A novel design method of empirical if-then rules for diagnosis of plant start-up sequences is proposed. The rules dealt with in this paper take form of "If variable Y is out of the determined range when variable X becomes X_0, then raise alarm". When sufficient number of normal and abnormal data is available, one can build empirical if-then rules for early detection of abnormal start-up sequences. Present study shows that a combination of dynamic time warping and correlation ratio can give an optimal design method of rules. A simulation study of a natural gas fueled plant is used as an example of applications of the proposed method.

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In this study, a model-based fault diagnosis approach of a beam is proposed. The distinguishing feature of the method is to construct a mathematical model considering the uncertainty of any elements in the structure. The mathematical model with uncertainty is constructed as an updated model with standard deviations of some elements in the structure. In the estimation of the location of abnormality, considering the uncertainty of the model, the objective function to identify the location of abnormality is defined with uncertainty. After that the cause of abnormality and its degree are identified. The feasibility of the proposed method is checked using the experimental data of a free-free uniform beam excited at the center. As a result, the location of abnormality can be identified based on the mean value and the standard deviation of the objective function, and the cause of abnormality can also be determined by using the proposed method. Using the proposed method is a feasible way to diagnose the practical structure.

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The failure diagnosis by vibration and acoustic signals on reciprocal engine is more difficult than independent mechanical elements, because almost reciprocal engine is composed of great number of structural bodies and mechanical elements. Reciprocal engine find it hard to identif' of failure elements to exist a number of noise sources within the engine. This paper experimentally examines the possibility of diagnose failure conditions about a four stroke twin cylinder reciprocal engine based on generated vibration and acoustic signals measured by two accelerometers and two microphones. Artificially assumed failure condition in the four stroke twin cylinder reciprocal glow engine is concerning push rod driven rocker arm and intake and exhaust valves. Identification of above the failure conditions has been carried out based on cross correlation function of close two points signals and paralleled ARX model (Auto Regressive with Extra Input) at diagnosed location within the engine. It is possible to diagnose above failure condition by the proposal SN ratio improvement method.

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When we are creating a diagnostic support system for troubles, the expertise is unnecessarily if we create it upon a statistical-based system, but often the lack of real data can become the problems. In addition, using a model-based system, the close analysis is possible, but there are some problems, difficulty modeling the application objects and necessity of expertise diagnosing the analysis results. In this study, we are propose a better diagnosis system fusing model and semantic networks in order to solve those problems and consider the new system.

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The continuous monitoring of vibrations and other signals is critical to predicting mechanical behavior and efficiency and usually requires continuous data acquisition and online signal processing. In order to deploy newly-developed algorithm for machine condition monitoring, embedded custom instrumentation needs to be developed and often requires a variety of commercial off-the-shelf (COTS) hardware. This report aims to show a reference design for embedded sensor monitoring system with signal processing capabilities using COTS such as FPGA by showing architecture overviews and system benchmarks.

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We developed a novel technique for bolt tightening control by utilizing SrAl2O4:Eu (SAOE) paint film to detect axial force generated during bolt tightening. The prevalently used bolt tightening control method is torque control, which indirectly controls the axial force in the bolted joint, but only a small proportion of the torque actually contributes to the bolt extension that generates the axial force to fasten bolt. Therefore, it is urgently necessary to directly measure the axial force in order to realize a smart tightening control. In the present work, we also demonstrated the correlation between the elastico-luminescence intensity and tightening conditions including tightening speed and strain as well as axial force.

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Delicious taste of puffer meat has been determined by texture and its degree of freshness in Japan. If more exact estimation method of delicious taste is desired, the method associated with nondestructive method is most suitable. The texture of puffer meats is defined as its stiffness associated with mechanical dynamics. This paper experimentally proposes new estimation method on texture of raw puffer meat. Proposed method has been exercised by the measurement about frequency response function based on added vibration to puffer meat. This estimation method is characterized by nondestructive, quantitative, speedy and concise procedure. In this research, determination parameter on texture of puffer meat has been composed by applied non dimensional parameters called area ratio which is obtained from frequency response function of raw puffer meat.

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Many rotors are supported by an oil film bearing which has high stiffness. Since the gap of an oil bearing is very small, we must suppress vibration as much as possible to prevent metal contact by well oil lubrication. Therefore the damping ratio is an important index to evaluate the rotor system stability. However it is difficult to identify the damping ratio under various operational conditions. In this paper, we introduce a new method using the modal open ioop transfer function. This method provides a more accurate Q-value by identifying the damping ratio considering only the selected mode to be measured. We evaluate experimentally the damping ratio of the oil film bearing with or without a dynamic damper. This development will be contributed to suppression of oil whip instability.

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Determination of the aged human bone stability is very important when arranging for rehabilitation. Usually, to determine the bone stability, surgeons inspect X-ray photographs by subjectively with their experiences. Thus, a clinically feasible method to determine the bone stability is awaited. We have attempted to develop such a method for quantitative evaluation of the stability by image processing X-ray photographs. As a result, we successfully established the method for quantitative evaluation of the aged bone stability.

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In this paper, a method to identify the geometrical shape and the location of the defect embedded in a concrete structure by processing nonstationary thermal images of the structural surface captured by a infrared thermography camera is presented. In the proposed method, the structure is modeled as a homogeneous infinite plate whose boundary condition on the observed surface is known. The temperature field in the plate is represented by a truncated power series with respect to time, and a layer-by-layer inverse analysis scheme using a regularized interlayer transfer matrix based on 2D Fourier transform is carried out to obtain the sharper image of the defect as well as the depth of the damaged layer. The estimated depth information is mapped on a depth image which can display the shape of the defects as well as their depth.

