圓孔을 포함하는 傾斜直線 CRACK을 가진 有限板의 應力擴大係數 및 破壞進路에 한 硏究

郭相國 영남이공대학 1981 論文集 Vol.10 No.-

On being straight oblivion Crack with a circular Hole, The Author tried to obtain K_(Ⅰ) and K_(Ⅱ) Value on the mixed mode by varing oblivion Angle (β) and crack length (H), In the result, It is well Known that the value of H/D is larger, The final value of K_(Ⅰ) is less. And It is known that the value of H/D is larger, The final Value of K_(Ⅱ) is larger. And then, In case of β<45˚, without indifference on the Value of H/D It is known that K_(Ⅰ) is larger than K_(Ⅱ) And the value of Fracture Angle is ploted as Fig 6. On this graph, the Value of Fracture Angle is known to be distributed to -β+88<Θ<-β+98 Arrange.

2 1/4 Cr-1 Mo강 劣化材의 微小 疲勞龜裂의 발생 및 진전거동

곽상국,장재영,권재도,최선호,장순식 대한기계학회 1992 대한기계학회논문집 Vol.16 No.1

본 연구에서는 약 10년 정도 사용하여 경년 열화가 되었다고 예상되는 실구조 물의 일부를 입수하였으며 열화재의 특성과 비교하기 위하여 열처리에 의해 충격치를 회복시킨 재료를 회복재로 하여 두가지 재료에 대해 시험편을 제작하였따.열확현상 을 파악하기 위하여 평활재로 피로과정, 즉 미소 균열의 발생, 진전 및 복수 균열이 간섭합체하여 파단에 달하는 과정에 대하여 파괴역학적 견지에서 열화재와 회복재를 해석하고 이결과로 부터 확율변수를 추정하여 통계학적인 수명예측방법의 하나를 제시 하여 실구조물에 적용하는 방법에 대해 시도해 보았다. Material can be degraded by using it for a long service under the high temperature and pressure circumstances, Therefore, material degradation can affect the strength of mechanical structures. At present, the life prediction of the degraded structures is considered as an important technical problem. In this paper, the degraded 21/4Cr-lMo steel is the material used for about 10 years around 400.deg. C in an oil refinery plant. The recovered one was prepared out of the above degraded steel by heat treatment for one hour at 650.deg. C. The degradation effect was investigated through the tension test, Hardness test and Charpy impact test. On the smooth surface material, the fatigue crack initiation, growth and coalescence stages of the distributed small cracks were investigated with photographs, and the crack length and density were measured. The measuring results were analyzed by quantative and statistical methods.

신뢰성 공학적 피로 균열의 발생 , 진전 수명 평가 및 예측

곽상국,권재도,최선호,황재석,전경옥,진영준,장재영 대한기계학회 1990 대한기계학회 춘추학술대회 Vol.- No.-

차량용 점화코일 고속가공기에 관한 연구

곽상국,한창우 영남이공대학 2002 論文集 Vol.31 No.-

Automotive Ignition coil is to transform the normal battery voltage of 12V to the second voltage of approximately 20∼30KV by discharging and mutual induction., then the induction current loss should be happened by insulation resistance, increasement. In this study, the new model of high speed machine of the automotive ignition coil to solve the problem by completing the wire alignment and speeding the wire winding is introduced. By analysing mechanism of the system governing equations of the system is obtained. In these cautions it is known that the wire tension can be controlled by the constant velocity control. Which is proved by the experiment. In addtion to, it is proved that tension profile is the indicator which judges wire alignment situation by the experiment. Pm velocity controller in winding bobbin motor, PI position, PID velocity controllers in winding guide motor, tension controller in electrical brake, and tension bar make wire winding speed and tension be stable. As the result, the high speed machine of the automotive ignition coil in the winding speed of 600 RPM is developed. Therefore by compacting wire winding alignment and speeding wire winding, it is expected that the performance of automotive ignition pail should be improved, the efficiency of engine output should be increased, and the amount of the emission gas should be decreased.

