3論 文 抄 録

Fatigue Behavior of CFRP Cross-Ply Laminates

under Axial Cyclic Load

K. Tohgo, X.-J. He, H. Ishii and K. Kageyama

主軸方向繰返し荷重を受ける

CFRP直交積層板の疲労挙動

東郷敬一郎、賀　小軍、石井　仁、影山和郎

　Laminated composites consisting of unidirec-

tional plies exhibit the complicated characteris-

tics on deformation and strength because

ply-cracking damage, delamination and fiber

breakage develop from an early stage of defor-

mation. In this paper, the damage and fracture

process of CFRP cross-ply laminates under

monotonic and cyclic loading has been investi-

gated. Tensile tests in various directions and

fatigue tests in the axial direction were carried

out on three kinds of CFRP cross-ply laminates.

In the tensile tests, the ply-cracking damage

develops under 0°and 90°tension, while the

nonlinear deformation due to nonelastic prop-

erty of the matrix resin is predominant under

off-axis tension. On the semi-log S-N curves

obtained by the fatigue tests in the 0°direction,

the fatigue fracture is described by a straight line

in the high cycle fatigue region and the fatigue

limit is not recognized clearly. In the fatigue

tests, the fiber-peeling damage in 0°plies de-

velops in addition to the ply-cracking damage in

90°plies. Ply-cracking density in 90°plies is

characterized as a function of number of stress

cycles. On the specimen fractured by fatigue,

the most of ply-cracking damage develops at the

first cycle, and slightly increases during fatigue.

This damage behavior is insensitive to the stress

level. Therefore, it is concluded that the

ply-cracking damage is not a main factor con-

trolling the fatigue fracture. On the other hand,

fiber-peeling damage in 0°plies initiates from

the edges of 0°plies and evolves in the whole

area of the laminate with an increase in stress

cycles. The evolution of the fiber-peeling dam-

age strongly depends on the stress level. The

fatigue fracture seems to occur when the 0°

plies lose their load carrying capacity by the

evolution of the fiber-peeling damage. There-

fore, it is concluded that the fiber-peeling dam-

age in 0°plies is the main factor controlling fa-

tigue fracture.

［Int. Conf. Advanced Technology in Experi-

mental Mechanics 2003, （2003. 9）］

Influence of Coarsening Treatment on Fatigue

Strength and Fracture Toughness of Al-Si-Mg

Alloy Casting

Keiichiro Tohgo1 and Masahide Oka

Al-Si-Mg合金鋳物の疲労強度と

破壊靱性に及ぼすコースニング処理の影響

東郷敬一郎、岡　政秀

　In this paper, the influence of the coarsening

treatment of eutectic Si particles on fatigue

strength and fracture toughness of a peak-aged

Al-7%Si-0.4%Mg alloy casting has been investi-

gated. By the coarsening treatment at 808°K for

100 hours, the eutectic Si particles grew to be

spherical and were uniformly distributed, but

casting defects remained without any changes.

On tensile tests, the 0.2% proof stress and tensile

strength were almost the same in both as-re-

ceived material and Si-coarsened material, but

the ductility was much higher in the Si-coars-

ened material than in the as-received one. Fa-

tigue fracture occurred by crack initiation from

the casting defects and succeeding crack growth

on both materials, and the fatigue strength of the

materials was affected by the size of defects

rather than by the coarsening treatment. On the

other hand, the fracture toughness was distinctly

improved by the coarsening treatment. It is

suggested that the improvement of fracture

toughness in the Si-coarsened material is at-

tributed to the energy dissipation due to the

damage of Si particles around a crack and the

rough fracture path.

［5th Int. Conf. Fracture and Strength of Solids,

（2003. 10）］

4 論 文 抄 録

形状記憶合金複合材料の特殊機能制御に

関する基礎的研究

村澤　剛、米山　聡、東郷敬一郎、隆　雅久

Basic Research for Controlling Unique

Performances of Shape Memory Alloy

Composite

G. Murasawa, S. Yoneyama,

K. Tohgo and M. Takashi

　本研究では、まず、形状記憶合金複合材料 （SMAC）

における形状記憶合金繊維とマトリックスの組合せ、

繊維体積率による特殊機能発現に関して解析的検討を

行った。続いて、数種類のSMACの熱負荷による変形

特性をデジタルイメージ修正法を用いて測定し、さら

に、マトリックスの内部応力を光弾性法を用いて測定

した。本研究により以下の結果が得られた。SMAC

の熱負荷による変形特性とマトリックス内の圧縮応力

は繊維体積率およびマトリックス材料に依存し、得ら

れた特性マップはSMACの設計に有益である。ポリ

エステルに予ひずみを与えたNiTi繊維を含むSMAC

を加熱すると、大きな収縮変形とマトリックス内の圧

縮応力が生じる。実験により得られた変形特性と解析

結果には若干の差が見られた。したがって、より精度

の高い解析モデルの開発が必要である。

［実験力学、Vol. 3, No.3, pp. 172-178, （2003. 9）］

Control of Mechanical Deformation of a Laminate

by Electrical Load to Piezoelectric Actuator

Considering the Effects of Damping and

Transverse Shear

Masayuki ISHIHARA, Naotake NODA

Abstract:

　In this paper, we treat the control of dynamic

deformation of a laminate by applying electrical

load to piezoelectric actuator. Dynamic behav-

ior of the laminate is analyzed considering the

effect of damping due to interlaminar shear and

the effect transverse shear. The analytical

model is a rectangular laminate composed of

fiber-reinforced laminae and piezoelectric lay-

ers. The model is assumed to be a symmetric

cross-ply laminate with all egdes simply sup-

ported and to be subjected to unavoidably me-

chanical load and to electrical loads to piezo-

electric actuator. Behavior of the laminate is

analyzed based on the first-order shear defor-

mation theory. The effect of damping due to

interlaminar shear is incorporated into our

analysis by introducing the interlaminar shear

stresses which satisfy the Newton's law of vis-

cosity. The following quantities are obtained:

natural frequencies of the laminate, weight

functions for the deflection and rotations and

transient deflection due to loads varying arbi-

trarily with time. Moreover, the methods to

control the deflection due to mechanical load by

applying electrical voltage to the piezoelectric

actuator are shown.

