Lipid membranes including human skin are very interesting because of their mechanical properties. The stress-strain curve of them is far different from the ordinary one expected by the standard elasticity theory. To understand such an extra-ordinary property, we construct a model for membranes by using the notion of Finsler geometry. This model has a degree of freedom for the polymer direction in addition to its positional degrees of freedom. Using Monte Carlo simulation technique, we calculate the tensile stress-strain curve. We find that the numerical results are consistent with the stress-strain diagram of real membranes.

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The oviductal mucus has high viscosity and non-Newtonian properties. Under these surrounding fluids, the motion characteristics of spermatozoa changes as approaching the egg, which is called the hyperactivation. In order to induce the hyperactivation, we prepared culture solution which contains cBiMPS and CaCl_2・2H_2O. We mixed bovine semen and this culture solution, and cultured it about 1.5 hours. After culturing, we added methylcellulose (MC4000) which is non-Newtonian fluid to these culture solution. We observed the typical characteristics of the hyperactivation from the control with cBiMPS and CaCl_2・2H_2O. We conducted a PTV analysis and calculated the sperm velocity. For hyperactivated sperm, the results indicated that the sperm velocity with MC4000 was lower than that without MC4000, whereas the linearity with MC4000 increased compared with that without MC4000. These experimental results will provide useful data for understanding the mechanics of the hyperactivation.

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The purpose of this study is development of a Blood Collection Assistance System (BCAS) for accident prevention. Previous studies have developed assistance units for vein detection and vein puncture, which are difficult operations. However, the large size (400×330×440mm) of the units tend to place a psychological burden on users and errors occurring in each unit are large. This study aimed to achieve downsizing the equipment, improvement of the needle control accuracy and integration of the control system. The puncture unit was downsized (195×170×210mm) with redesign. The error in vein detection was 2.6mm (max) which was larger than the target accuracy of 0.1 mm for safety puncture, depending on the position of near infrared illumination. The maximum errors of needle positioning, directing and puncturing were 0.09mm, 0.59° and 0.21 mm, respectively. As the standard deviation was small, it seems that optimization of the control system could reduce the error.

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High Intensity Focused Ultrasound (HIFU) was developed for treating tumors non-invasively. In this treatment, ultrasound is focused on the target inside the body and ablates cancerous tissues. Small size HIFU devices have been developed, because large size HIFU devices are expensive for using at a private hospital. However, the small size HIFU uses also small transducers, there is a disadvantage that the focal distance is short. In this study, we proposed a method to control the heated area for the tumor location. First, we presented a ring-shaped transducer model with the spherical auxiliary vibration plate. Second, we calculated pressure distributions from computer simulation using the Finite-Difference Time-Domain (FDTD) method. From these results, we found that the proposed control method was useful for effective HIFU treatments.

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A stem cell-based self-assembled tissue (scSAT) biosynthesized using synovium-derived mesenchymal stem cells is expected as a novel medical material for cartilage, tendon, and ligament. However, it is necessary to improve the mechanical properties of the scSAT for clinical application. It is well known that the mechanical stimulus to the scSAT is an effective method to improve its strength. In the present study, scSAT was biosynthesized under a static compressive loading of 72 Pa. As a result, the tangent moduli of all loaded groups were significantly lower than that of control group. In addition, the strain energy densities of scSATs were increased with the increase of loading period. It is suggested that the scSAT became tough and flexible in response to the compressive stress.

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The purpose of this study is to establish a defect detection method using stress stethoscopes. The specimens used in the experiments have notch as an artificial defect. When the cyclic load was applied to a specimen with an artificial defect, we measured the strain distribution by using these devices placed around the defect found on the reverse side of specimen. In addition, the effect of notch geometry on the strain distribution was investigated. As a result, it was proved that a stress stethoscope can be used for the defect detecting method.