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Piezoelectric elements are often used as actuators and sensors. In the case that the target is flexible structure, a piezoelectric element should be attached to the position where the curvature is large because the electromechanical coupling coefficient of the piezoelectric element becomes large value. However, the improvement is usually insufficient. To improve the value drastically, a new technique of attachment of a piezoelectric element which uses spacers was proposed in this paper. The optimum height of the spacers was formulated, and the relationship between the value and the size of the piezoelectric element were investigated in the theoretical analysis. The effectiveness of the proposed method and the theoretical analysis were validated by calculation and experiment.

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This paper proposes a vibration testing and health monitoring system based on an impulse response excited by a laser ablation. In conventional vibration testing using an impulse hammer, the excitation force hardly includes high frequency element over tens of kilohertz. High power YAG pulse laser is used in this system for producing an ideal impulse force on structural surface. It is possible to measure high frequency FRF (Frequency Response Function) in this system. And water droplet overlay on the metal is used to adjust the force magnitude in laser excitation. A health monitoring system is constructed by this vibration testing system and damage detecting filter. A microscopic damage of structures can be extracted by detecting fluctuations of high frequency vibration response with this health monitoring system. The vibration testing system is validated by comparing an aluminum block's FRFs that are obtained by laser excitation, impulse hammer and FEM.

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In this paper, history of vibration energy regeneration is briefly summarized. In the case of energy regeneration, active control system was drove by using regenerated vibration energy. In the case of energy harvesting, however, generated energy was stored to the rechargeable battery because of its low generated energy output.

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Rotating machinery is widely used in the industrial plant, for example, power plant, chemical plant, mass-production plant and so on. In order to ensure safety operation of the rotating machinery, the vibration condition monitoring of the machinery can play a crucial role. In this study, the vibration power generator of the piezoelectric bimorph cantilever beam was proposed for vibration condition monitoring applications of rotating machinery. Proposed piezoelectric vibration power generator consisted of piezocomposite (Macro-Fiber Composite (MFC) actuator). The mechanical resonant frequency of the cantilever beam was tuned to the rotating speed of rotating machine. This study experimentally evaluates both AC and DC power generation performance of the proposed power when subjected to vibration source input magnitude of 0.71mm/s (RMS value of velocity) at the resonant frequency of the cantilever beam by using the electrodynamic shaker.

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In this paper, a nondestructive, in-service structural integrity monitoring methodology that can detect and characterize local structural damages of contact-type, i.e. damages and failures which come along with generation, growth and/or changes of contacting surfaces, such as cracks, debonding, preload-loss in bolted joints, etc., is presented. The presented monitoring system consists of piezoelectric elements bonded on the structural surface, a high-frequency harmonic voltage source, and a current detector. When the piezoelectric elements are driven by a fixed amplitude high-frequency harmonic voltage source, and the structure is excited by low-frequency external load, the nonlinear effects of vibro-acoustic interaction between the low-frequency vibration and the high-frequency wave field at the contact-type damages causes the amplitude and phase modulation of the current flowing through the piezoelectric element. A modeling and analytical study of the nonlinear piezoelectric impedance modulation is presented in the case of single mode excitation both in quasi-static and dynamic conditions. The comparison between the modulated admittance functions solved under both conditions has validated the damage evaluation measures constructed under the quasi-static assumption.

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The objective of this study is the loosening detection of bolted joints without human involvement by applying the concept of structural health monitoring. The smart washer consists of the cantilever available to detect bolt loosening by iasing flexibility of cantilever and self-sensing/actuation function. The loosening is detected by the dynamics change of a smart washer system. This paper describes the overview of the evaluation and diagnosis for Loosening of bolted joint.

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This paper deals with smart film sensors and actuators used with electrode patterning films. Almost all conventional distributed parameter sensors and actuators, PVDF film have to be shaped and attached on the substrate. To overcome handling ability and radical thickness, electrode patterning PVDF film using photoresist technique applies to distributed parameter modal sensor and actuator. First, this paper overviews the design process for modal filtering method and modal actuating method using two-dimensionally distributed modal sensor and actuator. And manufacture method for high-definition electrode patterning PVDF film is proposed. Furthermore, sensibility of the proposed films are experimentally measured in the case of one-dimensional structure. Then, efficient vibration-mode filtering and actuating used with electrode patterning film and effectiveness of proposed method are demonstrated by experimental results.

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Nondestructive testing method for steel structure inspection byultrasonic guided wave has been newly developed. Frequencycontrolled pseudo random wave is applied as a transmitted wave.Results of proof experiment which was conducted with cranerunway girder show that this method can be used to detect a small crack in the girder without stopping crane. operation.

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In order to detect abnormalities in ball bearings, this study applies an ultrasonic technique to bearing life tests. Ultrasonic wave pulses (UWP) emitted from a piezoelectric UWP generator can partially reflect from the interfaces of contact zones within the housing and the bearing with regard to the different acoustic impedance between a solid-to-solid contact and a contact dominated by some fluid layers. Hence, the intensity of the resultant UWP echoes can be determined by the real contact area formed at the interfaces, so that this intensity can be used as a measure of the local contact pressure. The experimental results under the different operating conditions have demonstrated that the time intervals between peaks of UWP echoes varied in accordance with the movement of rolling balls and the lubricating phenomena in bearings. This behavior has further suggested the possibility of the early detection of abnormalities in ball bearings by using the variation in UWP echoes.

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