승용차용 자동 변속기의 토크 변환기 특성에 관한 연구

곽상국 영남이공대학 2000 論文集 Vol.29 No.-

Recently, melt cars adopted auto transmission(A/T) due to the development of automobile transmission. For example, American automobiles am equipped with A/T over 43096 and Japanese nearly takes A/T. Also most Korean passenger cars are the same and multiplied vehicles are developed with A/T tendency and some small automobile equipped C.V.T. Therefore, it is necessary that Torque Converter(T/C) must be equipped with both of A/T and C.V.T. and TIC plays very important roles for transferring engine output. The T/C performance of passenger car was investigated in this study. The advancement of T/C performance contained variable factors. Among them, Efficiency, Torque Ratio and Capacity Factor were mainly studied as the important factors in this thesis

疲勞크랙의 進展 및 破斷壽命豫測에 關한 硏究

郭相國,朴淳碩 영남이공대학 산업기술연구소 1990 産業技術硏究 Vol.4 No.-

Life prediction or residual life of structures or machines are one of the most strongly world loide needed problems as requirement in the stage of slowly developing economy which comes after rapidly and highly developing stage. For the purpose of life, Prediction fatigue test was conducted under a stress level, and for this stress level, 24 specim?ns are used. The properties of the crack growth parameter m and c in the fatigue crack growth law of da/dN=C(△K)^(m), and the relation ship between m and C, and the distribution pattern of fatigue crack growth and failure lives can be obtained by experimental results.

피로균열 진전 수명의 통계학적 분포 특성

郭相國 영남이공대학 1990 論文集 Vol.19 No.-

The previous studies are concerned with crack growth about a small number of specimens fatigue test. It seems not to be satisfied that predict the statistical fracture life of a flaw, notch or craked body which are used by these data because of being lack of statistic study results about the crack, growth life among studies like these. Consequently, it needs to investigated the fatigue crack growth and the probability particularity of fatigue crack growth rates to build up the variable analysis of structures about fatigue fracture, But there are not so many exact experimental data for investigating this characteristic. In this paper, as a part for a fundamental study for the life predection of a flaw body. The probability characteristic was studied for the fatigue crack growth life from data which are obtained through many experiments.

마이코로 컴퓨터 시뮬레이숀에 의한 자동차 제동장치의 최적설계

郭相國,朴熙代 영남이공대학 1989 論文集 Vol.18 No.-

In general, the ride stability of driving vehicle is determined by the steering device, brake system.... etc. which is attached in a car. Brake system of these is necessary caused for presenting automotive accidents. Therefore, in this paper, brake system data for all vehicle is studied to be optimized through micro-computer simulation. It is developed for brake system to be optimized with micro-computer simulation. Comparation of this simulation and E. E. C. 75/524 regulation is to adopt with optimal brake system design.

自動車에 장착된 Torsion-Bar 서스펜션 스프링 (Suspension Spring) 特性에 關한 硏究

郭相國 영남이공대학 1987 論文集 Vol.16 No.-

determined by the tire, damper, and spring which are attached in a car. In this study, the characteristic of torsion bar susoension spring in vehicle suspension system is considered as follow. The stiffness of torsion bar suspension spring is variously changed by Unloaded Settling Angle. It has the value of about 0.6~0.8 to optimize the ratio of Unloaded Settling Angle and equilibrium position ratio(α/αeq). And the torsion bar suspension spring has bright driving stability in the condition of low α/αeq. high road frequency and more fit heavy loaded automobile at the same value of α/αeq.

Pin 결합구조물에서 Crack이 存在時 光彈性的 應力解析

郭相國 영남이공대학 1987 論文集 Vol.16 No.-

Multipin connectors come in many varies, Fig.2 illusstrates the joint geometry and introduces the nomenclature, Fig.2-1 illustrates the load direction in single row parrallel of pin connectors. In fig.2, this description of two outerlaps sandwiching the inner lap. Where, two outer laps are acrylic plates, and inner lap is epoxy plate. The Applied load and varied pin hole diameter will be denoted as P&I) In this paper, The author tried to obtain stress concentration factor and K₁/K_(0) by oaring D/A and P₁/P_(0) In the result, It is known as the following 1) On being the value of constant .D/A, the value of P₁/P versus D/A have reverse ratio, and at approching the D/A=0.9, α₁ is minimum. 2) Without relating in P,/P and D/A, When as is increased, ae is decreased. When a, becomes decreasing, as is increased. 3) When PIP becomes in creasing, K₁/K_(0) is increased without being relation in the D/A. and at being constant D/A, When P₁/P_(0) is increased, K₁/K_(0) is increased.