［International Journal of Engineering Science,

41 （15）, pp. 1667-1684］

Effect of Damping on Dynamic Behavior of a

Piezothermoelastic Laminate

Considering the Effects of Transverse Shear

Masayuki ISHIHARA & Naotake NODA

Abstract:

　In this paper, we analyze dynamic behavior of

a piezothermoelastic laminate considering the

effect of damping due to interlaminar shear and

the effect of transverse shear. The analytical

model is a rectangular laminate composed of

fiber-reinforced laminae and piezoelectric lay-

ers. The model is assumed to be a symmetric

cross-ply laminate with all egdes simply sup-

ported and to be subjected to mechanical, ther-

mal and electrical loads varying arbitrarily with

time. Behavior of the laminate is analyzed based

on the first-order shear deformation theory.

The effect of damping due to interlaminar shear

is incorporated into our analysis by introducing

the interlaminar shear stresses which satisfy the

Newton's law of viscosity. Solutions of the fol-

lowing quantities are obtained: natural fre-

quencies of the laminate, weight functions for

the deflection and rotations and unsteady

deflection due to loads varying arbitrarily with

time. Moreover, numerical examples of the so-

lutions are shown to examine the effects of

5論 文 抄 録

damping and transverse shear on dynamic be-

havior of the laminate and how the voltage ap-

plied to the laminate decreases the deflection

due to mechanical or thermal loads.

［International Journal of Solids and Structures,

40 （22）, pp. 6077-6094］

Non-linear Dynamic Behavior of a

Piezothermoelastic Laminate

Considering the Effect of Transverse Shear

Masayuki ISHIHARA, Naotake NODA

Abstract:

　Non-linear dynamic behavior of a piezother-

moelastic laminate subjected to mechanical,

thermal and electrical loads is analyzed consid-

ering. Non-linear deformation of the laminate is

analyzed based on the von Kármán strains and

the first-order shear deformation theory using

the Galerkin Method. The buckling tempera-

ture, the large static deflection, the natural fre-

quencies of infinitesimal or finite oscilation are

discussed. The effect of transverse shear on

non-linear behavior and the methods to rise the

buckling temperature, to linearize thermal de-

flection and the natural frequencies by applying

the electrical voltage to piezoelectric actuators

are investigated.

［Journal of Thermal Stresses, 26 （11-12）, pp.

1093-1112］

Development of torsional damper with crowd

of solid balls for engine crankshaft

Takashi MATSUDA and Motohiro SATO

エンジンのクランク軸用の

粒子トーショナルダンパの開発

松田　孝、佐藤元宥

　In this paper, new torsioinal damper is devel-

oped in order to improve the defects of known

dampers such as rubber dampers, oil dampers

and solid frictional dampers, which are used for

vibration reduction of crankshafts in most of

reciprocating engines for automobiles. The

damper is designed and manufactured, and the

experiments on the vibration reduction carried

out. As a result, it is suggested that those defects

can be improved by this experimental damper,

and that the effective damping is achieved by

the new damping mechanism, that is, the fluc-

tuation of the natural frequency of testing

crankshaft system caused by alternating be-

tween the angular sliding and the coupling of

damper mass to the damper casing in every pe-

riod of the torsional vibration of the crankshaft.

［J. Mech. Eng., Vol.54, No.2, pp. 101-110 （2003）］

粒子トーショナルダンパの開発

（制振機構のシミュレーション）

佐藤元宥、松田　孝、今田琢己

Development of Torsional Damper

with Crowds of Solid Balls

（Simulation of Damping Mechanism）

Motohiro SATO, Takashi Matsuda

and Takumi IMADA

　これまでに、新開発の粒子トーショナルダンパは粒

子の量の調整により、クランク軸系のねじり振動を効

果的に低減することが実験的に明らかにされてきてい

る。本研究では、ダンパの最適設計のための基礎とし

てこの減衰機構が明らかにされている。まず、本ダン

パを備えた供試クランク軸系のねじり振動のモデリン

グとコンピュータシミュレーションを行い、ついで、

それらの結果を実験結果と比較検討して、本ダンパの

制振機構は、粒子群とダンパマス間の摩擦損失および

ねじり振動の一周期中にダンパマスとダンパケース間

にカップリングとすべりが交互に生じることから構成

されていることを明らかにしている。

［日本機械学会論文集 （C編）、69巻 680号、pp.

1178-1183 （2003）］

6 論 文 抄 録

Accuracy Improvement of Parallel Kinematic

Machine: Compensation Method for Elastic

and Thermal Deformation of Machine Frame

Takaaki OIWA

パラレルメカニズム型機械の精度向上に関する研究

・機械フレームの弾性および熱的変形の補正方法̶

大岩孝彰

　To improve the machining and measuring ac-

curacy during the process, it is extremely im-

portant to obtain an accurate relative position

between the tool and the workpiece. Thus, not

only moving accuracy but also structural and

thermal stability in the whole machine is re-

quired. In general, to compensate such thermal

deformation, many researchers have investi-

gated prediction methods with limited tempera-

ture sensors and analyzed by using the finite el-

ement method. However, the thermal deforma-

tion is hard to predict and analyze because the

sensors can not measure the temperatures of all

parts of machine. Moreover, the analysis in the

machine comprised of beam structure involves

the great difficulties because of its complexity of

the deformation at rapid fluctuation of the room

temperature. This study deals with the accuracy

improvement for parallel kinematic machine

consisting of closed loop link mechanism. This

paper describes a compensation method for

both elastic and thermal deformations of the

machine flame supporting the mechanism.

These deformations are caused by the heat, the

external forces and the internal forces. Nine

displacement sensors with nine Super-Invar

rods measure the variation of distances between

the surface plate and three joint supports on the

frame. The direct kinematics of Hexapod

mechanism calculates the displacement and the

attitude variations of the frame during operation

from measured displacements. Consequently,

the coordinates of the end effector are com-

pensated by these displacements and attitude of

the mechanism. Experimental results show re-

duction of the influence of the temperature

fluctuation.

［The euspne International topical conference

on precision engineering, Micro-Technology,

Measurement Techniques and Equipment, Vol.1,

pp. 125-128 （2003）］

Accuracy Improvement of Parallel Kinematic

Machine-Error Compensation Methods for

Elastic and Thermal Deformations of Joints,

Links and Machine Frame-

Takaaki OIWA

パラレルメカニズム型機械の精度向上

ジョイント・リンクと機械フレームの弾性

および熱的変形の誤差補正方法̶

大岩孝彰

　This paper describes compensation methods

for deformations of both the parallel kinematic

mechanism and the frame supporting the

mechanism. In general, these deformations are

caused by the heat, the internal forces and the

external forces during the processes. First,

runouts and deformations of spherical joints and

revolutionary joints are measured and compen-

sated by nine displacement sensors built in

above joints or by linear scale units built in the

prismatic joints. Second, the longitudinal de-

formation of the prismatic joints is mechanically

compensated by Super-Invar rod connected to

the joints and the linear scale units. Moreover,

nine displacement sensors with nine Super-In-

var rods measure the variation of distances be-

tween the surface plate and three spherical joint

supports. Consequently, the forward kinematics

of Hexapod mechanism calculates the displace-

ment and the attitude variations of the mecha-

nism during operating from measured data.

