Modified Pipkin-Rogers Modeling of Elastomeric Bushing in Torsional Mode

이성범(Seongbeom Lee) Korean Society for Precision Engineering 2020 한국정밀공학회지 Vol.37 No.12

Elastomeric bushings are structural elements and used in automotive suspension systems. An idealized bushing is an elastomeric hollow cylinder between an outer steel cylindrical sleeve and an inner steel cylindrical rod. The outer sleeve is connected with the components of the suspension system and transfer forces and moments from the wheel to the chassis. The accurate determination of the transmitted forces and moments among autocomponents, the motion of the components, the stresses in the components, and energy dissipation are affected by the quality of the elastomeric bushing model. Force- Displacement relation, moment-rotational angle relation, and coupled relations for elastomeric bushings are imperative for multi-body dynamics simulations. The boundary value problem in the bushing response leads to force-displacement relation and moment-rotational angle relations which require extensive computation time for implementation. Herein, an explicit moment-rotational angle relation has been introduced for use in multi-body dynamics simulations, a modified Pipkin-Rogers model is proposed and a boundary value problem is formulated for torsional mode elastomeric bushing response. Lianis experimental equation and Pipkin-Rogers model are used for numerical experimental research. The proposed method and the prediction of the proposed moment-rotational angle relation are observed to exhibit excellent agreement with the original results.

고효율 페로브스카이트 태양전지 광활성층을 위한 가압열처리 방법

이성범 ( Seongbeom Lee ),김단비 ( Danbi Kim ),정우현 ( Woo Hyeon Jeong ),양현석 ( Hyun-seock Yang ),이보람 ( Bo Ram Lee ),최효성 ( Hyosung Choi ),박성흠 ( Sung Heum Park ),손세모 ( Semo Son ) 한국화상학회 2021 한국화상학회지 Vol.27 No.1

페로브스카이트 태양전지는 빠른 속도로 효율 개선이 이루어지며 차세대 친환경 에너지원으로 각광받고 있다. 가공 매개변수의 영향을 강하게 받는 유-무기 혼합 페로브스카이트 태양전지에서 고품질의 광 활성층을 제조하는 것은 매우 중요하다. 본 연구에서는 Methylammonium Lead Iodide(MAPbI₃) 광활성층 제작 시, 결정화가 이루어지는 열처리 과정에서 압력을 가함으로써 용매가 증발하는 속도를 조절할 수 있는 가압열처리 공정방법(pressure assisted annealing process, PA method)을 개발하였다. 본 연구에서 개발한 광 활성층 제조방법은 보다 오래 용매를 활성층 내에 머물게 할 수 있어서 MAPbI₃의 중간단계에서 그레인의 성장을 극대화 할 수 있으며, 이를 통해 고품질 페로브스카이트 광 활성층의 제조를 가능하게 한다. 또한 본 가압열처리 방법으로 형성시킨 페로브스카이트 광 활성층을 도입하여 태양전지를 제조하였을 경우, 소자의 최고 성능은 기존의 방법으로 제조된 소자와 비교하여 24.4 mA cm^-2의 높은 단락 전류밀도, 0.96 V의 개방전압, 0.75의 필 팩터를 나타내며 17.3 %의 에너지 전환효율을 나타내었다. Perovskite solar cells have been rapidly improved in device efficiency and are in the spotlight as a next-generation eco-friendly energy source. Achieving high-quality photo-active layer influenced by processing parameters is critical to the device performance of organic-inorganic hybrid perovskite solar cells. In this study, a pressure assisted annealing process (PA method) was developed to control the evaporation speed of the solvent inside perovskite layer. By applying pressure during the annealing process for crystallization of the methylammonium Lead Iodide (MAPbI₃), we could control the evaporation speed of solvent to promote crystal growth of MAPbI₃ which enables to manufacture high-quality perovskite photo-active layers. As a result, the PA device exhibited a high PCE of ~17.3 % with significantly enhanced short-circuit current of ~24.4 mA cm^-2, an open-circuit voltage of 0.96 V and a fill factor of 0.75.

