• Earthquakes and Structures
• /
• 제18권2호
• /
• pp.215-222
• /
• 2020

In this paper, slit steel rubber bearing is presented as an innovative seismic isolator device. In this type of isolator, slit steel damper is an energy dissipation device. Its advantages in comparison with that of the lead rubber bearing are its simplicity in manufacturing process and replacement of its yielding parts. Also, slit steel rubber bearing has the same ability to dissipate energy with smaller value of displacement. Using finite element method in ABAQUS software, a parametric study is done on the performance of this bearing. Three different kinds of isolator with three different values of strut width, 9, 12 and 15 mm, three values of thickness, 4, 6 and 8 mm and two steel types with different yield stress are assessed. Effects of these parameters on the performance characteristics of slit steel rubber bearing are studied. It is shown that by decreasing the thickness and strut width and by selecting the material with lower yield stress, values of effective stiffness, energy dissipation capacity and lateral force in the isolator reduce but equivalent viscous damping is not affected significantly. Thus, by choosing appropriate values for thickness, strut width and slit steel damper yield stress, an isolator with the desired behavior can be achieved. Finally, the performance of an 8-storey frame with the proposed isolator is compared with the same frame equipped with LRB. Results show that SSRB is successful in base shear reduction of structure in a different way from LRB.

• 한국지진공학회논문집
• /
• 제17권3호
• /
• pp.117-125
• /
• 2013

Seismic isolation has been considered and utilized in various industries as a way to prevent huge damage on to structures by large earthquakes in various industries. The laminated Laminated rubber bearings is are most frequently used in seismic isolation systems. The structural Structural safety could not be assured unless the performance of the rubber bearing is not guaranteed for the life time of the structure under the consideration that the bearing is a critical structural member to sustain vertical loads in the seismically isolated structure. However, there are few studies on the deterioration problems of rubber bearings during their service life. The long term performance of the rubber bearings was not considered in past designs of seismically isolated structures. This study evaluates the long term performance and creep characteristics of laminated natural rubber bearings that are used in seismically isolated buildings. For the this study, a set of accelerated thermal aging tests and creep tests are were performed on real specimens. The experimental results show that the natural rubber bearings would have a stable change rate of change for durability under severe environmental conditions for a long time.

• 한국철도학회논문집
• /
• 제13권4호
• /
• pp.440-446
• /
• 2010

본 논문은 적층고무받침을 이용하여 지진으로부터 교량의 손상피해를 줄이기 위한 연구이다. 적층고무 받침은 지진 발생시 변위를 증가시키고, 주기를 길게하여 하중을 전환시킨다. 적층고무받침과 같은 면진장치에 몇 가지 지진파를 가진하여 진동대 실험을 하였다. 이 실험에서는 가속도계와 하중계, 변위계를 설치하여 상판의 가속도 및 전단력 등을 측정하였다. 더구나 적층고무받침을 설치한 경우와 지진격리장치를 설치하지 않은 경우로 구분하여 진동대 실험하여 그 성능을 비교 평가하였다. 실험결과 상판의 가속도 및 전단력은 적층고무받침을 사용할 경우 응답이 감소하였다.

• 대한토목학회논문집
• /
• 제39권3호
• /
• pp.441-449
• /
• 2019

최근 국내에서 경주지진(2016.09)과 포항지진(2017.11) 등 규모 5.0 이상의 지진이 발생하여 구조물의 내진안전성에 대한 관심이 증가하고 있다. 특히, 인명피해나 재산손실을 유발하는 생활시설물은 더욱 중요성이 강조되고 있다. 생활시설물 중 가스와 유류 등의 저장시설물이 있으며 물을 저장하는 탱크가 대표적이다. 본 연구에서는 액체저장탱크의 내진성능향상을 위해 면진의 일종인 납고무받침(Lead Rubber Bearing)을 적용하고자 한다. 액체저장탱크의 기초를 고려하여 납고무받침을 설계하였으며, 실험체를 제작하여 압축 및 전단특성실험을 통해 납고무받침의 일반적 물성을 확인하였다. 납고무받침에 대한 내구성 실험 이후 진동대 실험 및 ANSYS를 이용한 유한요소해석을 통해 비면진 및 면진 적용에 따른 액체저장탱크의 거동을 분석하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.1126-1131
• /
• 2010

Experimental studies for the high damping rubber bearing, lead rubber bearing and natural rubber bearing, those are often used to improve the seismic capacity if the structure recently, are conducted to evaluate the seismic capacity of the seismic isolation bearings. The shear stiffness of the bearings decrease and the shear strain amplitude or the constant axial load level increase, but not sensitive to the strain rate effect. Bearings are strong for the axial compression but weak for the axial tension.

