Tribological properties of fullerene suspended lubricant oil on hardened alloy steel interface was investigated. Poly Alfa Olefin (PAO), having 5cst@40°C of a viscosity and hardened chromium alloy steel (SUJ2) were used for the lubricant oil and specimen. The tribological properties was evaluated with a 3 ball and disc type testing apparatus. Results showed that the suspension of fullerene was effective means to decrease in the friction coefficient and the wear loss estimated from surface profile. In particular, effectiveness of the small amount of the fullerene suspension less than solidification limit was found on lower applied loads. Nano sized particular matter was detected on the ball surface.

Since joints of heavy machinery and the like are high surface pressure and highly eccentric load, bearings of iron based sintered alloy which can withstand this state are used. However, under certain conditions, fatigue wear occurs and breaks faster than the original life. In this study, we aim to elucidate the fatigue wear condition and mechanism of bearings by observing the change of wear state under unbalanced load, the change of surface condition etc. due to the difference of wear condition.

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 of ABS, PLA and metal containing PLA for the purpose of evaluating the mechanical performance on the material.

Vacuum assisted resin transfer molding (VaRTM) process consists of thermosetting resin impregnation to fiber preform and is one of the cost effective way for manufacturing composites. Permeability defined in Darcy’s law corresponds with the magnitude of flowability and the key parameter in VaRTM process. Measurement of permeability was conducted by unsaturated unidirectional flow due to simplicity of apparatus and flow front observation with epoxy resin for test fluid. Race-tracking is phenomenon which includes faster test fluid flow between laminated fabrics and bagging film compared with fabrics and provides large variation of permeability. This paper shows fabric preparation and materials arrangement to reduce effect of race-tracking to permeability. Pulling out of fiber bundles at the edges restricted race-tracking and flow front shape nearly parallel to inlet. However the scatter between experimental data was still large thus conditions of nesting and epoxy resin need to control strictly.

Currently, metallic struts are used in a foot orthosis for medical treatment. They are heavy and burdens for paralysis patients. Thus, carbon fiber reinforced plastics (CFRP) attracts attention recently, because CFRP has excellent specific strength and fatigue resistance. However, the usage of CFRP is still limited, since CFRP has lower compressive strength than metal. To evaluate the possibility of replacing metal with CFRP, an foot orthosis with L-shaped strut made of CFRP having the same mechanical characteristics as general foot orthosis with metal strut was investigated. In this paper, the reproducibility of appropriate rigidity for CFRP specimens with three different thicknesses was investigated. Compression load was applied to specimens using a universal testing machine, and the resultant moment and the deformation angle at the ankle joint were measured. The measurement angle ranged 0° to 15°. As a result, it was confirmed that three type of specimens have similar stiffness. It is possible to prepare specimens having arbitrary rigidity regardless of the thickness.

In recent years, the application of carbon fiber reinforced plastics to airframes has been expanding to reduce weight of aircraft. Further, by replacing mechanical fastening with adhesive bonding, it is possible to achieve further weight saving of the airframe. In this study, we investigate the influence of curing conditions on the strength of CFRP single lap adhesive joint using epoxy resin adhesive. 9 kinds of specimens with different curing conditions such as curing temperature and curing time were prepared. The reaction ratio of the adhesive under each curing condition was evaluated by differential scanning calorimetry measurements. Further, tensile shear adhesive strength and failure mode of the joints were evaluated by performing tensile shear tests on specimens and observing the failure surface after the test. As a result, the relationship between the reaction ratio of the adhesive, the strength of the joint and the failure mode was clarified.

Natural fiber, such as cellulose fibers (CeF), are inflected in polymer matrix, during composite molding. The fiber waviness is closely related to composite strength. Analytical models for strength prediction, which were proposed previously, do not account for the fiber waviness. In this study, a theoretical method to predict strength considering fiber waviness was proposed. High density polyethylene (HDPE) composites with various aspect ratio of CeF (16, 176 and 399) had been prepared and characterized. The strength of CeF/HDPE composites was calculated based on the proposed analysis and was compared with the experimental values. It is confirmed that the proposed analysis underestimates the strength of the CeF/HDPE composites.

This study investigated thermoplastic resin impregnation behavior in carbon fiber reinforced thermoplastic (CFRTP). The Aim is to clarify the relationship between the molding conditions and the resin impregnation to the fiber yarn and the effect of resin impregnation on the mechanical properties. Specimen prepared using Film Stacking (FS) method are investigated. As a result, the resin impregnation property was improved with increasing molding temperature. Resin impregnation analysis on the Darcy's law showed good agreement with the experimental values.