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Fiber waviness is a deformation of fibers in carbon fiber reinforced plastics (CFRPs), and is one of the process-induced defects that occur in molding of CFRPs. Because fiber waviness causes significant degradation of compressive strength of CFRP structures, nondestructive technique for waviness detection is in great demand. In this study, eddy current-based nondestructive technique for detection of in-plane fiber waviness in CFRPs is developed. Authors newly propose a test probe specialized for detection of in-plane fiber waviness in cross-ply CFRP. The proposed probe is sensitive to in-plane deformation of eddy current paths, can select inspected layers and the output signal is insensitive to lift-off. We carried out measurement on 20 layer cross-ply laminate with artificially induced in-plane waviness. It was found that the probe can detect waviness up to 18 layers away from the surface of cross-ply CFRP. The minimum size of the detected subsurface waviness has an amplitude of 1.4 mm and a length of 10.5 mm.

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Carbon fiber reinforced polymer (CFRP) laminates have been getting adopted as structural components for aircrafts due to their high mechanical performances. For the purpose of the evaluation of damage caused by a lightning strike, electric current analysis for CFRP laminates is indispensable. The authors have already proposed the analysis method using orthotropic electric potential function, which is applicable to the large structure that cannot be dealt with by general numerical methods such as FEM and FDM. In the case of unidirectional and cross-ply CFRP laminates, the effectiveness of this method has already been shown. The actual CFRP structures, however, have 45°, -45° carbon fiber plies in many cases. The present study proposes the improved method which can be applicable to the laminates having 45°, -45° plies. The effectiveness of this method was shown through the comparison with a numerical method.

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Recently, ultrasonic flaw detection among the non-destructive testing is used extensively. Generation laser scanning method is known as one of the ultrasonic flaw techniques, and it has an advantage that defects are easily visualized as a time-resolved damaged region image. In this study, we propose improvement methods of detection accuracy as follows; (i)extraction of A_0 signal from A-mode wave which is one of the Lamb waves, (ii)compensation of the attenuated intensity during wave propagation. In addition, the optimization of sensor position was carried out. For CFRP laminates and aluminum plates with surface/internal detects, the improvement of image quality was achieved by the combination of these methods.

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Thermal reactor tubes for petrochemical plants are stainless steel tubes manufactured by centrifugal casting. Because their surface is casting surface, conventional UT using piezoelectric elements cannot be used. Also, acoustic wave cannot propagate through inside easily because stainless castings are high-damping materials due to their large grain structure. For this reason, product has not been almost defect test. In this study, we attempt visualization of internal defects in the thermal reactor tubes by using electromagnetic ultrasonic flaw detection method.

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In this study, the complex modulus and Poisson's ratio are measured by the dynamic viscoelasticity tests that gives the sine wave in the epoxy resin. The lateral and transverse strains of an uniaxial specimen under cycling loading test are measured by using a digital image correlation method. Poisson's ratio is calculated as the ratio of lateral and transverse strains. Then, storage and loss moduli are calculated by using the phase difference between the input strain and stress response. Master curve is created by using the time-temperature superposition principle superposition principle.

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In this study, we aim to clarify the strength properties of the adhesively wavy-lap joints with dissimilar adherends subjected to tensile shear loads. To evaluate the strength properties for each joint, experiments to measure the rupture loads and FEM analysis to investigate the mechanical characteristics were carried out. As a result, it was found that the tensile shear strength and the maximum displacement increase case, where the material of other adherends in the dissimilar joints was used mild steel SS400. In addition, it was also found that the stress distribution at the adhesive layer indicated maximum value at bounded central part in all of joints.

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We aim to evaluate mechanical property for wood treated with far-infrared radiation under low temperature. Relationship between stress and strain in the wood dried by presented method was examined, using vertical compressive test. In addition, effects of drying methods and tree spices on the mechanical properties were investigated. In this study, the drying methods are three types "natural, convectional and infrared drying". Cypress as specimen materials were used. From the experimental results, it was found that maximum stress and strain in the case where far-infrared drying was applied become more increasing than these of natural drying method. Moisture content of wood specimen dried by high temperature convection proved to be the lowest in the three kinds of drying methods.