• Smart Structures and Systems
• /
• 제8권4호
• /
• pp.399-412
• /
• 2011

This study compares the performance of two smart isolation systems that utilize superelastic shape memory alloys (SMAs) for seismic protection of bridges using energy balance concepts. The first isolation system is a SMA/rubber-based isolation system (SRB-IS) and consists of a laminated rubber bearing that decouples the superstructure from the bridge piers and a SMA device that provides additional energy dissipation and re-centering capacity. The second isolation system, named as superelastic-friction base isolator (S-FBI), combines the superelastic SMAs with a flat steel-Teflon bearing rather than a laminated rubber bearing. Seismic energy equations of a bridge structure with SMA-based isolation systems are established by absolute and relative energy balance formulations. Nonlinear time history analyses are performed in order to assess the effectiveness of the isolation systems and to compare their performance. The program RSPMatch 2005 is employed to generate spectrum compatible ground motions that are used in time history analyses of the isolated bridge. Results indicate that SRB-IS produces higher seismic input energy, recoverable energy and base shears as compared to the S-FBI system. Also, it is shown that combining superelastic SMAs with a sliding bearing rather than rubber bearing significantly reduce the amount of the required SMA material.

• 한국지진공학회논문집
• /
• 제2권4호
• /
• pp.53-62
• /
• 1998

구조물의 내진 성능 향상을 위해 현재 종종 사용되어지고 있는 기초분리장치인 적층고베어링과 납-고무 베어링의 내진성능을 실험적으로 파악하였다 베어링의 전단 변형률 또는 가해진 수직 하중이 클수록 베어링의 전단 강성은 감소하며 가력 속도에 대한 영향을 무시할 만하다. 베어링은 순수압축력에는 강하며 인장력에는 그 반대이다.

• 한국자동차공학회논문집
• /
• 제15권4호
• /
• pp.47-53
• /
• 2007

A bearing is one of core parts in automobile. Rubber seal of the bearing is important to improve performance of bearing, formed by hot-press die of rubber seal for the intricate shape. In this study, formed tools are used to machine die of bearing rubber seal and the machining operation is classified into the several process of high precision. Design of experiments is used to optimize selection of the formed tools for the efficient machining of the hot-press die. The cutting force, tool wear and tool life are determined to characteristics. And, the clearance angle, the rake angle and the length cutting edge are considered as the major factors. Experiments are repeated to use one-way factorial design, and tool life is predicted by regression model.

• 한국정밀공학회지
• /
• 제23권1호
• /
• pp.145-151
• /
• 2006

Wheel bearing unit has been exclusively applied to car wheel supporting device. The seal for wheel bearing is required to have both high sealing effects and low reaction forces because wheel bearing are operated on adverse environmental conditions such as mud and splash water. High sealing effects are for the protection of bearing ball wear from dust influx. In order to ensure high sealing effects, it is a easiest way to increase contact force which are affected by geometric characteristics, material properties and interferences between seal and inner bearing but induces higher wear phenomena. Interferences in all variables are most important factor to determine the performance of wheel bearing. In this study, optimization of interference amount was performed with finite element analysis with commercial code ABAQUS. For the sake of finite element analysis, tensile tests of rubber material were conducted and governing equation of nonlinear behavior was achieved. Hock-up bearing was manufactured with optimized interference amount. Results of torque and mud spray tests using this bearing unit are performed. Less torque and moisture influx of bearing with optimized interference amount is evidence to validity of this study.

• 한국구조물진단유지관리공학회 논문집
• /
• 제25권6호
• /
• pp.95-102
• /
• 2021

유연한 고무재료를 사용하는 탄성받침은 최근 교량의 내진보강용으로 많이 적용되고 있다. 그러나 다양한 요인에 의하여 고무재료의 노화가 진행되고 이로 인해 탄성받침의 전단강성에 변화가 생기고 이는 교량의 내진성능에 영향을 미친다. 천연고무를 대상으로 노화촉진시간과 노출시간을 변수로 하여 노화촉진시험을 수행하여 전단특성의 변화를 분석하였다. 노화가 진행될수록(노화촉진온도 및 노출시간이 증가할수록) 최대전단응력과 전단변형율은 감소한다. 또한 동일한 전단변형률에서 전단강성이 크게 증가한다. 이는 고무재료가 경화됨을 의미하며 탄성받침의 내진성능이 저하되는 것을 암시한다.