In this study, we applied fatigue damage evaluation in pure copper and aluminum plates subjected to zero-to-tension fatigue loading through monitoring with non-contacting NRUS (Nonlinear resonant ultrasound spectroscopy), and nonlinear three-wave mixing methods, which are resonance-based techniques exploiting the significant nonlinear behavior of damaged materials. In NRUS, the resonant frequency of an object is studied as a function of the excitation level. As the excitation level increases, the elastic nonlinearity is manifest by a shift in the resonance frequency. In nonlinear three-wave mixing method, two intersecting ultrasonic waves produce a scattered wave when the resonance condition is satisfied. The wave amplitude is measured. NRUS and nonlinear three-wave interaction methods exhibit high sensitivity to micro-structural change of the damaged material. They rapidly increase from 60 % of fatigue life to the fracture. TEM (Transmission Electron Microscope) observation in copper specimens supported this view. Three-wave interaction methods sensitivity is higher than NRUS. These noncontact resonance-EMAT measurements can monitor the evolution of non-linear ultrasonic phenomena throughout the fatigue life and has a potential to assess the damage advance and to predict the fatigue life of metals.

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Fatigue limit estimation based on the dissipated energy measurement using infrared thermography has been getting an increasing attention in various industries. Most of the studies on dissipated energy have been discussed based on the mean temperature rise or irreversible component of heat generation due to energy dissipation. In this study, phase information of energy dissipation was investigated and was applied to the accuracy improvement of dissipated energy measurement for fatigue damage estimation. The material under test is JIS type 316L austenitic stainless steel. The stress ratio R was set to be -1, -0.8 and -0.5. It is found that the phase difference takes certain constant value during significant energy dissipation and unique value corresponding to the stress ratio. It is concluded that band pass phase filtering is effective to the improvement of the measurement of dissipated energy.

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Recently, fatigue limit estimation based on the dissipated energy measurement using infrared thermography has attracted attention in various industries. In this study, dissipated energy measurement was applied to the evaluation of fatigue properties for composite material. The short glass fiber reinforced plastics, which is called BMC (Bulk Molding Compound) was used. In a staircase-like stress level test, dissipated energy increased with increase of stress level and there was a liner relationship between dissipated energy and energy loss caused by viscoelastic deformation. In constant stress level fatigue test, dissipated energy and thermoelastic temperature change showed the constant value in initial period of fatigue test, and then slightly decreased. On the other hand, energy loss increased with increase of loading cycles. It was considered that this deference between the change of dissipated energy and energy loss were due to the initiation of crack and fiber/matrix delamination. Therefore it was found that dissipated energy for BMC could evaluate plastic deformation of matrix and the condition of fiber/matrix interface.

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Austenite stainless steel is widely used in power plants and nondestructive damage estimation method is required to determine the damage on the structure due to fatigue or earthquake. Eddy current method is one of the nondestructive inspection technique, and it reflects the surface condition of the metal. Surface roughness of the specimen increased by the deformation and the roughness change is used to estimate the damage by the low cycle fatigue. This report deals with the eddy current signal change due to the surface roughness. Test pieces of SUS316 with 6mm in diameter were prepared, and the surface was ground with emery paper. Eddy current testing was carried out with two types of the probe and testing frequency of 200kHz and 1MHz. Eddy current signal, which is output of the eddy current instrument, were measured. Eddy current signal was changed by surface grinding. Grinding on the surface showed significant effect on the eddy current signal. It is caused by removal of residual stress near the surface of the test piece that induced by the drawing process. Difference in the eddy current signal by the surface roughness within 1μm in Ra is quite small and higher testing frequency is required to distinguish the difference.

