Recently, a muatiferoic sensor using the ME effect (magnetoelectric effect) by combining magnetism and piezo-electricity has been studied.. Up to the present, Terfenol-D was used as a magnetostrictive actuator material in the composite structure. however, Terfenol-D has faults such as weakness and high cost. Then, we used polycrystalline Fe-Ga-Al ribbon instead of Terfenol-D. Fe-Ga-Al ribbon has characteristics such as high magnetostriction, better mechanical properties and low cost. We prepared magnetic sensors using lamination forming of a Fe-Ga-Al ribbon/PZT. We measured output voltage and frequency dependency of these sensors in several alternative magnetic fields.

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This study's purpose is development of Fe-Ga Al (Galfenol) system alloy with large magnetostriction and high strength by precipitation hardening effect of the dispersed carbides for torque sensor system. Three kinds of composition bulk samples which added elements of Carbon, Zirconium, Niobium and Molybdenum to Fe-Ga Al alloy, (Fe-Ga_<0.15>-Al_<0.05>)_<99.0>-X_<0.5>-C_<0.5>(X=Zr, Nb, Mo) [at%], were prepared Those bulk samples were given heat treatment after the arc melting. Then, metallurgical characterization, the magnetic characteristic and strength property were studied. As a result (Fe-Ga_<0.15>-Al_<0.05>)_<99.0>-Zr_<0.5>-C_<0.5> [at%] arc melted and annealed sample showed a maximum magnetostriction of λ_<max>=90ppm and tensile stress σB=800MPa level, (Fe-Ga_<0.15>-Al_<0.05>)_<99.0>-Nb_<0.5>-C_<0.5> sample showed λ_<max>60ppm, σ_B=730MPa class, and (Fe-Ga_<0.15>-Al_<0.05>)_<99.0>-Mo_<0.5>-C_<0.5> sample showed λ_<max>=90ppm and tensile stress σ_B=780MPa level. As magnetostrictive alloy with high tensile strength like an 800MPa was not reported up to the present Those materials developed here have a potential of industrial applications such as torque sensor under severe environment.

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Hydrogenation operated bending motion device, which was a platinum coated LaNi_5 hydrogen storage alloy film deposited on a polyimide sheet at elevated temperatures, had been successfully developed. When the substrate temperature was 373K, the strain (Δε) was 550ppm, which displacement was 1.8 times larger than that (300ppm) at room temperature (323k). LaNi_5 alloy thin films were prepared by DC magnetron sputtering process at different substrate temperatures from 323K to 525K and different Ar gas pressure from 0.4 Pa to 1.0 Pa. As a result, the bending motion after 10000s, there sample expressed different bending motion strain at each DC magnetron sputtering process.

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Influences of deformation resistance on bending motion angle, strain and force of composite mover device driven by magnetic field of Fe-45at%Pd alloy thin film deposited on titanium, substrate thickness by direct current magnetron sputtering process were investigated. When the residual gas pressure before argon sputtering and the sputtering pressure of argon gas (5 N) were less than 5.0×10^<-4> Pa and 2.0×10^<-1> Pa, respectively, the thickness of the Fe-45at%Pd films deposited was about 2.5μm. Bending motion strain of Fe-45at%Pd alloy film largely depended on the bending deformation resistance controlled by substrate thickness from 50 to 300μm. The largest strain of bending motion induced by magnetic field and its highest susceptibility were found in the Fe-45%Pd alloy film deposited on titanium thin sheet of 50μm thickness.

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In order to develop magnetostrictive actuator induced by low magnetic field, we investigated magnetostrictive (positive magnetostriction/negative magnetostriction) bimorph-layers, that is, rapidly solidified Fe-Pd, Fe-Ga ribbons (100 μm)/Ni(50 μm). Displacement of the upper part of bimorph-layers with length of 20 mm was 230 μm under low magnetic field (500Oe). The bimorph-layers actuator was applied in micro-gas-valve. Flow rate of Ar with 7kPa is driven by magnetic field of 350Oe.

