• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.389-392
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• 2000

Gouge-free tool-path generation is an important issue in mold & die machining and researches on cutter interference avoidance can be found in many articles. One of the various methods is construction of tool-offlet surface or cutter-location (CL) surface on which the cutter-center point (CL-point) locates. Provided that the CL surface is represented in a suitable form, cutter-interference avoidance can be performed without the burden of computing CL data for every cutter-contact (CC) point. In the paper, various methods of constructing a CL surface in the z-map form are presented, where z-map is a special form of discrete nonparametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z［i,j］.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.121-128
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• 2001

This is a case study of stability analysis and reinforcement design for the tunnel where the collapse of the entrance slops occured along the fault zone developed in the bed rock. According to the site investigation, the main factor of sliding is the influence of fault gouge and heavy rainfall. Considering the in-situ condition, the versatile reinforcement methods is needed, and so the close investigation on the site area was accompanied with the stability analysis of tunnel and slops. The FRP(Fiberglass reinforced plastic) grouting method improved the defect of Steel Umbrella Arch Method, such as oxidation, low work efficiency, the material's heavy weight, is adapted as the reinforcement methods.

• 대한산업공학회지
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• 제26권4호
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• pp.325-335
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• 2000

Gouge-free tool-path generation is an important issue in mold & die machining and researches on cutter interference avoidance can be found in many articles. One of the various methods is construction of tool-offset surface of cutter-location (CL) surface on which the cutter-center point (CL-point) locates. Provided that the CL surface is represented in a suitable form, cutter-interference avoidance can be performed without the burden of computing CL data for every cutter-contact (CC) point. In the paper, various methods of constructing a CL surface in the z-map form are presented, where z-map is a special form of discrete nonparametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z[i,j].

• 지질공학
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• 제15권3호
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• pp.349-363
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• 2005

울산단층 동부지역에는 제4기로 추정되는 미고결 퇴적층을 절단하며 파쇄대 와 단층비지를 수반하는 제4기 단층이 여러 곳에서 발견되고 있다. 본 연구에서는 제4기 단층비지대의 성분변화, 체적변화, 실리카의 손실 그리고 유체-암석비를 XRF, XRD, EPMA를 이용하여 계산하였다. 단층비지의 성분변화는 모암에 비해 단층비지대에서 $SiO_2,\;K_2O,\;Na_2O$는 감소하고, $Al_2O_3,\;MgO,\;P_2O_5,\;Fe_2O_3,\;MnO,\;CaO,\;LOI$는 증가한다. 단층별 체적감소는 개곡 제1단층 $56\%$, 개곡 제2단층 $22\%$, 신계단층 $34\%$, 마동단층 $8\%$, 원원사단층 $2\%$, 진현단층 $53\%$이다. 체적감소, 실리카 손실, 유체-암석비가 낮게 나타난 마동단층과 원원사단층 비지대는 유체활동에 대하여 닫힌계 이 고, 체적감소, 실리카 손실, 유체-암석비가 높은 개곡 제1단층과 진현단층의 비지대는 유체 활동의 통로로 작용한 열린계였을 것으로 볼 수 있다. 단층의 유체-암석 체적비는 모든 단층에서 $10^2\sim10^4$로 나타나지만 기질의 함량이 각각 $88\%$와 $77\%$로 높고 체적감소가 큰 개곡 제1단층과 진현단층에서 가장 높게 나타난다. 따라서 이들 단층에서 유체의 활동이 가장 활발하였다.

• 자원환경지질
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• 제56권3호
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• pp.293-300
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• 2023

Shape Preferred Orientation (SPO) 분석법은 단층의 운동학적 연구에 기초자료로 사용되는 단층면 운동 방향 분석을 위해 사용할 수 있는 방법으로 이용되어왔다. 단층비지 내 석영, 장석 등의 암편들로 이루어진 강성체들은 주어진 전단력에 의해 강성체 회전을 통해 P-전단 방향으로 배열되며, 이 특성을 이용해 역으로 SPO로부터 단층 운동 방향을 추정할 수 있다. 최근 X-선 CT 영상을 활용해 3D-SPO를 측정하여 빠른시간 내에 다수의 입자들의 형태를 조사함으로서 정밀도와 신뢰성을 확보하는 방법이 개발되었다. 이로서 SPO 분석법은 수천~수만개 이상의 입자들의 방향성을 빠른 속도로 분석하여 단층 운동 방향을 제시하며 용이한 접근성과 신뢰도 높은 데이터를 제공한다. 더불어 SPO 분석과정에서 획득되는 부산물인 입자들의 형태학적 정보와 방향성 분포 데이터는 단층 활동 당시 일어난 단층암의 국부적 변형, 단층 발생 메커니즘과 같은 다양한 연구를 진행할 수 있는 기초데이터로서 활용 할 수 있을 것으로 기대된다.