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In hydraulic turbine runner made of stainless cast steel,SCS6, accidents due to fatigue often occur. In the previous studies, the following results were reported. (1) The S-N curve of aged stainless steels has wide scatter. (2) From SEM observation of the fracture surfaces, crack initiation sites were found to be the casting defect which consist of dendritic phase and pore. (3) It is possible to evaluate the fatigue life by using the casting defect size area and the initial stress intensity factor calculated by defect size. In this study, simulation of fatigue crack growth from defect was conducted and simple estimation method of fatigue life of stainless cast steel SCS6 with casting defects was proposed.

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In recent years, fatigue limit estimation based on energy dissipation has been attracting considerable attention. In this method, temperature change due to irreversible energy dissipation is measured by infrared thermography in various levels of stress amplitude, under cyclic loading. It is experimentally observed that dissipated energy increases with increasing stress levels, and that there is a certain stress level where the dissipated energy undergoes a sharp increase, which has been proven to coincide with the fatigue limit in certain BCC and FCC metals. In this study, this method was applied to an HCP metal, AZ31B magnesium alloy. Fatigue limit estimation based on dissipated energy and conventional fatigue test are conducted on two types of AZ31B magnesium alloy; rolled and extruded material. The estimated fatigue limit obtained for rolled AZ31B agrees well with results from conventional fatigue tests, with fatigue strength at N=10^7. The dissipated energy showed the two characterisitic changes for the plastic strain energy. It was considered that these changes imply twinning and slip deformation restated to fatigue damage, respectively.

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Fretting fatigue characteristic of Ti-6Al-4V with various contact pressures were carried out using fatigue testing machine. The fretting fatigue limit of Ti-6Al-4V at 10^7cycles were σ=150MPa for CP=30, 40, 60MPa and 120MPa for CP=10MPa. In the low-cycle region (10^4-10^5 cycles), fatigue life decreases with increasing of the contact pressure. The other hand, in the high-cycle region (10^6 cycles), fatigue life decreases with decreasing of the contact pressure because of relative slip. Fretting fatigue crack initiating from contact area was observed. Then crack growth is radial.

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In the present study, fatigue fracture behavior of commercially pure iron thin wires with the diameter of 700 and 500 μm was investigated under completely-reversed cyclic bending. For all thin wire specimens under completely-reversed cyclic bending (stress ratio R=-1), the initiation and propagation of fatigue cracks were observed, while for those subjected to tension-tension cyclic loading (R=0.1), ratcheting failure and necking at the final stage of fatigue process were occurred and the initiation and propagation of fatigue cracks were not observed. The scatter in fatigue life for completely-reversed cyclic bending was much smaller than that for tension-tension fatigue where the scatter in the number of cycles to start ratcheting deformation was very large. For completely-reversed cyclic bending of thin wire specimens, fatigue cracks initiated at both the upper and lower surfaces, and propagated toward the neutral axis of the specimen. Microscopic observation of fracture surfaces suggests that not only intragranular fracture but intergranular fracture occurs at the region of low crack propagation rate.

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Rotating bending fatigue tests were conducted to investigate the effect of zirconia shot peening on fatigue properties of Ti-6Al-4V ELI alloy. Specimen was treated in three different shot peening conditions. As a result, the fatigue lives of shot peened specimen were longer life than non-peened specimen. Fish eyes were observed in the fracture surface of the most shot peened specimen. And there was the facet or the fine granular region in near the crack initiation site of the fish eye. And then, fracture morphology of shot peened specimens is different by peening conditions. From the investigation result of some peening effects, the fatigue properties were affected to compressive residual stress values at the surface of specimen.

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The powder layered manufacturing has attracted attention as a technique for producing implants in near net shape. In this study, the bending fatigue property of plane specimen of titanium alloy fabricated by means of electron beam melting method (EBM) is evaluated. The bending fatigue properties of the EBM materials subjected to fine particle peening (FPP) were also studied. The fatigue properties of EBM material was found lower than that of conventionally manufactured material because of defects introduced during manufacturing process worked as initiation sites of fracture. It was found that the surface modification process examined in this study, FPP is effective on improving the plane bending fatigue properties of EBM material. Therefore, it is believed that FPP is effective treatment.

