The environment where Japanese industry has been paid with respect is changing tremendously due to the globalization of economics, where Asian countries are undergoing economical and technical development as well as advancing in information technology. With acceleration of manufacturing bases relocating abroad, industrial hollowing out is happening; hence effort to transfer the technology and the design knowledge of machine design in a company is becoming an important subject. For example, in the design of custom casting product, a designer who is lack of casting knowledge may not be able to produce a good design. In order to obtain a good design and manufacturing, it is necessary to equip the designer and manufacturer with a support system related to casting process or so called, knowledge transfer and creation system. This paper proposes a new knowledge transfer and creation system for manufacturing technology; where machine design, which requires added values such as advanced technology, high quality, short delivery time, is taken as an example and both its explicit and tacit knowledge are cooperated by using synchronized multimedia and immersive virtual environment.

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[in Japanese]

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In industrial fields many jointed structures such as bolted joints, shrink-fit shaft couplings, welded joint and adhesive joints are used. And we experienced many failure troubles in these joint structures. The fundamental reasons of these troubles will be the difficulty of precise stress analysis on these structures and strong dependency of joint strengrth on production processes. So, in this paper firstly l'll introduce many trouble examples of these joint structures. And then discuss the design problems and their solution techniques.

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Fatigue strength of welded joints is usually much lower than that of steel plates and does not increase as the strength of steel plates. One of the principal causes of this phenomenon is the existence of tensile residual stress around a weld toe. It has been shown that the low-temperature transformation welding consumable(LTTW) that contains Cr and Ni can bring compressive stress into around weld toes. Then it can improve the fatigue strength of welded joint. In this study, the effect of LTTW on fatigue property of the non-load-carrying cruciform welded joints is investigated. As a result, it is revealed that the fatigue strength of the welded joint applied 11%Cr-9.5%Ni covered electrode was superior to conventional welded joint and it increased as the yield strength of steel plate while that of conventional welded joints was independent of yield strength of the steel plates

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Advanced structural systems are required to have specific functions associated with operating environments. For the purpose of realizing these functions of smart structures, many research activities have been performed. Functional materials and their characteristics, analysis method of smart structures, sensor and actuator placement, controller design, and many other relevant topics have been studied. This article introduces some analytic and experimental research on the application of smart materials, especially shape memory alloys (SMAs), optical fiber, and piezoelectric materials. The numerical analysis of the thermomechanical responses of the structures with initial strained SMA layer has been performed. For the numerical simulation in this research, the incremental formulation of the 3-D SMA constitutive model is used to predict the thermomechanical responses of SMAs. The unique SMA responses such as pseudoelasticity and the shape memory effect are investigated by using finite element procedure. The actuation force applied by SMA layer is used to suppress the deflection induced by thermal buckling of the host structure. In addition, the controllable recovery force or displacement of the SMA strip placed on host structure is used to modify or control the host structural shape. Also, the application of fiber optic sensor, extrinsic Fabry-Perot interferometer (EFPI) and fiber Bragg grating (FBG) sensors has been investigated. The dynamic sensing characteristics of fiber optic sensors were explored and the vibration measurement and suppression of composite structures have been performed. In addition, the stability boundary characteristics and the suppression of dynamic aeroelastic instability have been investigated utilizing piezoceramic actuators and adaptive controller. It is expected that more realistic functions of smart composite structures can be developed and the multi-functional smart structures can be realized.

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Experimental researches on active control of smart structures with piezoelectric actuators have been conducted in the laboratory. The major objective of the researches is to develop a robust and reliable control system for smart structures considering system uncertainties such as structural parameter errors and system failures. Two topics are introduced in this paper. One is the study on a discrete-state sliding mode control (SMC) for vibration control of smart structures. The discrete-state subspace system identification (4SID) is used in combination with the discretestate SMC design, and a software module for seamless transformation from discrete system to continuous system has been developed. The proposed discrete-state sliding mode control has been applied to the flexible cantilever beam equipped with a piezoelectric actuator. It is shown both by numerical simulations and by hardware experiments that the discrete-state SMC has high performance of vibration suppression and robustness against system uncertainties. The second topic is a new method for the fault detection and health monitoring of smart structures. The Eigensystem Realization Algorithm (ERA), a time-domain system identification algorithm, is applied to detect system failures by monitoring the estimated eigenvalues of the system matrix. The ERA is a powerful tool for detecting the small variation in the stifftiess parameter that indicates a structural damage.

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The objective of the current research is to develop a multi disciplinary design approach of piezoelectric actuator and control system for smart structures that have a characteristics variation. The length of a beam-type smart structure changes and the characteristics of the system is varied. The structure is modeled by FEA, and then the model reduction with the modal coordinate transformation is carried out. The control system is designed according to the H_2 pecification with the reduced-order model. An adaptive control is conducted by scheduling the controllers to keep the stability and performance against the characteristics variation. The design problem for improving the H_2 performance is defined, and the piezoelectric placement and the scheduled control system are simultaneously optimized by the resented 2-step procedure with genetic algorithm (GA), resulting in an enhanced performance for the vibration control.