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Artificial esophageal actuator with peristaltic motion was developed. This actuator utilizes SME property of SMA coil springs, and has a role of transporting boluses. First of all, the human esophageal properties were detailed description, and an SMA spring used here was estimated experimentally in order to design the actuator. Based on those data, the actuator making use of SMA springs was designed and fabricated. In addition, sequential logic control system for actuator motion was constructed to imitate esophageal function, namely peristalsis. Its conveying ability was estimated using jelly as a pseudomasticated food. It was found that the actuator was able to transport jelly against gravity. Bolus transporting velocity, however, was a little lower than that of the human esophagus.

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In this paper, a preliminary study on a shape-recoverable shock absorption structure consisting of hysteretic spring elements combined with a buckling mechanism which could achieve both high energy absorption efficiency and high energy dissipation efficiency is presented. In order to illustrate the basic idea, a conceptual model consisting of a two-link mechanism and a hysteretic spring is investigated. A proof-of-concept experimental model consisting of a two-link mechanism and a superelastic shape memory alloy (SMA) spring is developed for the demonstrative purpose. A prototype of superelastic SMA-based "woven" shells is also developed to show a possible application of the proposed concept.

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A self-deployable composite structure using a partially flexible composite (PFC) with shape memory alloy wires is developed here. The fabrication process of the PFC is briefly mentioned first. The results of carbon fiber breakages during the folding process are investigated by using changes in electrical resistance. An SMA wire is embedded in the PFC to keep the folded configuration without loading and self-deployment is achieved using Joule heating. The results confirm that a flexible part of adequate length enables foldable composite structures without causing carbon fiber breakages, while the cyclic folding tests reveal that the PFC is reliable when a long flexible part is used. The embedded SMA wire realizes compactly folded composite panel structures without loading and Joule heating of the SMA wires enables self-deployable composite structures.

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In this research, we proposed a sandwich structure that consists of a shape memory alloy (SMA) honeycomb core and carbon fiber reinforced plastic (CFRP) facesheets as a lightweight geometric variable structure. First, the CFRP facesheets were bonded to the SMA honeycomb core and a pre-shear-strain was applied to the SMA core. Then the ends of the upper and lower facesheets were fixed together. After that, the SMA core was heated to generate the recovery shear stress. As a result, the sandwich panel curved in the out-of-plane direction. In addition, we analyzed qualitatively the deformation of the sandwich beam with the finite element method. The calculation result showed that the shear stress simulating the recovery stress deformed the beam in the same shape as the results of the experiments.

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This paper describes effect of the fiber volume fraction of SiC/Al active composite on its thermal deformation characteristics. The results obtained are as follows: (1) The room temperature curvature of the active composite after the optimum heat treatment increases with increasing the volume fraction of the SiC fiber. (2) The shape change of the active composite of the fiber spacing p=1 mm is continuously and monotonously during thermal cycle between room temperature and 833 K. (3) The curvature change of the active composite has no hysteresis up to 413 K.

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The aim of this study is to investigate the effect of the hardness and thickness of elastomer on the thermal deformation of high performance, that is, large deformation and high output force type active laminate using elastomer. The conventional active laminate was made by hot-pressing of an aluminum plate as a high CTE material, a unidirectional CFRP prepreg as a low CTE/electric resistance heating material and an epoxy adhesive layer as an insulating material. And the high performance ones were basically stacks of thin and large deformation type active laminates sandwiching elastomer. In this study, it was found that the thermal deformation of the active stack increases with decreasing hardness and thickness of the elastomer layer in the experimental range and the large deformation close to the level of single laminate can be achieved by using the soft rubber sheet of hardness H_s=1 (Shore A). Theoretical analyses were also carried out and the stress concentration around the edges of specimen at the interface of laminates and rubber sheet was found to be the important factor in determining the shape of active stacks.

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This paper describes the fabrication and evaluation of the active laminates having hollow channels to develop new functions such as cooling and healing. The active laminate was made by hot-pressing of an aluminum plate as a high CTE material, a unidirectional CFRP prepreg as a low CTE material and an electric resistance heater, a unidirectional GFRP prepreg as an insulator between them and copper foils as electrodes. The hollow channels were formed in the GFRP layer. In this study, it was found that the thermal deformations and output forces of the active laminates having one hollow channel decreases with increasing the volume fraction of the hollow channel up to 0.9. However, they were improved by increasing the number of the hollow channels.

