Browsing by Author "Hung, Ching-Hua"

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Analysis of stresses in adhesive joints applicable to IC chips using symbolic manipulation and the numerical method
(2006)
Cheng, Tung-Hua
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Tseng, Ching-Huan
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Hung, Ching-Hua
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機械工程學系
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Department of Mechanical Engineering
In this study, a concentrated force is applied to both adherends bonded by an adhesive under pin-pin boundary conditions. First a mathematical model is derived with governing equations and boundary conditions. These complicated, and analytically problematic, coupled equations are solved numerically using symbolic manipulation and singular value decomposition (SVD). Also discussed are the effects of major factors, including the relative thickness of adherends, joint length and the action point of the concentrated force on the peel and shear stresses in the adhesive layer. This study identifies the conditions under which the upper adherend without breakage can be fully separated from the lower adherend. Particularly, it is found that the thickness of the lower adherend should be greater than ten times that of the adhesive layer but less than one-third that of the upper adherend, the adhesive layer should be relatively thin (h(a) <= 0.01 mm), and the adhesive joint should be relatively short (thickness to length ratio gamma(1) >= 0.08).
Application of a Genetic Algorithm Associated With Adhesive Joint Analysis to the IC Chip Pick-up Process
(2008)
Cheng, Tung-Hua
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Tseng, Ching-Huan
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Hung, Ching-Hua
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機械工程學系
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Department of Mechanical Engineering
In the condition investigated here, a concentrated force is applied to both IC chip and blue tape bonded by an adhesive under pin-pin boundary conditions. The experimental results show that even though IC chips of 0.1 mm thickness are subjected to a concentrated force of 4.8 N, they cannot be fully separated from the blue tape and fail easily during the pick-up process. However, when IC chips of 0.34 mm thickness are subjected to a concentrated force of only 3.5 N, they can be fully separated from the blue tape without breakage. These two experimental findings are then explored analytically by applying the C++ program of the genetic algorithm associated with adhesively bonded joint analysis to the IC chip pick-up process. In accordance with the experimental results, the results for the 0.1 mm thick IC chips reveal no solutions for the material properties or adhesive thickness to satisfy the conditions of the IC chip successful pick-up process, although those for the 0.34 mm thick IC chips show solutions for the values of both the elastic modulus and the adhesive layer's thickness. As regards the easy failure of IC chips with 0.1 mm thickness, if the blue tape's mechanical properties are appropriately chosen and then used in this process and its elastic modulus is greater than one-tenth that of the IC chips, the probability of the IC chips being fully separated from the blue tape can be expected to increase. (C) Koninklijke Brill NV, Leiden, 2008
Biomechanical comparison of three stand-alone lumbar cages - a three-dimensional finite element analysis
(2013-10-02)
Chen, Shih-Hao
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Chiang, Ming-Chieh
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Lin, Jin-Fu
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Lin, Shang-Chih
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Hung, Ching-Hua
Background: For anterior lumbar interbody fusion (ALIF), stand-alone cages can be supplemented with vertebral plate, locking screws, or threaded cylinder to avoid the use of posterior fixation. Intuitively, the plate, screw, and cylinder aim to be embedded into the vertebral bodies to effectively immobilize the cage itself. The kinematic and mechanical effects of these integrated components on the lumbar construct have not been extensively studied. A nonlinearly lumbar finite-element model was developed and validated to investigate the biomechanical differences between three stand-alone (Latero, SynFix, and Stabilis) and SynCage-Open plus transpedicular fixation. All four cages were instrumented at the L3-4 level. Methods: The lumbar models were subjected to the follower load along the lumbar column and the moment at the lumbar top to produce flexion (FL), extension (EX), left/right lateral bending (LLB, RLB), and left/right axial rotation (LAR, RAR). A 10 Nm moment was applied to obtain the six physiological motions in all models. The comparison indices included disc range of motion (ROM), facet contact force, and stresses of the annulus and implants. Results: At the surgical level, the SynCage-open model supplemented with transpedicular fixation decreased ROM (>76%) greatly; while the SynFix model decreased ROM 56-72%, the Latero model decreased ROM 36-91%, in all motions as compared with the INT model. However, the Stabilis model decreased ROM slightly in extension (11%), lateral bending (21%), and axial rotation (34%). At the adjacent levels, there were no obvious differences in ROM and annulus stress among all instrumented models. Conclusions: ALIF instrumentation with the Latero or SynFix cage provides an acceptable stability for clinical use without the requirement of additional posterior fixation. However, the Stabilis cage is not favored in extension and lateral bending because of insufficient stabilization.