• Journal of Welding and Joining
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• 제14권5호
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• pp.95-105
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• 1996

Korea Gas Corporation has operated high pressure gas transmission line of about 600 kilometers and, therefore, a series of repair welding processes are required in order to cope with external defects such as dent, gouge, cracking usually due to mechanical attacks. Most of gas pipelines repair processes are performed after completely venting remaining gas. However, in some case, though it is very unusual, repairs require without venting gas. For instance, this case is that damaged pipeline is remedied with split sleeve by welding. In this paper, in an effort to confirm a safe application of the split sleeve welding, residual stress, strain and temperature distributions are evaluated by computer simulation and experiments. The results obtained are as follows : 1) Computer modelling is supposed to be reasonable because microstructure changes due to welding is simulated coincidently as compare to that of real condition. 2) The maximal temperature on inside surface of pipeline is 50$0^{\circ}C$ for the repair welding process. 3) The amount of residual stress is estimated as the stress corresponding to 0.8% strain. 4) The repair process employed is determined to be technically preferable because of its avoiding cracks and fractures in the course of welding.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2124-2135
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• 2006

In this paper, the reliability estimation of pipelines is performed by employing the probabilistic method, which accounts for the uncertainties in the load and resistance parameters of the limit state function. The FORM (first order reliability method) and the SORM (second order reliability method) are carried out to estimate the failure probability of pipeline utilizing the FAD (failure assessment diagram). And the reliability of pipeline is assessed by using this failure probability and analyzed in accordance with a target safety level. Furthermore, the MCS (Monte Carlo Simulation) is used to verify the results of the FORM and the SORM. It is noted that the failure probability increases with the increase of dent depth, gouge depth, operating pressure, outside radius, and the decrease of wall thickness. It is found that the FORM utilizing the FAD is a useful and is an efficient method to estimate the failure probability in the reliability assessment of a pipeline. Furthermore, the pipeline safety assessment technique with the deterministic procedure utilizing the FAD only is turned out more conservative than those obtained by using the probability theory together with the FAD. The probabilistic method such as the FORM, the SORM and the MCS can be used by most plant designers regarding the operating condition and design parameters.

• 한국정밀공학회지
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• 제32권8호
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• pp.705-711
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• 2015

Five-Axis machines can generate undesirable defects such as the undercutting and overcutting errors that frequently occur in the three-axis machining process. It is therefore necessary to develop a program for NC-code generation, whereby the cutter posture is considered to decrease the occurrence of defects. In previous studies, the Easy-Impeller CAM(E-ICAM), an automatic CAM program used for the five-axis machining of impellers, was developed; however, when E-ICAM is used to machine an impeller, it is possible to gouge the hub and blade. Therefore, the aim of this study is the establishment of a formula for each type of endmill to minimize gouging according to the cutter posture, in consideration of several factors that affect accuracy in the machining of an impeller. This study also aimed to improve the performance and accuracy of E-ICAM in the manufacturing of impellers.

• 대한기계학회논문집A
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• 제29권3호
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• pp.447-454
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• 2005

This paper presents a new paradigm for 3-axis tool path generation based on an incomplete 2-manifold mesh model, namely, an inexact polyhedron. When geometric data is transferred from one system to another system and tessellated for tool path generation, the model does not have any topological data between meshes and facets. In contrast to the existing polyhedral machining approach, the proposed method generates tool paths from an incomplete 2-manifold mesh model. In order to generate gouge-free tool paths, CL-meshes are generated by offsetting boundary edges, boundary vertices, and facets. The CL-meshes are sliced by machining planes and the calculated intersections are sorted, trimmed, and linked. The grid method is used to reduce the computing time when range searching problems arise. The method is fully implemented and verified by machining an incomplete 2-manifold mesh model.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.245-248
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• 2001

During the core drilling for the design of a railway bridge crossing over the inferred fault system along the river, fracture zone, extends vertically more than the bottom of borehole, filled with fault gouge was found. The safety of bridge could be threatened by the excessive subsidence or the reduced bearing capacity of bedrock, if a fault would be developed under or around the pier foundation. Thus, a close examination of the fault was required to rearrange pier locations away from the fault or to select a reinforcement method if necessary. Geophysical methods, seismic reflection method and electrical resistivity survey over the water covered area, were applied to delineate the weak zone associated with the fault system. The results of geophysical survey clearly showed a number of faults extending vertically more than 50m. Reinforcement was not desirable because of the high cost and the water contamination, etc. The pier locations were thus rearranged based on the results of geophysical surveys to avoid the undesirable situations, and additional core drillings on the rearranged pier locations were carried out. The bedrock conditions at the additional drilling sites turned out to be acceptable for the construction of piers.