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This paper discusses the active vibration control of a smart beam having piezoelectric fibers with metal cores where they function as sensors and actuators in the CFRP composite [1]. However, multiple piezoelectric fibers are embedded to gain more actuator power, creating unevenness in the actuator outputs. Unevenness of the actuator outputs degrades the control performance when all fibers are driven with a single piezo amplifier. Hence, we designed a controller using synthesis considering the actuator unevenness for the new smart beam embedded thirty piezoelectric fibers. First, we established a finite element model of a cantilever beam embedded with the piezoelectric fiber and a reduced-order model for controller design. We next transformed the reducedorder model into a linear fractional transformation (LFT) representation considering the actuator unevenness as the perturbation. Next, using the controller designed by using μsynthesis, control experiments were carried out. The experimental results demonstrated that the piezoelectric fiber with a metal core functions effectively as a sensor or actuator for active vibration control, and our control design method resolved the actuator unevenness issue.

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Shape memory alloy wires are nowadays available in small diameters, allowing their direct integration into polymer composite materials without altering the integrity of the structure. These hybrid materials offer the potential to adapt their shape, thermal or vibration response, when they are heated above the transformation temperature of the SMA. This requires to master both their design and processing to reliably produce the desired level of activation. Additionally, strain and temperature sensing should be integrated as well in the composite, to allow for a closed-loop control. This is achieved by embedding Fiber Bragg Grating optical fibers. Recent results will be reviewed, with particular emphasis on the processing issues including the choice of materials and of a manufacturing route for the embedment of pre-strained wires, the development of internal stresses in the host material during post-cure and activation, and the evaluation of the interfacial strength required to sustain the activation induced stresses. The use of coupled FBG sensors to simultaneously measure temperature and strain will be presented, with results from on-going research.

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The electrostrictive graft elastomer is a new type of electromechanically active polymer developed by NASA Langley Research Center. The material has demonstrated promising electromechanical properties including large electrical field-induced strain, high electromechanical output, and a relatively high mechanical modulus. As a two-component system, the elastomer contains flexible backbone chains and electro-responsive polar grafted crystal domains. The two-component material system enables optimization of the electrostriction by controlling the relative fraction of the two components and the molecular morphology. The present work is a systematic study of the effects of the relative fraction of the two components and of the morphology on the electrical field-induced strain. The results show that the elastomer containing more polar grafted domains and higher crystallinity yields higher electric field-induced strains. Therefore, the mechanism in the electroactive polymer provides a new route, which allows the material to receive enhancement in both the electric field-induced strain and the mechanical modulus. Consequently, the enhancement in the electromechanical output power can be achieved.

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This paper presents the concept of microwave remotely-driven smart actuator. The features of remotely-driven smart actuator offer unique performance and application capabilities and exploit many of these unique capabilities. Since the microwave-driven actuator does not require carry-on-battery, ultra-lightweight, and distributed micro size actuators can be made. A dipole rectifying antenna (rectenna) array receives the microwave and converts it into a DC power. Since the rectenna is a thin film, it can be easily integrated into smart material actuator. The converted DC Power from the rectenna array is fed into the actuator through the microwave conversion/control circuit. Recently, cellulose based paper has been came across as an electro-active paper (EAPap) material so as to be used as artificial muscles for biomimetic insects. Since the power requirement of EAPap is less than the safety limit of microwave power in air, the EAPap actuators can be driven by wireless microwave power. So far, the magnitude in the order of tens mW/cm^2 has been successfully transmitted via microwave in a laboratory level experiment, which is enough power to activate EAPap actuators. This idea is useful for specific applications that require multifunctional capabilities such as smart skin, ultra-lightweight space structures, micro robots, flapping wing for insect-like flying objects and smart wan paper as well. Current research status along with its issues will be addressed.

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From the first synthesis of amorphous carbon films by Aisenberg and Chabot [1], Diamond-like Carbon (DLC) films are widely used as protective insulating coatings due to their attractive properties, such as high hardness, low friction coefficient, chemical stability, biocompatibility, etc. The above properties of DLC films are strongly dependent on deposition conditions and post-deposition heat treatment as well. Relatively recently it was shown that above properties can be modified also by doping of the films by different elements. The doped DLC, which can be related to a class of nanocomposites, possess the new interesting properties. Among others the enhanced adhesion to a variety of materials and relatively high conductivity in metal-containing diamond-like nanocomposites (Me-DLN) close to the value typical for the amorphous metals were observed [2],In this paper the results of recently initiated experiments on characterization of Me-DLN films as temperature sensors are presented. The experimental dependences of the conductivity on temperature in the temperature range 80-400 K and metal concentration range 12-38 at. % are well explained in the framework of the model of inelastic tunneling of electrons between metal clusters dispersed in amorphous insulating matrix. The observed power-law character of the conductivity-temperature dependences allows to expect the successful application of the investigated Me-DLN films as temperature sensors.

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Fullerene nanowhiskers (FNWs) are needle-like crystals composed of fullerene molecules such as C_<60>, C_<70> and their derivatives. The fullerene nanowhiskers were first discovered in a colloidal solution of PZT (lead zirconate titanate) with added C_<60> in 2001 [1]. The FNWs can be synthesized in the liquid phase at room temperature by the liquid-liquid interfacial precipitation method (LLIP method) [2]. The C_<60> nanowhiskers grow into fibers longer than 500 μm with a constant diameter ranging from about 80 nm to several hundreds nanometers, can be flexibly bent with a small curvature radius and exhibit a high electrical conductivity by heating at high temperature. The LLIP method can produce various needle-like crystals of C_<60> and C_<70> with tubular or capsular structures as well, and we have first succeeded in fabricating "C_<70> nanotubes". The C_<60> nanowhiskers are also converted to unique nano carbon tubes "fullerene shell tubes" by heating in vacuum [3]. The above nanocarbons composed of fullerenes will have a variety of applications as low-dimensional semiconductors, fuel cell electrodes, nanochannels for microreaders, catalysts and so on.

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