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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作,涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.
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Item type:Item, Three Dimension Finite Element Model for Neck-spinning Process of Tube at Elevated Temperature(2012-01-01) ;Huang, Chi-Chen ;Hung, Chinghua ;Hung, Jung-Chung ;Lin, Chia-Rung機械工程學系The aim of this research is to investigate numerically the neck-spinning process of a tube at elevated temperature. The commercial software Abaqus/Explicit was adopted in the simulation. For the construction of the material model, special uni-axial tensile tests were conducted at elevated temperature and various strain rates, since the material is sensitive to strain rates at high temperature. The influence of the element type and mass scaling factor were investigated through numerical simulation. Full-integration shell element is the better choice in the simulation of the neck-spinning process at elevated temperature. The use of suitable mass scaling factor will make the analysis more efficiency. Comparisons between experimental and simulation results on thickness distribution and the outer contour of the spun tube are discussed. Good agreement was found between experimental and simulation results.Item type:Item, Finite Element Analysis of an Ultrasonic Vibration Device at High Temperatures(2016-06) ;Lan Phuong Nguyen ;Tsai, Yen-Pin ;Hung, Jung-Chung ;Hsieh, Yi-ChunHung, ChinghuaUltrasonic-vibration-assisted forming has been extensively adopted in plastic manufacturing processes. Ultrasonic vibration contributes to enhancing material formability and product quality and to reducing manufacturing costs by improving frictional conditions and increasing the temperature of materials. However, designing a suitable ultrasonic vibration system for processes conducted at high working temperatures, such as the ultrasonic vibration-assisted glass hot embossing process, is difficult because of complex thermal boundaries and material properties. In this study, an ultrasonic vibration system that can be used at high working temperatures was analyzed using the finite element method and ANSYS commercial software. The simulation results obtained from thermal, modal, and harmonic response analyses were compared with experimental measurements to confirm the validity of the numerical analysis. The resulting finite element module can be used in designing the components of ultrasonic vibration devices that can be used at high working temperatures.Item type:Item, Characterizing failure behaviors of debonded composite sandwich structures under compressive loading(2015-09-01) ;Nieh, Yi-Hsin ;Lai, Yen-Kun ;Tsai, Jia-Lin ;機械工程學系Department of Mechanical EngineeringThis research investigated the failure behaviors of the composite sandwich structures with face sheet and core debond subjected to compressive loading. Experiments and numerical simulations were conducted to determine the effects of the face sheet thickness and debond length on the compressive strength and failure mechanisms of the composite sandwich structures. Experimental results revealed that sandwich structures with either thicker face sheets or a shorter debond length exhibited a higher buckling load and greater failure strength. Moreover, when the debond length was short, failure was primarily caused by global buckling; conversely, when the debond length was long, failure was caused by local buckling and crack extension from the debond edge. To characterize the failure mechanism, a nonlinear finite element simulation of sandwich specimens containing imperfections was conducted. The simulation revealed that, when the dominant failure mode was global buckling, failure occurred at the intermediate portion of the foam core and strength could be characterized using the maximum principal strain criterion. However, when the failure mode was local buckling, failure was initiated at the debond tip, and strength could be predicted using the damage zone method.Item type:Item, 垂直軸式層狀型風力發電系?i之研製-子計畫四:垂直式層狀堆疊型風力機之複材結構及機械元件的測試平台、允收標準及壽命試驗的建立(II)(2011) ;金大仁 ;KAM TAI-YAN國立交通大學機械工程學系(所)Item type:Item, Finite element prediction of the lens shape of moulded optical glass lenses(2011) ;Tsai, Y-C ;Hung, C. ;Hung, J-C ;Tseng, S-F交大名義發表Glass moulding is a high-volume fabrication method suitable for producing optical components embedded in computer, communication, and consumer products, such as optical glass lenses in the camera modules of mobile phones. Despite the advantages of glass moulding, several difficulties encountered in the manufacturing process have yet to be overcome. The most critical issue is deviation between the formed lens and the original lens shape design. To overcome this obstacle, this study constructs a precise material model for optical glass with detailed thermal expansion, structural relaxation, and stress relaxation properties