Last, the coordinates of the end effector are

compensated by these displacements and at-

titude of the mechanism. Experimental results

show reduction of the influence of the tempera-

ture fluctuation and variation of measured val-

ues.

［Tokyo Institute of Technology The 6th Interna-

tional Workshop of the Department of Me-

7論 文 抄 録

chanical Sciences and Engineering, （2003）］

６自由度パラレルメカニズムにおける

アッベの原理に関する研究

（対偶の回転誤差が機構の運動誤差に及ぼす影響）

大岩孝彰、玉木雅人

　直動型の能動対偶６本を持つ表記機構の球対偶の回

転誤差が機構の運動誤差に及ぼす影響とリンク配置の

関係を調査した。微小運動学を用いた誤差解析の結果、

直進対偶方向の回転誤差のみが運動誤差に強く影響す

ること、この影響が最小となるリンク配置があること、

このとき位置決め分解能や作業領域は最小化し、出力

点は直進対偶の延長線と最も近づくが、延長線上を通

る必要はないことなどがわかった。またこのような配

置の時、パラレルメカニズムはアッベの原理を満たす

ことがわかった。

［日本機械学会論文集Ｃ編, 69巻678号, pp. 472-477

（2003）］

パラレルメカニズムを用いた三次元座標測定機の

校正に関する研究・ダブルボールバーと

タッチプローブを用いたキャリブレーション̶

大岩孝彰、片岡頼洋

　リンクを並列に配置した閉ループ機構から成る表記

測定機において、あらかじめ校正されたダブルボール

バーの移動球をタッチプローブで測定して得られる位

置誤差から、対偶位置などの機構パラメータを最小自

乗法により推定した。移動球の配置、繰返し計算の打

ち切り回数の検討、および校正後の測定精度について

述べた。

［精密工学会誌, 69巻2号, pp. 222-226 （2003）］

外径絞りを伴う二段充てん法による平歯車の成形

沢木洋三、吉田　始、坂井田喜久、鈴木　正

　著者らは前報で二段階の冷間押出しで内歯車やイン

ナーヘリカルスプラインを成形する方法を提案した。

この方法を外歯である平歯車の成形に適用した。すな

わち、円筒試料の外径を二段階で絞り平歯車を成形す

るための特別な形状のダイスを用いた。対象とした平

歯車の諸元はモジュール1.25、歯数18である。33%とい

う低い断面減少率の場合であっても、低いパンチ面圧

で実験したほとんど全てで良好な平歯車が得られた。

この方法の有利な点を調べるために FEM 解析を行っ

た。１） 一段目の押出しでは大きな歯形のために歯先

（半径方向） に向かう素材の流動が容易である。２） 一

段目の大きな歯形から目標とした歯形に成形する二段

目の押出しで、円周方向の素材の流動も生ずる。

［塑性と加工，44巻507号，pp. 462-466，（2003）］

Evaluation of Fracture Toughness of Porous

Ceramics

Yoshihisa Sakaida and Keisuke Tanaka

多孔質セラミックスの破壊靭性評価

坂井田喜久、田中啓介

　The indentation fracture （IF） method, the

single-edge precracked beam （SEPB） method,

and the single-edge V-notched beam （SEVNB）

method were applied to evaluate the fracture

toughness of four kinds of porous ceramics of

SiC, Al2O3 and Mg2Al4Si5O18 with porosity rang-

ing from 37 to 43%. The microstructures of these

materials were composed of ceramics grains,

glassy grain boundaries and pores. Each grain

was joined together with the glassy grain

boundary phase. The IF and SEPB methods

were not applicable because both precracks and

indenter traces were not visible. On the other

hand, the SEVNB method was applicable be-

cause the V-notch could be easily machined by

grinding. In the case of the SEVNB method, the

applied load versus back-face strain plots under

four-point bending showed nonlinearity prior to

the maximum load. The R-curve behavior was

estimated from the compliance change of spec-

imens. The fracture toughness of porous ce-

ramics was smaller than that of dense ceramics,

and increased with increasing crack extension.

Since the stable crack predominantly propa-

gated along glassy grain boundaries, the

R-curve behavior depended on the loading rate

and matrix grain size. The increment of the

8 論 文 抄 録

R-curve by grain bridging became larger for

coarser-grain sized ceramics.

［JSME International Jornal, Series A, Vol.46,

No.1, pp. 30-39 （2003）］

Prediction of Homogenized Elastic Moduli of

Ceramics

Using Polycrystalline Grain Model

（Influence of Two-Dimensional

Microstructual Model Size）

Yoshihisa Sakaida and Koji Sato

多結晶粒子モデルによるセラミックスの

等価弾性係数評価

（二次元微構造モデル寸法の影響）

坂井田喜久、佐藤功二

　Microstructures of polycrystalline Al2O3, ZrO2

and Al2O3-ZrO2 ceramics were modeled as

two-dimensional heterogeneous bodies com-

posed of geometeric Al2O3 and ZrO2 grains. The

crystallographic 3D-directions of each grain

were assumed to be randomly distributed.

Elastic properties of grain were derived from

elastic stiffnesses, cij, of single crystal Al2O3 and

ZrO2. In calculation, some square plates with a

unit thickness were cut from the initial grain

models. A simulation method was developed to

predict homogenized elastic moduli of models

using a finite element method. An influence of

the microstructual model size on apparent elas-

tic moduli was examined. Next, actual micro-

structual models that were traced the SEM mi-

crographs of samples were used in same calcu-

lation. And then, the optimum model size was

determined by comparing calculated elastic

moduli to experimental data measured by a

pulse-echo method. As a result, the scattering

of apparent elastic moduli, such as Young's

modulus, of both models including Al2O3 grains

varies narrowly with increasing model size.

While, the deviation of apparent elastic moduli

for actual model is wider than that of geometric

model on the same model size. The number of

Al2O3 grains within the optimum model size was

found to be about more than 400, in which the

scattering of apparent elastic moduli is below

the ±1% deviation of the mean value of model

samples.

