Tribological properties of tin coating on a ductile cast iron surface were evaluated with a ring-on-disc type testing apparatus mated with a quenched carbon steel ring in lubricated condition. The tin coating was carried out using a mechanical plating method, similar to that of a shot peening process. The coating thickness was several micro meter. Results of the friction experiment showed that the friction coefficient and the wear loss were considerably smaller than those of the mirror finished cast alloy surface. In addition, effects of heat treatment and roller burnishing on the tribological properties were investigated. As results, tin layer protected the removal of the piled up graphite was found. Combined effects of graphite and tin on the tribological properties were discussed.

In this study, rolling contact fatigue of zinc powder peened alloy steel surface was investigated. Zinc particle having 180 μm in size was sued for the impact media. Transfer of the fragment of the impact media and application of the residual stress were found on the shot peened surface. The rolling contact fatigue was evaluated with 3 silicon nitride ball in lubricated condition. The residual stress of the sample was measured by X-ray diffraction method. As a result, compressive residual stress was applied by forming a zinc film using shot peening. The fatigue life determined from the occurrence of peeling was considerably larger at the zinc peened surface despite that the residual stress was smaller than that of glass bead peened surface. The depth of the peeling on the zinc peened surface was larger, it is estimated that the zinc transfer results in a decrease of the friction resistance at the interface. Consequently, the shot peening with zinc powder is effective means to increase of the fatigue life rolling contact.

The present study describes tribological properties segmentally aligned tin (Sn) coating formed on copper-based alloy. A shot peening technology was connected to coat Sn thin film. Heat treatment was conducted to enhance diffusion process resulting in hard layer consisting of solid solution and intermetallic compounds between the interfaces. As results, the hardness measured with a micro indentation was lower near the surface and higher at subsurface. Tribological properties evaluated with a face-to-face contact testing apparatus in lubricated condition showed that the friction coefficient and the wear loss was low at the surface treated at low temperature less than 240 deg. Celsius. In addition, tribolological properties of segment structured tin coating were evaluated.

In the mechanical industries, forging process with dies is one of the deforming methods for steels and non-ferritic materials. In order to use forging dies for long lifetime and with less wear and seizure, a sulfornitriding process was sometimes applied to the dies made of die steels. This surface treatment consists of sulfidation to form sulfide layer and nitridation to make nitride diffusion zone. A sulfide layer is able to reduce the friction coefficient and improve seizure resistance. A nitrided diffusion zone increases hardness, abrasion resistance and lifetime. The sulfide layer is mainly composed of iron sulfide (FeS). It is very necessary to investigate and clarify its tribological functions of FeS. Details of the physical and mechanical properties of FeS, for instance, hardness and fracture toughness are also very important. However, the physical properties of FeS have not been investigated well, especially in high temperature conditions. In this study, high-temperature deformation behavior of FeS sintered bulks in compressive experiments are conducted at room and several high temperatures．

Recently，the number of resin parts used for bearings and gears is on the rise，and two kinds of ABS resin and PLA resin are mainly used as 3D printer molding material．

Although metal-containing PLA resin has been developed in recent years，there are few research examples on this material，so we evaluate the strength and sliding property of ABS · PLA ·XT-CF20 and metallic PLA for the purpose of evaluating the mechanical performance on the material．

It is important to understand and improve the wear and friction characteristics of the materials used for the sliding parts. In particular, improving the condition of the friction surface leads to improved safety and longer material life. Therefore, in this study, a friction and wear test was conducted using a sintered copper alloy and lubricating oils containing different additives. As a result, more stable friction was exhibited when the lubricating oil containing the additive was used. In addition to the components of the lubricating oil, the viscosity is considered to have a great influence on the friction surface.