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Wear resistance of commercially pure titanium (CP titanium) is improved by nitriding. However it is usually reported that nitriding decreases the fatigue strength due to grain-coarsening. Besides, a low-temperature nitriding process is able to improve the fatigue properties by inhibiting the grain-coarsening. In order to improve both of the fatigue strength and wear resistance of CP titanium, a low temperature nitriding process was developed. This work will evaluate the effects of nitriding temperature on the microstructure and particularly the grain size of CP titanium. Then, 4-points bending fatigue properties of CP titanium were discussed based on the microstructures obtained.

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Fatigue properties of TiCrAlSiN/CrN coated high-speed tool steels, JIS SKH51, with different film thickness were investigated under four point bending fatigue tests. Two types of specimens with 2.64 μm (S-2.5) and 5.24 μm (S-5.0) film thicknesses were prepared by AIP (Arc Ion Plating) processing. From the experimental results, Static bending strength of the two coated steels was lower than that of the substrate and effect on the strength of film thickness was little. However the two coated steel have higher fatigue strength than that of the substrate. The difference of fatigue strength between the two coated steels appeared over a range of number of cycles from 10^5 to 10^6.

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The effect of shot peening on the fatigue strength in an artificial aged magnesium alloy AZ80 was investigated. The cast ball with an average diameter of 0.1mm was used for shot peening and the Almen intensity was set to 0.15 and 0.40mmN. The specimen surface became rough with an increase in Almen intensity. Shot peening at low Almen intensity improved the fatigue strength. However, the shot peening at high Almen intensity decreased the fatigue strength. In the specimen loaded parallel to extrusion direction, the polishing after shot peening improves the fatigue life. On the other hand, the fatigue life of the specimen loaded perpendicular to extrusion direction decreased by polishing after shot peening. This may be resulted from the difference of distribution of β phase precipitated by aging treatment.

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The purpose of this study is to investigate the effect of peening on the fatigue limit of steels for welded structure with a crack in the weld toe zone. An artificial semicircular slit was created in the weld toe, and peening was conducted. Then, bending fatigue tests were carried out. Owing to the shot peening, the maximum slit depths that can be rendered harmless were 1.0 and 1.2 mm in SUS316 and SM490, respectively. (2) During the fatigue test, the fracture of a peened specimen originated outside the slit, which indicated that peening eliminated the effect of the slit on the fatigue limit. (3) The fatigue limit of a slit specimen was improved by the enhanced residual stress distribution and the decreased stress concentration due to plastic deformation at the weld toe.

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Under multiaxial loading conditions, high temperature fatigue crack growth tests for SUS 304 stainless steel was conducted. DC electrical potential drop method was applied to thin-walled cylindrical specimen subjected cyclic tension and torsion. Crack initiation life, N_i, crack propagation life, N_p, and fatigue life, N_f were evaluated and effects of combined stress condition, Δτr/Δσ, phase difference of loading waveform and shape of slit on the life, N_i, N_p and N_f are examined. These experimental results were discussed with the results of elastic-creeping FE analyses.

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Experiments have been performed for the coplanar fatigue crack growth under non-proportional mixed mode loading. In the experiments, sequential and overlapping mode I and mode II, or mode I and mode III cycles were applied to the crack in the specimen made of wheel or rail steel. The growth rates were obtained and compared in terms of equivalent stress intensity factor ranges. Fracture surfaces near the crack tip region of tested specimens were observed by SEM. For the investigation of incipient crack path direction, the elasto-plastic finite element analyses were performed with the combination of the maximum tangential stress criterion.