Calcium alginate gel (CAG) is easy to form and is nontoxic. Therefore, it is expected to use for a Drug Delivery System (DDS). In DDS, the particle diameter is required to be μm or nm. To formation CAG micro particle, microfluidic method has attracted attention. In this work, Isoamyl alcohol was used to improve the production stability of CAG in microfluidic method. Isoamyl alcohol can dissolve calcium chloride and cannot dissolve sodium alginate. Thus, the sodium alginate solution and the calcium chloride solution surely react. In this report, the droplet were formed at different types and different concentrations of sodium alginate and their particle size were investigated. As results, droplet size and formation process of alginate droplet changed depending on sodium alginate type and concentration. Under the condition measured this report, the diameter of the alginate droplet were found to be in the range between 200 and 300 μm.

Currently 3D printing technology has attracted much attention as new molding methods for carbon fiber reinforced thermoplastics (CFRTP). The purpose of this study is to investigate in situ resin impregnation during 3D printing of continuous carbon fiber reinforced plastics. The specimen was manufactured by fused deposition molding (FDM) using carbon fiber yarn including 3000 mono-filaments and polylactic acid (PLA) filament. Resin impregnation ratio measurement and tensile tests were conducted on the molded specimens in order to investigate the effect of process parameters during 3D printing on mechanical properties. As a result, the modeling temperature T and filament extrusion speed f were parameters that influenced the tensile strength. In this study, we recommend the modeling temperature T = 200°C and filament extrusion speed f=19 mm/min for the PLA composites. The layer height h was a parameter that remarkably influenced the impregnation ratio. The quality of the part can dramatically be improved by using continuous carbon fiber, so it was shown that this technology could be applied to various applications.

A molding method of carbon fiber reinforced thermoplastic (CFRTP) has been developed. In this study, open molding method of CFRTP pipe was developed with braiding technology. In this method, braiding and heating process were performed at the same time. Then, carbon fiber with partially impregnated resin was used for braiding yarn. Braiding yarns run from bobbins to a core (mandrel) and braiding structure was made on the mandrel. During braiding process, braiding yarns were also heated by the heating unit. Resin on carbon fiber became melt and impregnated into carbon fibers. After this process, stainless tape wounded around the CFRTP pipe while it was heated. Rejecting the tape and mandrel after cooling, braided CFRTP pipe was molded. To assess the mechanical property of braided CFRTP pipe, compression test was conducted. In addition, compression test at elevated temperatures from 40°C to 120°C were also conducted. The results showed that braided CFRTP pipe compressed at the temperatures lower than 60°C was broken with crack around pipe surface in the circumstance direction. Braided CFRTP pipe compressed at the temperatures equal and over 60°C was broken with crack along braiding yarn.

In this work, the effect of filament feed rate on printing quality was experimentally investigated for FDM (Fused Deposition Modeling) 3D printer. Filling behavior of TPU (Thermoplastic PolyUrethane) resin was evaluated from in-situ observation under various feed rates and head temperatures of FDM 3D printer. It was shown that the filling ratio of TPU filament decreased with feed rate of FDM 3D printer. Therefore the maximum filament filling ratio achieved only 93% because sliding between filament and drive wheel caused the mismatch of filament feed amount. By applying the correction factor of feed amount, the above mismatch was almost eliminated. Then the filament filling ratio increased to almost 99% of the initial set. The maximum tensile strength of this 3D printed TPU showed still the lower value than those of injection molded TPU by 32%.

Porous materials are expected to utilize heat protection materials, adsorption / desorption materials, electrodes, etc. Generally, mechanical, thermal and other properties of them are changed by pore size, pore shape and porosity. Therefore, it is necessary to control the structure of the porous material. In the present study, phenol monolith, which can be used as precursor to fabricate porous carbon. In this study, the fabrication process of phenol monolith by polymerization induced phase separation (PIPS) was established. Furthermore, microstructure was controlled by changing the monomer concentration, curing temperature and solvent. Experimental results showed that phenol monolith with pore size of 0.5 ~ 2.7 μm was obtained.