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C_<60> fullerene nanotubes with diameters ranging from about 100 nm to 1000 nm have been successfully prepared by the liquid-liquid interfacial precipitation method. Further, C_<60> microtubes vertically aligned on a porous alumina membrane have been synthesized using a newly developed method that injects isopropyl alcohol into a toluene solution saturated with C_<60>. These Cso micro and nano tubes will have a wide application for solar cells, field-effect transistors, composite fillers for plastics and so forth in future.

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Effects of metal evaporation coating on stress-strain curve of carbon fiber have been studied. D.C magnetron sputtering device was used for evaporation coating which used Nickel target and to change film thickness, sputtering time was changed. Tensile test was conducted by twisting free tensile tester. As results of experiments, the stress was little gone down, but strain was raised substantially. After tensile test, the sample was observed by FE-SEM. The Carbon was not diffusion to Nickel on the inter face.

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Joining with high strength is also expected to apply to airplanes or racing cars to save their energy and to enhance their mobility. However it is difficult to join between metals and polymers. In order to enhance the joining strength, a carbon fiber reinforced interface has been suggested. To prevent to decay the carbon fiber by decomposition, the fiber has been coated with nickel film, which protects the carbon fiber against metal liquid. One side plain of the coated fiber is dipped into metal liquid. After solidification, another side of the coated felt is also dipped in other materials. The nickel coated carbon fiber reinforced interface between metals and differential materials probably acts as one of ideal original bonding.

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A metallic closed cellular material containing polymer has been fabricated. Polymer particles coated with nickel-phosphorus alloy layer using electro-less plating were pressed into the green pellets and sintered at high temperatures in a vacuum condition. These particles were also sintered by a spark plasma sintering method. Metallic closed cellular materials containing polymer were then fabricated. The three points bending tests were carried out to measure the mechanical properties of these materials. Damping properties were also measured. The results showed that these metallic closed cellular materials have different strength and different internal frictions among the specimens that containing different polymers.

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A room temperature solvent casting (RTSC) treatment, that is solidification after dissolving plastics into organic solvent, has been applied to bulk articled. The attractive points are not only the casting at room temperature, but also saving the production period and cost on molding of polymer. Thus, influences of acetone, one of typical solvent in environmental closed system, on mechanical properties of ABS polymer treated by RTSC-treatment have been studied. Although the RTSC-treatment softens the ABS polymer, it improves the Charpy impact value, which is 1.75 times larger than that before the RTSC-treatment. The improvement of impact value is mainly explained by residual mass of acetone in ABS polymer molecule.

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Joining between Nylon-film and silicone, polycarbonate, PMMA and polypropylene were successfully developed by using homogeneous EB irradiation. Effects of electron beam (EB) irradiation on joining strength of different polymers without adhesive materials were investigated. As a result, The EB irradiation on 0.216 MGy apparently enhances the joining strength of Nylon-film and all substrates. To discuss the influences of EB irradiation on the joining strength, electron spin resonance (ESR) signals related to dangling bonds were observed. Since EB irradiation generated dangling bonds on all samples, dangling bonds probably supported the joining at interface.

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A mismatch of different material properties in joints may cause stress singularities, which lead to the failure of the bonding part. Furthermore, thermal residual stresses occur in a cooling process after bonding the joints, and the stress singularity for thermal stress also occurs. In the present study, a boundary element method is used for evaluating the intensity of stress singularity. Analysis model is 3-layer model, and consist of silicon, resin and FR4.

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We experimentally investigated forces working on the contact interfaces between metal and resin molds of resin mold structures, which are made of metal cylinders covered with resin mold. The results are discussed from the viewpoints of friction force, bonding force, and contact pressure based on residual stress. As a result, we introduce a new concept for treating bonding coefficients. Moreover, we developed FEM modeling for forces acting on the bonding interface. We found that the calculation results for the forces were in very good agreement with those we measured.

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In this study, butt joint specimens which have various interfacial edge angles (notch type:0=45,70,80 degrees, cylinder type:0=90 degrees, protrudent type:0=100, 110, 110 degrees) are used. All specimens are tested after the heat treatment of 50 degrees for 12 hours to get stable results. Adhesive strength increases with increasing interfacial edge angle, and has the peak amount at the edge angle of 100 degrees. This is because that stress concentration at the interfacial edge becomes small for a larger edge angle. On the other hand, the apparent adhesive strength decreases with increasing edge angle for the protrudent type specimen which has no stress concentration. This is because the protrudent area of the specimen does not take so much load. Adhesive strength increases a little with an increase of loading rate.

