The layer grooves are generated on the all Fused Deposition Modeling (FDM) 3D printed structures. The principle of FDM is piling up melted printing material (mainly resin material). And crevice of each layer generates layer grooves. The layer grooves make the 3D printed structures mechanical characteristics deteriorate. For example, friction and strength. Currently 3D printing technology are not able to control the 3D printed structures to have constant friction and strength value. The 3D printed Structures are difficult to use for mechanical parts. Therefore authors already devised the 3D-CMF (Chemical Melting Finishing). The 3D-CMF is the method that dissolve the convex part of the layer grooves and filled in the concave part of the layer grooves and smoothen the layer grooves. The 3D-CMF changes the surface statement of the 3D printed structures, which is considered to affect the coefficient of friction. In this paper, we investigated the fundamental characteristics of the 3D-CMF and demonstrate of the change of the coefficient of static friction of the 3D printed structures.

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Global competition adds to intensity in manufacturing industry year by year these days. Reduction of the production cost and shortening of the delivery date in this way become the important problem for a company. The use of the 3D printer is considered as this one solution. Therefore we aim at the development of the grinding wheel for the laboratory of ELID cuts which on-demand can produce which does not need a die by developing the whetstone production technology that put 3D printer and droplet discharge technology PELID together and push forward a study. In this report, I investigated the characteristics including the electrolysis dressing characteristic of the conductivityTPU resin to use for the production of 3D printer and thecomposition whetstone production device of the whetstone by the PELID technology and 3D printer aiming at the production of the on-demand whetstone.

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With the performance of such optical and electronic parts, lens, high machining accuracy silicon wafer or the like, the processed surface quality is required. It can be mentioned that refining the grains of the grinding wheel to a technique for improving the machined surface quality. But the fine abrasive grains are easily aggregated, there may not have effective. Therefore, we focused the PELID method which is a discharging technique of droplets utilizing electrostatic force as an abrasive dispersion method. Droplets ejected by the PELID method repeatedly one after another division by electrostatic force, it is possible to form fine droplets. For this reason by mixing abrasive grains into the discharge liquid to form fine droplets, it is possible to spray without aggregation of abrasive grains. And working to establish a new grinding wheel fabrication process by utilizing such properties.

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According to recent trends, nonspherical shape optical elements is more required by optical instrument is going miniaturization and high-precision. Nonspherical shape optical elements is made by die. So, die is required high-precision. It requires grinding by fine grain whetstone. This experiment purpose making fixed abrasive by fine grain whetstone. This has subject that fine grain whetstone is condensing. The subject can clear by method of PELID. But, this way has new subject. It is repulsion. The method of PELID is using electricity for spraying fine grain whetstone. And it has electricity. It hinder spraying next fine grain whetstone. So, I propose spraying with changing electricity direction. By this way can be laminating fine grain whetstone and making fixed abrasive. Furthermore, by combining the laminate shaping technique which can control in the thickness direction using Green sheet, it is possible to disperse abrasive grains in the grinding wheel in three dimensions. We have developed a grinding wheel dispersed nano- diamond in three dimensions using this technique

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We investigated the deposition of the nano dots DLC film using porous alumina film. Porous alumina film, which is formed by anodization of aluminum in acidic electrolyte, is a typical self-ordered material. The pore size and thickness of is controllable with the anodization voltage, time, and etching time. The porous alumina film was used to cover the substrate, it deposited the DLC film. The DLC film deposited using the unbalanced magnetron sputtering (UBMS), and the nano dots DLC film could be obtained whereby the porous alumina film removed. The substrates after deposit the DLC film was investigated by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and scanning probe microscope (SPM). The nano dots DLC film could be obtained by this process.

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Static characteristics of injection molded carbon short fiber composite material were evaluated. Test specimens cut out from injection molded plates at different angles (0°, 45°, 90°) with the injection direction are tested in static tension and compression at room temperature and 80°C, respectively. In-plane strain field in a gauge part of a specimen is measured using DIC, from which the average strains are calculated. The orientation and temperature dependences of static strength and elastic modulus are identified. The orientation dependence of static strength can adequately be described using the Tsai-Hill failure criterion. The orientation dependence of elastic modulus in the loading direction can be predicted using the orthotropic elasticity theory. The Arrhenius relation is found to be applicable for description of temperature dependence of static strength in tension and compression, respectively.

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Off-axis static and fatigue strengths of injection molded discontinuous carbon fiber reinforced polyamide (DCF/PA) composites are investigated. Static tension and compression tests are first performed on off-axis specimens of different orientations (0°, 45°, 90°) at different temperatures (RT, 80°C), respectively, to identify the orientation and temperature dependences of the basic mechanical properties of the composites. Then, constant amplitude fatigue tests are carried out at different stress ratios (0.1, 10), respectively. The fatigue test results demonstrate that the fatigue strength depends on fiber orientation in line with the static strength, and fatigue life scatters significantly, especially in the transverse loading. It is suggested that the distribution of fatigue life data can approximately be described by means of a lognormal distribution function.

