The present on-board monitoring system for overhead contact lines mainly provides dynamic states of contact wire. However, its static states are more required for the maintenance work of the overhead contact line. Therefore, the authors have been developing on-board monitoring system to estimate static condition of the overhead contact line utilizing contact force measurement. This paper shows method to estimate static contact wire height and stagger only from on-board measurement data.

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Milling is one of the most importyant metal cutting processes. If we measure the cutting force, we can make cutting process optimum, prevent tool breakage, and improve efficiency of process. Especially in the case of using a micro end mill, It is very difficult to dentify whether cutting process is good or not. In this paper, we proposed the cutting force measurement technique by using image processing. In the technique, we captured images of end mill during cutting process from x-y direction, determined deflection of the tool and then estimated cutting force. Finally we can estimate small cutting force in two-dimension plane and determined the experimental equation of cutting force based on the measured data.

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This paper proposes an easy and convinient speedy method to estimate the lubrication condition and properties of the lubricant oil on Piston-Cylinder liner mechanism like the reciprocating engine based. Typically sampling oil on condition monitoring and diagnosis, which its has assessed to analysis density, type, form and chemical property of wear perticle.These conventional analysis is practical to highly reliable and often obtained information. However, it is necessary that long time to analisys and assesses. This proposed method has create a three-dimensional graph among for the high frequency vibration measured at the sensers when happened direct contact at sliding parts of Piston - Cylinder liner machanism (named Sliding Ultrasonic Vibration) , and the area values of obtained frequency domain and theory film thickness then,further the counting degree of contamination obtained from sampled lubricant oil. By using this proposal method will be higher than the conventional one efficiently.

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In this study examined the application of borehole point load test the deterioration diagnosis of the alkali silica reaction of a concrete degradation phenomenon. The borehole point load test was an examination that examined in a concrete core hole. And, the compressive strength and modulus of elasticity of a concrete structure coefficient were tried by this examination. In the result, compressive strength and modulus of elasticity in the core gathered from a concrete test piece and a deteriorated structure were the same as the estimation of borehole point load test. In addition, the decrease in the modulus of elasticity coefficient because of the alkali silica reaction was able to be confirmed by the borehole point load test. It has been understood to be able to use the borehole point load test to diagnose concrete above.a

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Immediate detection of abnormalities which occur in a production machine and taking a prompt and appropriate action are essential to maintain. Repair is required before the defective product is made in an actual production plants. This study aims to develop a condition monitoring methodology for a punching machine based on wavelet analysis of the impulsive acceleration response during the punching process. The acceleration response on the die in a turret punch press was measured during a repetitive punching test and analyzed with wavelets whose mother wavelet was the third derivative of the Gaussian function. The signal concentration measure evaluated from the extrema of the wavelet transform showed a considerable correlation with the wear transition, thus, it was suggested that it could be a signature of the tool wear progress and useful as a potential measure for the tool wear monitoring.

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It is reported that an unexpected breakdown occurs in reciprocating hydrogen compressors. Although the monitoring and the regular maintenance are carried out to avoid these accidents, the investigation about a trouble part is necessary to improve efficiency and safety. Previous research has shown that, the natural vibration characteristic of a system influences on the dynamic characteristic of operation. The purpose of this research is to examine the effect of stiffness change in the sliding part both on the crosshead-piston and the rod-piston system. Hence, vibrational experiments are conducted under two kinds of boundary conditions.The stiffness of the supporting points' about the crosshead and the piston are identified based on a beam model. As a result, it is found that, estimation of the system's boundary condition is possible using an identified dynamic model' s characteristics .

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Additional plastic deformation for a certain period of time is important to evaluate defects in important structures, such as atomic power plants, tall buildings and high-pressure hydrogen infrastructures, after an earthquake. Since residual magnetizations gradually approach to its anhysteresis curve during plastic deformation, this phenomenon could be used for non-destructive tests for detecting additionally plastically deformed area. The mechanism of the phenomenon is explained and some experimental results are shown. Merits and demerits of the method are discussed.

