• 한국공간구조학회논문집
• /
• 제9권4호
• /
• pp.97-103
• /
• 2009

면진장치는 기초와 구조물 사이 에 면진장치를 설치하여 상부로 전달되는 지진에너지를 감소시키는 장치로 면진장치의 설치위치에 따라서 기초면진과 중간(지붕)면진으로 구분할 수 있다. 본 연구에서는 면진장치 설치 위치에 따른 아치구조물의 지진응답을 비교 분석하여 면진장치의 효용성을 검증하였다. 지붕면진 시스템은 기초면진 시스템과 비교하여 상부 지붕구조의 지진응답 저감에 있어서 보다 효과적이다. 또한 하부구조와 상부구조의 강성 및 질량변화 그리고 시공성에 있어서 지붕면진이 기초면진 시스템 보다 우수한 것으로 사료된다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2006년도 정기 학술대회 논문집
• /
• pp.437-444
• /
• 2006

Recently, as large structures become lighter and more flexible, the necessity of structural control for reducing excessive displacement and acceleration due to seismic excitation is increased. As a means to minimize seismic damages, various base isolation systems are adopted or considered for adoption. In this study, a base isolation system using Magneto-Sensitive(MS) rubbers is proposed and shown to effectively protect structures against earthquakes. The MS Rubber is a class of smart controllable materials whose mechanical properties change instantly by the application of a magnetic field To demonstrate the advantages of this approach, the MS Rubber isolation system is compared to Lead-Rubber Bearing(LRB) isolation systems and judged based on computed responses to several historical earthquakes. The MS Rubber isolation system is shown to achieve notable decreases in base drifts over comparable passive systems with no accompanying increase in base shears or in accelerations imparted to the superstructure.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2003년도 추계 학술발표회논문집
• /
• pp.403-410
• /
• 2003

This paper presents the results of experimental studies on the equipment isolation effect in the nuclear containment. For this purpose, shaking table tests were performed. The isolation system, known as Friction Pendulum System (FPS), combines the concepts of sliding bearings and pendulum motion was selected. Peak ground acceleration, bidirectional motion, effect of vertical motion and frequency contents of selected earthquake motions were considered. Finally, it is presented that the FPS systems are effective for the small equipment isolation. Key word equipment isolation, nuclear containment, shaking table test, Friction Pendulum System (FPS)

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 추계학술대회 논문집
• /
• pp.179-183
• /
• 2001

Vibration isolation of mechanical systems, in general is achieved through either passive or active vibration control system. Although passive vibration isolators offer simple and reliable means to protect mechanical system from vibration environment, passive vibration isolator has inherent performance limitation. Whereas, active vibration isolator provide significantly superior vibration-isolation performance. Recently, many studied and applications are carried out in this field. In this study, vibration-isolation characteristics of active vibration control system using electromagnetic force actuator are investigated. Some control algorithms. Optimal Feedforward are used for active vibration isolation. Form the experimental results of each control algorithms, active vibration isolation characteristics are investigated.

• Smart Structures and Systems
• /
• 제26권2호
• /
• pp.195-211
• /
• 2020

Among anti-seismic technologies, base isolation is a very effective means of mitigating damage to structural and nonstructural components, such as equipment. However, most seismic isolation systems are designed for mitigating only horizontal seismic responses because the realization of a vertical isolation system (VIS) is difficult. The difficulty is primarily due to conflicting isolation stiffness demands in the static and dynamic states for a VIS, which requires sufficient rigidity to support the self-weight of the isolated object in the static state, but sufficient flexibility to lengthen the isolation period and uncouple the ground motion in the dynamic state. To overcome this problem, a semi-active VIS, called the piezoelectric inertia-type vertical isolation system (PIVIS), is proposed in this study. PIVIS is composed of a piezoelectric friction damper (PFD) and a leverage mechanism with a counterweight. The counterweight provides an uplifting force in the static state and an extra inertial force in the dynamic state; therefore, the effective vertical stiffness of PIVIS is higher in the static state and lower in the dynamic state. The PFD provides a controllable friction force for PIVIS to further prevent its excessive displacement. For experimental verification, a shaking table test was conducted on a prototype PIVIS controlled by a simple controller. The experimental results well agree with the theoretical results. To further investigate the isolation performance of PIVIS, the seismic responses of PIVIS were simulated numerically by considering 14 vertical ground motions with different characteristics. The responses of PIVIS were compared with those of a traditional VIS and a passive system (PIVIS without control). The numerical results demonstrate that compared with the traditional and passive systems, PIVIS can effectively suppress isolation displacement in all kinds of earthquake with various peak ground accelerations and frequency content while maintaining its isolation efficiency. The proposed system is particularly effective for near-fault earthquakes with long-period components, for which it prevents resonant-like motion.

• 한국공간구조학회논문집
• /
• 제18권4호
• /
• pp.81-88
• /
• 2018

Seismic isolation systems have typically been used in the form of base seams in mid-rise and low-rise buildings. In the case of high-rise buildings, it is difficult to apply the base isolation. In this study, the seismic response was analyzed by changing the installation position of the seismic isolation device in 3D high - rise model. To do this, we used 30-story and 40-story 3D buildings as example structures. Historic earthquakes such as Mexico (1985), Northridge (1994) and Rome Frieta (1989) were applied as earthquake loads. The installation position of the isolation device was changed from floor to floor to floor. The maximum deformation of the seismic isolation system was analyzed and the maximum interlaminar strain and maximum absolute acceleration were analyzed by comparing the LB model with seismic isolation device and the Fixed model, which is the base model without seismic isolation device. If an isolation device is installed on the lower layer, it is most effective in response reduction, but since the structure may become unstable, it is effective to apply it to an effective high-level part. Therefore, engineers must consider both structural efficiency and safety when designing a mid-level isolation system for high-rise buildings.