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The unnotched and notched strengths of multidirectional CFRP laminates have been examined with a particular emphasis on the effect of internal symmetric angle-ply layers of different orientations. Static tension tests are performed on unnotched and notched specimens for different orientations of angle-ply layers, respectively. The unnotched strength is shown to depend on the orientation of angle-ply layers. On notched strength, similar effect of angle-ply layers is observed. A notched strength prediction method using a finite fracture mechanics model in conjunction with an off-axis notched strength model for unidirectional ply is tested on the CFRP laminates with different internal angle ply layers. The accuracy of prediction is found to be sensitive to that of prediction of laminate fracture toughness.

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This study provides that effects of interface edge shape on bonding strength of ceramics to metal joint system with arc-shaped free surfaces. Each joint specimen, Si₃N₄ to Ni joint which was composed of silicon nitride as electro-conductive ceramic and the pure nickel, was bonded at 780°C in a furnace maintained vacuum condition. Relationship between bonding tensile strength and the edge shape was clarified experimentally. These experimental results were compared with our past results using the Si₃N₄ to Ni specimens bonded at 880°C. It was clarified temperature dependence of optimum interface edge shape which the maximum bonding strength appears range over 780°C ≤T≤880°C.

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The statistics distribution of fatigue life of a short carbon fiber-reinforced polyamide-6 composite and its stress ratio dependence are examined. A procedure for predicting S-N relationships for different constant values of probability of failure P, i.e. P-S-N curves, is proposed. Fatigue tests are performed at different stress ratios R = 0.1, 10 and R = χ = σ_UTS/σ_UCS, respectively. To identify the statistical nature of fatigue life, lognormal and Weibull distributions are fitted to the fatigue data obtained. The plot of fatigue data on a probability paper and the goodness-of-fit tests using the modified Kolmogorov–Smirnov suggest that both lognormal and Weibull distributions are acceptable as the distributions for the static strength data as well as fatigue life data. The P-S-N curves at different stress ratios for different probabilities of failure (10%, 50% and 90%) are constructed not only using the experimental data but also a theory developed in this study, and they are compared to each other to evaluate the accuracy of the theory.

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Effects of random R-ratio loading on fatigue life of a quasi-isotropic woven fabric CFRP laminate have been studied. A new methodology for generating random R-ratio loading is first developed with the help of the anisomorphic constant fatigue life diagram approach. In the random fatigue testing, different R-ratio waveforms of different stress levels are randomly generated for two constant values of life, respectively, and they are alternately sequenced to form a block that is repeatedly applied to specimens of the composite. Random loading test results suggest a strong interaction between the waveforms consecutively applied. It is demonstrated that the Miner rule is excessively optimistic for the random R-ratios loading. In contrast, the use of the Miner rule in conjunction with the rain flow method allows much better prediction with an accuracy of a factor of two.

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Fatigue characteristics of notched thin-ply woven carbon fiber composite laminates have been studied. Woven cross-ply composite ([(0/90)₃₂]) and woven quasi-isotropic composite ([(0/90)/(±45)]_8S) were tested. Unnotched (UN) and center-notch (CH) coupon specimen are prepared, respectively. First, static tension and compression tests were performed. They were followed by fatigue tests at stress ratio R = 0.1, 10, respectively. As a result, the static strength of unnotched cross-ply specimen was found to be larger than that of quasi-isotropic specimen. The notch sensitivity of cross-ply specimen was larger than that of quasi-isotropic specimen. The decrease of fatigue strength of cross-ply specimen was smaller than that of quasi-isotropic specimen. The notch sensitivity and notched fatigue life of the two kinds of composites were predicted using the notch sensitivity prediction method and fatigue life prediction method, respectively. The predicted notch sensitivity and notched fatigue life of the both materials were shown to agree well with the notch sensitivity and fatigue life observed.

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In this study, the effects of strut shapes on buckling behavior of cubic lattice cellular structures are investigated using a homogenization theory of finite deformation. For this, the updated-Lagrangian formulation is employed in the homogenization theory to cosider finite deformation of struts in cubic lattice cellular structures. Buckling analysis is conducted at each incremental calculation to judge the buckling of struts. After buckling, buckling modes are calculated using the eigenvalue analysis. Using these methods, elastic buckling behavior of cubic lattice cellular structures with different strut shapes in uniaxial compression is analyzed to investigate the effects of strut shapes on their buckling behavior. It is shown that the buckling stress of the cubic lattice cellular structures strongly depends on the strut shapes.