［日本機械学会論文集 （A編）, 69巻, 684号, pp.

1311-1317 （2003）］

In-situ Local Stress Measurement near Notch

Tip in Alumina Ceramics

Using Synchrotron Radiation Source

Yoshihisa Sakaida, Keisuke Tanaka, Yoshiaki

Akiniwa and Yozo Sawaki

シンクロトロン放射光による

アルミナの切欠き先端近傍の局所応力

坂井田喜久、田中啓介、秋庭義明、沢木洋三

　In order to measure loading and residual

stresses near the notch tip in Al2O3 ceramics

using a micro X-ray beam of SPring 8 （Super

Photon ring-8GeV）, X-ray elastic constants were

first determined experimentally. Mechanical

elastic constants of the used material were E=372

GPa and n=0.23. The diffraction from Al2O3 2.0.14

plane by 8keV radiation was used for X-ray

stress measurement. The 2q-sin2y diagrams un-

der several applied stresses were measured.

From the relationship between both slope, M,

and intercept 2qy＝0 of 2q-sin2y diagram and ap-

plied stress, X-ray elastic constants were deter-

mined to be Ex=416 GPa and nX=0.20. Next, the

local stress measurement in the irradiated area

with 100×100 mm2 was examined in comparison

to that with 100×500 mm2. Loading stress in a

local area with 100×100 mm2 can be measured by

the sin2y method. Finally, the local loading

stresses, sy （x）, near the V-notch tip under a

four-point bending load were measured across

the minimum ligament of SEVNB

（Single-Edge-V-notched Beam） specimen by

scanning the micro X-ray beam along the x-axis.

The stress concentration near the notch root

was first difficult to be measured directly be-

cause of the grinding residual stress by V-notch

machining. After annealing, the stress concen-

9論 文 抄 録

tration was detected by changing the irradiated

area of X-ray from 100×100 to 50×50 mm2. The

degradation of the measured stresses in the

notch tip was caused by the X-ray irradiation to

the notch, and almost agreed with the results of

a finite element analysis. The local stress and

residual stresses were found to be measured by

the sin2y method using synchrotron micro X-ray

beam with a spatial resolution of about 50 mm.

［材料, 第52巻, 第10号, pp. 1225-1230 （2003）］

Micro and Macro Stress Analysis of Ceramics

Using Microstructural Models

Yoshihisa Sakaida, Yasushi Ikeda, Hiroshi

Kawamoto and Yozo Sawaki

微構造モデルによるセラミックスの

ミクロ・マクロ応力解析

坂井田喜久、池田　泰、河本　洋、沢木洋三

　Modeling techniques using either finite ele-

ment or homogenization methods were devel-

oped for predicting micro/macro stress fields in

ceramic components. In case of polycrystalline

film ceramics, the microstructure was modeled

as two dimensional grain models using the SEM

micrographs. Homogenized elastic moduli and

micro/macro stress fields were calculated by fi-

nite element analysis. Influence of the model

size on homogenized elastic moduli and mac-

rostress field was examined. Homogenized

elastic moduli and macrostress field for thin film

formed in limit number grains, such as MEMS

device, were found to be directly controlled by

both elastic anisotropy and crystallographic

orientation of grain within the microstructure.

Elastic anisotropy and crystallographic orienta-

tion of grain must be considered even if the

crystal structure of the material was cubic which

had relatively simple stiffness matrix. In case of

porous ceramics, the microstructure was mod-

eled as three dimensional porous models using

the computerized tomograms by X-ray. Ho-

mogenized elastic moduli were calculated by

homogenization analysis, and then macrostress

fields in joint bars composed of two different

porous materials were found to be estimated

from finite element analysis under four-point

bending.

［構造物の安全性および信頼性, Vol.5, pp. 159-166

（2003）］

Estimation of Elastic Modulus of

Polycrystalline Ceramics

using Microstructural Grain Model

Yoshihisa Sakaida, Yozo Sawaki and

Syusui Ogawa

微構造粒子モデルによる多結晶セラミックスの

弾性係数評価

坂井田喜久、沢木洋三、小川秋水

　The simulation method was developed to pre-

dict homogenized elastic moduli of ceramic

materials from elastic stiffness of each grain

within its microstructure. Polycrystalline Al2O3,

ZrO2 and Al2O3- ZrO2 ceramics were produced

as model samples. Elastic stiffness, cij, of single

crystal cubic- ZrO2 was measured by four-point

bending method. Microstructures of model

samples were modeled as two and three-di-

mensional heterogeneous bodies composed of

Al2O3 and ZrO2 grains. The crystallographic

3D-directions of each grain were assumed to be

randomly distributed. Some square plates with a

unit thickness that cut from the initial two-di-

mensional grain models and some cubes com-

posed of geometeric cube grains were used to

calculate apparent macroscopic elasitc moduli

such as Young’s modulus, Poisson’s ratio and

modulus of rigidity. An influence of the model

size on apparent elastic moduli was examined

by a finite element method. And then, the opti-

mum model size was determined by comparing

calculated elastic moduli to experimental data

measured by a pulse-echo method. As a result,

the scattering of apparent Young’s modulus

varies narrowly with increasing the number of

anisotropic Al2O3 and ZrO2 grains. The number

of anisotropic grains within the optimum model

10 論 文 抄 録

was found to be about 400. The calculated elas-

tic moduli for the optimum model coincided

with the experimental data.

［Proceeding of International Conference on

Advanced Technology in Experimental Me-

chanics 2003, OS08W0215, pp. 1-6 （2003）］

Strength Evaluation of Aluminum Alloy Bold

by Nano-Indentation Hardness Test

Yoshihiro Kubota, Tamotsu Nakamura,

Mitsuo Kobayashi, Katsumi Fukuda

ナノ硬さ試験によるアルミニウムボルトの強度評価

久保田義弘、中村　保、小林光男、福田克己

　Aluminum alloy bolts are used to joint two or

more aluminum space frames. Such aluminum

alloy bolts are required high strength. A high

strength aluminum alloy bolt （7050, T7 temper）

has been developed by the authors. The bolt

has a small grain size in all area of the bolt by

thermo-mechanical treatment. Moreover, the

ductility and stress corrosion cracking resis-

tance have been improved by over aging treat-

ment by T73 temper treatment. Recently, a

nano-indentation hardness has been developed

to evaluate the hardness in microscopic area. In

the present paper, the distribution of

nano9indentation hardness of microscopic grain

structure in the high strength aluminum alloy

bolt has been measured by nano-indentation

hardness tester.

