Browsing by Author "Cheng, Fu-Ping"

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A Study of Tip-off Problem for Dynamical Interactions between a Launched Vehicle and Its Guideway System
(2011)
Chou, Sheng-Nan
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Cheng, Fu-Ping
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土木工程學系
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Department of Civil Engineering
This paper investigated the tip-off effect problem for dynamical interactions between a launched vehicle and an elastic guideway system. The launcher guideway system is idealized as an inclined uniform simply supported elastic beam, while the vehicle is treated as a rigid beam which is forced to move along the elastic beam under the action of the prescribed thrust force. We developed a concise solution technique for the tip-off problem analysis. Equations governing interaction between the vehicle and its guideway are derived by taking account of the effects of the inertia force, Coriolis force and centrifugal force, based on the Euler-Bernoulli beam theory. Numerical results are compared with other reported literatures under several testing conditions and show excellent agreement. This study can provide valuable information on the vehicle guideway system design.
Fire Resistance of Concrete Slabs in Punching Shear
(2014-03-01)
Liao, Jen-Shou
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Cheng, Fu-Ping
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Chen, Cheng-Chih
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土木工程學系
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Department of Civil Engineering
Twelve specimens of reinforced concrete slab-column connections were tested to investigate fire resistance of punching shear. Half of the specimens were tested at room temperature to determine punching shear strength. Half were tested for fire resistance. The parameters of the specimens included steel reinforcement ratio, concrete compressive strength, and fire loading type. Fire resistance tests were carried out under constant maximum service loads at elevated temperatures according to ASTM E119 time-temperature curve. Temperature distribution, time-deflection relationship, and fire resistance were measured to determine the mechanical behavior of the slab-column connections subjected to fire loading on either the tension side or the compression side of the slabs. Experimental results showed that slabs heated on the compression side did not fail for up to 8 h, whereas those heated on the tension side failed at around 4 h. Specimens using normal-strength concrete have better fire resistance than those using high-strength concrete. The normal-strength concrete specimen also showed no spalling, whereas the high-strength-concrete specimen spalled under fire loading on the compression side. (C) 2013 American Society of Civil Engineers.
Multiple crack identification of a free-free beam with uniform material property variation and varied noised frequency
(2008-04-01)
Lin, Ren-Jeng
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Cheng, Fu-Ping
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土木工程學系
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Department of Civil Engineering
It is common to apply damage-sensitive features from vibration responses of a structure to assess structural damage. Few damage identification algorithms have focused on the material variation and measurement noise. For engineering practices, the material variation could be caused by many reasons and there always exists a certain level noise in measurement; those facts may affect the features that are used for structure monitoring and also lead to inaccurate assessment. In this research the authors have proposed a model to assess the statistical structural damage of a beam structure. The modal curvature-base feature was used to identify crack locations. The statistical damage databases were built by applying the Latin hypercube sampling method in Monte Carlo simulation. By mapping features of noised modal frequency to the statistical damage database, the damage probabilities among various crack depths were estimated; the statistical significance of damage level was examined by the t-test. Simulated beams and their experimental modal analysis data demonstrated the assessment procedures. The authors concluded that the proposed algorithm was robust and able to identify the damage of a free-free beam with uniform mass density and stiffness variations incorporated with noise in measured frequency. (C) 2007 Elsevier Ltd. All rights reserved.
Tip-off effect analysis of a vehicle moving along an inclined guideway by considering dynamic interactions
(2013)
Chou, Sheng-Nan
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Cheng, Fu-Ping
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Huang, Chiung-Shiann
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土木工程學系
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Department of Civil Engineering
This study investigates the tip-off effect responses of an accelerated vehicle by considering the dynamic interaction between the vehicle and its guideway system. The launch system is considered as an inclined simply supported uniform elastic beam, whereas the vehicle is regarded as a rigid beam moving along the elastic beam under the action of a predetermined thrust force. A technique for tip-off effect analysis that takes into account the dynamic interactions is developed. Equations governing the interaction between the rigid beam and its guideway are derived by taking into account the influences of the inertia force, Coriolis force, and centrifugal force, on the basis of the Euler-Bernoulli beam theory. A comparison of the tip-off analysis results of the elastic and rigid guideway models indicates that the dynamic response obtained for the elastic guideway model was 20% greater than that obtained for the rigid guideway model. The simulation results of the influences of several parameters by tip-off effect analysis can provide information that is valuable when designing vehicle launch systems.