휠 제동 장치의 스퀼 소음 해석을 위한 해석 모델 구축

차정권(Cha Jung-kwon),박영일(Park Yeong-il),이동균(Lee Dong-Kyun),조동현(Cho Dong-Hun),김기남(Kim Ki-Nam),백진성(Beak Jin-Sung) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-

Squeal of disk brake is a noise and self excited vibration with frequency range of 1~10Khz cause by the friction force between the disk and the pad of the automobile. Passengers in a cehicle feel uncomfortable. In this paper modal analysis of wheel brake system was performed in order to prediction of squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. finite element model of that brake system was made. Some parts of a real brake was selected and modeled. The normal mode analysis method performs analyses of each brake system component. Experiment of modal analysis was performed for each brake components and experimental results were compared with analytical result from FEM.

소형 전기구동 상용 특수차량용 ADAS 통합 주행 제어 시스템 개발에 관한 연구

이정권(Jung-Kwon Lee),윤태봉(Tae-Bong Yoon),차병기(Byeong-Ki Cha),이정환(Jung-Hwan Lee),김민수(Min-Su Kim) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

소형 상용 전기차량용 ADAS 기반 통합 주행 제어 시스템 개발에 관한 연구

이정권(Jung-Kwon Lee),윤태봉(Tae-Bong Yoon),차병기(Byeong Ki Cha),김영구(Young Goo Kim),정진범(Jinbeom Jeong),김민수(Minsu Kim),이정환(Jung-Hwan Lee) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.5

틸팅차량용 휠 제동장치의 스퀼 소음 해석

차정권(Cha, Jung-Kwon),박영일(Park, Yeong-Il) 한국소음진동공학회 2010 한국소음진동공학회 논문집 Vol.20 No.1

Squeal, a kind of self-excited vibration, is generated by the friction between the disc and the friction materials. It occurs at the ending stage of the braking process, and radiates and audible frequency range of 1 kHz to 10 kHz. Squeal is generated from unstability because of the coupling between the translation and rotation of the system. This instability is caused by the follower force and follower force is normal component of the friction force. In this paper modal analysis of wheel brake system was performed in order to predict the squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. A finite element model of that brake system was made. Some parts of a real brake was selected and modeled. Modal analysis method performs analyses of each brake system component. Experimental modal analysis was performed for each brake components and experimental results were compared with analytical results from FEM. To predict the dynamic unstability of a whole system, the complex eigenvalue analysis for assembly modeling of components confirmed by modal analysis is performed. The finite element models of the disk brake assembly have been constructed, and the squeal noise problems have been solved by complex eigenvalue analysis. The complex eigenvalue analysis results compared with real train test.

휠제동장치의 스퀼소음 제어를 위한 해석결과 분석

차정권(Cha Jung-kwon),박영일(Park Yeong-il),이동균(Lee Dong-Kyun),조동현(Cho Dong-Hun) 한국철도학회 2009 한국철도학회 세미나자료 Vol.2009 No.5

Passengers in a vehicle feel uncomfortable due to squeal noise. Squeal noise, a kind of self-excited vibration, is generated by the friction force between the disc and the pad of the automobile. In this paper, modal analysis of wheel brake system was performed in order to prediction of squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. Finite element model of that brake system was made. Some parts of a real brake was selected and modeled. The normal mode analysis method performs analyses of each brake system component. Experiment of modal analysis was performed for each brake components and experimental results were compared with analytical result from FEM. The complex eigenvalue analysis results compared with braking test. The analysis results show good correlation with braking test for the squeal frequency at an unstable mode.

건설비 절감을 위한 고무차륜 경량전철 상하식분기기 개발 (Development of Up-Down Turnout System of AGT for Reduction of Construction costs)

차정권(Kwon-Jung Cha),윤일로(Il-Ro Yoon),김동활(Dong-Howal Kim),후쿠모토(Yozo Fukumoto) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.5

Light Rail Vehicle(LRT) is “New Transit System” that has transportation capacity as well as physical size of vehicle is in-between bus and subway. The demand of LRT system is increasing rapidly; both domestically and internationally. Reason being is that it is more economical and eco-friendly compare to existing heavy rail vehicle. Especially, Busan Subway Line 4 K-AGT (Rubber-tired LRT) being the first of its kind to start revenue service in Korea, it is very much likely that application of its demand will continue to increase. Considering its trend, study to reduce implementation cost of LRT is being pursued in many different aspects; reducing construction cost is one that aspect. In this study, on-site application of ‘Up-Down Turnout System’ implementation research has been carried out which can replace existing ‘Left-Right Turnout System’. When safety of its type gets verified, application of this system to line which intends to use K-AGT, Shin-Lim Line and Dong-Book Line, expects to save its construction cost. This thesis paper reports ongoing research of AGT ‘Up-Down Turnout System’ development and main component design factors, fundamental principle, performance test result.