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Integrity analysis of knee joint involves a detail study of several anatomical parts such as bones, cartilage,tendons, motor strategies (muscle recruitment patterns) etc. The damage of these anatomical parts causes several knee diseases. Particularly, the incidence of knee osteoarthritis (OA) increases with age due to some damages in cartilage. Although acoustic emission (AE) technique has been using in industry for several damage evaluation of materials, the AE signal processing technique has been applied for evaluating the disorderness of knee joint in the present paper as well. The present investigation especially focuses on the dynamical behavior of knee joint for its integrity analysis with several non-destructive imaging conditions. AE signals have been collected from different positions of tibia, patella, and femur for getting sufficient information about the condition of cartilage of knee joint. Data shows the influences of increasing ages on knee problems which may cause pains like osteoarthritis, a vital knee disease of aged people.

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This study concerns adhesion failure detection of bonded parts by utilizing a sensitive baseline-free structural health monitoring methodology referred to as nonlinear piezoelectric impedance modulation method. According to the progress of adhesion technologies, adhesion joints have been used more often replacing conventional mechanical joints such as bolted and riveted joints. Thus, a nondestructive technique which can detect and monitor the development of adhesive failures in-situ to investigate the health state of adhesive joints would be required. This technique evaluates failures in the structure under the pump eχcitation at low frequency, by demodulating the current response in amplitude and phase when a PZT patch on the surface is driven by a high frequency probe voltage source. It has distinctive features of being sensitive to incipient defects inside the structure and theoretically baseline-free because no modulation exists in a structure which has no defect. In this study, thin plate specimens with bonded parts in healthy and incomplete conditions are subjected to the probe and pump excitations, and the resultant damage evaluation indices are investigated in terms of the probe amplitudes as well as probe excitation frequencies.

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In a reciprocating compressor, unexpected accidents have been reported under long-term operation. These machines are managed by monitoring and periodic maintenance work, but not reached to accident prevention or clarification of cause about troubles. Therefore, the purpose of this study is to build a mathematical model that is able to evaluate the stiffness of the connecting portion and sliding portion. l have studied the validity of the model by the eigenvalue analysis based on mathematical model and the vibration experiments using experimental equipment. Consequently, the vibration modes from 3rd to 5 th in the experimental equipment are associated with Eigen modes that can be considered as a stretching mode and bending mode. Therefore, the possibility to be evaluated the stiffness change of the connecting portion and the sliding portion by using this model was suggested.

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This paper shows chatter monitering technique for normal and vibration cutting system. 0n the vibration cutting system, the chatter vibration often arised when the cutting speed is faster than v_c/3. The critical cutting speed v_c is defined by v_c=2πaf, a is the tool amplitude and f is the tool frequency. When the chatter vibration occure, the work-piece oscillates at its natural frequency. Our experiments show the beginning of the chatter vibration can be detected by FFT analysis using an eddy current sensor and suitable filter bandwidth. This method will be useful for development of system for preventing chatter in cutting.

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Recent years, bearings frequently suffer from early damage caused by flaking. This is thought to be due to hydrogen embrittlement in connection with hydrocarbon decomposition when greases contact the nascent clean metal surface created under the current severer frictional situations. This study proposes the evaluation method of grease decomposition and hydrogen generation by a controlled atmosphere cutting apparatus. Mass spectrometry of this method provided the evidences of hydrogen generation and hydrocarbon decomposition in relation to the nascent metal surface appearance by cutting. The further investigation demonstrated additives in greases greatly influenced the amount of hydrogen generation. Recent years, bearings frequently suffer from early damage caused by flaking. This is thought to be due to hydrogen embrittlement in connection with hydrocarbon decomposition when greases contact the nascent clean metal surface created under the current severer frictional situations. This study proposes the evaluation method of grease decomposition and hydrogen generation by a controlled atmosphere cutting apparatus. Mass spectrometry of this method provided the evidences of hydrogen generation and hydrocarbon decomposition in relation to the nascent metal surface appearance by cutting. The further investigation demonstrated additives in greases greatly influenced the amount of hydrogen generation.