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Torsion fatigue tests were conducted for smooth bars and circumferentially notched bars of Ti-6Al-4V alloy. The purpose of this work is to evaluate fatigue strength and notch sensitivity under stress concentration factors of Kt=2.0 and 4.0. Fatigue life and fatigue strength decrease with increasing stress concentration. To investigate the crack initiation and propagation, the crack length were calculated with Hooke's law. When compared at the same fatigue life, the crack initiation life for Kt=4.0 was much shorter than that for Kt=2.0. Difference of the fatigue fracture mechanisms between blunt and sharp notch is considered to cause this phenomenon. Under low stress amplitude, the crack propagates under tensile mode toward a 45° to the axial direction. The crack propagated all over the blunt notch, and the crack propagated in the cross section of the sharp notch root under low stress amplitude. As a result, the fracture surface of blunt notch specimen under low stress amplitude was flat, and that of sharp notch specimen showed factory-roof pattern. The formation of factory-roof increases contact areas in the fractured surface and lengthens crack propagation time.

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In order to develop high efficient power plants (A-USC), it is essential to examine some mechanical properties for candidate high corrosion and heat-resistant steels. These materials, if employed, can reduce CO_2 emissions due to good performances in high temperatures and high pressure. Ferritic steel which has a low coefficient of thermal expansion are required to prevent thermal fatigue due to frequent start-stop operations. In this study, low cycle fatigue tests were conducted at 630 ℃ with a smooth bar specimens which are made from high Cr steel (P92), one of advanced heat-resistant steels. Initiation of creep fatigue crack was investigated with interrupted tests. In the case of conventional fatigue test, the crack initiation life is 1100 cycle act strain range of ΔEr_t=0.8%. Although the crack initiation life at the fatigue test with tensile holding is different from the triangular creep fatigue test, both the crack initiation life is 50% of the failure life.

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The spread of a yield zone ahead of a notch root is analyzed under a plane stress, plane strain and axisymmetric condition by finite element method (FEM). A model for predicting the yield zone size is devised by utilizing Dugdale Model and proposed newly as Notch Root Yield Zone Model. The model explains very well the relationship between the maximum yield zone size ahead of the notch root and the sectional average of Mises Equivalent Stress, which are obtained by FEM analyses. The notch size effect is considered based on the model proposed and is formulated with support of a Notch Behavior Map from two viewpoints; (1) Replacement of the notch root with a plain surface, and (2) Replacement of the notch root with a crack tip.

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To clarify the effect of density of entanglement points of molecular chains on mechanical behavior of PEM, we at first employ molecular dynamic (MD) method to constitute the computational models for PEM with different density of entanglement points of molecular chains. And then, MD simulation for Nafion membrane under simple tension is performed. The results show that relatively high deformation resistance together with a distinct yield point appears in the Nafion membrane, which has a high density of entanglement points of molecular chains.

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In the strain measurement under tensile testing by digital image correlation (DIC) method, the error factors were investigated including sprayed texture, laser processing and chucking. It was shown that the density of sprayed texture was influential on the strain value. Instead of providing texture manually, a spraying apparatus was developed, which could provide higher quality texture for DIC measurement. Finally, the influence of uncertainty parameters including size and location of holes, specimen width and chucking length was investigated numerically. The stepwise limited sampling (SLS) method could predict a possible high stress value by a pair of many uncertainty parameters.

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To prevent the accident during drilling the mandible in oral implant surgery, a surgery simulator to learn the drilling force sensing has been developed as an educational system. This paper presents the system configuration and the results of evaluation by dentists. The main hardware consists of one-dimensional actuator, which is controlled by the input force and the pre-calculated force database by stochastic multiscale finite element method. The micro-CT images are used for the calculation in order to consider the trabecular bone quality. The inter-individual difference was taken into account using a calibrated numerical model by human vertebral trabecular bone. Through the use of the system by eight dentists, its usefulness has been shown.

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A new method is proposed to detect a tilted planar and deflected flaws on the back surface of a plate using the interference of ultrasonic waves. Parameters for flaw evaluation are developed and examined through experimental results for artificial flaws. The effect of tilt and deflect angles (0°〜30°) of the flaw on parameter ΔΔ_<max>, which indicates the amount of asymmetry of the interference fringe along the direction normal to the flaw, is investigated.