자동차 스풀의 설계 및 해석

이재원(Jayone Lee),이성범(Seongbeom Lee),예수해(Soohae Ye) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

Seat belt is the most fundamental safety device to protect passenger’s life from a clash or collision accident of vehicle. The role of seat belt system is preventing passenger from shock and getting out when the vehicle stops suddenly or turns over. Seat belt system consists of mainly four restraining parts: D-ring, buckle, anchorage, and retractor. Retractor is the major part which controls spool-in or out of webbing according to acceleration pulse in seat belt. Currently, spool of automotive seat belt is made of Al-alloy due to its light weight. In this paper, we performed solid model of spool using 3D scanner and CATIA V5. Moreover, for optimization of spool, we performed finite element analysis under various load between webbing and spool. In conclusion, we obtained optimized shape of automotive spool, and predicted fractural of spool through the result values of structural analysis.

Machine Learning을 이용한 LCD 3D프린터 공정조건 추천시스템 개발

성시헌(Siheon Seong),이성범(Seongbeom Lee),김현수(Hyunsoo Kim),김현철(Hyunchul Kim) 한국생산제조학회 2023 한국생산제조학회지 Vol.32 No.2

With the development of the fourth industry, production methods using 3D printers are increasingly being used to compensate for the limitations of mold processing. Under the existing mold method, the production time is slow and no fixed production process exists. These result in low product reliability and expensive equipment, making the existing mold method inefficient and limited in use. This study develops a liquid crystal display(LCD) 3D printer process parameter recommendation system that can solve the unspecified production processes . To indicate the stacking height and direction, the system is divided into X and Y axes, respectively, and each axis is raised from 0° to 90° in increments of 5° to test samples. After manufacture, a hardness test is performed, and the output accuracy and precision are measured. Using a Gaussian regression, we implement the system to recommend grade results from 1 to 9 to workers and verify performance.

SLA 기반 LCD 3D 프린터 제작에 관한 연구

성시헌(Siheon Seong),이성범(Seongbeom Lee),김현철(Hyunchul Kim) 한국생산제조학회 2023 한국생산제조학회지 Vol.32 No.1

With the development of the Fourth Industrial Revolution, the use of three-dimensional (3D) printers has drawn attention as an approach to supplementing the limitations of mold processing by reducing various materials, complex shapes, and discontinuation cycles. However, there are limits to its application because its extended manufacturing time and expensive equipment do not satisfy the efficiency requirements of the existing mold method. This paper presents a method for solving the problems of existing 3D printers by producing liquid crystal display 3D printers with low cost, high manufacturing speed, and high precision. And for the verification, products of various shapes were printed and evaluated.

실험계획법을 이용한 고효율 소형 열병합 시스템 성능 해석

류미라(Mira Ryu),이준식(Junsik Lee),박정호(Jeongho Park),이성범(Seongbeom Lee),이대희(Daehee Lee) 한국자동차공학회 2012 한국 자동차공학회논문집 Vol.20 No.3

As a kind of distributed energy system, the co-generation system based Diesel engine using after-treatment device was devised for its environmental friendly and economic qualities. It is utilized in that the electric power is produced by the generator connected to the Diesel engine, and waste heat is recovered from both the exhaust gases and the engine itself by the finned tube and shell & tube heat exchangers. An after-treatment device composed ceramic heater and DOC(Diesel Oxidation Catalyst) is installed at the engine outlet in order to completely reignite the unburned fuel from the Diesel engine. In this study, mutual relation of each experimental condition was derived through minimum number of experiment using Taguchi Design and ANOVA recently used in the various fields. It is found that the total efficiency (thermal efficiency plus electric power generation efficiency) of this system reaches maximum 94.4% which is approximately higher than that of the typical diesel engine exhaust heat recovery system.