In recent years, recycling of industrial products were worked for environmental problems and realizing the sustainable society. Almost half of the automotive parts such as door trims and bumpers were made by polypropylene and recycling is required. Polypropylene is thermoplastic resin which can reuse by reheating. However, bumper surfaces were consisted of thermosetting resin with the cross-linked structure. Small amounts of abrasion of coatings were occurred by milling. However, most of coatings were remain with adhesive of PP. Remoldings with milled coatings cause decreases of mechanical properties. Chemical treatments are usually used for removing of coatings. Costs of recycled products were increased due to the high costs of chemical treatments. In this study, remoldings were molded by injection molding without remove coatings. Moreover, glass fiber contained remoldings were molded by Direct Fiber Feeding Injection Molding (DFFIM) method. Influences of the mixing milled coatings on remoldings and GF contained remoldings on mechanical properties were investigated. Izod impact strength of remoldings were decreased cause of milled coatings made a role of crack occurring point. Additionally, Izod impact strength of GF contained remoldings were decreased 65% compared with cut out specimens. Bending properties were increased both of remoldings and GF contained remoldings.

Equivalent expression is derived for a mixed double inclusion which is a misoriented inhomogeneous inclusion embedded in an inclusion and it is developed to the composite material containing many clusters consistent of many misoriented inhomogeneous inclusions. Then the macroscopic elastic moduli and stress-fields of such composite materials are analyzed by the resultant equivalent expression. As a result, the magnitude of total internal stress occurring in the composite material is good agreement with that obtained by Taya et.al (JSME A,43-1(2000), pp.46-52.) under high-level clustering condition. Moreover, effects of co-existing various clusters on macroscopic elastic moduli and stress-fields induced in the composite material are examined.

Hand lay-up molding method is the simple molding method which alternates between setting mat and impregnation. This method is able to mold complex shapes with low-costs. However, this method is performed all processes by human hands so that defects of voids and resin ununiformly are easy to happen. A lot of tacit knowledge such as sensory elements exists on the work with human hands. These disadvantages are able to solve by achieving robotization. Formalization of tacit knowledge on the expert is necessary to develop the robot with high-quality molding technology. The moldings and processes analysis with different skill level workers were investigated. In this study, molding conditions were three worktable angles to simulate actual products. The different of molding time with expert and non-expert was found. Non-expert took 1.9 to 2.9 times. It can be noted that the molding time of non-expert longer than expert. Especially, non-expert affected the molding time due to large numbers of handling the roller in the impregnation and finalization processes. Thickness coefficient of variation of non-expert at worktable angles 90 degrees was twice larger than expert. The percent different of bending strength between expert and non-expert was about 5.0%. It can be noticed that the bending strength of expert higher than non-expert. Worktable angles such as 45 degrees and 90 degrees were required more skills and experiences.

Various models are proposed to the composite materials including clusters of chopped-strand fibers. In such models, the concentration of fibers in the cluster is generally very high or low compared to the outside region of the cluster. However, in realistic chopped-strand FRPs, the difference of concentrations inside and outside of the cluster is relatively small. In the present study, such a low-level clustering of fibers is modeled by replacing the cluster with the mixed double inclusion of the first kind by focusing on some reinforcement and smearing out of its surrounding. As a result, the total internal stresses occurring in the composite material are good agreement with those obtained by Taya et.al (JSME A,43-1(2000), pp.46-52.) in the high-level clustering of fibers. Moreover, they also agree with the results obtained by low-of-mixture when both aspect ratio of cluster and that of fiber becomes relatively large.