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The purpose of this study is to clarify the strength properties of the adhesively wavy-lap joints under compressive shear loads. Therefore, compressive shear test to measure the fracture loads of the joints and FEM analysis to investigate the stress distribution and deformation at bonded part were carried out. As a numerical result, it was found that the stress distribution in the adhesive layer is maximal at center of lapped part as the case where tensile shear is applied. From the experimental results, it was found that the compressive shear strength of the adhesively wavy-lap joint become more increasing than that of ordinary single-lap joint.

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Non-heat treated steels have been widely used like a shaft, in terms of low cost and energy saving. These members for the complicated stress of the stress amplitude during operation and the average stress, such as residual stress and clamping force is loaded, it is important to predict the fatigue life. Continuum damage mechanics is able to analyze the development of damage and fracture to the material, even the high cycle fatigue is reproducible by using the two scale model. In this study, damage mechanics is applied to non-heat treated carbon steel, and performed the material modeling. Then, the fatigue life is predicted under the influence of mean stress, to verify the usefulness by comparing with the experimental results.

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Carbon nanotubes (CNTs) can be used as templates where polycyclic aromatic hydrocarbon (PAH) molecules are stacked. Since coronene molecules have fluorescence characteristics, such columnar stacks of coronene molecules within CNTs can be used as fluorescence probes standing a severe environment. In this report, the morphology of coronene molecules encapsulated in a CNT is investigated. First, the minimum-energy structures of them are obtained by conjugate gradient minimization. Next, encapsulation of coronene molecules into a CNT is simulated by molecular-dynamics simulation. The tilt angle, relative rotational angle, and intermolecular distance of the stacked coronene molecules within a CNT are calculated both from the minimum-energy structures and from the final structures in the dynamic simulations. It is found that the tilt angle decreases with increasing the CNT diameter up to about 1.56 nm, and that the intermolecular distance is almost a constant for all the CNT diameters.

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The electronic and mechanical properties of carbon nanotubes (CNTs) and graphene are extraordinarily superior, and they are applicable to electronic devices, nano-electro-mechanical-systems (NEMS), thermal treatment, etc. To make the most of the advantages of CNTs and graphene, the hybrid structures of them are devised. Pillared-graphene is one of such hybrids. It consists of parallel graphene sheets and CNTs. In this report, the mechanical properties of pillared-graphene are investigated using molecular-dynamics. The indentation simulations for pillared-graphene models are performed, and their hardnesses are calculated. It is found that the hardness of pillared-graphene increases with increasing the diameter of the CNTs, whereas it decreases with increasing the distance between CNTs or temperature. The increasing rate of the hardness with increasing the diameter of CNTs decreaces with increasing the distance between CNTs or temperature. Such tendency will be explained by considering the ratio of the deflections of CNTs and graphene.

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Carbon fiber reinforced plastic (CFRP) possess high specific strength and is applied to various elements of the mechanical structure. It has been clarified that delamination and deformation occurred on a fiber composite and a laminate in CFRP, from repeatedly applying of loads. However, report on the damage characteristics of CFRP with a stress concentration zone such as groove and circle hole by combined loading of tensile and torsion have not a lot yet. In this study, we conducted cyclic combined loading examination of tensile and torsion. We paid attention to residual strain from the relationship between stress and strain, and examined the relationship of stress and the cycle of damage. As a result, it is showed that the relationship of stress and the cycle of damage is affected by the fiber orientation.

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The purpose of this study was to clarify the flexural strength properties for adhesively single-lap joints composed of quasi-CFRP and metal adherends subjected to bending moment. The quasi-isotropic CFRP adherend has four different lay-up patterns. Three points bending tests using precious universal test machine were carried out to measure the failure loads of each joint. In addition, the effects of lay-up patterns of quasi-isotropic CFRP adherends on flexural strength were investigated. According to three points bending tests, flexural strength depends on the angle of the fiber of the outermost layer. From the analytical results, it was found that eccentric stress distribution at the adhesive layer occurs in the case when fiber direction of the outermost layer was 45degrees.