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Recently, aluminum alloys are widely used for automobile applications. During forming of aluminum parts, rupture or cracking are sometimes occurred and it is necessary to predict those failures by numerical simulations. Extended Mohr-Coulomb criterion successfully predicted ductile fractures of metals and the calibration scheme of parameters in extended Mohr-Coulomb criterion has been developed. However, the shape of calibration specimens are very complicated and simpler test technique is necessary. In this paper, simple test specimens are proposed, those are based on JIS No.5 tensile specimen to make biaxial stress state or shear stress state around fracture points. Then, we applied proposed test specimens to evaluate extended Mohr-Coulomb ductile fracture criteria for Aluminum alloy A5052-H32.

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In recent years, intelligent tires are under developing, and it is expected to detect road condition using intelligent tires from a traffic safety point of view. By detecting the coefficient of friction of road where you drive a car, we expect to enhance vehicle braking performance (ABS). The detection of road surface condition using one-axis acceleration meter had been conducted previously. However there is disadvantage not being able to measure lateral force, while in a corner. In the present study, we propose that the coefficient of friction, lateral force, slip angle, and contact patch length are estimated using the triaxial acceleration meter attached on the inner surface of a tire. We conducted tire rotation tests with various slip angle and measures a triaxial acceleration during the tests. It was found that it was possible to estimate lateral force, coefficient of friction by triaxial acceleration meter accurately, and we demonstrated the validity of estimating methods of lateral force and coefficient of friction.

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The present study investigated crack visualization in metallic structures using time-domain reflectometry (TDR) with differential circuit of microstrip line (MSL). It was problematic that single ended of two-dimensional (2D) MSL was affected by the cross talk voltage because of the interference of adjacent MSL. Differential circuit enables to suppress the cross talk voltage by taking the difference. Crack visualization experiments were conducted using the proposed TDR with differential circuit of 2D MSL for different crack lengths. The experimental results demonstrated that crack propagation could be clearly visualized by determining the appropriate threshold. To observe the time change of the electric field, the electromagnetic fields of the differential circuit was numerically simulated using the finite-difference time-domain method. The simulation results clarified that the cross talk voltage decreased, because the electric field of the differential circuit caused by interference of adjacent MSL was in phase and obtained the visualization result like the experiment.

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The fatigue limit did not appear within the range of 10^8 cycles at temperatures higher than 500℃ as a result of the high temperature rotary bending test of modified 9Cr-1Mo steel. It was clarified that fatigue cracks always started at the surface of the samples regardless of the existence of inclusions. Therefore, in order to discuss the mechanism of the crack initiation, the change of the micro texture of the alloy under the fatigue loading at elevated temperature was evaluated quantitatively by applying an EBSD method. As a result, both the reduction of the misorientation and change in the martensite structure were observed at the surface of the damaged specimens.

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Copper thin films are indispensable for the interconnections in the advanced electronic products, such as Through Silicon Via (TSV), fine bumps, and thin-film interconnections in various devices and interposers. However, it has been reported that both electrical and mechanical properties of the films vary drastically comparing with those of conventional bulk copper due to the fluctuation of the crystallinity of grain boundaries in the films. Porous or sparse grain boundaries cause the very high resistivity and brittle fracture of the films. Thus, the thermal conductivity of the electroplated copper thin films should be varied drastically depending on their micro texture based on the Wiedemann-Franz's law. Since the copper interconnections are used for not only electrical conduction but also thermal heat conduction, it is very important to evaluate the crystallinity of the polycrystalline thin film materials quantitatively and clarify the relationship between the crystallinity and thermal properties of the films.