Poly(lactic acid) (PLA) attracts much attention as a material of bone fixation device which is used for fracture treatment. However, the material has drawbacks, such as lower elastic modulus and no osteoconductivity. On the other hand, the bioactive ceramics has higher stiffness and osteoconductivity. In this study, PLA and -tricalcium phosphate (β-TCP) which is one of bioactive ceramics were compound. And, β-TCP/PLA composite was drawn to improve the strength. The purpose of this study is to clarify effect of drawing on mechanical properties of β-TCP/PLA composites. The mechanical properties of PLA and β-TCP/PLA composites which were drawn to drawing ratio of 1.5 and under drawing temperature of 70 °C were measured by tensile test under room temperature. As a result, the tensile strength of β-TCP/PLA composites increased by tensile drawing. In comparison of β-TCP contents, the ratio of tensile strength of drawn and without drawing composites increased from about 1.1 of 0 mass% to about 1.6 of 30 mass%. On the other hand, there were no significant differences in elastic modulus due to drawing. Therefore, tensile strength of β-TCP/PLA composites increase with β-TCP contents. And, the tensile strength of β-TCP/PLA composites of 15 mass% reached the same strength as that of PLA by drawing at drawing condition in this study. It was suggested by acoustic emission (AE) generated during tensile test that fracture behavior dependent to β-TCP content and drawing.

For further application of carbon fiber reinforced plastics (CFRPs), it is necessary to obtain fatigue properties up to very high-cycle fatigue (VHCF) regime. In this paper, CFRP laminates were subjected to fatigue test up to 10⁹ cycle using an ultrasonic fatigue test machine in order to evaluate the transverse crack initiation life of laminates and the propagation behavior. In this experiment, T800S/2592 prepreg used as the cross-ply [0/90₆]_s laminates. Using an ultrasonic fatigue test machine tension-compression fatigue tests were conducted with stress ratio of R= -1 at a frequency of 20kHz. The specimen dimension was determined by finite element analysis to resonance at the vicinity of the test frequency. It was found that the test was carried out as designed, since the temperature distribution obtained by IR-thermography camera and the displacement measurement by the Laser Doppler vibrometer showed close agreement with the finite element analysis result. It was confirmed that the slope of the S-N diagram would be gradual in the VHCF regime.

This study aims to development the ultrasonic spot welding process of CFRTP using PPS energy director and carbon fiber reinforced PPS energy director. The materials used for spot welding are woven-CF/PPS laminates and energy director consisting of PPS polymer and spread carbon fiber. It is expected to improve the ultrasonic heating efficiency and the joining strength by using continuous carbon fiber reinforced energy director. The ultrasonic oscillator for ultrasonic spot welding has an oscillation frequency of 40 kHz and a maximum output of 600 W. The welding load and displacement of ultrasonic horn during the ultrasonic spot welding were precisely controlled using a servo press unit. The effects of ultrasonic power, pressing force, welding time and types of energy director on ultrasonic welding behavior and joining strength were investigated to obtain the proper welding conditions. The temperature of the joining part during ultrasonic welding was measured by a ultrafine thermocouples. From the experimental results, it was revealed that the volume fraction of carbon fiber in the energy director was significantly affects the ultrasonic welding behavior. From the result of single lap shear strength test, it was found that there was proper fiber volume fraction in energy director to increase the joining strength.

In this study, we propose a combinatorial evaluation method for evaluating the corrosion resistance of the Ti-Ni-based high formable shape memory alloys (HFSMAs) based on anodic polarization tests. The proposed evaluation substrates compose nine samples which have different compositions. These samples are deposited on a glass substrate by carousel sputtering system and microelectromechanical processes. Further, we performed anodic polarization tests on the Ti–Ni–Zr and Ti–Ni–Cu HFSMAs samples. The polarization curves are obtained by sweeping the potential and the current density at the passive state (i_ps) of each composition tested is compared. In case of the Ti–Ni–Zr alloy, i_ps varied depending on the Zr content. When the Zr content ranged from 10 to 15 at.%, their i_ps were comparable with that of Ti₄₈Ni₅₂ used in medical devices. On the other hand, in case of the Ti-Ni-Cu alloy, their i_ps were similar to that of Ti₄₈Ni₅₂ regardless of Cu content. We obtained Ti–Ni–Zr and Ti–Ni–Cu HFSMAs having a corrosion resistance equivalent to that of Ti₄₈Ni₅₂. Furthermore, we conducted XPS analysis to investigate the passive film of HFSMAs. The thin surface film of Ti-Ni-Zr alloys were composed of TiO₂ and ZrO₂, while that of Ti-Ni-Cu alloys were composed of only TiO₂. We have concluded that the formation of TiO₂ enriched protective thin surface film might have been responsible for the high corrosion resistance.