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The strength properties of adhesively single-lap joints composed of ceramics and metal adherends subjected to tensile shear load were investigated numerically and experimentally. Tensile shear tests to measure the rupture loads of each joint were carried out. Stress distribution at the adhesive layer and deformation of whole joint were analyzed, using Finite Element Method. To confirm the reliability of the analytical results, strain measurement experiments using strain gauges were performed. As a result of this experiment, it was found that the tensile shear strength of SS400/Si3N4 joints is approximately equal to that of SS400/SS400 joint. From the analytical results, it was also found that significant stress at one side edge of adhesive layer in the case of SS400/Si3N4 joint becomes more decreasing than that of another joint.

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This paper described several fracture behaviors of in-plane stress and out-plane shear stress of CFRP prepreg with an initial defect in the twisting state when the impact pressure due to gas explosion applied them. Methane/air mixture gas was burst in a closed vessel equipped with a CFRP prepreg. In a typical material, although destruction by the progress of a crack from the initial defect was confirmed, in the CFRP, the resin material was melted by the temperature change caused by gas explosion, development of cracks was not confirmed. The maximum pressure value of CFRP in the twisted state was lower than that in the plane state.

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Mod.9Cr steels are widely used as boiler materials in ultra-super critical power plants. Creep damage was detected at welded joints in the boiler components. It is an important subject to establish life assessment methods of welded joints. In this study, creep deformation properties of local portions like a heat affected zone(HAZ) and a weld metal in a welded joint are obtained by creep tests using the miniature creep test specimens. Creep tests were also conducted with both standard and miniature size welded joints. Rupture time of the miniature welded joint specimen is shorter than that of the standard specimen. Finite element creep analyses of the welded joint specimens were performed to clarify stress and creep strain distribution within the welded joints. It was found that the difference of rupture time between the standard and miniature specimens is caused by the difference of the stress multiaxiality at the HAZ between them.

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It is important that evaluations of thermal fatigue life of the lead-free solder joints under temperature changes are performed accurately. In the estimation of the fatigue life of the lead-free solder joints, we have to get accurate low cycle fatigue properties of the solder. Inelastic strain range by low cycle fatigue test using small shearing test pieces is generally acquired by FEA. However, acquisition of inelastic strain range by FEM isn't verified that acquire the correct data by this way. I do acquisition of inelastic strain range by low cycle fatigue test using small shearing test pieces and FEM by same condition. Through comparing that data, acquiring inelastic strain range by FEM will be judged its validity.

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When honeycomb core sandwich panel (hereafter, HSP for brevity) is used as a floor panel, a dent will be formed on the face sheet of the HSP. If the high toughness material such as Carbon fiber reinforced plastics (hereafter, CFRP for brevity) is used as the face sheet, it is thought that the period for use as the floor panel will extend. In this study, by using HSPs on which 4-ply CFRP of [(0/90),(+45/-45)]s and [(0/90)_4]_T was used as the face sheet(hereafter, CFRP-HSP for brevity), local compression fatigue tests were carried out in consideration of usage condition as floor panel. The fatigue life was similar for both CFRP-HPSs. The rigidity was superior to CFRP-HSP used face sheet of [(0/90),(+45/-45)]s rather than CFRP-HSP used face sheet of [(0/90)_4]_T.

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Honeycomb core sandwich panel (hereafter, HSP for brevity) are superior in impact absorption under whole surface compression. However impact properties of HSP under local compression such as drop weight impact are affected by mechanical properties of the plate as the face sheet in addition to the core layer. This paper describes drop weight impact properties of double layer HSP which consists of two core layers and three plates. In order to investigate an influence of core geometry on drop weight impact properties of double layer HSP, a series of drop weight tests was carried out by using double layer HSPs with several cell sizes and several thicknesses of cell wall. From test results, influences of cell size and thickness of cell wall have been discussed in terms of 1) the deformation resistances of the load increase regions, 2) the peak loads, 3) the loads of the load equilibrium regions, and 4) the absorption energy.

