• Journal of Magnetics
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• 제17권1호
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• pp.51-55
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• 2012

This paper presents an eddy current loss analysis for a transverse flux rotary machine (TFRM) with laminated stator cores, which consist of inner and outer cores whose laminated directions are perpendicular to each other. Although the TFRM is laminated to reduce eddy current losses, it still exhibits rapidly increasing core losses as the frequency increases. To solve this problem, slits are introduced to the stator outer core. 3-dimensional finite element analysis (3D FEA) based on the T-${\Omega}$ formulation is used to solve the eddy-current problem for a various numbers of slits in the nonlinear lamination core. The effects of the slits are confirmed using experiment data and 3D FEA results.

• Steel and Composite Structures
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• 제32권5호
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• pp.633-642
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• 2019

In this work, lightweight sandwich plates consisting of a functionally graded porous (FGP) core and two laminated composite face sheets resting on elastic foundation have been proposed. Three different profiles are considered for the distributions of porosities along core thickness. The main aim of this paper is the investigation of the buckling behavior of the proposed porous sandwich plates (PSPs) by reporting their critical mechanical loads and their corresponding mode shapes. A finite element method (FEM) based on first order shear deformation theories (FSDT) is developed to discretize governing equations for the buckling behavior of the proposed sandwich plates. The effects of porosity dispersion and volume, the numbers and angles of laminated layers, sandwich plate geometrical dimensions, elastic foundation coefficients, loading and boundary conditions are studied. The results show that the use of FGP core can offer a PSP with half weight core and only 5% reduction in critical buckling loads. Moreover, stacking sequences with only ${\pm}45$ orientation fibers offer the highest values of buckling loads.

• 한국강구조학회 논문집
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• 제10권1호통권34호
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• pp.11-24
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• 1998

복합샌드위치평판은 복합재료를 갖으면서 강성이 있는 얇은 면재와 저밀도인 두꺼운 심재로 구성되어 있다. 본 연구에서는 국부전단변형을 고려한 복합면재를 갖는 샌드위치평판을 해석을 위한 지배방정식을 유도하였고, 해석적인 방법으로 해석을 하였다. 해석방법의 타당성을 확인하기 위하여 전체 전단변형을 고려한 일반 적층판 이론의 값과 비교하였다. 그리고 복합면재와 심재의 국부전단변형을 고려하였으므로 일반 적층판 해석에도 적용시킬 수 있음을 보였다.

• Journal of Advanced Marine Engineering and Technology
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• 제30권5호
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• pp.629-635
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• 2006

Manufacture of motor by laser has been studying realization that was demands on market for lightening and miniaturization. Moreover. early in the 1980s. manufacture of parts for automobiles by laser welding was already successfully introduced. The purpose of this study was to develop production technology of the high quality laminated stator core for motor by pulsed Nd:YAG laser heat source. In the event of adjusting defocus and voltage to control humping in laser welding of the laminated core. sound bead could be obtained. but deep penetration was not. Therefore. explosive evaporating plasma was controlled by adjustment of peak power on pulse width. Particularly, because explosive evaporating plasma induced high peak power, made molten metal in keyhole scatter. a suitable adjustment of peak power was required to obtain sound bead. As a results of experiment. sound bead and deep penetration could be obtained.

• 소성∙가공
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• 제26권4호
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• pp.240-245
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• 2017

Mixed-model production technology is a method of producing multiple products with one production process and production line in order to reduce wasted manpower and adjust to market trends. In other words, mixed-model production is a flexible production system that changes production volume by model according to market demand. This study has developed a progressive laminated stamping die technology to enable flexible production of a motor core consisting of attaching and detaching the Cam on the back of the punch so that two kinds of stator and two kinds of rotor could be produced in one progressive die.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.608-617
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• 2020

For efficient use and expansion of domestic small- and medium-diameter woods, cross-laminated wood panels composed of tropical hardwoods and domestic temperate woods were fabricated, and the bending creep behavior under long-term loading was investigated. The bending creep curve of the cross-laminated wood panels showed an exponential function graph with a sharp increase at the top right side. The wood panel composed of a teak top layer and larch core and bottom layers recorded the highest initial deformation, and that composed of a merbau top layer and tulip core and bottom layers showed the lowest initial deformation. Creep deformation of the cross-laminated wood panels showed the highest value in that composed of a teak top layer and larch core and bottom layers and showed the lowest value in that composed of a merbau top layer and tulip core and bottom layers. The obtained creep deformation is 3.1-4.3 times that of merbau, however, it is remarkably lower than that of tulip and larch. The highest relative creep was recorded by the wood panel composed of merbau top layer and larch core and bottom layers, whereas that composed of the teak top layer and tulip core and bottom layers showed the lowest relative creep.