Design and manufacture of plunge shaving cutter for shaving gears with tooth modifications
(2009-08-01)
Liu, Jia-Hung
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Hung, Ching-Hua
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Chang, Shinn-Liang
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機械工程學系
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Department of Mechanical Engineering
Gear plunge shaving is one of the most efficient ways to finish gears. It has been a challenge for a long time to design and manufacture a plunge shaving cutter to induce gear tooth modification. This paper proposes a method for designing plunge shaving cutters to manufacture gears with modifications analytically. By integrating B-spline interpolation, differential geometry, and design optimization, the goal is achieved. Efficiency is greatly improved by avoiding the traditional trial and error method.
Development of vital signs detection system with ground noise cancellation
(2014-11-01)
Liu, Chih-Chieh
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Hung, Ching-Hua
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Chien, Huai-Ching
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機械工程學系
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Department of Mechanical Engineering
This study provides an experimental procedure and a noise immunity method for detecting the vital signs of a person in a vehicle. Velocity sensors that are convenient and accurate at acquiring data are adopted to detect the involuntary body vibrations. Two kinds of algorithms were proposed for detecting the vital signs in different environments with various ground noise level. To reduce the ground noise effect generated from extreme environments, a ground sensor also is used to measure the vibration amplitude of ground surface for calculating the car body response to provide excellent noise cancelling method. Measuring and processing the vibrations are effective methods for detecting people concealed in a vehicle. The complete detecting system was verified through experiment conducted with a passenger car.
Finite element comparison of retrograde intramedullary nailing and locking plate fixation with/without an intramedullary allograft for distal femur fracture following total knee arthroplasty
(2014-01-01)
Chen, Shih-Hao
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Chiang, Ming-Chieh
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Hung, Ching-Hua
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Lin, Shang-Chih
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Chang, Hsiao-Wei
Purpose: Periprosthetic distal femur fracture after total knee arthroplasty due to the stress-shielding phenomenon is a challenging problem. Retrograde intramedullary nail (RIMN) or locking plate (LP) fixation with/without a strut allograft has been clinically used via less invasive stabilization surgery (LISS) for the treatment of these periprosthetic fractures. However, their biomechanical differences in construct stability and implant stress have not been extensively studied, especially for the osteoporotic femur. Methods: This study used a finite-element method to evaluate the differences between RIMN, LP, and LP/allograft fixation in treating periprosthetic distal femur fractures. There were sixteen variations of two fracture angles (transverse and oblique), two loading conditions (compression and rotation), and four bony conditions (one normal and three osteoporotic). Construct stiffness, fracture micromotion, and implant stress were chosen as the comparison indices. Results: The LP/allograft construct provides both lateral and middle supports to the displaced femur. Comparatively, the LP and RIMN constructs, respectively, transmit the loads through the lateral and middle paths, thus providing more unstable support to the construct and high stressing on the implants. The fracture pattern plays a minor role in the construct stabilization of the three implants. In general, the biomechanical performances of the RIMN and LP constructs were comparable and significantly inferior to those of the LP/allograft construct. The bone quality should be evaluated prior to the selection of internal fixators. Conclusions: The LP/allograft construct significantly stabilizes the fracture gap, reduces the implant stress, and serves as the recommended fixation for periprosthetic distal femur fracture. (C) 2013 Elsevier B.V. All rights reserved.