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Recently, composite materials using natural fibers have been noted. However, the mechanical characteristic dispersions of natural fibers are greater than those of artificial fibers. Therefore, the mechanical properties of the composites made with natural fibers tend to have short stability, making industrial use difficult. This paper presents the method of dispersion reduction of mechanical characteristics of windmill palm (Trachycarpus fortune) as a natural fiber. The fibers are taken four height position categories in one tree. The strength properties were obtained by tensile tests and the dispersion of mechanical strength was analyzed by three-parameters-Weibull-distribution. It was found that the minimum dispersion of mechanical strength and high rigidity fibers were the second highest position category in the tree.

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Stop hole is a known repair method for fatigue crack. Purpose of the method is to show the life extension due to stress relaxation by carrying out a circular void on the fatigue crack tip. More stress relaxation that applies this method, several circular voids added around the stop hole. The effectiveness of this method is analyzed using fatigue test and FEM. We observed the stress disturbances around the stop hole using a two-dimensional isotropic elastic medium (matrix) under the in-plane problems and analysis of FEM(ANSYS). We focused on the disturbances of the stresses due to the span, size and arrangement between the stop hole and additional voids. In this paper, several numerical examples are presented with graphs.

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It is important to manage the growth of fatigue cracks for a long time. These cracks are growing due to vibration or welding heat, generally. When a crack length runs into the limit, it becomes unstable fracture state. Then, it cannot be managed. In this study, fatigue crack from the stress distribution at the crack tip is to clarify the process until the limit crack length, to perform the development of stress relaxation and the remaining life extension using elasticity. The results of the study, it is possible to stress relaxation by utilizing the piezo-electric actuator, it is possible to keep the remaining life extension of the steal materials under cyclic loading.

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In this study, we have newly proposed some joint configurations to improvement of various strength property of the adhesively bonded joint. In this instance, we report tensile shear strength of some joint configurations. Mechanical property in the presented joint subjected to static tensile load was analyzed, using Finite Element Method. FEM analyses were carried out to clarify the stress distribution at the bonded part. As a numerical result using FEM, it was found that stress concentrations occur at near the adherend holed parts in adhesive layer. From the tensile shear experiments, it was also proved that the fracture load of D3TC joint becomes increase than that of conventional joint.

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In this study, the constitutive equation for the materials including voids is proposed. Anisotropy and compressibility caused by distribution of voids are taken into account. Influence of voids distribution is represented by damage tensor in order to represent anisotropy and compressibility. The constitutive equation is derived by consideration based on thermomechanics. Dissipation inequality and yield function are proposed so that anisotropy is represented. Accuracy of this theory is validated by comparing the theoritical value and the finite element analysis of the model which assumes regularly arrangement of voids. The yield loci predicted by the theory showed good agreement with the curves calculated by FEA.

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The fatigue fracture consists on the crack initiation region and crack growth region. The life in the crack initiation region depends on the stress amplitude. On the other hand, the life in the crack growth region depends on the effective stress range. Under the two-step loading, a crack closure points of high and low stress levels changes to the closure levels under constant loading. Therefore, the fatigue mechanism must be considered in order to precisely predict the fatigue life. Moreover, transition criteria from crack initiation region to crack growth region is different between high and low stress amplitudes. Therefore, there is the transition region between transition points of high and low stress levels under two-step loading. In this study, this region was discussed in the detail.

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In this study, the characteristic of a viscoelastic material under high strain rate is evaluated by use of a Split-Hopkinson pressure bar method. In the Split-Hopkinson pressure bar method, the specimen is sandwiched between elastic sticks. The strain, strain rate and stress are obtained from the strains of the input and output bar. Observing the deformation by a high-speed camera at the speed of 1 million frames per second, the experimental data which is obtained by Split-Hopkinson pressure bar method is validated. In addition, the equivalent nature of the temperature and time of the viscoelastic body is investigated by comparing the impacts and static experiments.

