• 제목/요약/키워드: excitation performance

검색결과 701건 처리시간 0.026초

LR형 지반분리계의 내진효과 (Aseismic Effectiveness of LR type Base Isolated System)

  • 정연경;예광일;김재웅
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1997년도 가을 학술발표회 논문집
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    • pp.231-238
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    • 1997
  • Many methods have been proposed for achieving optimum performance of structures subjected to earthquake excitation. The conventional approach requires that structures passively resist earthquakes through a combination of strength, deformability, and energy absorption. Base isolation is a technique for mitigating the effects of earthquakes on structures through the introduction of flexibility and energy absorption capability. In this paper, a parametric study of effectiveness of isolation systems with various main structures' properties is carried out through the response spectrum analysis. It is shown that, most base isolators with its longer period and higher damping can significantly reduce the base shear force transmitted to the structures.

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비틀림비정형을 갖는 건물의 비선형 시간이력해석 (Non-linear time history analysis of building with torsional irregularity)

  • 이한선;고동우
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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    • pp.219-222
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    • 2005
  • Many RC building structures of multiple uses constructed in Korea have the irregularities of torsion and soft story at bottom stories. A typical irregular building was selected as prototype and shaking table tests were performed to investigate the seismic performance of this building. The objective of this study is to evaluate the correlation between the experimental and analytical responses of this irregular building structure subjected to the earthquake excitation by using OpenSees(Open System for Earthquake Engineering Simulation). The results of analyses simulate well the behavior of the building having torsional irregularity and weak stories.

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실물크기 점탄성 감쇠기의 동적 특성 (Dynamic Characteristics of Full-Scale Viscoelastic Dampers)

  • 민경원
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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    • pp.367-374
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    • 1999
  • this paper focuses on the dynamic characteristics of full-scale viscoelastic dampers through the experimental study. Viscoelastic dampers which dissipate the response energy of a building under earthquake excitation make a role of increasing damping capacity of the building. Therefore it is important to recognize the damping behavior of viscoelastic dampers. Full-scale viscoelastic dampers are made of three types of rubbers for experimental test. The hysteretic behavior is obtained through the load-deformation experiment over the various loading frequencies and damper strains The experimental results show the good performance of viscoelastic dampers under earthquake excitations,

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Core Material Design of a High Performance Rotating Machine Considering Magnetic Anisotropy

  • Ikariga Atsushi;Enokizono Masato;Shimoji Hiroyasu;Yamashiro Hirofumi
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제5B권3호
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    • pp.248-252
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    • 2005
  • This paper deals with a new design method for a small-size rotating machine with high power. In order to achieve high performance, secondary excitation by Nd-Fe-B magnets and the grain oriented electrical steel sheets were selected and a new design using dual rotors is proposed. The outline of the high-performance rotating machine will be presented and the results of the finite element analysis by using this method combined with the E&SS modeling will be shown in the paper.

전극길이 변화에 따른 실린더 형태 ER밸브의 성능고찰 (Performance Investigation of Cylindrical-Type ER Valves With Different Electrode Length)

  • 전영식
    • 한국생산제조학회지
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    • 제7권6호
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    • pp.1-11
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    • 1998
  • This paper presents performance analyses of three types of the cylindrical-type ER(electro-rheo-logical) valves, which have different electrode length and width but same electrode area. Following the composition of silicone oil-based ER fluid, the field-dependent yield stresses are obtained from experimental investigation on the Bingham property of the ER fluid. The ER valve which is dependent on the applied electric field is devised and its theoretical model is derived. On the basis of the pressure-drop analysis, three types of the ER valves are designed and manufactured. After experimentally evaluation field-dependent pressure drops, PI controller is formulated to achieve tracking control on desired pressure drop. The controller is then experimentally implemented and tracking control performance is presented in order to demonstrate superior controllability of the ER valve. In addition, the response characteristic of the ER valve with respect to the excitation frequency of the electric fiedls is provided to show the feasibility of practical application.

