변후(變厚)용접판재에서의 피로균열성장거동에 미치는 잔류응력의 영향에 관한 파괴역학적 연구

차용훈 한국산업안전학회 1993 한국안전학회지 Vol.8 No.1

The welding implementation used widely in the industrial field is gradually increasing due to weight reduction unlimited material thickness simplified structure design, and 1 manufacturing time and cost reduction. The most significant factor that influences the fatigue crack growth rate is the residual stress generated during the welding process. Many researchers have studied the effect of the residual stress on crack growth behavior. Through a fatigue test in a various-thickness welded specimen redistributed residual stress is measured as the crack is developed. Then, by superposing the measured residual stress on the K value obtained by the finite element method.

자동차 차체 다점용접부의 면외변위측정에 관한 연구

차용훈,성백섭,이연신,박영문,김충환 朝鮮大學校 機械技術硏究所 2002 機械技術硏究 Vol.5 No.1

The very few non-contact method are still in the early stage. One of the non-contact methods is by the use of the laser that has high-level of the accuracy for the measurement, and this laser also has excellent characteristics on which many studies for its applications are focused throughout the many fields. The dissertation is on the measurement of the strain caused by the characteristics of the spot welded zone which is used with 3-D ESPI system that is functionally modified through the laser ESPI(Electronic Speckle Pattern Interferometry) system. This system employed the SGCC 1.2t which are mainly used for the steel plate such as automobile, structure, electronics instrument, building material and electronic appliances.

Photo Stress를 이용한 압력용기 용접부의 잔류응력 측정

차용훈,김덕중,장훈 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

Recently, studies on the deformation and residual stresses measurement in pressure vessel welded zone have been obtained from strain gaging method which had directly attached the gage on the surface of the material. But the non-contact method are not still general. In this paper, we will study effect on residual stress at the pressure vessel welded zone under the high pressure. The strain and residual stresses are measured by the photo-stress and hole drilling method. The material of Butt weld specimens are A516 GR70 steel for pressure vessel.

알루미늄合金 熔接部의 疲勞破壞擧動에 關한 硏究

車龍勳 조선대학교 동력자원연구소 1990 動力資源硏究所誌 Vol.12 No.1

This study practices the fatigue test of base metal, weld metal and HAZ specimen using 5052-H38-aluminum alloy welded by the GTA welding method and investigates the effect of initial residual stress which influences the fatigue crack growth rate. The results of this experimentation are summarized as follows ; 1. This experimentation confirms that the number of repeated cycle from each specimen to the last rupture is the most in the HAZ specimen and is in the order of weld metal specimen and base metal specimen. 2. The condition of crack growth retardation is occured by the effect of compressive residual stress from edge and HAZ specimen is greater than the weld metal specimen of the initial crack growth. 3. In the stable growth region of each specimen, m values are showed that m value of HAZ specimen is the greatest as 2.3, weld metal specimen is 2.2 and base metal specimen is 1.8. 4. Crack growth retardation by the compressive residual stress can be interpreted as superposition technique of kres.

인장-전단하중을 받는 점 용접재의 변형률 분포 특성 평가

차용훈,김덕중,이연신,성백섭 한국공작기계학회 1999 한국생산제조학회지 Vol.8 No.6

In order to evaluate strength of spot welded joint, at first it is importent that we should know strain distribution near nugget zone. During loading, in HAZ, compressive strain increase with Increase of load, but in nugget zone, tensile strain increase. During unloading, on the other hand, even though the load decreases, the strain variation is not almost appeared in nugget zone and HAZ. In nugget boundary zone, the strain range increases continuously along with load increase on outer surface, but the strain increases continuously and decreases rapidly beyond yield strength on inner surface. In this paper, strain distribution are measured in inner and outer surface with variation of thickness and load under tensile-shear load. Tensile-shear strength increased as with increase of specimen thickness. As for thickness increase rates are 25%, 50%, 100%, and 150%, tensile-shear strength increase rates are 40%, 81%, 130% and 228%.