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The strain measurement method using a CMOS inverter oscillator circuit including a strain gage is simple and can reduce amplifiers, filters, and A/D converters, because the circuit output, oscillating frequency which relates with resistance changes of a strain gage are measured by a simple pulse counting device. However, the sampling frequency is low (more than 1 second) in this method because this method has used the direct counting method for downsizing and simplifying of the measurement system. In this report, the improvement of the sampling frequency using the reciprocal counting method was proposed and studied. We manufactured a frequency adjusting circuit for reciprocal method. It was shown that, although greatly affected by the contact resistance the sampling frequency was improved to 196Hz.

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The strain measurement system using CMOS inverter oscillator circuits can be omit an amplifier because a counting device measures frequency changes of circuit voltage output caused by resistance changes of a strain gauge, then the miniaturization of this system become possible comparatively easily. In this study, the authors manufactured a new small type of digital output strain sensor using CMOS inverter oscillator circuits. This digital output strain sensor was applied to the strain measurement on static tensile tests of specimens and its measurement accuracy was examined. The test results showed that the same level of accuracy as conventional sensor has been achieved by this digital output strain sensor.

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Effects of test temperature and crystal orientations on Stage I fatigue crack growth in a Ni-based single crystal superalloy, NKH-304, were experimentally investigated. Four types of CT (Compact tension) specimen with different combinations of crystal orientations were prepared, and fatigue crack propagation tests were carried out at room temperature, 450℃ and 650℃. At room temperature and high ΔK regime at 450℃, the Stage I fatigue crack growth was observed, while the Stage II fatigue crack growth was taken place at low ΔK regime at 450℃ and 650℃. Such a transition of crack propagation mode and its effect on crack growth rate were discussed, taking account the 3D effect of inclined Stage I cracks and temperature dependence of CRSS along the octahedral slip systems.

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The purpose of this research is to develop the technology for aluminum alloy is weld in short time and a little change shape in atmosphere. It was welded using high frequency induction heating and ultrasonic vibration for it. As a result, when applying the ultrasonic vibration to the bonding portion, the tensile strength increases with junction temperature. When applying the ultrasonic vibration to the bonding portion, it increases in the tensile strength more than the case when isn't applied to the ultrasonic vibration. This is ultrasonic vibration destroys oxide layer of aluminum alloy, and to make a joint surface generate more material flow.

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In this study, the effect of compressive strain on free surface roughening is investigated by proposed compression test. In this test, specimen is held between flexible tools to prevent buckling. As a result of metal sheets such as C1220P-O, SPCC and A5052-O with thickness of 0.5mm, specimen surface contacting flexible tool is equal to free surface roughening. For pure copper sheets, the roughness evolution under compressive strain state is lower than that under tensile strain state. Furthermore the surface roughness decreases in the order of plane strain, uni-axial compression, pure shear. It is found that the free surface roughening under compressive strain depends on strain state.

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It is difficult to the molding and processing of CFRP in room temperature. Moreover it take many time and costs. It is necessary to CFRP production made by press forming in order to more widely prevalent in low cost. Therefore, the strength characteristic of CFRP composite at the press forming is important to clarify the forming limit point. In this study, we investigated the hot press properties of CFRP laminate, and we considered formability using the press molding simulation software. Moreover, the displacements compared with the results of the actual hot press experiments.

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This study is to investigate the joint strength of lead-free solder/Cu by the tensile test and the influence of additional elements and Ag concentration on mechanical properties. SAC305, SAC107, SAC0107 and SAC107 added 0.2mass%Bi, Sb, Ni were jointed between pure Cu plate and block by reflow process. After the tensile tests, microstructures of fracture surfaces were observed by SEM. The joint strength of SAC305 is the highest in all specimens. This result indicated joint strength of lead-free solder bulk depends on Ag concentration. The addition of Bi or Sb to SAC107 did not affected the joint strength, while the addition of Ni to SAC107 decreases the joint strength. From the observation of fracture surface, cracks occurred within the bulk solder away from either Cu or IMC.