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In this study, creep analysis of plain-woven GFRP laminates based on a homogenization macroscopic constitutive model is conducted. To this end, an elastic-creep macroscopic constitutive model which is able to express strong anisotropy of composites is introduced, and the material parameters in the model are determined based on the results of a triple-scale homogenization method using a unit cell at room temperature (25°C) and elevated temperature (80°C), respectively. Then, creep analyses of plain-woven glass fiber/epoxy laminates are conducted on four uniaxial loading condition, i.e. θ = 0°, 15°, 30° and 45°, using the macroscopic constitutive model and the triple-scale homogenization method at the both temperature. It is found that the analysis results of constitutive model are in good agreement with those of the triple-scale homogenization method.

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In this study, a through-the-thickness negative Poisson's ratio of an angle-ply carbon fiber-reinforced plastic (CFRP) laminate is experimentally investigated using a digital image-based method. For this, a novel image-based measurement method consisting of a 3D digital scanner and a digital image correlation (DIC) measurement system is developed to obtain the thickness change of CFRP laminates. Then, a tensile test of a [±30] angle-ply CFRP laminate is performed, and both the in-plane and the through-the-thickness Poisson's ratios are measured based on the developed method. The results obtained suggest that the through-the-thickness Poisson's ratio exhibits negative values which become increasingly negative as the viscoplastic deformation progresses in the laminates.

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Low cycle fatigue tests with stress ratio 0.1, frequency 5Hz were performed on samples of amine cured epoxy resin. Samples fatigued to varying degrees were characterized by using two different methods, the change in the molecular bond energy Raman spectroscopy and the change in free volume by positron annihilation lifetime spectroscopy (PALS). Fatigue damage caused a shift in the Raman spectra with the fatigue damage samples shifted to lower wavenumbers compared to the as-received sample. The PALS measurement showed an increase in the ortho-positron lifetime for fatigued samples, suggesting that there is a correlation between fatigue damage and free volume size in the epoxy resin.

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Positron annihilation lifetime measurement and Electron Backscatter Diffraction (EBSD) were evaluated the fatigue damage by detecting defects such as dislocations or strain in Ti-6Al-4V. Samples of various degrees of low-cycle fatigue with strain control in room temperature were carried out. This alloy changed the microstructure by heat treatment of furnace cooling, air cooling and water quench. In the case of air cooling or water quench sample, the lamellar structure was observed. Positron lifetime was changed by the rate of cooling. In the case of fatigued sample, KAM map was not changed before and after fatigue. However, the positron annihilation lifetime measurement exhibited a proportional increase in the positron lifetime with the fatigue damage to cycle to failure, showing that the relationship between fatigue damage and positron lifetime.

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Electromagnetic forming is most attractive forming to improve its mass production for automotive field. Optimization experiment and analysis for Electromagnetic forming were carried out in this research. Magnesium alloy, AZ31 was subjected to a contraction process. As a result, the deformation was increased by heating specimen with increasing temperature from room temperature to 250 degrees. It was shown that the processing temperature is important for electromagnetic forming of AZ31. FEM analysis based on the experimental data was carried out. The result of FEM calculation showed good agreement with experimental data, showing that the amount of shrinkage deformation increased with increasing temperature in AZ31.

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Carbon fiber-reinforced thermoplastic (CFRTP) is most attractive material, which is expected to reduce the weight of mass-produced automobile or airplane and to improve short-term production. In this study, Fiber orientation analysis was carried out for press-formed CFRTP laminates based on a thermoplastic carbon fiber sheet using micro focus X-ray CT system. As a result, it was revealed that about 60% short carbon fibers were distributed in the direction of tension axis in both skin and core layer. While, fibers with injection molded CFRTP was distributed in the direction perpendicular to a tension axis in core layer. The CFRTP laminates exhibited higher tensile and fatigue strength than the injection molded specimen.

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Three dimensional shell elements were used to simulate welding residual stress profiles of multi pass bead on plate specimen. The specimen was low alloy steel SQV2A (JIS G3120) and its thickness was 10 mm. Nine pass bead on plate specimen was fabricated. Gas tungsten arc welding was used to fabricate the specimen. Residual stress profiles were measured with the strain relief method. Temperature histories during the welding process were calculated by using transient heat transfer analysis. Welding residual stress profiles were calculated by using the thermal elastic plastic analysis. Phase transformation occurs during the welding process and phase transformation property was taken into consideration through thermal strain behavior in the analysis. The analysis results by three dimensional shell element show good agreement with those by three dimensional solid element and experimentally measured results.

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