［Acta Physica Universitatis Comenianae

Vol.XLIII, pp. 45-52 （2002）］

環境に優しい鍛造のトライボロジー技術

中村　保

Ecological Tribology in Forging

Tamotsu Nakamura

　鍛造のトライボロジー技術は、摩擦管制、製品表面

仕上げ向上、焼付きや工具摩耗防止等の要求から必要

不可欠である。しかし、最近はとくに環境負荷の大き

な潤滑剤の使用は極力避けることが要求されている。

究極的には、潤滑剤なしで塑性加工を実現することが

理想的であるが、現状では、そこに至るまでの過程に

おいて、環境負荷を軽減するための種々のトライボロ

ジー技術が提案され、すでに実用化が進んでいる。本

論文では、環境負荷を軽減するために開発されてきた

種々の鍛造のトライボロジー技術について、調査した

結果をまとめる。

［月刊トライボロジー, 186号, pp. 33-37 （2003）］

Tribo-Testing Method for Estimating

Tribo-Characteristics at Piercing Punch in

Backward Can Extrusion

Tamotsu Nakamura, Shigekazu Tanaka,

Kunio Hayakawa, Isao Takahashi

缶の後方せん孔押出しのパンチ頭部の

トライボロジー特性評価方法

中村　保、田中繁一、早川邦夫、高橋　功

　The authors have proposed a new type of

tribo-testing method based on a combined for-

ward straight can-backward straight can extru-

sion in order to evaluate tribo- characteristics at

the piecing straight punch with a long bearing

length. By this method the friction shear factor

mUP at the upper punch bearing can be deter-

mined after knowing the friction shear factor mD

along the die wall. The die wall friction shear

factor mD is determined by a tribo-testing

method based on a combined forward-back-

ward can extrusion. Calibration curves repre-

senting the relationship between punch travel,

can heights and friction shear factor for the two

11論 文 抄 録

tests have been calculated based on a

rigid-plastic FEM analysis. Experimental fric-

tion tests have been carried out with some min-

eral oils using a mechanical press.

［Lubrication Engineering, Vol.59, No.4, pp. 12-17

（2003）］

大学におけるトライボロジー教育 （塑性加工部門）

中村　保

University Education for Tribology in Metal

Deformation Processes

Tamotsu Nakamura

　全国的に工学部の機械系学科のほとんどで、専門の

講義は基礎的な科目をみっちりと教えることに重点が

置かれ、専門の個別の分野の講義の種類はかなり削減

されているものと推測される。生産加工関連の講義も

例外ではなく、ここ数年で塑性加工単独の講義を実施

している大学はほとんどなくなっているのが現状では

なかろうか。日本技術者教育認定機構 （JABEE） の機

械および機械関連分野の分野別要件の「材料と構造」の

項目中に、「トライボロジー」のキーワードがあるため、

機械の一般的な摺動に関するトライボロジーについて

は、今後も、大学の講義でしっかりと学ぶ機会が残る

と考えられる。

　JABEEにおける大学卒業後の技術者の生涯教育に

ついては、通産省の委託を受けて、例えば、機械分野

については、日本機械学会の「機械技術者生涯教育調査

委員会」が、教育プログラムや講習会の教材作成に責任

を持って当たることになりそうである。したがって、

たとえば、塑性加工のトライボロジーについては、日

本塑性加工学会が責任を持つことになる可能性が高い。

本稿では、塑性加工のトライボロジーに関する教育を

実施する際に、学会が果たすべき役割について考察す

ることにしたい。

［トライボロジスト, 48巻, 8号, pp. 615-621 （2003）］

直接通電加熱圧接による各種金属の接合条件

中村　保、田中繁一、早川邦夫、今泉晴樹、中川雄太

Pressure Welding Characteristics of Various

Metals by DC Pulse Resistance Sintering

Apparatus

Tamotsu Nakamura, Shigekazu Tanaka,

Kunio Hayakawa Haruki Imaizumi

& Yuhta Nakagawa

　The authors haveproposed a new type of fric-

tion test based on combined forward straight

can-backward straight can extrusion in order to

evaluate friction characteristics at the long

bearing of the piecing straight punch. By this

method the friction coefficient at the punch

bearing is determined after knowing the friction

coefficient along the die wall. The die wall fric-

tion coefficient is determined by a combined

forward and backward can extrusion of straight

cans. Calibration curves determining the rela-

tionship between punch travel, can heights and

friction coefficient for the two tests are calcu-

lated based on a rigid-plastic FEM analysis.

Experimental friction tests are carried out in a

mechanical press with aluminum alloy A6061 as

the work-piece material and different kinds of

lubricants. They confirm that the theoretical

analysis results in reasonable values for the

friction coefficient.

［塑性と加工, 44巻, 512号, pp. 931-936 （2003）］

Recent Trends on Researches and

Technologies in Forging Processes in Japan

Tamotsu Nakamura

最近の日本における鍛造技術研究開発の動向

中村　保

　The amount of production orders from Japa-

nese car and construction machine industries

have slightly increased in 2002, but the costs of

the forged parts have decreased due to severe

12 論 文 抄 録

competitions with the other Asian countries.

Most of the forging industries and some univer-

sities are making more efforts for technological

researches and developments to meet the de-

mand for higher accuracy and higher quality

products, shortening of delivery time, and de-

velopment of forged parts for new industrial

fields. Some helical gears of which surfaces can

be net-shaped have been started for commercial

base production to be shipped to car industries.

Some non-graphite lubricants for hot forging

and some conversion coating free lubricants for

cold forging have been developed to improve

some environmental problems.

［Proceedings of the 8th ASPF, pp. 123-127 （2003）］

Strength Evaluation of Aluminum Alloy Bold

by Nano-Indentation Hardness Test

Yoshihiro Kubota, Tamotsu Nakamura,

Mitsuo Kobayashi, Katsumi Fukuda

ナノ硬さ試験によるアルミニウムボルトの強度評価

久保田義弘、中村　保、小林光男、福田克己

　Aluminum alloy bolts are used to joint two or

more aluminum space frames. Such aluminum

alloy bolts are required high strength. A high

strength aluminum alloy bolt （7050, T7 temper）

has been developed by the authors. The bolt

has a small grain size in all area of the bolt by

thermo-mechanical treatment. Moreover, the

ductility and stress corrosion cracking resis-

tance have been improved by over aging treat-

ment by T73 temper treatment. Recently, a

nano-indentation hardness has been developed

to evaluate the hardness in microscopic area. In

the present paper, the distribution of

nano9indentation hardness of microscopic grain

structure in the high strength aluminum alloy

bolt has been measured by nano-indentation

hardness tester.