obtained from material experiments. This study also uses finite element analysis (FEA) to predict lens shape by incorporating this precise material model at 30 degrees C above At (which is widely adopted by the industry). A subsequent verification moulding experiment demonstrates consistency between the predicted and experimental results. This study establishes and confirms a comprehensive FEA model for predicting the shape of moulded glass lenses.Item type:Item, Fabricating High-Aspect Ratio Microchannels on Metallic Sheets Using Hydroforming(2012) ;Lin, Chih-Chia ;Yan, Jhen-Jie ;Hung, Chinghua ;Hung, Jung-Chung交大名義發表High-aspect ratio microchannels on bipolar plates have the advantage of improving fuel cell performance. This study formed high-aspect ratio microchannels by increasing the forming pressure, and predicted excellent aspect ratio of micro-flow channels by optimization analysis during the hydroforming process. This study used an experimental high-pressure hydroforming apparatus that provides various pressures to form microchannels on 304 stainless steel sheets with 0.1 mm thickness. Simultaneously, finite element analysis software was used to analyze the hydroforming process. First, the precision of the finite element model was verified by comparing simulations with experiments. Subsequently, the optimization software was connected to the finite element software to determine the optimal aspect ratio of microchannels by changing the dimension of micro-flow channels and pressures. Furthermore, the results of the simulations, hydroforming experiments, and related literature were discussed. The result indicated that the high-pressure hydroforming technique was feasibility, which formed high aspect ratio microchannels with 200 MPa, and the optimization predicted aspect ratio could reach 0.478 when changing geometries of channels and pressures. This research proposed a design process through hydroforming experiments, finite element analysis, and optimization analysis when predicting and designing the dimensions of micro-flow channels on metallic bipolar plates.Item type:Item, Development of Glass-fabric Composite Wind Turbine Blade(2011) ;Kam, T. Y. ;Su, H. M. ;Wang, B. W. ;機械工程學系Department of Mechanical EngineeringThe development process of a glass-fabric composite wind turbine blade is presented. A finite element model is constructed for the design and stress analysis of the wind blade. The wind blade parts were fabricated using the vacuum-bag molding technique. The assembling process of the wind blade is described in detail. The wind blade was tested to validate the suitability of the design. The finite element method is used to predict the failure wind loads of the wind blade.Item type:Item, Biomechanical comparison of instrumented posterior lumbar interbody fusion with one or two cages by finite element analysis(2006-09-01) ;Chiang, Ming-Fu ;Zhong, Zheng-Cheng ;Chen, Chen-Sheng ;Cheng, Cheng-KungShih, Shih-LiangStudy Design. Using finite element models to study the biomechanics of lumbar instrumented posterior lumbar interbody fusion (PLIF) with one or two cages. Objective. Analyzing the biomechanics of instrumented PLIF with one or two cages as to evaluate whether a single cage is adequate for instrumented PLIF. Summary of Background Data. Implantation of a single cage in instrumented PLIF of lumbar spine is still controversial. Methods. Three validated finite element models of L3-L5 lumbar segment were established [intact model (INT), one cage model (LS-1), and two cages model (LS-2)]. The available finite element program ANSYS 6.0 (Swanson Analysis System Inc., Houston, TX) was applied. To analyze the biomechanics of these models, 10 Nm flexion, extension, rotation, and lateral bending moment with 150 N of preload were respectively imposed on the superior surfaces of the L3. Results. Compared with the INT model, the decrease of ROM in the LS-1 and LS-2 models were exaggerated from 0.67 degrees to 3.73 degrees and ranged from 37.2% to 86.1% in all motions. The mean subsidence was found to be slightly higher in the LS-1 model. Most of the cage dislodgement in both models was less than 0.03 mm. The mean dislodgement was slightly higher in the LS-1 model. The stress of cage was found to be high in the LS-2 model. The mean stress of screw was raised to 4.5% to 9.7% in the LS-1, which was higher than that in the LS-2 model. In general, stress of adjacent disc was more pronounced in the LS-2 model. The most stress distributed at the anterior portion of the adjacent disc, which could be used to interpret the clinical findings of the early adjacent disc degeneration. Conclusions. A single cage inserted in an instrumented PLIF gains approximate biomechanical stability, slight greater subsidence, and a slight increase in screw stress but less early degeneration in adjacent disc. Adjusting these factors, instrumented PLIF with one cage could be encouraged in clinical practice.