• Steel and Composite Structures
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• 제51권1호
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• pp.73-91
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• 2024

This paper has focused on presenting vibration analysis of trapezoidal sandwich plates with a damaged core and FG wavy CNT-reinforced face sheets. A damage model is introduced to provide an analytical description of an irreversible rheological process that causes the decay of the mechanical properties, in terms of engineering constants. An isotropic damage is considered for the core of the sandwich structure. The classical theory concerning the mechanical efficiency of a matrix embedding finite length fibers has been modified by introducing the tube-to-tube random contact, which explicitly accounts for the progressive reduction of the tubes' effective aspect ratio as the filler content increases. The First-order shear deformation theory of plate is utilized to establish governing partial differential equations and boundary conditions for the trapezoidal plate. The governing equations together with related boundary conditions are discretized using a mapping-generalized differential quadrature (GDQ) method in spatial domain. Then natural frequencies of the trapezoidal sandwich plates are obtained using GDQ method. Validity of the current study is evaluated by comparing its numerical results with those available in the literature. After demonstrating the convergence and accuracy of the method, different parametric studies for laminated trapezoidal structure including carbon nanotubes waviness (0≤w≤1), CNT aspect ratio (0≤AR≤4000), face sheet to core thickness ratio (0.1 ≤ ${\frac{h_f}{h_c}}$ ≤ 0.5), trapezoidal side angles (30° ≤ α, β ≤ 90°) and damaged parameter (0 ≤ D < 1) are carried out. It is explicated that the damaged core and weight fraction, carbon nanotubes (CNTs) waviness and CNT aspect ratio can significantly affect the vibrational behavior of the sandwich structure. Results show that by increasing the values of waviness index (w), normalized natural frequency of the structure decreases, and the straight CNT (w=0) gives the highest frequency. For an overall comprehension on vibration of laminated trapezoidal plates, some selected vibration mode shapes were graphically represented in this study.

• Journal of the Korean Wood Science and Technology
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• 제38권1호
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• pp.1-10
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• 2010

이 연구에서는 목재의 효율적인 이용의 일환으로 스프루스 직교형적층재의 중층을 중밀도섬유판(medium density fiberboard, MDF), 파티클보드(particle board, PB) 및 오에스비(oriented strand board, OSB)의 3종류의 시판용 목질보드를 복합적층한 3층 목질계 복합적층재(패널)를 제작하여, 중층 목질보드라미나의 구성엘리멘트가 복합적층재의 휨 크리프성능에 미치는 영향을 조사하였다. 복합적층재의 휨 크리프곡선은 우측상변이 급증하는 지수함수 그래프를 나타내었고, 각 복합적층재의 중층 목질보드라미나의 종류에 따라 다른 경향을 나타내었다. 복합적층재의 크리프변형은 표층섬유직각방향($C_{\perp}$ 타입)에서는 중층에 PB, MDF, OSB를 배열한 $C_{\perp}$(P)타입 > $C_{\perp}$(M)타입 > $C_{\perp}$(O)타입의 순으로, OSB를 중층에 배열한 타입의 크리프변형이 MDF나 PB를 중층에 배열한 것의 2배 이상 적은 것이 확인되었고, 복합적층에 의해 스프루스 섬유직각방향의 크리프변형의 현저한 감소가 나타났다. 한편, 표층섬유방향($C_{\parallel}$ 타입)의 크리프변형은 중층에 PB, OSB, MDF를 삽입한 $C_{\parallel}$(P)타입 > $C_{\parallel}$(O)타입 > $C_{\parallel}$(M)의 순이었으나, 복합적층에 의해 적층재상호간의 비는 현저히 감소하였고, 중층에 PB와 OSB를 배열한 복합적층재의 크리프변형의 차이는 매우 적은 것이 확인 되었다. 이 값은 목질보드의 크리프변형보다는 0.108~0.464배의 적은 크리프변형을 나타내어 복합적층에 의해 목질보드의 크리프변형의 현저한감소가 나타났다. 복합적층재의 표층섬유방향에 대한 표층섬유직각방향의 크리프이방성은 초기변형보다 크리프변형이 현저히 컸지만, 스프루스 평행형적층재의 크리프이방성보다는 현저히 감소하는 것이 확인되었다.

• 복합신소재구조학회 논문집
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• 제3권4호
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• pp.17-26
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• 2012

This study presents a governing equations of bending behavior of anisotropic sandwich plates with multi-layered laminated composite faces. Based on zig-zag models for through thickness deformations, the shear deformation of composite faces is included. All edges of plate are assumed to be simply supported. Results of the bending analysis under lateral loads are presented for the influence of various lay up sequences of antisymmetric angle-ply laminated faces. The accuracy of the approach is ascertained by comparing solutions from the sandwich plates theory with composite faces to the laminated plates theory. Since the present analysis considers the bending stiffness of the core and also the transverse shear deformations of the laminated faces, the proposed method showed higher than that calculated according to the general laminated plates theory. The information presented might be useful to design sandwich plates structure with polymer matrix composite faces.

• 전기학회논문지P
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• 제59권2호
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• pp.151-153
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• 2010

This paper is presented for the development of the brushless DC(BLDC) motor for the spindle motor of hard disk drives(HDD). A new BLDC Motor has the use of insulated, compacted, and iron powder for the armature core material of BLDC motors. Insulated iron powder in this paper is generally called soft magnet composite(SMC). The SMC is used for the stator of the motor instead of the laminated steel core. The motor used by SMC can have the good advantages in condition of the high frequency input power and small sized motor. It gets much more high efficiency than laminated steel core at same input power. The proposed motor has a technique of speed sensorless control. Experimental results show the performance of the proposed BLDC motors for an HDD.