Selective laser sintering (SLS), which is one of 3D printing techniques, has attracted attention in recent years as a processing technique with high degree of freedom of modeling. Generally, high-power laser of 200-400 W is used for SLS. In this study, cubes with a side length of 5 mm were fabricated using a low-power laser below 50 W with small spot diameter, and mechanical properties and structure were investigated by compression test and observation with SEM. In order to investigate the influence of fabrication conditions, four parameters of laser power, scanning speed, scanning pitch, laminating thickness were varied. As a result, the filling rate was proportional to the energy density. In this study, the equivalent Young's modulus didn't depend on the filling rate although it is said that the equivalent Young's modulus depends on the filling rate in general. The reason why the equivalent Young's modulus didn't depend on the filling rate is thought to be due to different deformation behavior for each sintered structure. The test pieces showed an equivalent Young's modulus of 1.7 GPa at the minimum and 101.2 GPa at the maximum.

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 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 fabricate.

Twin roll strip casting of aluminum alloy ADC12 using commercial scale machine was operated. Roll diameter is 1,000 mm and the width is 240 mm. Roll material is SKD61. The aims of this study is to investigate the possibility of strip casting for aluminum alloy. The effect of the gap between the rolls and the roll speed on the strip surface condition was researched. ADC12 strip was able to be produced at the conditions of pouring temperature 590°C, initial roll gap 0.5 mm and roll speed 10 m/min. However, Maximum rolling load reached. At the roll gap of 1.0 mm, this strip was able to be produced continuously. Strip surface had a metallic luster. Flakes were created with the roll gap of 2 mm. At the roll gap of 3 mm, the molten metal passed through without solidifying at the roll gap portion. The strip was able to be produced continuously at the conditions of initial roll gap 0.5 mm, 1.0 mm and roll speed 20 m/min.

Three-layer clad strip could be cast by a vertical type tandem twin roll caster. Base strip and overlay strip were strongly connected. Interfaces between the base strip and overlay strips were clear. Effect of base strip temperature on conditions of the bonding was not clear. In this study, effect of the base strip-temperature on the bonding was investigated. When the base strip-temperature was higher than 450°C, strips were strongly bonded and the base strip was not melted by the molten metal of the overlay strip. In this research, copper rolls were used, and roll speed was 30 m/min. Base strip was 3003 aluminum alloy, and overlay strip was 4045. Bonding condition was investigated by cold rolling, continuous bending until broken and tension-shear test. The interface and microstructure were investigated by optical microscopy and SEM.

A single wheel caster equipped with rotating side dam plates was proposed to cast a rod. Diameter and width of the casting wheel were 600 mm and 10 mm, respectively. AC7A aluminum alloy was used. Rotating speed was 5m/min. Molten metal was poured from a hole nozzle on the rotating casting wheel. Cross sectional area was ranging from 91 mm2 to 154 mm2. Cross section of the rod became rectangular or convex by the effect of the rotating side plates and pool-less pouring method. The cross sectional shape was influenced by collision angle between molten metal poured from the nozzle and the casting wheel. There was tendency that the cross sectional area easily became convex as the collision angle became larger. The microstructure of the rod was fine.

The fiber content dependency on the weld strength of injection molded fiber reinforced polypropylene was investigated. It is suggested that there is a negative correlation between the fiber content and the weld strength. From experimental results, it is also clarified that weld strength of FRTP is determined by residual strain derived from thermal deformation during molding process and interaction force generated between fiber/matrix.

This study examines the tensile properties of polypropylene (PP) composites containing cellulose nanofibers (CNF). Two types of CNF with different lengths were used to assess the effect of fiber length of CNF on tensile properties. CNF have a length of 10 μm or more and a diameter of 20 nm. We developed a dry powder CNF with a moisture content of 3wt% or less. Dry powder CNF can be highly dispersed in the thermoplastic polymer such as PP and PA12 resins by twin-screw extruder. Using twin-screw extruder operating at 130rpm and 200°C, CNF/PP composites were prepared by melt-kneading. The dry powder CNF in PP resin are easily dispersed by melt-kneading using twin-screw extruder. The tensile strength and failure strain of the 0.3wt%CNF/PP and 1wt%CNF/PP composites were increased as compared with neat PP resin. It is clear that addition of CNF improves the toughness of PP resin at low CNF content.

Micromechanical analysis is performed to the chopped-strand fiber reinforced composite material containing many clusters constituted by misoriented fibers. Equivalent expression for the fiber in cluster is derived but it cannot be solved explicitly. Therefore approximations of flat-ellipsoidal cluster region and axi-symmetric distribution of fibers in the flat plane are introduced into the model. Then the model can be solved explicitly and strain and stress induced in the composite are also expressed explicitly.