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공기스프링과 압전작동기를 결합한 복합형 미진동 방진마운트 시스템 개발 (Development of a Hybrid Mount System Combined Airspring with Piezostack Actuator for Microvibration)

  • 문석준;정형조;신윤호;장동두;정종안;문영종
    • 한국소음진동공학회논문집
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    • 제21권1호
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    • pp.56-65
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    • 2011
  • A new hybrid mount system is proposed for microvibration control in a high-tech factory. The mount consists of an airspring as a passive device and a piezostack actuator as an active device. The two devices are connected in series. Some numerical simulations and experimental tests are carried out to evaluate isolation performance of the mount system comprising of four proposed hybrid mounts. As a control logic, the specific algorithm is adopted for considering multiple target frequencies of excitation based on a Filtered-X LMS algorithm. The results are compared with isolation performance of the passive airspring mount system. It is confirmed that the proposed hybrid mount system has great performance on microvibration.

레일의 운동마찰력을 고려한 TMD 최적 설계 (Optimal design of tuned mass damper considering the friction between the moving mass and the rail)

  • 이상현;우성식;조승호;정란
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.582-587
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    • 2007
  • In this study, based on the results from the sinusoidal base excitation analyses of a single degree of freedom system with a tuned mass damper (TMD), it is verified that optimal friction force can improve the performance of a TMD like a linear viscous damper which has been usually used in general TMD. The magnitude of the optimal friction increases with increasing mass ratio of the TMD and decreases with increasing structural damping. Particularly, it is observed that the optimized friction force gives better control performance than the optimized viscous damping of the TMD. However, because the performance of the TMD considerably deteriorates when the friction force increases over the optimal value, it is required to keep the friction force from exceeding the optimal value.

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내부 원형 그루브를 갖는 저속 드라이 가스 시일의 윤활 성능해석 (Lubrication Performance Analysis of A Low-Speed Dry Gas Seal having An Inner Circular Groove)

  • 이안성;김준호
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2004년도 학술대회지
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    • pp.201-208
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    • 2004
  • In this study a general Galerkin FE lubrication analysis method was utilized to analyze the complex lubrication performance of a spiral groove seal having an additional inner circular groove, which was designed for a chemical process mixer operating at a low speed of the maximum 500 rpm. Equilibrium seal clearance analyses under varying outer pressure revealed that the seal maintains a certain levitation seal clearance under the outer pressure of more than about 1.5 bar, regardless of a rotating speed. Also, under the normal outer pressure of 11 bar, the axial stiffness of the seal was predicted to have a high value of more than 7.0e+07 N/m, regardless of a rotating speed and thereby, the seal is expected to maintain a stable thickness of lubrication film under a certain external excitation acting.

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A Fast Harmonic Estimation Method for Low Bit Rate Harmonic Speech Coders

  • Park, Yong-Soo;Youn, Dae-Hee;Kang, Tae-lk
    • The Journal of the Acoustical Society of Korea
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    • 제20권4E호
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    • pp.24-30
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    • 2001
  • This paper describes a fast harmonic estimation, referred to as Delta Adjustment (DA), using a low resolution pitch. The presented DA method is based on modification of the Generalized Dual Excitation (GDE) technique[1] which was proposed to improve speech enhancement performance. We introduce the GDE technique and modify it to be suitable for low bit rate harmonic coding that uses only an integer pitch estimate. Unlike the GDE, the DA matches a frequency-warped version of the original spectrum that conforms to a fixed pitch at all harmonic bands. In addition, complexity and performance of the presented method are described in comparison with those of the conventional Fractional Pitch (FP) based harmonic estimation. Experimental results showed that the DA algorithm significantly reduces the complexity of the FP method while maintaining the performance.

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Analysis of Enhancement in Phosphor Performance induced by Surface Treatments

  • Jeon, Duk-Young;Bukesov, Sergey A.;Kim, Jin-Young;Park, Zin-Min;Lee, Dong-Chin
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.370-373
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    • 2003
  • A search for a new phosphor composition of excellent performance in systematic ways requires lots of research efforts, and often turns out to be very timeconsuming and difficult. Thus, usually practical ways are taken to improve the performance of phosphors. A few examples of practical surface treatments on phosphors such as $In_2O_3$ coating on $ZnGa_2O_4:Mn$, phosphoric acid treatment on ZnS:Ag,Cl, and base KOH treatment with ultrasonication on ZnS:Ag,Cl are presented. The reasons for the improvement of luminescence intensity or degradation properties after these treatments are discussed based upon careful analyses on the surface of the phosphors and a proposed model on charge carriers generated by electron beam excitation.

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