FeSi_2 thermoelectric elements are expected for high temperature applications because, of its low cost, nontoxic and superior oxidation resistance. The possibility of production of FeSi_2 thermoelectric conversion module by spark plasma sinter-joining method was examined. In addition, the thermoelectric conversion characteristics was evaluated by using the module processed in various kinds of shape. It was clarified that the p-n joining with sintering from powder was possible by spark plasma sinter-joining method. The module with excellent thermoelectric conversion characteristics was obtained by the direct joining further than the sinter-joining. It was made clear that the Seebeck coefficient depended on the shape of module.

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In this study, the method of laser cutting of a glass material was studied numerically as well as experimentally. Crack initiation behavior was investigated with a glass specimen without a starter notch. Surface roughness introduced by polishing with emery papers at the specimen edge affected significantly crack initiation behavior. Initial crack length was smaller in the specimen which has large roughness at the edge. The roughness introduced by the polishing of an emery paper was considered as a crack on fracture mechanics. Crack initiation behavior was observed by a high speed camera with a specimen polished by very fine alumina powder to miler finishing in the edge. Crack initiation and propagation mechanism was explained by the results of an experiment and a thermal stress analysis.

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An easy-release screw, which comprises a shape-memory alloy washer and a screw, to facilitate the recycling of resources has developed. We also experimentally examined the characteristics of the shape-memory washer. The screws are assembled by the same method as for conventional screws; once they are disposed of, the fastening washer is released simply by heating the screw to a predetermined temperature to enlarge the inside diameter of the washer, enabling easy disassembly of the screw. It was determined that the release temperature of the shape-memory alloy washer predominantly depends on the transformation point of the wire itself, as well as on the shape-memory alloy processing temperature and the amount of bending strain. By controlling these factors, it is possible to fabricate washers with the fastening release temperature in a specified range, and which can be easily disassembled.

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With the development of advanced medical treatment, the demand for fine tubes in the medical field is now very high. The technology employed must enable the production of tubes with various features, such as the following four; small size, high quality, high functionality, and low processing cost. We perform drawing of the tubes with mandrel using a fluid. We examined whether it would possible to manufacture high-quality fine tubes, whose diameter is less than 1mm.

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Micro shaped wires are widely used in various applications, such as in connecter terminals for laptop personal computers, mobile phones and building materials. In particular, wires with a round cross section have conventionally been used as orthodontics wires; however, the use of rectangular wires enables more efficient orthodontics treatment because rectangular wires are easier to handle and orthodontics strength is sustainable. In this study, drawing experiments and FEM analyses were carried out by varying the amount of reduction in order to improve the quality and dimensional accuracy for developing Orthodontics wires. We also succeeded in obtaining rectangular wires (0.63mm×0.42mm, R=0.1) by shaped drawing.

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Recently the die with cemented carbide is used for many industrial products, because that has high stiffness and long life. Hand lapping is mainly used in finishing of them because of high quality on the products. Non-traditional machining such as electron beam process finally does not catch up with the hand lapping level at state. On the other hand, there are several problems even the hand lapping; the geometric tolerance often become worse by manual control of human. In this study, new lapping system was developed without special units or tools using old CNC milling machine and reciprocating unit. Diluted starch syrup and diamond powder mixture is used as optimum cheap lapping slurry. Developed lapping system could machine effectively than hand lapping regarding surface roughness and process time. It is concluded from the results that, (1) The work piece with cemented carbide was finished below Rz=0.1μm without worsening of geometric tolerance, (2) Diluted starch syrup and diamond powder mixture could work effectively as lapping slurry, (3) Excellent new lapping system with simple setup was established.

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A numerical investigation by axi-symmetric finite element method (FEM) assumed the die deformation was carried out on diameter changing in a bar and a wire under cold-drawn through a wire drawing die. The mechanism of diameter changing was made clear and the factors influencing diameter were investigated. As a result, the final diameter of drawn bar is depend on the die expansion by contact pressure, the diameter decreasing at bearing area (Under shoot effect) and the spring back during drawing and unloading. The most influencing factors which are usually changed in field operation are approach semi angle, back tension, reduction and F value.

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Temper rolling which is the final process in cold rolling is important to determine product quality such as mechanical properties and surface qualities. Transcription mechanism of surface texture from a roll to a sheet was not been made clear. In practical operation, surface texture is controlled on the basis of experimental data. In this study, laboratory scale temper rolling experiments using shot dull roll and electric discharged dull roll and on the conditions that dry, soluble oil and mineral oil were conducted for low carbon steel sheet and high carbon steel sheet and effects of tribological conditions on transcription of surface texture from roll to sheet were investigated.