Selective laser sintering (SLS) is an additive manufacturing technique that uses a high power laser to fuse small particles of metal powders into a mass structural part that has a desired 3-dimensional shape. Using this selective laser sintering, a pours refractory metal was fabricated. Tungsten (W) powder was spread on the base plate and the laser beam was scanned on to the W powder. When the laser power was small, W powder was sintered partly and the Tungsten pours metal was then fabricated.

We have developed a novel method to estimate the support reaction in sandwich panels by the inverse analysis of the deformed shape data of the face sheet in order to clarify the deformation mechanism of sandwich panels. In this study, two types of sandwich panels which have foam core and honeycomb core were tested in two fixing methods. The result shows that estimated support reaction is divided into three regions where the estimated value is zero directly under the indenter, the estimated value gradually increases to the experimental value, and the estimated value agrees with the experimental value. The support reaction could be estimated even if the fixing method was changed. In addition, even if the core part is not homogeneous material, this method can be applied by considering the core part as a homogeneous material.

The fracture mechanism of the anode material of the lithium ion battery has been investigated by the tensile test on the specimens with different binder ratios. The SEM observation of the fracture surface after the tensile test shows that the origin of the fracture is at the binder. Therefore, the mechanical properties of the anode material are depended on the mechanical properties of the binder. Moreover, the tensile strength of the anode material at each binder ratio was estimated using the mechanical model of the anode material and the tensile strength of the binder. There was a proportional relationship between the tensile strength of the anode material and the volume ratio of the binder, and the estimated tensile strength of anode material was in good agreement with the experimental value.

Capacity and charging speed of secondary batteries with high energy density, such as lithium ion batteries (LIB), are increased. They are used as power sources for mechanical structures such as electric vehicles. However, damages of the electrode cause the performance deterioration and the abnormal heating because of high energy density. The electrode is composite structure which is composed of current collectors and electrode materials. The electrode materials are made of the binder resin and the particulate active material which is approximately 5 μm in diameter. The microscopic fracture of the electrode materials occurs when the binder resin connecting the active materials breaks. In order to prevent the malfunction of the electrodes，it is necessary to evaluate the stress of the electrode materials. This study has conducted the material tests on the electrodes; tensile test，bending test and buckling test. The material tests were performed by using the anode material of the LIB that is carbon powder solidified with binder resin. The strength of the anode material was calculated using the tensile strength of the binder resin. The fracture occurred in the anode material because the nominal stress exceeded the tensile strength of the binder resin in the tensile test and the bending test. Also there was no fracture in the buckling test, because the nominal stress was lower than the tensile strength.

This study aims to solve effector of coupling’s tensile strength and temperature measurement on tip of tool. This joining produce friction heat by pushing spinning tool to Al alloy, and adhere insert material into Al alloy and CFRP by friction heat and indentation force. This joining use tool made of SKD61. Tool’s diameter is 12mm. Tool’s rotating speed is 750rpm. Tool’s indentation speed is 5.0mm/min. Tool’s indentation hold time is 5.0s. Sample materials are Al alloy(A5052-H34) and CFRP. Insert material is Polyethylene terephthalate(PET). PET is held by Al alloy and CFRP, and pushed by spinning tool from Al alloy side. Tensile shear test is conducted in the atmosphere. Cross head speed is 0.5mm/min. Use load cell in indentation load measurement. Establish thermocouple into hollow tool, and use in temperature measurement. As a result of measurement, identified that coupling’s tensile strength increase by joining area’s size and indentation force’s volume. Total Energy by joining isn’t affect to tensile shear strength. Balance of heat energy and deformation energy is affect to tensile strength. PET’s molten state is affect to tensile strength because temperature occurred by joining isn’t over PET’s melting temperature in 0.3mm and 0.5 mm.

