Browsing by Author "Wu, MH"

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Axial load behavior of stiffened concrete-filled steel columns
(2002-09-01)
Huang, CS
;
Yeh, YK
;
Liu, GY
;
Hu, HT
;
Tsai, KC
This study investigates the axial load behavior of concrete-filled steel tubular (CFT) columns with the width-to-thickness ratios between 40 and 150, and proposes an effective stiffening scheme to improve the mechanical properties of square cross-sectional CFT columns. Seventeen specimens were tested to examine the effects of cross-sectional shapes, width-to-thickness ratios, and stiffening arrangements on the ultimate strength, stiffness, and ductility of CFT columns. Moreover, nonlinear finite element analysis was also conducted to investigate cross-sectional axial stress distribution at the ultimate strength. Comparing the measured ultimate strength with estimates by using some current specifications suggested that current specifications may considerably underestimate the ultimate strength of circular CFT columns, particularly for columns with a small width-to-thickness ratio. Results in this study demonstrate that the proposed stiffening scheme can significantly enhance the ultimate strength and ductility of square CFT columns.
General equations of a helical spring with a cup damper and static verification
(1997-06-01)
Wu, MH
;
Ho, JY
;
Hsu, W
;
機械工程學系
;
Department of Mechanical Engineering
In this study, we derive the general equations of motion for the helical spring with a cup damper by considering the damper's dilation and varying pitch angle of the helical spring. These dynamic equations are simplified to correlate with previous models. The static force-displacement relation is also derived. The extra stiffness due to the damper's dilation considered in the force-displacement relation is the first such modeling in this area. In addition, a method is presented to predict the compressing spring's coil close length and is then verified by experimental data. Moreover, the simulation results of the static force-displacement relation are found to correspond to the experimental data. The maximum error is around 0.6 percent.
General equations of a helical spring with a cup damper and static verification
(1997-06-01)
Wu, MH
;
Ho, JY
;
Hsu, W
;
交大名義發表
;
機械工程學系
In this study, we derive the general equations of motion for the helical spring with a cup damper by considering the damper's dilation and varying pitch angle of the helical spring. These dynamic equations are simplified to correlate with previous models. The static force-displacement relation is also derived. The extra stiffness due to the damper's dilation considered in the force-displacement relation is the first such modeling in this area. In addition, a method is presented to predict the compressing spring's coil close length and is then verified by experimental data. Moreover, the simulation results of the static force-displacement relation are found to correspond to the experimental data. The maximum error is around 0.6 percent.
How experience shapes reasoning skill: The role of collaboration and explanation
(2000-06-01)
Horng, RY
;
Wu, MH
;
Wu, TY
;
交大名義發表
;
工業工程與管理學系
Investigation of torsion springs by considering the friction and the end effect
(1999-12-01)
Wu, MH
;
Hsu, W
;
機械工程學系
;
Department of Mechanical Engineering
In this study, the nonlinearity in moment and angular displacement of torsion springs is studied analytically and experimentally. It is shown that the inclined angles at both ends have direct effects on the nonlinearity of a constant-pitch torsion spring. Also, an algorithm for determining the friction between the spring coils in close-wound torsion springs is proposed. From the comparison to experimental data, it is found that the spring rates are different at forward and backward strokes. The dynamic equations for the close-wound torsion spring is also derived by considering the friction between the spring coils, and two different natural frequencies are found in simulation.
Modelling the static and dynamic behavior of a conical spring by considering the coil close and damping effects
(1998-07-02)
Wu, MH
;
Hsu, WY
;
機械工程學系
;
Department of Mechanical Engineering
A method to calculate the load-deflection relation of the conical spring is proposed and verified by experimental data statically. The non-linearity of the spring rate and coil close effect by influencing the end effect are considered in the formulation. It shows that the maximum error between simulation and experimental results is 4 . 6%. The dynamic equations for the conical spring are also derived by considering the non-linear spring rate and damping effect due to coil clash. This is the first such modelling for a conical spring. The dynamic equations are solved by perturbation and the numerical methods. It is found that the natural frequency varies with the initial amplitude due to the coil clash in compression. Also, the maximum amplitude in compression is found to be smaller than the maximum amplitude in extension. (C) 1998 Academic Press Limited.
NBTI effects of pMOSFETs with different nitrogen dose imlantation
(2004)
Lee, YJ
;
Tang, LC
;
Wu, MH
;
Chao, TS
;
Ho, PT
NBTI effects with different nitrogen dose implantation and regions were investigated. High nitrogen dose implantation in the channel or source/drain extension results in serious NBTI degradation. Both the dynamic NBTI effects and substrate hot holes effects were also discussed. DNBTI and I-CP were measured simultaneously. Reduction of DeltaV(TH) and I-CP after positive gate bias stressing is related with the recovery of interface states.
Nonlinear analysis of axially loaded concrete-filled tube columns with confinement effect
(2003-10-01)
Hu, HT
;
Huang, CS
;
Wu, MH
;
Wu, YM
;
土木工程學系
Proper material constitutive models for concrete-filled tube (CFT) columns are proposed and verified by the nonlinear finite element program ABAQUS against experimental data. The cross sections of the CFT columns in the numerical analysis are categorized into three groups, i.e., circular section, square section, and square section stiffened by reinforcing ties. Via the numerical analyses, it is shown that for circular CFT columns, the tubes can provide a good confining effect to the concrete especially when the width-to-thickness ratio D/t is small (say D/t<40). For square CFT columns, the tubes do not provide a large confining effect to the concrete especially when the width-to-thickness ratio B/t is large (say B/t>30). The confining effect of square CFT columns with reinforcing ties is enhanced by the use of reinforcing ties especially when the tie spacing is small and the tie number (or tie diameter) is large.
Parallel-coupled microstrip filters with over-coupled stages for multispurious suppression
(2005)
Jiang, MS
;
Wu, MH
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
An inherent zero of a microstrip coupled stage near twice the design frequency (2f(o)) is found tunable by varying its coupling length. This zero is used to suppress the unwanted response of parallel-coupled line filters at this frequency by using over-coupled end stages. The above idea is extended to design over-coupled middle stages for suppressing the spurious vertical bar S-21 vertical bar peaks at 3f(o) and 4f(o) of the filter, so that the upper stopband can be greatly enhanced up to 5f(o). The passband preserves a response as good as the traditional design. Measured results have a good agreement with simulation data and show that the idea works very well.