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In recent years, automotive lightening is required in the automotive industry so as to increase the efficiency of fuel. And so some automotive parts are made from aluminum and/or plastics for automotive lightening. A purpose of this study is to examine a cross-section of an aluminum frame superior for energy absorbency at the crush. At first, in case of bending square pipes, results of FEM analysis are compared with experimental results and efficacy of analysis results are confirmed. As the next stage, quantity of energy absorption of cross-section with various lib are calculated. And effects of lib on quantity of energy absorption are investigated.

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These days, new high efficient systems that are provided by CAE are been developing in the bending. The high accurate prediction is strongly needed to use appropriate tools. However, especially in bending of plates that have holes near bending line, the prediction is not good enough and adjustment is done by intuition and experience. Moreover, the unnecessary deformation of bended product occurs in springback. So, in this study, a database about the bending is composed through the FEM analysis and measuring bended plates. In this report, a slot that decreases unnecessary deformation of hole is explored and it is clear that shape of slot is most suitable. It is success to predict the effects of bending condition with the slot on the deformation of bending product.

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Aluminum space-frame is one of the candidates to be applied to a structure of car bodies in future because of its light weight as well as high strength. To omit the secondary forming process in the production of aluminum space-frame, variable shape extrusion apparatus employing a taper mandrel and four movable dies has been developed and the characteristics of hot extrusion were investigated. As a result, the step mandrel provides good dimensional accuracy due to its bearings which is parallel to the extruding direction. On the other hand, severe pick-up occurred easily on the surface of extrusions by using the step-mandrel. DLC coated dies has a remarkable effect to suppress generation of pick-up even under extrusion temperature of 673K.

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Ring compression tests were carried out to clarify the friction behavior occurring at tool/work material interfaces in micro/meso-scale metal forming. The minimum size of the ring used was 0.6mm in outer diameter. In the case of the test using lubricant oil, the friction coefficient is larger as the ring size becomes smaller. In the case of dry test, the more scattered results were obtained as the ring size becomes smaller, although the average of the coefficients does not vary with the ring size.

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Air-atomized pure aluminium powder was mechanically milled (MM) using a vibrational ball mill, and mechanically milled powder was sintered by spark plasma sintering (SPS). Solid-state reactions of MM powder after various heat treatments were studied by X-ray diffraction (XRD). The mechanical properties of the SPS materials were evaluated by hardness testing. Characterisations of the solid-state reactions between the MM powder and process control agent after heating at temperatures from 573K to 873K for 24h suggested the following products: No solid-state reaction was observed after heating up to 573K for 24h. Formation of γ-Al_2O_3 occurred in the 4h MM powder after heating at 773K for 24h, whereas the mixture of γ-Al_2O_3 and Al_4C_3 was observed in the 8h MM powder after heating at 773K for 24h. The full density of the SPS material was obtained with the condition of applied pressure at 49MPa at 873K for 1h The Vickers hardness of the SPS materials produced from no MM process and 64h MM powders exhibited HV39 and HV159, respectively.

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Carbon nano-fiber dispersed pure aluminum composites were fabricated by spark sintering. Effect of heat-treatment on interfacial structure and reaction was estimated by high-resolution electron microscopy. Carbon nano-fiber has low reactivity for pure aluminum compared with other carbon fibers. Interfacial reaction products covered with carbon nano-fiber completely with uniform thickness, which is carbon layer with irregular structure.

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Aluminum borate whisker (Al_<18>B_4O_<33>) reinforced AZ91D magnesium alloy composites was fabricated by squeeze casting process. By observing the microstructure and the interfacial structure between whisker and matrix in composites, the stability of the composites was estimated. Then, the effect of microstructure on the strength was discussed.

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A numerical study was performed on the fracture toughness test to obtain the critical strain energy release rate (G_<IC>) of Glass Fiber Reinforced Plastic (GFRP) laminates in wind turbine blade. Two-dimensional numerical analysis, based on an elastic finite element method (FEM) using the static explicit method and the cohesive damage model, was performed to simulate the fracture toughness test. The cohesive damage model used to predict the delamination occurrence and growth is based on a special developed interface finite element including an exponential damage process. The numerical prediction showed good agreement with the experimental results.