• 토지주택연구
• /
• 제4권2호
• /
• pp.185-192
• /
• 2013

이 논문에서는 저층 경량건물을 대상으로 고성능 내진을 구현하기 위하여 적용된 복합면진시스템의 적용효과가 비선형해석과 현장실험을 통하여 제시되었다. 이 연구에서 적용된 복합면진시스템은 슬라이딩베어링(sliding bearing)과 적층고무베어링(laminated rubber bearing)을 혼용하는 방법으로 전체 면진시스템의 고유주기를 신장시키는데 있어서 적층고무베어링이 지니는 한계를 극복하기 위한 것이다. 비선형해석결과, 복합면진시스템을 채용하여 설계된 면진건물은 아주 드물게 발생하는 강진에 대해서도 최대응답변위가 허용설계변위 이내이며, 최대응답전단력이 설계지진력 이하이므로 안전하게 유지될 수 있음을 알 수 있었다. 또한 현장실험결과, 면진층의 강성은 설계 등가강성 값의 약 95.8%에 해당하는 값을 나타내 전체 면진시스템의 실제 특성이 설계값과 잘 일치하고 있음을 확인할 수 있었다.

• 한국공간구조학회논문집
• /
• 제10권3호
• /
• pp.49-56
• /
• 2010

본 연구에서는 스마트 최상층 면진시스템을 적용한 고층건물의 풍응답 제어성능을 검토해보았다. 이를 위하여 77층 초고층 건물을 예제구조물로 선택하였고 풍동실험을 통해서 얻은 풍하중을 사용하여 수치해석을 수행하였다. 예제구조물의 최상층은 FPS 및 MR 감쇠기로 구성된 스마트 면진시스템을 이용하여 주구조물과 분리된다. 주구조물의 동적응답을 저감시키는 것이 스마트 최상층 면진시스템의 가장 중요한 목표이지만 면진된 최상층의 과도한 응답은 구조물을 불안정하게 만들 수 있다. 따라서, 본 연구에서는 면진된 최상층과 주구조물을 효과적으로 제어하기 위하여 스카이훅제어기를 제어알고리즘으로 사용하였다. 제안된 스마트 최상층 면진시스템의 제어성능을 검토하기 위하여 일반적인 수동 최상층 면진시스템의 제어성능과 비교하였다. 수치해석결과 제안된 스마트 최상층 면진시스템을 이용하면 일반적인 수동 최상층 면진시스템에 비해서 면진층의 변위를 효과적으로 줄이면서도 구조물의 응답을 저감시킬 수 있음을 확인할 수 있었다.

• Structural Engineering and Mechanics
• /
• 제40권3호
• /
• pp.315-334
• /
• 2011

Seismic isolated building structures are examined in this study. The triple concave friction pendulum (TCFP) is used as a seismic isolation system which is easy to be manufactured and enduring more than traditional seismic isolation systems. In the TCFP, take advantage of weight which pendulum carrying and it's geometry in order to obtain desirable result of seismic isolation systems. These systems offer advantage to buildings which subject to severe earthquake. This is result of damping force of earthquake by means of their internal constructions, which consists of multiple surfaces. As the combinations of surfaces upon which sliding is occurring change, the stiffness and effective friction change accordingly. Additionally, the mentioned the TCFP is modeled as of a series arrangement of the three single concave friction pendulum (SCFP) bearings. A two dimensional- and eight- story of a building with and without isolation system are used in the time history analysis in order to investigate of the effectiveness of the seismic isolation systems on the buildings. Results are compared with each other to emphasize efficiency of the TCFP as a seismic isolation device against the other friction type isolation system like single and double concave surfaces. The values of the acceleration, floor displacement and isolator displacement obtained from the results by using different types of the isolation bearings are compared each other. As a result, the findings show that the TCFP bearings are more effective devices for isolation of the buildings against severe earthquakes.

• 한국소음진동공학회논문집
• /
• 제14권11호
• /
• pp.1066-1074
• /
• 2004

A vibration isolation system for a large reverberation chamber (1,228 $m^3$ and 1,000 ton) has been installed and verified. The reverberation chamber generates loud noise and induces high level of vibration while performing spacecraft acoustic reliability tests. The isolation system prevents vibration transfer from the chamber to the enclosure buildings. This paper describes design process and commissioning experiments of the system. Design criteria have been derived from rigid body model of the chamber. The stiffness of neoprene pads has been selected by employing finite element analysis of the reverberant chamber and isolation system. A total of 21 neoprene pads have been installed between the chamber and supporting Pedestals. A sand bag of 800kg was dropped on the chamber floor to measure the natural frequency of the isolation system. While 136.9 dB noise is generated in the chamber, absolute transmissibility of the isolation system has been measured. The measured natural frequency of the chamber is 10.2Hz, which is 80% of the predicted value. Overall transmissibility at working frequency range (25∼10.000 Hz) is less than -12.4 dB.