• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10a
• /
• pp.507-512
• /
• 1998

An experimental investigation was conducted to examine the behavior of high strength R/C columns subjected to reversed cyclic and axial loads and to find the relationship between amounts of lateral reinforcement and axial loads ratios. The test parameters of column specimens were the compressive strength of concrete($f`_c$=250, 320, 460, $517kg/\textrm{cm}^2), $ the yield strength of longitudinal steel($f_y$=3700, $5254kg/\textrm{cm}^2), $ axial load ratio(0.3, 0.5, 0.6$f`_cA_g$). The results indicated that axial load can significantly affect and alter the behavior of HS R/C column under inelastic cyclic loadings. Also we found that the relationship between amounts of lateral reinforcement and axial load ratios was $\rho$ =(0.37η+0.15)f`/f.

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.1
• /
• pp.95-106
• /
• 2001

When the crankshaft of diesel engine has more than 3 throws, which are arranged in a different plane, its vibration induces coupled motions, especially the coupled torsional and axial vibration. Nowadays, the torsional vibration which is influenced rather weak than axial one, can be theoretically calculated fairly accurately, but theoretical calculation results of the axial vibration which is influenced strongly from torsional vibration is not so good. To get accurate calculation results of axial vibration, coupled axial-torsional vibration must be treated. In this investigation, coupled effects of vibration of diesel engine propulsion shafting are analyzed theoretically and some simple calculation methods are also studied. On this first report, effects of coupling on natural frequencies and their modes are mainly studied, setting the each mass in 4 degrees of freedom.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.12 s.243
• /
• pp.1561-1566
• /
• 2005

In this paper, a new compact active magnetic bearing(AMB) is proposed in which radial and axial bearings are integrated in one bearing unit. It consists of four U-shaped cores circumferentially connected by yokes and two-layer coils for radial and axial controls. For the radial control action, it has the same principle as conventional homopolar AMBs, while for the axial control, it uses the Lorentz force generated by the interaction of the bias flux for radial control and the axial control flux. The proposed structure makes it easy to design a compact AMB because it has no disk for axial control. This paper introduces the proposed structure, principle, and design process based on the magnetic flux analysis. By using a control algorithm with feedforward action to compensate the coupled flux effect, the feasibility of the proposed AMB is experimentally verified.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.12
• /
• pp.31-39
• /
• 1999

Previous researches and experiments have already verified that the primary noise source of high pressure tandem axial thpe piston pump is fluid-borne noise from the process of oil distribution between the kidney-shaped port and valve plate. So, many researchers have improved pressure gradients and reduced sound levels by applying pre-compression and pre-decompression metering grooves to valve plate. In practice however, the sound level of th high pressure tandem axial type piston pump is still undesirable. This paper testified the effect of pumping phase of the piston on vibration and noise of th high pressure tandem axial type piston pump on the best of theoretical research in $this^(1)$. Therefore considering the pumping phase of the piston when assembling the tandem axial type piston pump, it is possible to reduce 1.5~2[dB]of sound level.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2000.05a
• /
• pp.60-71
• /
• 2000

When the crankshaft of Diesel engine has more than 3 throws which are arranged in a different plane its vibration induces coupled motions especially the coupled torsional and axial vibration. Nowadays the torsional vibration which is influenced rather weak than axial one can be theoretically calculated fairly accurately but theoretical calculation results of the axial vibration which is influenced strongly from torsional vibration is not so good. To get accurate calculation results of axial vibration coupled axial-torsional vibration must be treated. in this investigation coupled effects of vibration of Diesel engine propulsion shafting are analyzed theoretically and some more simple calculation methods are also studied. On this first report effects of coupling on natural frequencies and their modes are mainly studied setting the each mass in 4 degrees of freedom. later this problem may be studied again by setting each mass as 6 degrees of freedom.

• Advances in nano research
• /
• v.9 no.2
• /
• pp.69-82
• /
• 2020

In this paper, a new explicit analytical formula is derived for the critical buckling load of Double Walled Carbon Nanotubes (DWCNTs) embedded in Winkler elastic medium without taking into account the effects of the nonlocal parameter, which indicates the effects of the surrounding elastic matrix combined with the intertube Van der Waals (VdW) forces. Furthermore, we present a model which predicts that the critical axial buckling load embedded in Winkler, Pasternak or Kerr elastic medium under axial compression using the nonlocal Donnell shell theory, this model takes into account the effects of internal small length scale and the VdW interactions between the inner and outer nanotubes. The present model predicts that the critical axial buckling load of embedded DWCNTs is greater than that without medium under identical conditions and parameters. We can conclude that the embedded DWCNTs are less susceptible to axial buckling than those without medium.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.2
• /
• pp.120-127
• /
• 2008

The constant velocity joint(CVJ) used for transmitting torque to the front wheels is an important part in automotive drive system. There are several types of constant velocity joints. Typically, they are classified by fixed and plunging constant velocity joints. The axial force generated in plunging constant velocity joints influences significantly the noise, vibration and harshness. For heaps of time, many constant velocity joint markers have been studying and developing a valid method to reduce the axial force and extensive tests have been carried out on rigs. This paper presents the analysis method to predict the axial force of a double offset constant velocity joint(DOJ), a kind of plunging constant velocity joint, and the influence of ball-cage dimension tolerance on the axial force.

• Structural Engineering and Mechanics
• /
• v.1 no.1
• /
• pp.17-30
• /
• 1993

A practical multi-spring model is proposed for a nonlinear analysis of reinforced concrete members, especially columns, taking into account the interaction of axial load and bi-directional bending moment. The parameters of the model are determined on the basis of material properties and section geometry. The axial force-moment interaction curve of reinforced concrete sections predicted by the model was shown to agree well with those obtained by the flexural analysis utilizing realistic stress-strain relations of materials. The reliability of the model was also examined with respect to the test of reinforced concrete columns subjected to varying axial load and bi-directional lateral load reversals. The analytical results agreed well with the experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.389-392
• /
• 1997

This paper presents the dynamic analysis and experiment for rotor systems supported by angular contact ball bearings subjected to axial displacement preload. A dynamic software, which has been developed by the authors for the analysis of rotor systems supported by angular contact ball bearings, is used to simulate a uniform shaft system supported by two angular contact ball bearings with the axial displacement preload varied. Experiments are also performed to validate the simulation. An experimental system is constructed which consists of a uniform shaft, two bearings and a device for adjusting the axial displacement preload. Through a series of simulation and experiment, the dynamic characteristics of rotor systems with angular contact ball bearings subject to axial displacement preload are investigated.

• 유체기계공업학회:학술대회논문집
• /
• 2006.08a
• /
• pp.205-208
• /
• 2006

This paper proposes a new computational aeroacoustics method for an axial fan analysis. The major aeroacoustic noise source of an outdoor air-conditioner is the axial fan. It was revealed that the dominant noise source is the aerodynamic interactions between the rotating blade and stationary orifice. Many researches were focused on the fan only case. However, it does not fit to a real outdoor unit of air-conditioner. Especially, the inlet part of the axial fan of real system case is complex and not uniform. So, in order to identify the dominant noise source of axial fan, full outdoor unit analysis is important. Transient CFD analysis of full system was performed by commercial CFD code - SC/Tetra. Dominant noise source of the system was calculated by commercial CFN code - FlowNoise. The results show that not only BPF peaks but also broadband noise are similar to the measured data.