유한요소해석을 이용한 배관시스템의 유동속도 예측법 연구

양원석(Wonseok Yang),차주호(Juho Cha),이성범(Seongbeom Lee),이민영(Minyoung Lee) 한국소음진동공학회 2020 한국소음진동공학회 학술대회논문집 Vol.2020 No.11

기여도 해석을 이용한 스퀼소음 저감을 위한 실험적 연구

서영욱(Youngwook Seo),손민혁(Minhyuk Son),이성범(Seongbeom Lee),김흥섭(Heungseob Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

There are various noises generated by friction. Expecially, reducing the disc brake squeal noise is an important technical issue in the automotive industry. Eliminating squeal noise generated during braking is an important task for the improvement of vehicle passenger comfort. Recent studies on brake squeal caused by a self-excited vibration phenomenon in brake systems forcused on reducing the squeal occurrence by changing the dynamic characteristics of brake components. In this study, CPF(Component Participation Factor) is used to quantify the influence of each component modes on the unstable mode. The least modification was proposed from the sensitivities to reduce the squeal noise. To verify this proposal, a reasonable finite element model was generated by correlating component and assembly modal tests. In processing correlation with component modal test, MAC(Modal Assurance Criteria) was used as a reference value for mode shape correlation. The experiment focused on squeal noise from vehicle tests on the noise dynamometer.

사파이어 웨이퍼 DMP에서 마찰력 모니터링을 통한 재료 제거 특성에 관한 연구

조원석(Wonseok Jo),이상직(Sangjik Lee),김형재(Hyoungjae Kim),이태경(Taekyung Lee),이성범(Seongbeom Lee) 한국트라이볼로지학회 2016 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.32 No.2

Sapphire has a high hardness and strength and chemical stability as a superior material. It is used mainly as a material for a semiconductor as well as LED. Recently, the cover glass industry used by a sapphire is getting a lot of attention. The sapphire substrate is manufactured through ingot sawing, lapping, diamond mechanical polishing (DMP) and chemical mechanical polishing (CMP) process. DMP is an important process to ensure the surface quality of several nm for CMP process as well as to determine the final form accuracy of the substrate. In DMP process, the material removal is achieved by using the mechanical energy of the relative motion to each other in the state that the diamond slurry is disposed between the sapphire substrate and the polishing platen. The polishing platen is one of the most important factors that determine the material removal characteristics in DMP. Especially, it is known that the geometric characteristics of the polishing platen affects the material removal amount and its distribution. This paper investigated the material removal characteristics and the effects of the polishing platen groove in sapphire DMP. The experiments were preliminarily carried out to evaluate the sapphire material removal characteristics according to process parameters such as pressure, relative velocity and so on. In the experiment, the monitoring apparatus was applied to analyze process phenomena in accordance with the processing conditions. From the experimental results, the correlation was analyzed among process parameters, polishing phenomena and the material removal characteristics. The material removal equation based on phenomenological factors could be derived. And the experiment was followed to investigate the effects of platen groove on material removal characteristics.

기여도 해석을 이용한 저주파 스퀼 저감을 위한 연구

서영욱(Youngwook Seo),손민혁(Minhyuk Son),이재원(Jayone Lee),이성범(Seongbeom Lee),김흥섭(Heungseob Kim) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5

There are various noises generated by friction. Expecially, reducing the disc brake squeal noise is an important technical issue in the automotive industry. Eliminating squeal noise generated during braking is an important task for the improvement of vehicle passenger comfort. Recent studies on brake squeal caused by a self-excited vibration phenomenon in brake systems forcused on reducing the squeal occurrence by changing the dynamic characteristics of brake components. In this study, CPF(Component Participation Factor) is used to quantify the influence of each component modes on the unstable mode. The least modification was proposed from the sensitivities to reduce the low frequency squeal noise. To verify this proposal, a reasonable finite element model was generated by correlating component and assembly modal tests. In processing correlation with component modal test, MAC(Modal Assurance Criteria) was used as a reference value for mode shape correlation. The experiment focused on squeal noise from vehicle tests on the noise dynamometer.