• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.11 no.2
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• pp.46-51
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• 2012

In this paper deperm performance on deperm protocol cycle has been analyzed. As deperm protocol increases cycle, deperm performance improves and duration time will increase. Thus, it's essential that proper deperm cycle that is fit on vessel should be applied. To compare deperm performance according to cycle changes, small deperm system has been made and small vessel had been made with SM45C materials. As Anhysteretic deperm protocol applied, the result on the increase of deperm performance according to the increase of cycle has been gotten.

• Journal of the Korean Magnetics Society
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• v.23 no.2
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• pp.54-61
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• 2013

Ferromagnetic material's residual magnetization is remained because of the interaction between domains from external apply field, so the electrical and electronic industry and area of defense development request deperm protocol which makes the residual magnetization to 0. But the deperm protocols which are used theses days are developed by using only experience and experiment, so we have to develop deperm protocol considering hysteresis curve. In this paper, Anhysteretic Deperm, Deperm-ME, Flash-Deperm were analyzed using two dimensional finite element method and Preisach model that was formulated by property of magnetic materials. From that analysis, the relations between hysteresis curve and deperm variable are compared by analyzing the trace of Preisach plane. Also, an efficient current ratio of deperm protocol, is proposed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1693-1699
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• 2011

In this paper, for magnetic silence technology of naval vessel, is to make lab deperm system and to evaluate the deperm capacity of naval vessel regarding deperm protocol. Initial permanent magnetic field of naval vessel is magnetized before deperm, having the magnetic field of the same size, to evaluate the deperm capacity regarding a variety of deperm protocol for experimental reliability growth. Current dead time effect of deperm protocol is measured at the different initial current, which are 8A, 6A and 4A respectively. Furthermore, the experiment under the same condition except changing duty cycle into 50% is carried out. As a result, it is possible to compare the six different experiment outcomes. The result shows that the experiment with dead time improve the deperm capacity more than 48.51 percent comparing to the case without dead time.

• Journal of Magnetics
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• v.18 no.3
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• pp.326-330
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• 2013

Magnetic treatment of surface vessels and submarines (Deperm) is required to camouflage them against magnetic detection from enemy marine force. So far, deperm has been accomplished by applying an alternating magnetic field of which amplitude decreases linearly. However, the reduction of the residual flux density in the direction of magnetic field is not linear in the case of the linear protocol, since the ferromagnetic material used to construct a surface vessel, mainly Fe-C, shows a nonlinear behavior in an alternating magnetic field. This is one of main reasons to make an ordinary deperm protocol inefficient. In this paper, we propose the exponential deperming protocol and compare the exponential protocol to conventional linear protocol within the framework of deperm performance. We found out that step number could be reduced in the exponential protocol compare with in the linear protocol, because the larger numbers of deperm steps are dedicated in the irreversible domain process region on the magnetic hysteresis.

• Journal of Magnetics
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• v.19 no.1
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• pp.43-48
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• 2014

Magnetic materials with large coercive force and high squareness ratio are currently developing to meet an industrial demand. Since a ferromagnetic material has hysteresis characteristics, it is hard to demagnetize a ferromagnetic material precisely. In this paper, we describe deperm processes and conduct an analysis of residual magnetization of ferromagnetic material using the Preisach modeling with a two-dimensional finite elements method (FEM). From the results, it was shown that an exponential decrement form of deperm protocol is more efficient than a linear decrement form because of the demagnetizing field in the ferromagnetic material.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.359-363
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• 2011

An orthogonal magnetic field is often used for a military vessel in the deperm process such as Flash D deperm protocol and Anhysteretic deperm protocol. The effect of the orthogonal magnetic field on a deperm performance was investigated for a sample with strain-induced magnetization and field-induced magnetization given to different direction. A 70mm wide, 110mm long and 0.25mm thick rectangular steel plate was bent to have U-shape and to generate a strong strain on the bottom region of U-shaped steel plate. Field-induced magnetization was attached by NdFeB permanent magnet. Demagnetization was performed by applying magnetic field with a step decrement from the first field(the first shot) under the action of DC bias field.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1065-1066
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• 2011

본 논문에서는 함정의 피탐지 성능 개선을 위한 기초 연구로 dead time 적용시 탈자 프로토콜 변화에 따른 탈자 성능 분석에 관한 연구를 하였다. 함정의 재질은 SM45C로 원통의 형태이다. 자기장 측정에 사용한 자기센서는 영국 Bartington Instruments사의 MAG-03MCB70(Three-Axis Fluxgate Magnetometer)을 사용하였으며, inter-cardinal run 방법을 이용하여 유도자기장과 영구자기장을 분리하였다. Anhyteretic deperm 프로토콜을 적용하여 탈자를 진행하였고 전류의 지속시간이 증가하는 경우에 비하여 dead time을 적용하였을 경우 탈자 성능이 향상된 결과를 얻을 수 있었다.

• Journal of the Korean Magnetics Society
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• v.24 no.4
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• pp.128-133
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• 2014

The control and reduction of the magnetization of naval vessel is important technologies for safety against torpedo and sea mine installed magnetic sensors. In general, we used to conduct as a magnetic treatment for permanent magnetization reduction and to compensate induced magnetization using on-board-degaussing system for the naval vessel's magnetic stealth. Navies have operated magnetic treatment facility in order to protect from sea mines. LIGNex1 Corp. has developed the magnetic treatment facility for the korea navy.