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Electric and mechanical properties of the electroplated copper thin film interconnections vary drastically depending on not only the size of grains but also the crystallographic characteristics of grain boundaries. In particular, the effect of the quality of grain boundaries plays very important role on the physical properties when the volume ratio of grain boundaries increases with the decrease of average grain size. In this study, in order to evaluate the damage due to the electro migration (EM) of electroplated copper interconnections, the tensile strength at grain boundaries in the interconnection was measured by the micro-tensile test method using Focused Ion Beam (FIB) technique. The micro-texture dependence of the tensile strength and the change in the strength of electroplated copper thin-film interconnections after the EM test were evaluated quantitatively.

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Electroplated copper thin films have started to be applied to the interconnection material in TSV structures because of its low electrical resistivity and high thermal conductivity. However, the material properties were found to vary drastically comparing with those of bulk copper. This was because that the microtexture of the electroplated films was found to vary widely depending on their electroplating conditions. In this study, mechanical properties of the films were measured by a nano-indentation test. The result showed that it is very important to control the microtexture of the films to assure the stability and reliability of electronic products.

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Electronic devices with stretchability can apply to various areas because stretchability enables bending and stretching while in use. However, the conventional electrodes made of hard materials are not suitable for bending and stretching. Therefore, electronic devices consisting of stretchable electrodes enclosed in elastomer have been developed. We fabricated stretchable electrodes using Ga-In-Sn alloy (low melting point eutectic alloy consisting of 68.5 % Gallium, 21.5 % Indium, and 10 % Tin) enclosed in PDMS sheets. Purposes of this study is researching electrical characteristics of Ga-In-Sn alloy stretchable electrodes under stretching to demonstrate efficiency of Ga-In-Sn alloy stretchable electrodes. In this paper, we conducted the single tensile tests and the cyclic tests with Ga-In-Sn alloy stretchable electrodes and derived theoretical equation with contact resistance. In the tensile tests, it was found that Ga-In-Sn alloy stretchable electrodes fail at 50〜60 % strain due to leaking Ga-In-Sn alloy. In the cyclic tests, hysteresis was not observed and electrical resistance change responded to strain without delay. We found experimental value and theoretical value are closer, by deriving theoretical equation with contact resistance.

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Whisker occurs on the silver contact surfaces of signal relays under repeated use, thereby causing a short circuit. The whisker formation mechanisms of silver contacts were studied under cyclic sliding conditions. The dependency of whisker length on the sliding distance and contact stress was investigated experimentally. Surface shear deformation due to cyclic sliding contact was simulated to develop the prediction method for the whisker growth.

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Composite sintering is a critical fabrication process strongly correlated with an initial performance of solid oxide fuel cells. However, the controlling a composite sintering is still matter of debate because of its inherent complexities of the microstructural evolution during sintering. In this study, we numerically predict the sintering behavior of NiO-YSZ composites using a three-dimensional POTTS Monte Carlo simulation. We show that the green density, grain size distribution, composite volume fraction of the initial composite powder have a great impact on the densification rate and the geometric trajectories during sintering.

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A new highly sensitive strain sensor has been developed by applying the change of electronic conductivity of CNTs. In order to control the shape of MWCNTs, MWCNT is developed by applying a chemical vapor deposition (CVD) method. It was found that the shape of MWCNTs can be controlled by changing the thickness of catalyst particles and deposition temperature. The MWCNT bundles with the aspect ratio of 20 were grown by using the optimal growth conditions. This bundle structure showed the high load sensitivity of 10 mN.

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De-bonding stress between SiC particle and Aluminum matrix is studied with cast hybrid Metal Matrix Composite (MMC) with SiC particles and Al2O3 whiskers. A notch is machined in the MMC sample and a wedge is inserted into the notch to introduce a crack. Raman spectrum of a SiC particle ahead ofthe crack is observed along with the crack growth. The crack growth is also observed by an optical microscope. The peak frequency of Raman spectrum increases when the crack grows over the SiC particle.