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The shape recovery of Fe-28Mn-6Si-5Cr alloy was investigated without and with three kinds of the heat treatments: annealing at 600℃ for 1 min, water quenching from at 600℃ for 1 min and tempering at 600℃ for 1 min after quenching. All of the specimens with the heat treatments had better shape recovery than without the treatments. The austenite phase that contributes the stress-induced martensitic transformation increased in the annealed alloy and then its shape recovery could be improved. On the other hand the austenite phase less increased in the quenched and the quench-tempered alloys and the mechanism of recovery improved was the constraint of moving dislocation and then twining deformation had occurred at the deformation during the bending test because the crystal grains had been fined due to quenching.

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In this study, Fe-28Mn-6Si-5Cr alloys (cold-drawn wires) were annealed at 673 K, 773 K, 873 K, 973 K, 1073 K, 1173 K and 1273 K to reform the microstructure and enhance shape memory effect (SME). The specimens were investigated with electron backscatter diffraction analysis, X-ray diffraction line profile analysis, Vickers hardness test and bending test. These analyses and hardness test indicated recrystallization behavior of the alloys occurred as follows: recovery (above 673 K) → recrystallization (above 883 K) → grain growth (above 1073 K). Bending test showed the specimens annealed at 873 K and 973 K had the excellent SME. In contrast, the specimen at lower temperatures decreased SME because of less existence of austenite phase before deformation. The specimen at higher temperatures decreased SME because of the recrystallization and the grain coarsening, i.e., grain growth. The dislocation annihilation and rearrangement (recovery) encouraged γ ↔ ε transformation and enhanced SME.

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Thermal conductivity of top-coats (TCs) for thermal barrier coatings (TBCs) were investigated related to their porosities. Two kinds of free-standing TCs were produced by an air plasma spraying with different spraying powers and some TCs were subjected to the heat treatment at 1000〜1300℃ in air. The various porosities were measured based on the principle of Archimedes. The thermal conductivity was determined according to calculation using the thermal diffusivity, the specific heat capacity and the bulk density. It was found that the thermal conductivity depends strongly on the porosity as well as the size and the shape of pores. The TC sprayed with the lower power has a lot of microcracks between lamellas and exhibits the lower thermal conductivity.

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Thermal barrier coating (TBCs) are the indispensable technology for hot-section components of an advanced gas turbine. A TBC consists of a metallic bond-coat (BC) and a ceramic top-coat (TC) on a substrate. In present study, the Young's modulus of the TC from the TBC specimen, which is the substrate with the BC and the TC was determined by the newly developed flexural resonance method at an elevated temperature. Several kinds of TBC specimens with a different TC thickness were produced by an air plasma spraying. It was confirmed that the Young's modulus with high reproducibility can be obtained by this flexural resonance method.

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The purpose of study is to investigate the influence of testing temperature on tensile property of Sn-Bi alloys. Tensile tests of Sn-Bi alloy were carried out at various strain rates from 5.25×10^<-3> s^<-1> to 5.25×10^<-1> s^<-1> over temperature range from 25℃ to 80℃. Based on the experimental data, the specimen gave the highest strength at the fastest strain rate and at room temperature of 25℃. The lowest strength occurs when the specimen is subjected to the slowest strain rate at 80℃. The tensile strength decreases with decreasing strain rate and with increasing temperature. Moreover, strain rate sensitivity m increases with testing temperature.

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Some destructive techniques are required to evaluate the degradation of components for thermal power plants. However, conventional uniaxial creep specimens were sometimes too large to collect a sample from local area of target components. Miniature Creep (MC) test that employs smaller size of the specimen can be collected from the local site is well known as a better semi-destructive testing technique. Although the MC specimen of round bar needed a sample of 4 mm in thickness, that of thin plate shape can be collected under 2 mm in thickness. In this study, MC tests using thin plate and round bar specimens were performed in Argon gas and in vacuum to evaluate their creep properties. Test results were compared with uniaxial ones employing 2.25Cr-1Mo steel. It was shown that creep rupture lives of the MC plate specimens in vacuum were a similar trend to those of uniaxial creep, and that the MC test using the thin plate is able to substitute for the conventional uniaxial creep test.

