• Journal of the Korean Society of Safety
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• v.23 no.3
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• pp.8-11
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• 2008

In the present work, the measurement method of residual stresses in thermal barrier coatings(TBCs) which are received the thermal shock is performed numerically. For this, the internal residual stresses are predicted by commercial FEM software ABAQUS because the hole drilling strain gage method measures residual stresses only near the surface of a material. As the results of this study, the residual stresses are linearly increased when the surface temperatures are over $1,200^{\circ}C$. It is also found that the values of residual stress are increased as the coating thickness is thin.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.652-656
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• 2002

The HDM(Hole Drilling Method) is a relatively simple and accurate method in measuring residual stress of welded metal. Various methods of evaluating residual stress are studied in welding field. The method of cutting holes on the plate much affects the accuracy of result. Especially for the hard material like stainless steel difficult to cut preciously is difficult to measure residual stress on welded metal. Because heat conduction of stainless steel is lower than other general steel, the magnitude of residual stress might be different as to changing of welding conditions. Therefore, The distribution of residual stress on the STS304 steel after welding using HDM is evaluated in this paper.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.263-268
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• 1999

The most important things to the tube the of the heat exchanger are the precision of t hole position and the quality of the drill face. Nowadays, 6 and 12 spindle multi-drilling machine controlled by CNC or used to drill holes of the tube sheet. The drilling of 12 axes can offer high speover three times as fast as the drilling of axis. However, the drilling of 12 axes h difficulty in controlling many motors to d spindles and assigning a corresponded numbe accurately to each axis. In the past, conventional method to inspect the code the drilling was machining holes on a thin plate previously which resulted in the productivity because it required a h production cost by machining and weldin time. In this thesis, there are two drilling codes different from CNC code. M code is used to control many motors and S code is used to assign a correspondent number for each axis. For increasing the productivity by removing process, this paper is intended to take simulation of the drill machining c including 6 and 12 axis on the persona computer.

• Journal of Korean Society of Steel Construction
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• v.11 no.3 s.40
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• pp.301-309
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• 1999

The purpose of this study is to develop a method to deduce existing stress of steel member in inelastic range. Based on the previous experimental study, modified factor method considering the local plastification due to stress concentration was proposed. Finite element analysis was performed to investigate the stress distribution around hole and the results of the finite element analysis were compared with those from the Hole Drilling Method in elastic-plastic range. As a result of applying a modified factor method, proposed method shows very good approximation of 2% error for exact value of stress in the plastic range.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.22-27
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• 2012

Drilling process is usually the most efficient and economical method of making a hole in a solid body. However, there have been no analytical method to assess drilling process based on the shear and frictional characteristics. In this paper, procedures for analyzing shear and frictional processes of drilling have been established by adopting an equivalent turning system to drilling. A series of drilling experiments were carried out with varying feed, velocity and drill shape factors. Using the results of the experiments, the cutting characteristics including shear in the primary shear zone and friction in the chip-tool contact region of drilling process have been analyzed. The specific cutting energy tends to decrease exponentially with increase of feed rate. In drilling process 35-40% of the total energy is consumed in the friction process. This is greater than that of turning process in cutting of the same work material.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.657-660
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• 2002

In this paper, a study on the residual stress of plate with longitudinal stiffeners is explained in terms of the welding sequences. In order to verify the results of numerical analysis, the hole drilling method (HDM) is performed, to measuring the residual stresses of the test plates in $CO_2$ Flux Cored Arc Welding (FCAW) under various welding conditions. The non-linear transient analysis technique for the numerical analysis in a large and complicate structure is considered. The residual stress of plate in consideration of the welding sequences and directions is evaluated by some numerical simulations and also by experiments. Comparison of numerical analysis results with experimental data shows the accuracy and validity of the proposed method.

• Journal of Welding and Joining
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• v.15 no.2
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• pp.81-88
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• 1997

The residual stresses produced by a circumferential weld between axisymmetric cylinders are one of the most important problems concerning buckling strength, fatigue strength, stress corrosion cracking in shell structures, and arc quite different from those due to a butt weld between flat plates. This paper presents experimental studies on weld cylinder models of various heat inputs and thin cylinder diameters by blind hole drilling method. As a result, it is certified that weld residual stress (axial stress and hoop stress) is larger, as heat input and shell cylinder diameter are larger, and that experimental results show good agreement with the result of preceding researchers.

• 한국기계연구소 소보
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• s.15
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• pp.75-87
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• 1985

A review was performed on fatigue life prediction and strength evaluation of shot peened parts. Fatigue strength of machine parts can be improved by shot peening due to compressive residual stresses on such parts. Compressive residual stress cannot be uniquely define by peening intensity. Several measuring methods of residual stress and the principle of hole drilling method are presented. Exploratory measurement of residual stress was performed on the shot peened SM35C plate with the hole drilling method. Fatigue life and failure location of shot peened parts under bending load can be predicted by a damage parameter which is incorporated with material properties, residual stress, and applied stress conditions. Some method are presented to predict the fatigue strength of shot peened parts at any given life. Shot peening gives its full benefit to the notched machine parts of high strength steels.

• International Journal of Korean Welding Society
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• v.4 no.1
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• pp.10-14
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• 2004

In this paper, a study on the residual stress of plate with longitudinal stiffeners is explained in terms of the welding sequences. In order to verify the results of numerical analysis, the hole drilling method (HDM) is performed, to measuring the residual stresses of the test plates in $CO_2$ Flux Cored Arc Welding (FCAW) under various welding conditions. The non-linear transient analysis technique for the numerical analysis in a large and complicate structure is considered. The residual stress of plate in consideration of the welding sequences and directions is evaluated by some numerical simulations and also by experiments. Comparison of numerical analysis results with experimental data shows the accuracy and validity of the proposed method.

• Journal of Korean Society of Steel Construction
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• v.12 no.2 s.45
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• pp.197-207
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• 2000

A transient heat transfer analysis and thermo-elastic analysis have been performed for the residual stress distribution on the fillet weldment used by finite element method. Specimen is fabricated single-pass fillet welding. This computation was performed for conditions including surface heat flux and temperature dependent thermo-physical properties using by heat input as parameter. Also, cut-off temperature of residual stress estimation by thermo-elastic analysis is determined. The fillet weldment were measured to determined their residual stress distributions for using hole-drilling method. As result, it was found that large tensile residual stress is about material yield strength, and the numerical simulation results for finite element method similar to residual stresses by hole-drilling method and other exiting research. Also, cut-off temperature is effectively determined by temperature which calculated maximum thermal stress equal to material yield strength.