항회전 근위 대퇴 골수정을 이용한 대퇴골 전자간 골절치료에서 외반정복술의 유용성

박지강(Ji-Kang Park),손현철(Hyun-Chul Shon),김용민(Yong-Min Kim),최의성(Eui-Sung Choi),김동수(Dong-Soo Kim),박경진(Kyoung-Jin Park),조병기(Byung-Ki Cho),차정권(Jung-Kwon Cha),강상우(Sang-Woo Kang) 대한정형외과학회 2013 대한정형외과학회지 Vol.48 No.6

목적: 대퇴골 전자간 골절에서 외전 정복 후, 항회전 근위 대퇴 골수정으로 치료한 후의 임상적, 방사선적 결과에 대해 알아보고자 하였다. 대상 및 방법: 2008년 3월부터 2012년 8월까지 충북대학교병원에서 항회전 근위 대퇴 골수정으로 치료한 65세 이상의 대퇴전자간 골절 환자 중에서 1년 이상 추시가 가능하였던 51예를 대상으로 하였다. 추시 기간은 평균 15.6개월이었으며 연령은 평균 78.6세였다. 초기 골절의 AO/OTA 분류, 수술 후 대퇴 경부 전염각과 대퇴 경간각, 나선 검의 위치, 외전 정복 여부와 첨단-정점 거리 값, 합병증 발생 여부, 수상 전과 골유합 후의 Koval의 보행능력정도를 비교, 분석하였다. 결과: 49예에서 외전 정복(42예)과 해부적 정복(7예)이 되었으며 골유합은 술 후 평균 15.3주에 얻었다. 나선 검의 평균 활강은 3.5mm였다. 첨단-정점 거리는 평균 18.7 mm였고 합병증의 발생은 없었다. 수상 전에 보행이 가능하였던 42예 중 31예는 수상 전 보행능력을 회복하였고, 11예는 보행능력을 회복하였지만 다른 보행보조수단에 좀 더 의존하게 되었다. 결론: 대퇴골 전자간 골절에 있어서 외전 정복을 통한 항회전 근위 대퇴 골수정을 이용한 수술법은 합병증이 거의 없고 골유합에 매우 유용한 치료 방법이라 판단된다. Purpose: The purpose of this study is to investigate the functional and radiologic results of treatment of the old with intertrochanteric fractures by implementation of the proximal femoral nail antirotation (PFNA) with Valgus reduction. Materials and Methods: A retrospective review of patients (over 65 years old) with intertrochanteric fractures undergoing PFNA, during the period March 2008 to August 2012 at Chungbuk National University Hospital, with follow-up for at least 12 months, was conducted. Fifty-one patients were identified. The mean observation period was 15.6 months and the mean age of patients was 78.6 years old. In this study, AO foundation and Orthopaedic Trauma Association (AO/OTA) classification of initial fractures, post operative neck shaft angle, location of the blade tip (Cleveland index), tip-apex distance (TAD), incidence of complication, Wayne-County reduction, and Koval walking ability were analyzed. Results: Satisfactory reduced status was achieved by significant (p<0.05) valgus reduction in 49 out of 51 cases and the mean period for radiologic bony union was 15.3 weeks. The mean blade sliding distance was 3.5 mm and the mean TAD was 18.7 mm; however, the blade location did not affect the results. No complications, including surgical site infection, delayed union, nonunion, rotational angulation, and cutting out of the blade tip were found. Thirty-one patients out of 42 who maintained their pre-fracture ambulatory ability, 11 patients (out of 42) remained ambulatory but became more dependent on assistive devices. Conclusion: It is expected that the Wayne-County reduction followed by internal fixation with PFNA is a useful treatment option for intertrochanteric fractures in elderly patients because it shows few complications with good functional and radiologic results.

