• Title/Summary/Keyword: control vibration

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An analysis of cutting process with ultrasonic vibration by ARMA model (자동회귀-이동평균(ARMA) 모델에 의한 초음파 진동 절삭 공정의 해석)

  • I.H. Choe;Kim, J.D.
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.2
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    • pp.85-94
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    • 1994
  • The cutting mechanism of ultrasonic vibration machining is characterized as two phases, that is, an impact at the cutting edge and a reduction of cutting force due to non-contact interval between tool and workpiece. In this paper, in order to identify cutting dynamics of a system with ultrasonically vibrated cutting tool, an ARMA modeling is performed on experimental cutting force signals which have a dominant effect on cutting dynamics. The aim of this study is, through Dynamic Date System methodology, to find the inherent characteristics of an ultrasonic vibration cutting process by considering natural frequency and damping coefficient. Surface roughness and stability of cutting process under ultrasonic vibration are also considered

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Life Assessment of Automotive Electronic Part using Virtual Qualification (Virtual Qualification을 통한 자동차용 전장부품의 수명 평가)

  • Lee, Hae-Jin;Lee, Jung-Youn;Oh, Jae-Eung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.143-146
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    • 2005
  • In modern automotive control modules, mechanical failures of surface mounted electronic components such as microprocessors, crystals, capacitors, transformers, inductors, and ball grid array packages, etc., are mai or roadblocks to design cycle time and product reliability. This paper presents a general methodology of failure analysis and fatigue prediction of these electronic components under automotive vibration environments. Mechanical performance of these packages is studied through finite element modeling approach fur given vibration environments in automotive application. Using the results of vibration simulation, fatigue lift is predicted based on cumulative damage analysis and material durability information. Detailed model of solder/lead joints is built to correlate the system level model and obtain solder strains/stresses. The primary focus in this paper is on surface-mount interconnect fatigue failures and the critical component selected for this analysis is 80 pin plastic leaded microprocessor.

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Development of Remote Vibration Measurement System Using the Internet (인터넷을 이용한 원격 계측 시스템 개발)

  • Kwak, Moon-Kyu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.322-326
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    • 2000
  • This paper is concerned with the development of remote vibration measurement system using the internet. Recently, various techniques are developed based on the advance of the internet environment. In this study, we developed the remote vibration measurement system using the internet server programming technique, the client programming technique, the GPIB programming, and the A/D, D/A programming techniques. Hence, we can control the measurement devices remotely. The feasibility of the system is validated using the experimental setup. The output of the D/A is connected to the small exciter and the piezoceramic sensor is connected to the A/D port. By sending out the exciting signal to the structure, we can collect the response. The experiment shows that the proposed idea works well. Another experiment consists of the function generator and the low-pass filter circuit. The wave form, amplitude, and the frequency of the function generator is controlled by the GPIB program and the output of the circuit is collected by the A/D port. The output is then displayed in HTML format.

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A Study on the Disk Vibration Control by Disk Damper for 100 kTPI Hard Disk Drive Design (100 kTPI급 HDD 구현을 위한 Disk Damper에 관한 연구)

  • Y. S. Han;S. W. Kang;D. H. Oh;T. Y. Hwang
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.340.2-340
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    • 2002
  • A practical implementation method of squeeze-film aeroelastic disk vibration damping and its practical design performance are presented to provide a solution method to meet the tight TMR(Track Mis-Registration) design budget of high-TPI HDDs. Most previous research results are mainly based on the component-level study in the 'open-cover state' which is far from the realistic operations HDD condition. (omitted)

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Simple Method of Vibration Analysis of Three Span Continuous Composite Slab Bridges with Elastic Intermediate Supports (탄성지지된 3경간 연속 복합슬래브교량의 간단한 진동해석)

  • Han, Bong Koo;Kim, Duk Hyun
    • Journal of Korean Society of Steel Construction
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    • v.17 no.3 s.76
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    • pp.317-324
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    • 2005
  • The specially orthotropic plate theory is used to analyse three-span continuous composite slab bridges with elastic intermediate supports. A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions, was developed and the result of application of this method to the three-span continuous composite slab bridges with elastic intermediate supports is presented. This type of bridge represents either concrete or sandwich type three-span bridge on polymeric supports for passive control or on actuators for active control. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. The finite difference method is used for this purpose in this paper. The influence of flexural stiffnesses and the modulus of the foundation are studied.

A Study on the Applicability of Hybrid Mass Damper for the Vibration Control of the Structure under Base Excitation (지반 기진력을 받는 구조물의 진도제어를 위한 Hybrid Mass Damper의 유용성에 관한 연구)

  • 문석준;임채욱;정태영;한성용
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.4
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    • pp.1-8
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    • 2001
  • In this paper, a hybrid mass damper using AC-servomotor was designed and developed in order to reduce vibration levels of a 5-story test structure under base excitation. Control performances of the HMD under random and earthquakes excitations are compared with those of TMD through experimental test. It is confirmed that the HMD is more effective to reduce the vibration levels of the test structure especially for the earthquake excitation which excites more than 2 vibration modes of the structure simultaneously.