친환경 자동차기반 부품소재 인재양성센터

차용훈 한국자동차공학회 2009 한국자동차공학회 지부 학술대회 논문집 Vol.2009 No.10

CIM을 이용한 수문 설계시스템 개발

차용훈,성백섭 朝鮮大學校 機械技術硏究所 2001 機械技術硏究 Vol.4 No.2

Today manufacturing industries are at the threshold of utilizing innovative and improved computer related technologies for the betterment of manufacturing industries. Characteristics of the present world market include demanding and sophisticated customers, requirement of high quality and innovative products, greater product diversity, increasing labour and products costs, availability of diverse alternatives to the customers and smaller batch sizes to satisfy a variety of customer profiles. To fulfil these characteristics, manufacturing companies need to be flexible adaptable, proactive and able to produce variety of products in short time at low cost. The aim of this research is to develop a computer-aided design system for water-gate on AutoCAD R2000 system. The developed system has been written in AutoCAD and VisualLISP with a personal computer, and is composed four modules which are the gate-lifter input module, guide-frame input module, template input module and upgrade module. Based on knowledge-based rules, the system is designed by considering several factors, such as width and height of a water-gate, material, object of product and maximum depth of water.

압력용기 보강재의 용접 형태에 따른 피로균열성장 거동에 관한 연구

차용훈,김하식,성백섭 한국산업안전학회 2000 한국안전학회지 Vol.16 No.3

The study is to investigate the influence on the fatigue crack growth behaviors for the welded configuration in pressure vessel stiffener. In order to perform this goal, the automatic welded specimens were prepared. The material is ASTM A516 grade 60 steel used in pressure vessel mainly. In skip welding of pad-on-plate, continuous fillet welding and PWHT specimen, fatigue crack is generally initiated at the starting and end weld toe zone, and ruptured at the starting weld toe zone. The fatigue life of pad-on-plate of the continuous fillet welding specimen is larger than that of pad-on-plate skip fillet welding specimen about 85% under low load, about 20% under high load, and less than that of two-pad continuous fillet welding specimen about 85%. In da/dN-ΔK curve under low load, skip fillet welding specimen of pad-on-plate showed retardation on the initial crack, and the fatigue crack growth rate at the low region of ΔK greater specimen E(3.8 × 10^(-6) ㎜/cycle). And the fatigue life of welding specimen was smaller than that of PWHT specimen.

알루미늄 合金 熔接部의 疲勞龜裂成長擧動에 關한 破壞力學的 硏究

차용훈,김덕중 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.3

the objective of this study is to investigate the influence of welding residual stresses on the fatigue crack growth behavior of cracks located transverse to the weld bead. For this purpose G.T.A. (Gas Tungsten Arc) welding was performed on the A1 alloy 1100-O plate and the same initial crack is made on HAZ(Heat Affected Zone), weld metal and base metal respectively. Specimens were used CT(Compact Tension) specimens. Initial welding residual stresses were measured by using strain gage sectioning method. All specimens were tested under constant amplitude load with stress ratio R=01, It is possible to predict fatigue crack growth behaviors and the fatigue life, using numerical analysis together with distribution of initial residual stress and the values of C and m obtained from da/dN-ΔK

高張力鋼 被服 아아크熔接에서의 入熱量의 影響에 관한 硏究

차용훈,정종안 조선대학교 동력자원연구소 1992 動力資源硏究所誌 Vol.14 No.2

To study the effect of heat input on cracking ratio of high tensile strength steel weld metal, Y groove cracking test method was adopted and the samples were prepared by manual welding. Then the cracking ratio, microstructure and fracture surface were examined. The obtained results are as follows: 1. As heat input is increased, the hardness of fusion line in weld metal is decreased, but the hardness is increased. 2. As heat input is increased, the metal structure of HAZ consists of pearlite and ferrite. 3. Increasing the heat input results in the grain growth and the brittle fracture.