Nanotribological behavior of ZnO films prepared by atomic layer deposition
(2014-03-01)
Wang, Wun-Kai
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Wen, Hua-Chiang
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Cheng, Chun-Hu
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Chou, Wu-Ching
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Yau, Wei-Hung
We used atomic layer deposition to form ZnO thin-film coatings on Si substrates and then evaluate the effect of pile-up using the nanoscratch technique under a ramped mode. The wear volume decreased with increasing annealing temperature from room temperature to 400 degrees C for a given load. Elastic-to-plastic deformation occurred during sliding scratch processing between the groove and film for loading penetration of 30 nm. The onset of non-elastic behavior and greater contact pressure were evident for loading penetration of 150 nm; thus, full plastic deformation occurred as a result of a substrate effect. We suspect that elastic-plastic failure events were related to edge bulging between the groove and film, with elastic-plastic deformation attributable to adhesion discontinuities and/or cohesion failure of the ZnO films. (C) 2013 Elsevier Ltd. All rights reserved.
Nanotribological properties of ALD-processed bilayer TiO2/ZnO films
(2014-12-01)
Wang, Wun-Kai
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Wen, Hua-Chiang
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Cheng, Chun-Hu
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Hung, Ching-Hua
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Chou, Wu-Ching
TiO2/ZnO films grown by atomic layer deposition (ALD) demonstrated nanotribological behaviors using scratch testing. TEM profiles obtained an amorphous structure TiO2 and nanocrystalline structure ZnO, whereas the sample has significant interface between the TiO2/ZnO films. The experimental results show the relative XRD peak intensities are mainly contributed by a wurtzite oxide ZnO structure and no signal from the amorphous TiO2. With respect to tribology, increased friction causes plastic deformation between the TiO2 and ZnO films, in addition to delamination and particle loosening. The plastic deformation caused by adhesion and/or cohesion failure is reflected in the nanoscratch traces. The pile-up events at a loading penetration of 30 nm were measured at 21.8 mu N for RT, 22.4 mu N for 300 degrees C, and 36 mu N for 400 degrees C. In comparison to the other conditions, the TiO2/ZnO films annealed at 400 degrees C exhibited higher scratch resistance and friction with large debris, indicating the wear volume is reduced with increased annealing temperature and loading. (C) 2014 Elsevier Ltd. All rights reserved.
Robust design for gear transmission error
(2008-01-01)
Chang, Shinn-Liang
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Liu, Jia-Hung
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Jin, Kai-Wei
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Hung, Ching-Hua
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Chen, Shang-Hsin
Transmission error in gearing system is a critical index for product quality. Gears with appropriate tooth modification can always behave well in transmission error, i.e. the double crowned gears. Nevertheless, to manufacture a gear with double crowning by CNC gear shaving machine indeed costly. This paper investigated the manufacture of double crowned gears by traditional gear shaving machine. Taguchi Method was applied to find critical parameters in the shaving process and the transmission error had also been improved through the process of robust design.
Simulation of gear shaving with considerations of cutter assembly errors and machine setting parameters
(2007-12-01)
Hung, Ching-Hua
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Liu, Jia-Hung
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Chang, Shinn-Liang
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Lin, Hung-Jeng
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機械工程學系
Gear shaving is commonly used as a finishing process for gear manufacturing. The precision of the shaved gear tooth profile is highly dependent on both the parameter adjustments of the shaving machine and the cutter assembly errors. This paper develops the mathematical model of the shaved gear with crowning taking into account the setting parameters of the gear shaving machine and cutter assembly errors. The effects of the parameters on the work gear surface and the tooth lead crowning are also investigated. The results are thought to be relevant to the design, assembly, calibration, and control of a gear shaving machine.
The application of vital signs detection system for detecting in a truck with noise cancellation method
(2015-02-01)
Liu, Chih-Chieh
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Hung, Ching-Hua
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Chien, Huai-Ching
;
機械工程學系
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Department of Mechanical Engineering
This research proposes an experimental procedure and ground noise cancellation method for detecting the presence of a person in a 3.5 ton truck, in an environment with high levels of ground noise. This study addresses the need for non-intrusive detection system that involves using velocity sensors placed on the chassis-frame to detect the weak vibrations generated by any human inside the vehicle. An additional velocity ground sensor is placed near the front tire to collect the ground noise signals that are used to estimate the ground noise response of the truck by manipulating a 2-DOF (degree of freedom) equivalent truck model. To increase the discriminative rate in the context of two scenarios, a person present and a person absent from the vehicle, a valid algorithm is proposed that decreases the ground noise effect emanating from the environment. Furthermore, two types of sensor location are discussed to promote the practicability of the proposed system.