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Heavy-weight Impact Noise Reduction of Concrete Slab Reinforcement Using F.R.P (F.R.P 재료 보강에 의한 신개념 중량충격음 저감대책)

  • Jeong, Jeong-Ho;Yoo, Seung-Yup;Lee, Pyoung-Jik;Jeon, Jin-Yong;Jo, A-Hyoung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.383-386
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    • 2005
  • Low frequency heavy-weight impact noise is the most irritating noise in Korean high-rise reinforced concrete apartment buildings. This low frequency noise is generated by foot traffic due to the fact that Koreans do not wear shoes at home. The transmission of the noise is facilitated by a load bearing wall structural system without beams and columns which is used in these buildings. In order to control low frequency heavy-weight impact noise, floating floors using isolation materials such as glass-wool mat and poly-urethane mat are used. However, it was difficult to control low frequency heavy-weight impact sound using isolation material. In this study, reinforcement of concrete slab using beams and plate was conducted. Using the FEM analysis, the effect of concrete slab reinforcement using FRP(fiber-glass reinforced plastic) on the bang machine impact vibration acceleration level and sound were conducted at the standard floor impact sound test building. The $3{\sim}4dB$ floor impact vibration acceleration level and impact sound pressure level were reduced and the natural frequency of slabs were changed.

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Active Vibration Control of Automotive Engine Mount Using MR Fluid and Piezostack (MR 유체와 압전 작동기를 이용한 자동차 엔진 마운트의 능동진동제어)

  • Choi, Sang-Min;Nguyen, Vien-Quoc;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.237-242
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    • 2008
  • This paper presents vibration control of an active hybrid engine mount featuring magneto-rheological (MR) fluid and a piezostack actuator. On the basis of the conventional passive rubber mount, MR fluid is adopted to improve isolation performance at resonant frequencies, whereas the piezostack actuator is adopted for performance improvement at non-resonant frequencies, especially at high frequencies. Based on some particular practical requirements of engine mounts, the proposed mount is designed and manufactured. The characteristics of rubber element, piezostack actuator and MR fluid are verified for system analysis and controller synthesis. The model of the proposed mount with a supported mass (engine) is established. In this work, a sliding mode controller is synthesized for the mount system to reduce vibrations transmitted from the engine in a wide frequency range. Computer simulations are performed to evaluate the performances of the proposed active engine mount in time and frequency domains.

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Performance Evaluation of a Quarter Car Suspension System Installed with MR Damper Featuring Bypass Flow Holes in Piston (피스톤 바이패스 유로가 있는 MR 댐퍼 장착 1/4 차량 현가시스템의 성능평가)

  • Kim, Wan Ho;Hwang, Yong Hoon;Park, Jhin Ha;Shin, Cheol-Soo;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.1
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    • pp.65-71
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    • 2017
  • This work presents a comparative work on the ride comfort of a quarter car suspension system between two different magneto-rheological (MR) dampers; one is conventional type without bypass hole and the other is featured by several bypass holes in the piston. As a first step, two different MR dampers are designed on the basis of the governing equation and manufactured with same geometric dimensions except the bypass holes. After investigating the field-dependent damping properties, two dampers are installed to the quarter car suspension system. The suspension model is then derived and a sky-hook controller is implemented to identify vibration control performance under random road. It is shown that the suspension system with MR damper featured by the bypass holes can provide much better ride quality than the case without the bypass holes. This is validated via experimental implementation.

Analysis of Ground Improvement Effect of Low Vibration Sand Compaction Pile Method (저진동 모래다짐말뚝(LVSCP)의 지반개량효과 분석)

  • Kim, Jong-Kook;Cha, Jun-Tae;Lee, Jae-Chang;Chae, Young-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1234-1242
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    • 2010
  • In this study, the effect of noise and vibration, and influence of ground improvement are evaluated and its application is analyzed through the example of SCP designed at ground improvement in Song-Do international city. consequently, it showes even comfortable result that it is about 5.0m of inner space, when the LVSCP method is applied, rather than that it is about 30m of inner space when the existing SCP is applied in vibration control standards 2.0mm/sec. In the noise, now that the many differences according to environmental factors like other equipment noise, limited space and so on at the time of the construction by LVSCP method are coming out, so we think that appro itate measures are needed according to surroundings. By the way, when it comes to the estimation of the ground improvement work before and after an improvement of LVSCP method, its result shows that it is satisfacttion to all the standards of compaction control in dregded and reclaimed ground and sedimentary clay layer.

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