The effects of adhesive layer thickness and CFRP stiffness on the strength of the bonded assembly were investigated. It was found that the adhesive layer thickness changed between 0.2 kPa and 10 kPa. The region of pressure where the adhesive layer thickness changes was investigated. Adhesive joints having several adhesive layer thicknesses were prepared, and their tensile strength was examined by a tensile shear test. The adhesion pressure decreased from 0.2 kPa to 1 kPa. CFRP of various laminated structures using UD materials was produced, and their bending elastic modulus was examined by a bending test. A large value was obtained when the two surfaces that hit the surface of the plate had a fiber orientation perpendicular to the bending. An adhesive bonded body was manufactured from the CFRP and aluminum alloy, and the tensile strength was examined by a tensile shear test. The strength of the low-stiffness braided alternately was higher than that of the high-rigidity unidirectional.

Bobbin tool friction stir welding tools with five different shoulder fillet radiuses were employed to evaluate the effects of shoulder fillet radius on thickness distribution, microstructure and mechanical properties of FSWed A1050 sheets. It was found that the increase of bobbin tool shoulder fillet radius decreased the flash formation and increased the minimum thickness of weld except for 0.5 mm shoulder fillet radius (R0.5). The grain size in center of weld increased with increasing the shoulder fillet radius from R0.5 to R6. The UTS decreased from R0.5 to R1, increased from R1 to R3, and then decreased from R3 to R6.

The effect of T6 treatment on liquid phase diffusion bonding strength of A6061 alloy using formate coated Zn sheet was investigated by SEM and EDX observation of joint interface and fracture surface. The experiment was conducted at a joining temperature of 400℃. The surface of the Zn insert metal was modified by boiling in formic acid. From the results of this study, the bonding strength was improved about 6 times by applying formate coating. The obtained joint was subjected to T6 treatment. T6 treatment increased the bond strength by about 1.6 times. In addition, the base material hardness was approximately doubled. The reason why the bonding strength has been improved is that the base material added elements did not aggregate at the interface by liquid phase diffusion bonding. In the case of agglomeration, the additive element becomes coarse due to the T6 treatment. Previous studies have shown that this reduces joint strength.

Fretting fatigue tests were conducted in high-purity hydrogen, oxygen-hydrogen mixtures and vacuum. The material was austenitic stainless steel SUS304. The fretting fatigue strengths in the oxygen-hydrogen mixtures were significantly lower than that in the high-purity hydrogen. The fretting wear was not observed in the high-purity hydrogen. On the other hand, the fretting wear was developed in the oxygen-hydrogen mixture. Based on the X-ray photoelectron spectroscopy (XPS) analysis, it was found that an original oxide layer of the stainless steel was removed by the fretting in the high-purity hydrogen. However, the addition of ppm-levels of oxygen produced an oxide layer on the fretted surface by overcoming the removal effect of oxide layer by the fretting. The production of the oxide layer by the addition of ppm-levels of oxygen developed the fretting wear. For the shape of the contact part in this study, a high concentration of the contact pressure occurs at the contact edge. This concentration produces high compressive stress field in the vicinity of the contacting surface. This compressive stress suppressed the crack growth. However, the compressive stress was relieved in the oxygen-hydrogen mixture because of the fretting wear. This is one of the reasons for the reduction in the fretting fatigue strength in hydrogen by the addition of ppm-levels of oxygen.

It is very important to measure the deformation of the structural parts of the large constructions for the health onitoring or damage evaluation of the constructions. The Moiré methods are measurement methods of the deformation using moiré phenomena which can be observed when two grids were overlapped. In this study, a new moiré method to measure the crack width of the concrete structural materials has been developed.The crack width of concrete specimens with model grid during splitting tensile test was measured by this method.