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In order to clarify the effect of strain rate on the mechanical properties of textile composites, plain woven carbon fiber/epoxy composites were tensile tested with a hydraulic testing machine. The actuator speeds were selected as 0.5mm/min, 0.01, 0.1, 1.0 and 10m/s, which result in the strain rate ranges of 5×10^<-5>, 5×10^<-2>, 5×10^<-1>, 10^1, and 5×10^1s^<-1> , respectively. Experimental results indicated that the modulus of elasticity and the tensile strength increased at the strain rate more than about 10^1s^<-1> . The specimens after tensile tests were observed with SEM. The results indicated that resin exists around the fibers at the strain rate more than about 10^1s^<-1>. It was suggested that interfacial strength increased with increasing strain rate.

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Damage growth behavior of transverse crack and delamination in cyclic loading was studied with cross-ply laminates of carbon fiber reinforced plastics (CFRPs) composite. Damage of the specimens during the fatigue test was observed by soft X-ray photography. It was found that delamination growth behavior depended on the inter-laminer stress and the out-plane stress in thickness direction caused by free-edge effect. Quasi-isotropic, [45/0/-45/90]_s, laminates, are applied large peering stress at free edges of the specimen when the specimen is subjected to tensile stress. Therefore they showed edge delamination. On the other hands, cross-ply, [0/90_6]_s laminates, are applied large inter-laminer shear stress at transverse crack tips, and show local delamination originated by a transverse crack. Under the high-cycle loading, it was observed that depending on the applied stress level delamination growth behavior differed.

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In the present study, elasto-plastic analysis on the thick-walled filament-wound carbon fiber reinforced plastic (FW-CFRP) hybrid composite pipes subjected to internal pressure was proposed. The analysis is based on the Hencky relation and Ludwick's strain-hardening function. In order to evaluate the availability, the distributions of stress and strain based on the present analysis and finite element method were compared. Burst strength of the FW-CFRP hybrid composite pipes were predicted based on the maximum strain criterion. The analytical predictions are in good agreement with the experimental results.

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Influences of stress ratio on constant amplitude fatigue behavior of CFRP laminates have been examined and a rational fatigue life prediction method has been developed. First, constant-amplitude fatigue tests are performed at room temperature on three kinds of symmetric angle-ply CFRP laminates [±θ]_s (θ=30,45,60゜) for six kinds of stress ratios. The experimental results show that fatigue strength is lower for fatigue loading with larger amplitude. It is observed that the stress amplitude for a given fatigue life becomes largest under a fatigue condition in which stress ratio is equal to the ratio of compressive strength to tensile one. A procedure to construct a nonlinear constant fatigue life (CFL) diagram is developed on the basis of the static strengths in tension and compression and. the reference S-N relationship for a critical stress ratio equal to the compression-tension static strength ratio. The fatigue lives predicted on the basis of the nonlinear CFL diagram agree well with the experimental results over the range of fatigue life up to 10^6 cycles for all the stress ratios tested. Overall, the proposed fatigue life prediction method has moderately been successful for the fatigue behaviors of different kinds of angle-ply laminates.

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This paper describes in-plane shear mechanical properties of woven fabric reinforced plastics by the static and dynamic ±45° tension test method. Using the tension-type SHB apparatus, the dynamic tension tests were performed. 8-types of specimens were used. 2-types of epoxy resin (thermo-set and thermo-plastic) were combined with 4-types of fibers (E-glass, T-glass carbon, and aramid fiber). Comparing their mechanical properties, especially, the shear of glass fiber specimens more dependent on strain rate than other specimens.

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Recent years recycling is recommended as one of environmental pollution control measures. In this study, we report the effect of material recycling on mechanical properties of poly (butylene-succuinate) (PBS). After fifth cycles of reprocessing, bending strength and bending modulus remained constant. Then the effect of reprocessing on bending strength after immersion in water was evaluated. By reprocessing the material degraded by absorbance the bending strength recovered to that of virgin material. This is because the water absorbed into the material is removed during reprocessing. By reprocessing the material degraded by hydrolysis, the bending strength remained constant compared with before reprocessing.

