minimum percentage of the spiral scratch. Finally, the process with the optimal settings of the paddle to disk space at 3 mm, top cover edge sharpness at 0.002 inch, pitch static attitude at 0.01 inch and number of load/unload cycle at 10,000 times is implemented and monitored by the p control chart. After the improvement, the defective rate of the spiral scratch is decreased by 48.8% from 6.03% to 3.09%.

Abstract: The electric rolling doors are extensively used in Taiwan; however, the accidents of personal injuries caused by electric rolling doors frequently occur. The doors have caused injuries, and even casualties in worst cases. Based on TRIZ contradiction matrix and inventive principles, this study used a laser module, a photoresistor receiver, and mirror reflected refraction to construct a low-cost safety control circuit device. This safety control circuit device can be used for electric rolling doors (3m high and 8m wide) that are commonly used for residential houses. When the electric rolling door is in operation, any objects of the height over 10cm entering or existing in the range of the electric rolling door can be detected by the control device. The actuation of the electric rolling door is then stopped, and an alarm gives out warning sound, so that possible injuries may be prevented. The material cost of this control device is below 2,000 NTD, and this design is cost-effective.

Abstract: To explore the noise suppression effect of mesh on cavity, the wind tunnel experiment is carried out based on the analysis of clean cavity flow characteristics. The meshes are arranged both in the cavity and at the leading edge of the cavity. Through the analysis of pressure distribution on the cavity bottom and the noise spectrum monitored at front and rear walls respectively, noise suppression effects of mesh programs relative to the clean cavity and changes in the flow field are studied, the results show that the mesh inside the cavity has a better noise reduction effect. The work in this paper provides an effective way for cavity noise reduction.