［J. Material Testing Research Association of Ja-

pan, Vol. 48, No.4, pp. 232-236 （2003）］

FEM Analysis of Contact Mechanism in

Press-Forming of Lubricant Pre-Coated

Steel Sheet

Zhrgang Wang, Tamotsu Nakamura,

Kuniaki Dohda, Toshihiro Obika

潤滑処理鋼板のプレス成形における

接触機構のFEM解析

王　志剛、中村　保、堂田　邦明、小比賀俊博

　This paper describes the contact situation be-

tween the die and the lubricant pre-caoted steel

sheet in the press-forming by using FEM simu-

lation. The FEM simulation is carried out by

supposing that the lubricant pre-coated steel

sheet consists of the lubrication layer and thick

galvanized layer. Both the lubrication layer and

galvanized layer are assumed as rigid-plastic

material. The variations in the contact situation

between the die and the lubricant pre-coated

steel sheet are investigated by changing the

friction coefficient between the die and lubrica-

tion layer, the thickness and hardness of lubri-

cation layer, the velocity ratio of the relative

sliding velocity to pressing velocity, etc. The

simulated results show that the contact area is

influenced by the average contact pressure, the

velocity ratio, the thickness of lubrication layer,

and friction coefficient.

［J. of Materials Processing Technology, Vol. 140.

pp. 514-519 （2003）］

鍛造におけるトライボロジー

中村　保

Tribology in Forging

Tamotsu Nakamura

　鍛造のトライボロジー技術は、摩擦管制、製品表面

仕上げ向上、焼付きや工具摩耗防止等の要求から必要

不可欠であると考えられてきた。しかし、最近はとく

に環境負荷の大きな潤滑剤の使用は極力避けることが

要求されている。究極的には、潤滑剤なしで塑性加工

13論 文 抄 録

を実現することが理想的であるが、現状では、そこに

至るまでの過程において、環境負荷を軽減するための

種々のトライボロジー技術が提案され、すでに実用化

が進んでいる。

［プレス技術, 41巻, 12号, pp. 51-55 （2003）］

AEのフラクタル性を用いた鍛造用金型の

損傷・破壊の検出

早川邦夫、中村　保、米澤英樹、田中繁一

　本論文では、アコースティック・エミッション （AE）

のフラクタル性を利用した工具損傷の予知技術の確立

のための基礎として、繰返し冷間押出し加工工程にお

ける金型のAEによる損傷・破壊の検出を試みた。金型

の損傷状態の評価には、AE振幅分布のフラクタル解析

により得られるフラクタル次元の変化を追跡すること

により行う。

　まず、AE振幅分布のフラクタル性について説明し、

つづいて、本研究で用いる金型材料SKD11の引張り破

壊試験を行い、SKD11の変形および破壊に起因する

AE振幅分布特性のフラクタル特性を調べる。その結果、

それぞれのフラクタル次元として1.97および1.44で

あった。

　続いて、繰返し押出し実験を行い、そのフラクタル

次元の変化を調べた。潤滑剤として、被加工材に化成

被膜処理を施した。300回の繰返しにおいて、金型に損

傷や摩耗は観察されず、AE振幅分布のフラクタル次元

はほとんど変化せず平均値として2.04であった。

　つぎに、金型損傷を促進させた試験を、潤滑剤とし

て鉱物油とステアリン酸の混合物を用いて行った。繰

返し数101回において、被加工材に欠陥が観察され、金

型肩部半径にき裂の発生が認められた。その前後での

フラクタル次元の平均はそれぞれ2.01および1.52で

あった。以上より、フラクタル次元は金型の損傷の進

行の指標として有効であることがわかった。

　最後に、Kaiser効果を用いて金型起因のAEと被加

工材変形および摩擦起因のAEとを分離する手法を提

案した。

［塑性と加工, 44巻505号, pp. 72-76 （2003）］

FE Analysis of Interfacial Behavior of Cold

Forging Tool Coated by Hard Film Using

Interfacial Spring Model with Damage

Mechanics

K. Hayakawa, T. Nakamura,

K. Harada and S. Tanaka

　A behavior of interface of cold forging tool

coated by hard film is analyzed by FEM. Me-

chanical properties of the interface between

hard film and the tool material is modeled under

the framework of the irreversible thermody-

namic constitutive equations theory with con-

tinuum damage mechanics. The interfacial

damage variable and its evolution law are in-

troduced, which expresses the degradation of

the interface. The indentation of a hemispheri-

cal tool of SUJ2 in JIS coated by electroplated

coating of chromium into a cylindrical work-

piece of S25C in JIS is performed to examine the

validity of the proposed model. In FE analysis,

the proposed constitutive equations are imple-

mented by the non-linear springs between the

opposite nodes of the interface. Calculated re-

sults show that the maximum interfacial normal

displacement is seen at an immediately forward

from the lip of the indentation, whereas maxi-

mum interfacial tangential displacement is seen

the immediately backward of the lip of the in-

dentation. The region where the debonding will

first onset by the calculated results, shows the

good agreement with the behavior of the chro-

mium electroplated forging tool actually oper-

ated. Finally, a method for evaluating the inter-

facial debonding life of coated tool is proposed.

［4th International conference on industrial tool,

pp. 411-418 （2003.4）］

事故事例に学ぶ接合・複合－その２－

白井秀明、吉田一也、佐野村幸夫、

早川邦夫、桜井冨美夫

　製造品によるさまざまな事故は、発生当初は大きく

報じられるがその調査結果や事故防止対策は長い期間

14 論 文 抄 録

の後報告書等の形でまとめられその扱いは大きくない。

本論文は、日本塑性加工学会　接合・複合分科会　事

故事例研究班による、スポーツ用具および日用品によ

る接合・複合に関する事故とその後事故防止対策に対

する調査結果を解説したものである。スポーツ用品か

ら５例、日用品から５例の事故の様子とその後の対策

について紹介し、その社会的および技術的からの解説

をおこなった。

［塑性と加工, 44巻512号, pp. 922-927 （2003）］

FE ANALYSIS OF INTERFACIAL BEHAVIOR

OF COLD FORGING TOOL COATED

BY HARD FILM

Kunio HAYAKAWA

　A behavior of interface of cold forging tool

coated by hard film is analyzed by FEM. The

indentation of a hemispherical tool of SUJ2 in

JIS coated by electroplated coating of chromium

into a cylindrical workpiece of S25C in JIS is

performed. The proposed constitutive equa-

tions are implemented by the non-linear springs

model at the interface. Calculated results show

that the maximum interfacial normal displace-

ment is observed at an immediately forward

from the lip of the indentation, whereas maxi-

mum interfacial tangential displacement is at the

immediately backward of the lip of the indenta-

tion.