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Long-term durability of fiber-reinforced-plastics (FRP) under hostile environment is strongly influenced by the degradation of fiber strength. The degradation of the fiber strength has been quantified on the basis of microscopic stress corrosion cracking (SCC) of the initial defects on the fiber surface. In this paper, the fiber strength degradation in the single-fiber-composite (SFC) has been investigated under constant strain in water to represent the SCC of GFRP. By taking account of the fiber strain history, such as water absorption, thermal expansion, applied strain, the growth of the initial defect after the constant strain test was formulated. After the constant strain test, fragmentation test was conducted in order to estimate strength degradation of the embedded fiber. The remaining fiber strength distribution obtained from the fragmentation test was predicted using the model containing the Paris Law and the Arrhenius model presented by K. Liao.

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In the present study, degradation properties of the polymer blends of poly (lactide) (PLA) and poly (butylenes succinate) (PBSU) with different mixed fractions were investigated. PLA/PBSU (80/20) was exhibited highest water absorption during hydrolysis tests, while biodegradation rate was increased in PLA/PBSU (20/80, Non-Annealing) on soil burial. Tensile tests were conducted on the blends after 0, 8 and 16weeks degradation tests to evaluate the variation in Young's modulus and the tensile strength. Tensile strength of PLA/PBSU (50/50, 20/80 and 0/100, Non-Annealing) and all annealing specimen were sensitive to hydrolysis degradation.

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Rock bits are used in a variety of ground-drilling applications for the exploration of natural resources, such as petroleum, natural gas, water and geothermal energy. Cemented carbide with diamond powders are fabricated to extend bit life. The pulsed electric current sintering (PECS) was used to avoid graphitization of diamond powders by fast heating and short holding time for sintering. Additionally, phosphorus was added to raw powders to decrees a sintering temperature. The additive allows to decrease sintering temperature about 200K from 1200℃. Sintering period of 10min was enough to obtain dense matrix materials. Wear of fabricated rock bits was evaluated by grinding of a rock under 20MPa of pressure, and 0.2m/s of a turning velocity for 60min. Although, wear of a rock bit without diamonds was 36mm^3/h, and that of fabricated rock bits was negligibly small in those experimental conditions.

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Synthetic oils and greases are used for space lubricant. So, it is important to know the performances of these lubricants. The base oil 815Z and 2001A and the greases 600EF, 601EF and 602EF with base oil 815Z and grease R2000 were considered as the test fluid in this study. The highest wear scar has found for base oil 815Z but it showed the lowest coefficient of friction, whereas greases 600EF, 601EF and 602EF showed lower wear scar and considerable friction coefficient Investigating these phenomena, authors found that the base oil 815Z contains the acetal group (-OCF_2O-). At high shear rate in EHL conjunction the viscosity was decreased by mechanical shear. Hydrogen fluoride occurred with the decomposition of acetal group. It increases the wear rate of the contact surfaces. But that decomposition does not occurred in the greases with base oil 815Z and showed better result as space lubricant.

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This paper describes the frictional property in conducting the micro texture on the sliding surface for the purpose of improving the tribology property of slideway in machine tool. The numerical calculation that compared tribology properties on several kinds textured surface and smooth surface was carried out. We clarified the effectiveness of dimpled surface to reduce the change of the frictional force. The phenomenon is based on the existence of the local peak of the pressure distribution, which arises in the dimple area. The experiments by the apparatus of the practical size were also carried out in order to verify the calculation result.

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The present study describes the applicability of fine particle peening on surface modification of aluminum cast alloy in boundary lubricated condition against alloy steel. The specimens with modified surface were prepared with different treatment times. As results, the friction coefficient and the wear loss were larger at excess treatment of the peening and it was estimated that the crush of the silicon-rich segregated layer on the aluminum cast alloy during the sliding contact influenced on the wear loss of the alloy steel.

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A new film coating method based on a combination of hollow cathode discharge and glow discharge methods was developed in order to grow a DLC film on substrate of a dies for deep drawing and ironing process. One of features of HCD process was to be able to provide a uniform film thickness of DLC on inner surface of deep hole. When applying a new process to the surface of a small-sized dies, a surface had a uniform film thickness and high hardness and scratch force. Tribological properties were conducted with a pin-on-disk type tribometer under the constant operating conditions. A combination of hardened steel and DLC coated surface was much superior to steel/steel in terms of friction and antiwear properties.

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A metallic closed cellular material containing in-organic materials has been fabricated. Powder particles of in-organic materials coated with nickel-phosphorus alloy and copper layer using electro-less plating were pressed and sintered at high temperatures in a vacuum condition by a spark plasma sintering method. Metallic closed cellular materials containing inorganic materials were then fabricated. The three points bending tests were carried out to measure the mechanical properties of these materials. Damping properties and physical 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 materials.

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