홀드릴링 방법을 사용한 금속의 잔류응력 해석

이중원,박명균,박세만 명지대학교 산업기술연구소 2007 産業技術硏究所論文集 Vol.26 No.-

Hole drilling method is one of the powerful methods to estimate the amount of residual stresses quantatively on metal alloy. Since the residual stress causes the degradation of the products in strength and poor products in quality it is necessary to find out the easy and efficient method. Present paper discusses the methodology how to estimate residual stresses and investigates the heat treatment effects on residual stresses using the hole drilling method for heat treated and non heat treated metal alloy. And to verify the results obtained from hole drilling method, the obtained results from resonance method were compared. The results show that they are well agreeable in tendency of stress distribution and that the amount of residual stress varies with drilling depth nonuniformly and the designer can more effectively control the residual stresses by being able to estimate heat treatment condition quantitative through the drilling hole method.

Hole-drilling 방법을 사용한 Polycarbonate 소재의 잔류응력측정

방선호(Sun-Ho Bang),김선우(Sun-Woo Kim),이언석(Eon-Seok Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

Hole-drilling method for residual stress is a flexible technique as the measurements can be made over a small area. However, it is very difficult to use hole-drilling method in polymers not only because there has been no detailed study of its application to polymer but also because there is not a standard for hole-drilling method in polymer. The key of this method is the hole-drilling, which must be carried out to a high degree of precision in polymer. In order to minimize induced pressure and heat during drilling on polymer, this paper selected three parameters; drill speed, drilling depth, and relaxation time at each step. In this paper, the effects of these parameters on hole-drilling are investigated and the optimized condition of these parameters for measurement of residual stress in polycarbonate is provided.

Investigation on the Hole-producing Techniques of Residual-stress Measurement by Incremental Hole-drilling Method in Injection Molded Part

김채환 한국섬유공학회 2018 Fibers and polymers Vol.19 No.8

Injection molding is one of the most important processes for manufacturing plastic parts, but residual stresses are generated due to non-uniform temperature distribution in the mold cavity. It is important to predict the internal stress development during molding and after ejection and measurement of the residual stress distribution is needed to verify the prediction of the residual stresses. The incremental hole-drilling method was employed to evaluate residual stresses in injection-molded parts. An experimental investigation is performed to study the effect of induced drilling stresses in incremental hole-drilling method. While the ultra sonic mill for the through-hole drilling would tend to satisfy the lowinduced- stress requirement, UV laser processing could not somewhat satisfy the quality of the bottom surface of the hole. This study reports hole-producing techniques that might be suitable for the general requirements of residual stress measurement by the hole-drilling method.

Influence of Inclined Holes in Measurement of Residual Stress by the Hole Drilling Method

Kim, Cheol,Yang, Won-Ho,Heo, Sung-Pil The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.12

The hole drilling method is widely used in measuring residual stress in surfaces. In this method, the inclination of holes is one of the sources of error. This paper presents a finite element analysis of the influence of inclined holes on the uniaxial residual stress field. The error in stress has been found to increase proportionally to the correct inclined angle of the hole. The correction equations by which one may easily obtain the residual stress, taking account of the inclined angle and direction, have been derived. The error of stress due to the inclined hole has been reduced to around 1% using the correction equations.

Prediction of Error due to Eccentricity of Hole in Hole-Drilling Method Using Neural Network

Kim, Cheol,Yang, Won-Ho The Korean Society of Mechanical Engineers 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.11

The measurement of residual stresses by the hole-drilling method has been used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, we obtained the magnitude of the error due to eccentricity of a hole through the finite element analysis. To predict the magnitude of the error due to eccentricity of a hole in the biaxial residual stress field, it could be learned through the back propagation neural network. The prediction results of the error using the trained neural network showed good agreement with FE analyzed results.

Hole Drilling 방법의 열과 표면처리에 의한 잔류응력 계산

유재석,박세만 明知大學校 産業技術硏究所 2008 産業技術硏究所論文集 Vol.27 No.-

Residual stresses deteriorate strength of materials adversely affecting quality of industrial products. A removable or a reduction of the residual stresses is an essential procedure in successful product developments. Effective and convenient methods are necessary for detection and evaluation of the residual stresses. In this investigation Hole Drilling Method is chosen for identification and a quantitative determination of the residual stresses of specimen in different groups under three heat and surface treatment conditions. The specimen in the first group is standard reference specimen without the heat treatment. The ones in the second group is carburized specimen with the surface treatment. In another group specimen is exposed to high frequency electric power to achieve the desired heat treatment condition. The residual stresses of metal alloys are evaluated subsequently with an analysis for the specimens prepared under a variety of heat and surface conditions, revealing complex effects of the treatments on the residual stresses as well as on properties of the materials. The amount of the residual stresses comes in that order of the specimen with the high frequency, with the carburized treatment and the specimen without the heat treatment. The quantitative analysis as well as experience suggests reliable and effective processes to eliminate or reduce the residual stresses. Also, during process of pipe welding a high level of residual stresses is observed to develop and its level increases non-uniformly with a depth into a hole. Based on the experimental results and the analysis, proper treatment conditions can be predicted to reduce or even completely eliminate the residual stresses, leading to an establishment of reliable methods for a control of the residual stresses.