회전근 개 층간 분리 파열에서 관절경을 이용한 층상 교량형 봉합술의 임상 결과

최의성(Eui-Sung Choi),박경진(Kyoung-Jin Park),김용민(Yong-Min Kim),김동수(Dong-Soo Kim),손현철(Hyun-Chul Shon),조병기(Byung-Ki Cho),박지강(Ji-Kang Park),김동환(Dong-Whan Kim),금상욱(Sang-Wook Keum),차정권(Jung-Kwon Cha) 대한견주관절의학회 2013 대한견주관절의학회지 Vol.16 No.2

목적: 저자들은 회전근 개 파열 중 층간 분리 파열의 새로운 수술 방법인 층상 교량형 봉합술을 고안하고, 이 수술법을 이용하여 치료한 환자들의 임상 결과와 회전근 개 치유 정도에 대해 전향적으로 연구하였다. 대상 및 방법: 회전근 개 전층 파열로 층상 교량형 봉합술을 이용하여 수술한 환자 66명(67예)을 대상으로 하였다. 평균 추시 기간은 33개월이었으며, 임상적 결과의 평가는 수술 전과 수술 후 KSS점수, UCLA점수, ASES점수를 이용하였고, 수술 후 6개월째 자기공명영상 검사를 촬영하였다. 결과: KSS점수, UCLA점수, ASES점수는 각각 54.4점에서 90.7점, 15점에서 31.3점, 50.2점에서 92.3점으로 큰 호전을 보였다. 수술 후 6개월째 자기공명영상 검사를 추적 관찰한 38명의 환자에서 92%의 높은 비율의 해부학적 치유를 보였으며, 재파열(IV, V단계)의 비율은 7.9%였다. 결론: 회전근 개 전층 파열 환자 중 층간 분리 파열의 경우 관절경적 층상 교량형 봉합술을 이용한 수술시 해부학적으로 회전근 개의 우수한 치유 결과를 얻었으며, 임상적, 기능적으로도 우수한 결과를 얻을 수 있었다. Purpose: The purpose of this study was to evaluate the repair integrity and clinical outcomes of delaminated tears following arthroscopic layered suture bridge rotator cuff repair in a prospective fashion. Materials and Methods: A consecutive series of 67 patients with delaminated rotator cuff tears who underwent surgery using the arthroscopic Layered Suture Bridge Technique were followed prospectively. Of 67 shoulders, 26 patients were male and 40 patients were female (one patient had bilateral tears); the mean age was 58.8(40~76) years. The clinical evaluation was performed according to ASES, UCLA, and KSS (Korea Shoulder Scoring System) scores with an average follow up period of 33 months. Repair integrity was estimated using MRI, which was performed six months postoperatively. Results: The average clinical outcome in ASES, UCLA, and KSS scores showed significant improvement at the time of the final follow-up compared to preoperatively, from 50.2 to 92.3, 15 to 31.3, and 54.4 to 90.7, respectively (p<0.001 for all scores). Follow up by MRI showed that 16 shoulders had a type-I; 14, a type-II; five, a type-III; two, a type-IV; one, a type-V re-tear. The overall rate of re-tear (types IV and V) was 7.9%. Conclusion: Use of the Arthroscopic Layered Suture Bridge Technique can result in improved functional and structural outcome in cases of delaminated rotator cuff tear.

아레니우스-와이블 모형을 이용한 리드프레임 도금두께의 가속수명시험 설계

정권석,차종범,김광섭 대한설비관리학회 2001 대한설비관리학회지 Vol.6 No.4

This paper proposes the standardization in the field of education and training for maintenance personnel. This is particularly important because of the following reasons: firstly, most of sophisticated system or equipment are getting more and more important in terms of cost, quality, product liability, etc. and so the economic and social responsibilities of maintenance men play more important role in business activities. Secondly, maintenance works have been one of 3D jobs and so it is required for maintenance men to have motivation for higher performance. Even though maintenance works depend upon contingency factors, the development of standards of maintenance works and appropriate education and training, and implementation through the incorporation in national standards or possibly internationally are necessary. This paper identifies 5 kinds of skills and each skill includes 6 to 11 different kinds of sub skills and is classified as 3 levels, such as basic, technical and specialty.