［8th Asian Seminar of Precision Forging, pp.

18-21 （2003.10）］

傾斜機能材料のレーザフラッシュ法による

熱物性値測定と評価

大谷晃弘、吉田豊明、藤沢良昭、唐大偉、荒木信幸

Measurement and Evaluation of

Thermophysical Properties of FGM by Laser

Flash Method.

A. Ohtani, T. Yoshida, Y. Hujisawa,

D. W. Tang, N. Araki

　FGMの遮熱性能や熱移動特性を評価するには、熱物

性値分布と非定常温度応答との関係を明確にし、熱物

性値やその分布の測定・評価手法を確立しなければな

らない。本研究では、FGM （層状） の温度応答をレー

ザフラッシュ法を用いて測定し、熱拡散率および熱伝

導率を評価する方法について検討を行った。FGM試料

としてCuとNiおよびその合金から構成され4層試料

を用いた。また、計算にはパルス状加熱による多層試

料の温度応答の解析解を用いた。

　FGMの温度応答の測定結果及び計算結果は、試料裏

面の最高温度上昇の1/2に達するまでの時間t1/2を一致

させた均質材料に対するParkerの式による温度応答

とよく似ているので、温度応答の形からFGMと均質材

料を区別するのは困難である。このことより、FGMの

温度応答を均質材料と同様に扱いt1/2法を用いて熱拡

散率を求めることは意味あるものと考え、この熱拡散

率はFGMの相当熱拡散率とみなしてもよいことを提

案した。

［傾斜機能材料論文集 （FGM2002）, pp. 62-66 （2002）］

GHP排熱を駆動熱源とする

シリカゲル－水吸着サイクルによる冷房強化

（吸着器モデルにおける

熱および物質移動特性の最適化）

本間寛己、荒木信幸

　Augmentation of Cooling Output by Silica

Gel-Water Adsorption Cycle Utilizing the

Waste Heat of GHP

（Optimization of Heat and Mass Transfer

Characteristics for Adsorber Model）

H. Homma and N. Araki

　GHPの排熱を駆動熱源として利用することを想定

したシリカゲル－水吸着サイクルの高効率化には、吸

着剤における熱および物質移動の向上が必要となる。

本研究では吸着器のモデルとしてユニットモデルを製

作した。ユニットモデルとは、実際には大型で多数の

伝熱管が取り付けられる吸着器を、小型で一本の伝熱

管のみを用いる吸着器にしたものである。また、シリ

カゲルを表面に接着した一本の伝熱管をユニットセル

と名付け、このユニットセルの熱および物質移動特性

の最適化について実験的および解析的に検討を行った。

［日本冷凍空調学会論文集, Vol. 20, No. 2, pp.

143-154 （2003）］

15論 文 抄 録

Dynamical Thermoelastic Behavior Predicted

by an Extended Lord-Shulman Theory

D. W. Tang and N. Araki

拡張されたLord-Shulman理論による

動的熱弾性挙動

唐　大偉、荒木信幸

　The extended form of Lord-Shulman （L-S）

theory is formulated by the Jeffreys type heat

conduction equation at first. The combined

constitutive equations of the generalized ther-

moelastic theories, including the L-S theory, the

Green-Lindsay （G-L） theory and the extended

L-S theory, are given. The equations in the ex-

tended L-S and G-L cases are solved by the nu-

merical inversion of Laplace transform for the

Danilovskaya’s problem. The temperature and

strain fields in the semi-infinite elastic medium

are calculated for various relaxation parameters

and thermo-mechanical coupling factor. Vari-

ous propagating characteristics of the thermal

and elastic waves are discussed.

［JSME Int. Journal, A46, pp. 126-130 （2003）］

NUMERICAL MODELING FOR

THREE-DIMENSIONAL HEAT AND FLUID

FLOW THROUGH A BANK

OF CYLINDERS IN YAW

A. Nakayama, F. Kuwahara and T. Hayashi

Department of Mechanical Engineering,

Shizuoka University

3-5-1 Johoku, Hamamatsu, 432-8561 Japan

斜めに置かれた管群を横切る三次元流れと

熱流動の数値モデリング

中山　顕、桑原不二朗、林　朋博

　A numerical model for a three-dimensional

heat and fluid flow through a bank of infinitely

long cylinders in yaw has been proposed to in-

vestigate complex flow and heat transfer char-

acteristics a ssociated with manmade structures

such as extended fins and plate fins in heat

transfer equipment. Upon exploiting the peri-

odicity of the structure, only one structural unit

has been taken as a calculation domain. An

economical quasi-three-dimensional calcula-

tion procedure has been proposed to replace

exhaustive full three-dimensional numerical

manipulations. It has been shown that, under

macroscopically uniform flow, the three-di-

mensional governing equations reduce to

quasi-three-dimensional forms, in which all de-

rivatives associated with the axis of the cylinder

can be either eliminated or replaced by other

determinable expressions. Thus, only two-di-

mensional storages are required for the depen-

dent variables in question. Extensive numerical

calculations were carried out for various sets of

the porosity, degree of anisotropy, Reynolds

number and macroscopic flow direction in a

three-dimensional space. The numerical results

thus obtained for periodically fully-developed

flow and temperature fields were integrated

over a structural unit to determine the perme-

ability tensor, Forchheimer tensor and direc-

tional interfacial heat transfer coefficient, to

elucidate the effects of yaw angle on these

macroscopic flow and heat transfer characteris-

tics. Upon examining these numerical data, a

usefull set of explicit expressions have been es-

tablised for the permeability tensor, Forch-

heimer tensor and directional interfacial heat

transfer coefficient to characterize flow and heat

transfer through a bank of cylinders in yaw.

［Journal of Fluid Mechanics, Vol. 498, pp.