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Mg with graphite (Mg+5wt.%Gr) and Mg-TiFe_<0.8>Mn_<0.2> alloy with graphite ((Mg-30wt.%TFM)+5wt.%Gr) or stearic acid ((Mg-30wt.%TFM)+5wt.%SA) composites were gotten with ball milling. The TiFe_<0.8>Mn_<0.2> alloy was used as a catalyst for improving hydrogen absorption-desorption properties of Mg, and the graphite and stearic acid were used as process control agents. We conducted Pressure-Composition-Temperature (PCT) measurements, X-ray diffraction (XRD) analyses and differential scanning calorimetries (DSC) for the samples. Mg+5wt.%Gr, (Mg-30wt.%TFM)+5wt.%Gr and (Mg-30wt.%TFM)+5wt.%SA stored hydrogen up to 0.9 wt.%, 3.6 wt.%, and 1.7 wt.%, respectively at 200℃ on PCT measurements. It might be that the added graphite, which was coated on the fresh surfaces of the samples during the milling process, prevented them from oxidizing, and consequently enhanced the catalytic effect of TiFe_<0.8>Mn_<0.2> alloy. MgH_2 was observed in (Mg-30wt.%TFM)+5wt.%Gr and (Mg-30wt.%TFM)+5wt.%SA with XRD analyses. These samples desorbed hydrogen around 305-335℃ in the DSC processes.

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In this study, monofilament tensile strength of commercially available short carbon fiber reinforced thermoplastic (CFRTP) single wires ejected from a FDM (Fused Deposition Modeling) 3D printer nozzle was investigated together with their X-ray CT image analysis. Reconstructed 3D CT images of the present CFRTP single wires show that there were noticeable internal voids in the present samples of single wires. The CT slice image stacks were then used for cross-sectional area measurement of the wires. At least, from this preliminary and limited test results, any gauge length dependency in terms of monofilament tensile strength of the CFRTP wires for FDM-type 3D printing purpose was not observed in this study, which should be further discussed elsewhere.

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To serve the purpose of controlling the microstructure of metal materials, it is critical to build a quantitative model to predict static recrystallization behavior. The first step to develop this model would be to relate cold working conditions to the remained stress and strain in a specimen. In order to visualize stress and strain distributions in single crystal iron specimens after tensile tests, crystal plasticity finite element method(CP-FEM) which takes crystalline anisotropy into account is incorporated in the UMAT user subroutine of the commercial software package ABAQUS. To estimate the parameters in CP-FEM, single crystal iron tensile tests with various crystal orientations are conducted and strain-stress curves are derived based on the digital image correlation toolbox NCORR. Based on abundant experimental, parameters in CP-FEM are determined and good agreement with the experiments is derived.

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In this study, the initial corrosion behavior of several stainless steels were examined. The materials were SUS304, SUS316 and pure Sn plate. They were decided corrosion times up to 1000hr in the use of SUS304 and 2000hr in the use of SUS316 at 500℃, respectively. After corrosion test, they were observed the cross section of reaction layer by OM and SEM. As a result, it was found that the reaction layer was formed at the interface between stainless steel and Sn plate after an incubation time. In the incubation time, the passive film made by Cr_2O_3 suppressed the diffusion of Sn into stainless steels. The strong stability of Cr_2O_3 film by the presence of Mo made strong the corrosion resistance of SUS316 against Sn higher than SUS304.

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In this study, I propose to improve the material features such as heat dissipation and water absorption by using a fractal on material structure for the purpose of surface area expansion. The usefulness of the fractal structure having a self-similar in part and whole was revealed in conjunction with the analysis. In the analysis, the improvement of the water absorption and heat transfer in the fractal could be expected. Unfavorable shape to simple diffusion as linear square fractal was present in the test specimen experiment. In addition to that, the results show that heat transfer inhibition caused by the formation of the boundary layer by convection in the triangular fractal. Therefore, selection of the optimal fractal structure according to the various purpose is required.

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