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It is well known that the removal rate decreases with the progress of pad deterioration owing to the increase of the polishing time. In particular, the pad surface asperity is important for the polishing characteristics. It is well known that the removal rate decreases with the progress of pad deterioration owing to the increase of the polishing time. In particular, the pad surface asperity is important for the polishing characteristics. Moreover, the polishing apparatus has emitted the micro-vibration and noise. Therefore, it is thought as a very important matter for a diagnosis of the machine, and the related technology to identify the polishing conditions. This paper will investigate the relationship between the vibrations of the polishing head, coefficient of friction and -the polishing characteristics in Si-chemical mechanical polishing (CMP). As a result, we found that the coefficient of friction increases with the increase of the polishing time, and the coefficient of friction decreases by the conditioning process. Moreover, the removal rate decreases with both the increase of the vibration acceleration and the increase of the coefficient of friction. Furthermore, the result of multiple correlation analysis for each evaluation parameters of pad surface asperity can predict the removal rate precisely.

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This paper proposes a detective method of bolt loosening by laser excitation vibration measurement. Impulse force can be applied to a structure by laser ablation. By this ideal impulse force, measurement of frequency response in wide frequency range can be accomplished. This detective method is constructed by measurement of the frequency response in high frequency because frequency response varies depending on the bolt loosening. Degree of damage and damage location are evaluated by RT-method. Furthermore, finite-element analysis is conducted to compare the simulation results with the experimental results.

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Bolted joints are widely used in mechanical and architectural structures. However, many serious accidents occur because of loosening in bolted joints. The diagnosis of the bolt loosening is able to be achieved by evaluating the variation of tightening axial tension. Conventionally, the inspection method of the loosening bolted joint is generally the measurement of the axial tension of a bolted joint by using ultrasonic waves. These methods require the use of special measurement equipment and the human operation. In this study, a smart washer was proposed to detect the loosening without human involvement. The basic principle of how to detect bolt loosening is to the dynamics characteristics of a smart washer system which varies depending on bolt tightening axial tension. A novel bolt loosening detection method by adaptive observer with variable gain is proposed in this paper. The numerical simulations are performed to verify the possibility of the adaptive observer-based loosening detection.

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Many bridges had been constructed during the steep economic growth age. Presently, dealing with the deterioration of those bridges and maintaining them have become very important. Using robots for the bridge inspection to aim at the labor saving and lowering the cost is hoped for the management and maintenance of many old bridges because the conventional method will intensify the strains on the economy. We had created a four-wheel driving robot for trial purposes that can inspect cracks and corrosion in steel bridge substructures. In this study, we added the improvement to the size, the turning ability and the controller of the robot. We have confirmed better results than an old-type robot in the experiment concerning whether the robot can finish the running in a variety of exanimation courses.

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This study concerns integrity diagnosis method of bolted joint based on nonlinear vibro-acoustic modulation. When the structure that has the contact-type failure is vibrating at low-frequency, the pair of the contactsurfaces of two components is tapping and clapping owing to low-frequency vibration. In this condition, the scatter characteristics, such as wave transmissivity and reflectivity, of high-frequency waves in vicinity of the contact-type failure are fluctuated in synchronization with low-frequency vibration. The time fluctuation of reflection intensity, which eχpresses the scatter characteristics in the specific location, of high-frequency waves at the contact-type failure is given as the reflection intensity map which plots time-spatial map. It is possible to show in the modulation index, which is the time fluctuation of the reflection intensity, at each contact-type surface locations . The modulation index of reflection intensity at the contact-type surface location is increasing with the developement of the damage level. Especialy, in this paper,the theory of contact-type failures detection on the reflection intensity fluctuation caused by nonlinear vibro-acoustic modulation is applied to structure which has single bolted joint and the evaluation index of intensity of the bolt loosening which controled by tightening torque is proposed. The trend that the modulation index of reflection intensity at the bolted joint is increasing with the developement of the bolt loosening is verified.

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We are developing vibrational energy harvesting system using iron-based magnetostrictive material (Galfenol) utilized as power supply for wireless sensor module of automobile and industrial machinery. The harvester consisting of Galfenol plate wound with coil, yoke and magnet features simple, small, highly robust and high power output. Our conventional harvester based on cantilever can generate high power output at high frequency resonance, however, does not match the use in automobile and industrial machinery with 10w frequency vibration. In this paper, we propose harvester equipped with adjusting tip mass mechanism and resonator for the operation in low frequency vibration. The harvester with the mechanism has three low frequency resonances determined by tip mass, mass and spring of the resonator. We verified the prototype using Galfenol plate of 2 by 0.5 by 22 mm with the mechanism (tip mass of 7.4g) has resonant frequency around 63 Hz and can generate high power output at low frequency and wide bandwidth.

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