131-159 （2004）］

16 論 文 抄 録

Criterion to evaluate the stability of Nd

sintered magnets for refrigerant compressor

motors

Tadashi Yanagisawa, Mitsuhiro Fukuta,

Tadashi Iizuka, Akihiko Ishiyama, Masami Wada

and Yuko Ohtani

冷媒圧縮機モータ用Nd焼結磁石の

安定性を評価するための基準

柳沢　正、福田充宏、飯塚　董、石山明彦、

和田正美、大谷裕子

　This paper concerns the stability of Nd

（neodymium） sintered magnets used for

high-efficiency DC motors in refrigerant com-

pressors. Many kinds of Nd sintered magnets

with and without surface treatment were sub-

jected to the aging test of 140℃ and 1440 hours

under three different atmospheric conditions of

refrigerant, oil, moisture content and vacuum

level. Mechanical and magnetic properties of

the magnet were examined, and chemical char-

acteristics of the oil and refrigerant were also

analyzed. As a result, most of the tested magnets

retained the satisfactory properties after the ag-

ing test, but some magnets without surface

treatment showed deterioration in magnetic

properties. The deterioration was larger under

the condition with higher moisture content.

Concerning the oils and refrigerants, no re-

markable change in their chemical characteris-

tics was observed after the aging test. The test

conditions employed in this study become one

of the evaluation criteria of the Nd sintered

magnets.

［日本冷凍空調学会論文集、Vol. 20 No. 2, pp. 265-272

（2003）］

Performance characteristics of air cycle heat

pumps working with moist air

Tadashi Yanagisawa, Mitsuhiro Fukuta,

Yasuhiro Ogi and Kiyoshi Sawai

湿り空気で作動する空気サイクルヒートポンプの

性能特性

柳沢　正、福田充宏、小木康弘、澤井　清

　As the environmental issues become serious

due to synthetic refrigerants used for refrigera-

tion and heat pump systems, the use of natural

substance as refrigerant, so-called natural re-

frigerants or natural working fluids, is expanding

in many systems. The potential natural working

fluids are hydrocarbon, carbon dioxide, am-

monia, water, air and so on. In this study, an air

cycle heat pump water heating system using air

as a working fluid is focused, and the ways to

improve its performance are discussed. As one

of the ways, we propose to use moist air instead

of dry air and its performance characteristics are

examined theoretically. As a result, heating ca-

pacity and the expansion power increase with

the increase of the humidity ratio at the com-

pressor inlet, which leads to the improvement of

the cycle coefficient of performance. The heat

pump water heating system working with moist

air can be one of promising applications of the

air cycle.

［Proceedings of 21st International Congress of

Refrigeration, Paper No. ICR0229, pp. 1-7, （2003）］

Expansion type air dryer for compressed air

Tadashi Yanagisawa, Mitsuhiro Fukuta and

Yasuhiro Ogi

圧縮空気用の膨張形エアドライヤ

柳沢　正、福田充宏、小木康弘

　There are many types of air dryers for com-

pressed air such as refrigeration type, adsorp-

tion type and so on. In this study, a new type of

17論 文 抄 録

air dryer is proposed using an expander which

works with compressed air and produces low

temperature, low humidity air easily. Perfor-

mance characteristics of the expansion type air

dryer are investigated theoretically. Many types

of expander arrangements including the con-

ventional air cycle are possible, but the most

promising ones are the expander-compressor

and compressor-expander combinations work-

ing with the compressed air. The dryers can

achieve a pressurized dew point of 10 ℃ with

work less than 10 % of the isentropic air-com-

pression energy.

［IMechE Conference Transactions, Interna-

tional Conference on Compressors and their

Systems, C615, pp. 349-358, （2003）］

Performance prediction of vane type expander

for CO2 cycle

Mitsuhiro FUKUTA, Tadashi YANAGISAWA and

Reinhard Radermacher

CO2サイクル用ベーン形膨張機の性能予測

福田充宏、柳沢　正、Reinhard Radermacher

　Carbon dioxide （CO2） is one candidate of al-

ternatives to HFC refrigerants for refrigeration

or heat pump cycles. Since the inherent COP of

an air-cooled CO2 cycle is lower than that of

HFCs, both compressors and the cycle perfor-

mance should be improved. The most promis-

ing method for improving the performance of

CO2 cycle is to recover throttling loss by using

an expander as an expansion device. In this

study, a vane type expander is considered. The

expansion process from super-critical condition

to two-phase one in the expander and the per-

formance of the expander are analyzed with a

mathematical model. Although a large expan-

sion volume ratio is not achievable with the

vane type expander, decrease of the perfor-

mance due to the small expansion ratio is ac-

ceptable. The influence of leakage on the per-

formance of vane expander is dominant, while

the heat transfer from the expander body to the

fluid has relatively small influence on the per-

formance.

［Proceedings of 21st International Congress of

Refrigeration, Paper No. ICR0251, pp. 1-8, （2003）］

ベーン形圧縮機におけるベーン背圧とその計算モデル

福田充宏、柳沢　正、井尻　誠、依田誠一郎

Vane back-pressure of vane type compressor

and its mathematical model

Mitsuhiro Fukuta, Tadashi Yanagisawa,

Makoto Ijiri, Seiichiro Yoda

　ベーン形圧縮機ではベーンとステータの離間現象を

防ぐために吐出し圧力を利用してベーン背部空間を昇

圧しているが、圧力が高すぎるとベーン先端の摩擦や

摩耗を引き起こすため、適正な圧力とする必要がある。

本研究ではベーン形圧縮機のベーン背圧予測モデルの

構築を目的とし、ベーン背部空間につながる空間の可

視化およびベーン背圧の測定を様々な条件で行い、計

算値との比較を行った。その結果ベーン背部空間には

圧縮室側から冷媒ガスが漏れ込んでいること、ロータ

端面の漏れ流れはロータ外周の時間平均圧力分布を用

いてモデル化できることなどを示し、ベーン形圧縮機

のベーン背圧計算のモデル化の指針を得た。

［日本冷凍空調学会論文集、20巻、3号、pp. 375-385,

（2003）］

Influences of miscible and immiscible oils on

flow characteristics through capillary

tube-part I: experimental study

Mitsuhiro Fukuta, Tadashi Yanagisawa,

Toshinori Arai and Yasuhiro Ogi

キャピラリーチューブを通る流動特性に及ぼす相溶油

および非相溶油の影響－第１報：実験的研究

福田充宏、柳沢　正、新井聡経、小木康博

　A capillary tube is widely used as an expan-

sion device for small refrigeration cycles. In a

practical refrigeration cycle, some amount of

refrigeration oil is discharged from a compres-