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Experimental evaluations of interlaminar tensile strength for stitched CFRP curved panels were carried out. Vectran^[○!R] fiber with 200 denier was used as stitch thread. L-shape specimens were loaded by four point bending test, and interlaminar tensile strength was measured. Interlaminar tensile strength of stitched specimens show significant increment compared to those of unstitched one. The fracture behavior of stitched specimens were examined by cross sectional observation. Almost all of the stitch threads were not broken. Stitching process sufficiently improve the interlaminar tensile strength.

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Polypropylene has some merits such as lightweight, anti-chemistry, and good recyclability. However, it is problem that PP is unsuitable for adhesion. This because of the low surface energy PP has. Therefore, we introduce new adhesion method using undercut structure. Undercut structure is can be mechanically restrained because of its structural property. In this study, we transfer undercut structure to PP surface for the purpose of improving adhesion strength. To transfer the undercut structure, a roll imprint machine was built, and transferring was executed. PP which has undercut was tested to measure its tensile strength. The results showed much higher tensile strength in undercut than plane.

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Solid oxide fuel cell (SOFC) has been attractive as a way to solve global energy and environmental problems. Yttria-stabilized zirconia (YSZ) is mainly used as the electrolyte of SOFC. Its conductivity is strongly related with the power performance of SOFC. In the present study, we built an experimental device for four-point bending test to examine effect of stress on Raman spectrum of YSZ. The Young's modulus and the strength measured by the built device decreased with increasing the yttria concentration from 3 to 14. The Raman spectra of 8YSZ showed no change when the applied tensile stress was increased up to 160 MPa.

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There are three types of earthquakes, inter-plate, intra-plate and crustal earthquake. The amplitude of ground motion caused by an earthquake becomes large when the magnitude of the earthquake is larger and distance from the earthquake source is near. In addition, the amplitude becomes large when the observed point is located on the soft soil like in a basin. A crustal earthquake whose magnitude is about 7 causes severe damages in near source region. On the other hand, an inter-plate or intra-plate earthquake whose magnitude 8 or more causes severe damages in a wide area. A huge earthquake, whose magnitude is 8 or more, causes remarkable long-period ground motions also.

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Based on the part I of the reconnaissance report by the academic joint investigation committee of Tohoku branch on The Great East Japan Earthquake, a macroscopic and engineering features of an earthquake ground motion were described.

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The vibration isolation is a technology that lowers the natural frequency of the system and lowers the transmission rate of the object's vibration. The vibration isolation and seismic isolation are the similar technologies. However, the vibration that seismic isolation targets are only an earthquake. The device for seismic isolation is a seismic isolator. Seismic isolators are classified into three kinds "laminated rubber bearing", "sliding bearing", and "roller bearing". Recently, laminated rubber bearings might be applied for the skyscraper building. Accumulating laminated rubber bearing breaks when strongly pulled. However, laminated rubber bearing used for the skyscraper building is pulled at the earthquake. Here, it explained the mechanism because of not breaking the laminated rubber bearing.

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The long period oscillations during long period earthquake have been considered in the high-rise building since Mid Niigata Prefecture Earthquake in 2004 and its countermeasure is required. The application of the active mass damper to the seismic responses has been studied. The active mass damper is constituted of moving mass and controller, and is controlled based on the oscillation signal detected by the sensor. This system has been mainly used for the wind-induced vibrations and most of the systems installed into the real buildings before have seemed to be locked in the moving mass movements even in the relatively small earthquakes. This paper deals with the activity concerning the seismic response control using the active control mass dampers. The full-active type needless of spring and damping mechanism is proposed. At first, the full-active mass damper is described in the general idea and the linear motor driven system is introduced as a real system suitable for the seismic response control. Next, after the control method of the seismic response is briefly described, the real system monitored data during the 2011 off the Pacific coast of Tohoku Earthquake is introduced and the mass damper performance is evaluated.

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