냉간압연강판 SCP1-S 의 레이저 홀가공 공정시 발생되는 응력해석

이우람(Wooram Lee),김주한(Joohan Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

A laser machining process has been applied in many manufacturing fields and it provides an excellent energy control for treating materials. However, a heat effect during laser machining can deteriorate material properties. Specifically, a thermally induced stress can be a problem in laser-machined structures on a metal surface. In this study, temperature and stress on cold rolled carbon steel sheet machined with laser hole drilling were explored in an experimental approach and a numerical method. Stresses by temperature gradients inside the materials were generated in fast cooling. The stresses were measured by using a hole-drilling method and the material properties of SCP1-S were obtained in the experiment. It was found that the stress predicted from the numerical analysis was in agreement with the stresses measured by using the hole-drilling method. The analysis can be applied for evaluating structure characteristics machined with a laser.

열처리 조건에 대한 금속의 잔류응력 측정

박명균,박세만,구본성 명지대학교 산업기술연구소 2006 産業技術硏究所論文集 Vol.25 No.-

It's very important to estimate the amount of residual stresses quantatively depending on heat treatment condition on metal alloy since the residual stress causes the degradation of the products in strength and poor products in quality. Present paper discusses the methodology how to estimate residual stresses and investigates the heat treatment effects on residual stresses using the hole drilling method for heat treated and non heat treated metal alloy The results show that the amount of residual stress varies with drilling depth nonuniformly and the designer can more effectivly control the residual stresses by being able to estimate heat treatment condition quanatively through the drilling hole method. Through this method engineers can predict the heat treatment effects and can use to control the heat treatment.

레이저 드릴링을 통한 강판 가공 시 응력 모델링

이우람(Wooram Lee),김주한(Joohan Kim) 대한기계학회 2013 大韓機械學會論文集A Vol.37 No.7

레이저 정밀 가공은 고품질의 집속 광에너지를 이용하여 재료를 미세하게 가공하는 특수 가공으로 정밀 제조 분야에 적용되고 있다. 그러나 레이저 가공 시 열적 효과로 인해 재료 특성을 저하 시킬 수 있다. 또한, 압연 강재 및 강판의 경우 공정 단계에서 강한 압력으로 제작하기 때문에 반드시 잔류응력이 존재한다. 하지만 압연 강재에 존재하는 잔류응력의 양은 정량적인 예측이 불가능하다. 이러한 잔류응력이 존재하는 재료의 레이저 가공 시 레이저에 의한 부가적인 응력 발생 및 재료에 미치는 열적 영향의 예측 및 평가는 정밀 가공에 있어서 반드시 고려해야 하는 사항이다. 본 연구에서는 레이저홀 가공 시 발생되는 온도 및 응력을 유한요소 해석과 실험적 방법으로 분석하였다. 재료의 열응력을 예측하기 위해 레이저 홀가공 실험을 수행하여 가열 및 냉각 등의 대한 결과를 도출하였다. 또한 냉각시간에 따른 응력의 변화를 파악하였고 유한요소 해석으로 예측된 응력을 홀드릴링 응력 측정 기법에 의해 도출된 응력과 비교 검증하였다. A laser machining process has been applied in many manufacturing fields and it provides an excellent energy control for treating materials. However, a heat effect during laser machining can deteriorate material properties. Specifically, a thermally induced stress can be a problem in laser-machined structures on a metal surface. In this study, temperature and stress on cold-rolled carbon steel sheet machined with laser hole drilling were explored in an experimental approach and a numerical method. Stresses by temperature gradients inside the materials were generated in fast cooling. The stresses were measured by using a hole-drilling method and the material properties of carbon steel (SCP1-S) were obtained in the experiment. It was found that the stress predicted from the numerical analysis was in agreement with the stresses measured by using the hole-drilling method. The analysis can be applied for evaluating structure characteristics machined with a laser.

홀 드릴링 방법을 사용한 용접 파이프의 잔류응력 측정

박명균,박세만 明知大學校 産業技術硏究所 2004 産業技術硏究所論文集 Vol.23 No.-

It's very important to estimate the amount of residual stresses quantatively since the residual stress causes the degradation of the products in strength and poor products in quality. Present paper discusses the methodology how to estimate residual stresses and investigates the heat treatment effects on residual stresses using the hole drilling method for heat treated and non heat treated mild steel pipes. The results show that the amount of residual stress varies with drilling depth nonuniformly and the designer can more effectivly control the residual stresses by being able to estimate quanatively through the drilling hole method.