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Recently, adhesive bonding has been used in the many fields because recent chemistry has provided new strong adhesives. However, the durability of adhesive joints has not been studied sufficiently. In particular, degradation due to water accumulation in adhesive layers is one of the crucial factors. In this study, adhesive-adherend interfaces in the joints, which is immersed in water, was observed using Scanning Acoustic Microscopes (SAMs) because it was suitable to detect defects in materials. Additionally, the ultrasonic reflection signals monitored using the SAM were analyzed to visualize the water distribution in the adhesive layers.

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Dissimilar metals welding between SUS304 and A5052 has been carried out by using a pulse YAG laser. Weldable conditions were obtained at spot diameter of 0.8 mm. Shear-tensile test and peel test was conducted to evaluate strength of the joint. The maximum strength for both shear-tensile and peel was obtained for the joint welded with laser irradiation condition of 280V-4msec. Reason for degradation of strength of the joint welded with higher heat input could be occurrence of under cutting and large formation of intermetallic phase. Change of the strength due to change in heat input was significantly observed for peel mode compared to that for shear-tensile mode. According to FEM analysis, molten pool depth affects on strength of the joint. It was observed that the strength of the joint under peel mode is more sensitive to the change in molten pool depth.

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To investigate the effect of hydrogen concentration on fretting fatigue strength, fretting fatigue test was performed using two kind of hydrogen charged and uncharged specimens. Hydrogen concentration was 60ppm and 8ppm for the hydrogen charged materials and 0.13ppm for the uncharged material. The material was SUS304. The solution heat-treated and 40% strained materials were used. Fretting fatigue limit in air was decreased by hydrogen charge. Fretting fatigue limit of the hydrogen charged materials in hydrogen gas showed further decrease. Fretting fatigue limit in hydrogen gas was almost the same irrespective of hydrogen charge conditions.

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Loosening of the wheel bolts may be the cause of accidents where the wheel falls off while the trailer is running. When the transverse force of wheel bolts exceeds a certain proportion of the bolt shaft force, the wheel nut begins to loosen. Loosening of a wheel bolt may influence on the deformation of wheel and the transverse forces of other wheel bolts increase, and the bolts may also loosen. In this report the 3-dimensional deformation of the disk wheels and the transverse forces on the wheel bolt are determined by 3-dimensional numerical analysis. In the result, by loosening of 1 bolt the transverse forces at lower position of wheel increase and the concentration at the upper position of wheel cancel.

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Bolted specimens of the aluminum alloy plate (A2024-T3) were subjected to fatigue testing to evaluate effects of the tightening torque on the fatigue life and the failure mode at different levels of the stress amplitude. Two modes of failure were observed, i.e. mechanical fatigue failure from the bolt hole edge in the range of small tightening torque, and fretting fatigue near the bolt hole edge in the range of higher torque regardless the stress amplitude. Then the in-process ultrasonic measurement was carried out with the surface acoustic wave to detect initiation and propagation of a fretting crack of the bolted specimen during the fatigue testing. During the fatigue process, the intensity of the scattering wave gradually increased at the fretted region ahead of a bolt hole with the number of fatigue cycles. It was assumed that the fretting crack appeared at the edge of the fretted area when the average intensity of the scattered wave reached a critical value.

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We developed a new strength evaluation technique applicable to impellers manufactured using a new laser slot-welding process. The welding process uses laser light to join blades to a shroud. In this process, first, slots are formed by machining on the shroud. Then, blades are welded to the opposite side of the shroud by the laser beam coming through those slots. Finally, the slots are filled with powder of the same material, welded, and closed. We experimentally examined the strength of the welded parts and found their strength was almost equal to that of the base material. During this welding process, fillet welds are formed between the blades and the shroud. We then focused on finding an effective method to evaluate their fatigue strength. After theoretical and experimental consideration, we reached the conclusion that total strain calculated using elastic and elastic-plastic stress analysis is suitable for evaluating the fatigue strength of a stress concentration region produced by the laser-welding process.

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