• Transactions of the Korean hydrogen and new energy society
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• v.23 no.2
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• pp.183-190
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• 2012

The research shows the experiment results according to the combustion characteristics and configuration of the linear generator of powerpack for the generating power applying the 2-stroke compact linear engine. The powerpack used in this paper consists of 2-stroke linear engine, linear generator and air compressor parts. For identifying the combustion characteristics and generating power of linear engine, some parameters were varied sucha as electric load, fuel input calorie, spark timing delay and equivalence ratio. Also generating power was confirmed at each operation conditions, when the air gap length of linear generator part was changed as each 1.0 mm and 2.0 mm. During the all operations, intake air was inputted under the wide open throttle. Mass flow rate of air and fuel was changed using mass flow controller, after these were premixed by premixture device, and then premixed gas was supplied directly into each cylinder. As a result, piston frequency and combustion characteristics were different at each conditions according to parameters affecting the combustion such as fuel input calorie, resistive load, spark timing delay and equivalence ratio. Consequently, these had an effect on generating power.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.690-695
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• 2005

Flexible circular cantilever beams when excited externally introduce a lot of dynamic characteristics. The non-linear elements that these flexible beams develop include non-linearity due to inertia terms, spring, and damping. They show different characteristics of motion from each other. In the modes of lower order, the non-linearity due to spring is prevalent, while the non-linearity due to inertia Is prevalent in the modes of higher order. To analyze these effects the non-linear phenomena are analyzed experimentally. When the response characteristics of non-linear vibration are analyzed using autospectrum, it is possible to analyze the subharmonic and superharmonic mot ion by comparison. The phase change is analyzed using the method of phase portrait and the non-linear characteristics of response characteristics that are developed in flexible structures can be predicted and applied to the stage of design.

• Smart Structures and Systems
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• v.15 no.6
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• pp.1439-1461
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• 2015

Design criteria, modeling rules, and analysis principles of seismic isolation systems have already found place in important building codes and standards such as the Uniform Building Code and ASCE/SEI 7-05. Although real behaviors of isolation systems composed of high damping or lead rubber bearings are nonlinear, equivalent linear models can be obtained using effective stiffness and damping which makes use of linear seismic analysis methods for seismic-isolated buildings possible. However, equivalent linear modeling and analysis may lead to errors in seismic response terms of multi-story buildings and thus need to be assessed comprehensively. This study investigates the accuracy of equivalent linear modeling via numerical experiments conducted on generic five-story three dimensional seismic-isolated buildings. A wide range of nonlinear isolation systems with different characteristics and their equivalent linear counterparts are subjected to historical earthquakes and isolation system displacements, top floor accelerations, story drifts, base shears, and torsional base moments are compared. Relations between the accuracy of the estimates of peak structural responses from equivalent linear models and typical characteristics of nonlinear isolation systems including effective period, rigid-body mode period, effective viscous damping ratio, and post-yield to pre-yield stiffness ratio are established. Influence of biaxial interaction and plan eccentricity are also examined.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.133-137
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• 2004

The present study is focused on the small scale turbulent mixing processes in the scalar field. In order to deal with molecular mixing in turbulent flow, the linear eddy model is addressed. In each realization, the molecular mixing term is implemented deterministically, and turbulent stirring is represented by a sequence of instantaneous, statistically independent rearrangement event called by triplet map. The LEM approach is applied with relatively simple conditions. The characteristics of scalar mixing and PDF profiles are addressed in detail.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.43-45
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• 1999

This paper is presented about the development of magnetic levitation conveyor with a transverse flux linear synchronous motor (TFLSM). The TFLSM is proposed as the new type linear motor for the conveyor driving system. The flux density distribution. the thrust and etc. of TFLSM are analyzed by the finite element method. To analyze the dynamic characteristics of TFLSM, the parameter of equivalent circuit is calculated by the analytical method.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.266-268
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• 1998

The linear MHD(magnetohydro-dynamic) machine obtains the linear motion by replacing the solid conducting secondary of LIM with the ionized gas, plasma or the liquid metal. The electromagnetic pump which is a kind of MHD machine is divided into induction pump and conduction pump. This paper shows the classification and development trends of MHD machines and the characteristics of double sided flat linear induction pump (DFLIP).

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.2
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• pp.190-196
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• 2007

This paper presents the 3D finite element analysis of the Contact-less Power Supply(CPS) with linear servo motor. The primary, secondary self and leakage inductances of the contact-less power supply and the capacitances of a resonant circuit are calculated by the finite element analysis using current source. The voltage source is used to do accurate analysis of the characteristics of the contact-less power supply. The CPS with the linear servo motor is proposed. The characteristics analysis of the contact-less power supply considering the linear servo motor is done.

• New & Renewable Energy
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• v.7 no.3
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• pp.74-82
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• 2011

Because concern on the problem of the limited energy is growing and the wind energy is considered as one of the biggest solutions, the researches on the wind energy and turbine are accomplished vigorously. The simulation tools on the non-linear characteristics of wind turbine system are various and it could describe the non-linear characteristics well but, the tool and methodology to apply non-linear control theory rarely exist. In this paper, the application procedure of sliding mode control theory to 2-DOF non-linear wind turbine system is suggested and the application results of it are also shown as compared with a torque loop control theory.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1081-1082
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• 2011

In order to predict the accuracy of the linear motion machine tools, the force characteristics such as the detent force, the attraction force and the moment are estimated by analytical method or FEM. In this paper, we proposed the analytical calculation process for the force characteristics of a linear motor. The analytical results are good agreement with FEM one. They could be used for the precision prediction simulator with the information of linear bearings, encoders, etc.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.611_612
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• 2009

This paper deals with dynamic analysis of linear switched reluctance motor considering electromagnetic characteristics. First, inductance profile of linear switched reluctance motor calculate at align and unalign position and phase resistance using analytical method. Analytical method of this paper used space harmonics method, also, analysis result compares with data that is derived through an finite element method, and proved validity. In dynamic simulation of linear switched reluctance, we analyzed dynamic characteristic of linear switched reluctance motor according to single pulse waveform and hard chopping voltage PWM.