Tetsushi Koshino

Mechanical Property of CFRP by Carbon Spray Up Method

Spray up method is one of methods for composite molding and it is traditional and common molding method that can deal with various shapes according to workmen skill. The essence of the composite molding impregnates resin to fiber;, in other words, is to substitute air included in the fiber for resin. Spray up method can spray matrix on mold together while cutting reinforcements continually, and the cutting of the reinforcement, setting up and the impregnation of the matrix are carried out at the same time. That is why working process is made efficiency and can cope with a design change easily. However, the quality of the composites depends on the techniques of workmen and the judgment with Spray up technique is too difficult, because it has not clarified that the difference of that techniques has how influence with manufactured products. In addition, in a spray up method, glass reinforcements is usually used, but carbon reinforcements is not put to practical use. High quality is required with the CFRP composite, and this is because it is thought that techniques of Spray up method does not satisfy this demand. In this study, motion analysis was used to compare the difference between Spray up techniques by expert and non-expert. Expert’s carrier of Spray up was 19 years and non-expert’s carrier was a year. Motion analysis, which is applied to various fields like sports or traditional crafts and so on, can visualize human motion. The Mac 3D System was used as equipment, since it is the most powerful tool for the motion capture and analysis particularly. The sampling rate was 60 Hz. The object of this study was to contribute that technique back to fabrication fields by analyzing and considering what was important factor. Furthermore, this trial is thought that leads to the development of new technology. As the result, the motion of expert’s lower half of body indicated different motion compared with non-expert one. Expert’s centroid moved smoothly and his motion showed constant tendency. On the other hand, non-expert’s motion was awkward in several points and his motion didn’t show the tendency like expert. Furthermore, The CFRP structures that manufactured with Spray up method are cut for the tensile testing. Tensile test were performed by using an Instron universal testing machine under a speed 1mm/min. Spray up technique is discussed based on the motion analysis method and moreover it is shown that Spray up method is useful in CFRP materials production.Copyright

Evaluation of Metal Wire Network ‘Kana-ami’ Structure Between Expert and Non-Expert

As well known, Kyoto was a capital city of Japan with one thousand years history. The long ancient culture brings out a serious of traditional craft products, such as ‘Kana-ami’ — a kind of metal wire network. ‘Kana-ami’ was all made by hand work, for this reason there was no industrial pollution produced during the manufacturing process. In other words, ‘Kana-ami’ is a kind of green manufacturing product, whose processing motion and working experience make a big effect on final products’ quality. Product’s quality was judged by the standard structure of ‘Kana-ami’, which was established and developed in the long course of history and culture. That aesthetical standard has already been consistently rooted into Japanese peoples’ heart deeply. Dated back to around 50 years before, there were about 30 handmade wire net shops in Kyoto. However, it has decreased dramatic until 7 shops now. Therefore, it is urgent time to pay attention to this severe reality and try to do something to keep this traditional culture wealth and continue green manufacturing technique, skill to the next generation.In this research, cooperating with ‘Kanaami Tsuji’ workshop, the excellent products of Mr.Tsuji and his son were chosen as the investigation subjects for Kana-ami’s structure comparison. As well known, ‘Kana-ami’ product made by Mr.Tsuji have already been widely accepted and preferred among Japanese people, even his son’s finish also has beautiful looking. Therefore, the main target of this study was to clarify the difference in shape and hexagon structure of ‘Kana-ami’ products made by Mr.Tsuji and his son through mathematical measurement. Based on this structure evaluation system, hexagon angles and length were discussed and analyzed in order to help his son and other beginners to inherit this Japanese traditional craft technology.Copyright

Jute Fiber Reinforced Polymeric Composites With Flexible Interphase

In this research, the flexible interphase concept was introduced to enhance the poor mechanical properties of jute fiber reinforced unsaturated polyester matrix composites. The jute cloth reinforcement was obtained from recycled coffee bags. These jute cloths after washing by water and drying were soaked in mixture of Polybutadiene Epoxydied as flexible resin and acetone for 10 seconds. Several mixtures consist of 0, 2, 3.5, 5 and 8 wt% of Polybutadiene Epoxydied and 100, 98, 96.5, 95 and 92 wt% of acetone, respectively, to form flexible interface around the jute fibers. Jute cloth reinforced unsaturated polyester matrix composites with different flexible interphase incremental weight ((Wa-Wb)/Wb) ratios were fabricated by hand lay-up method and examined by a series of mechanical tests. The mechanical testing including tensile, bending, Izod strength impact and drop impact was carried out for these composites to evaluate the effect of the flexible interphase and acetone on the jute cloth composites. The flexible interphase succeed to control the mechanical properties of jute fiber reinforced unsaturated polyester matrix composites. Inserting flexible interphase between unsaturated polyester matrix and jute fibers leads to smooth fluctuation, less matrix cracking, in the second part after the knee point of each stress-strain curve as exhibited in composites with higher flexible interphase incremental weight ratio. This means not only the brittle matrix but also interface/interphase dominates the multiple matrix cracking behavior in jute cloth reinforced unsaturated polyester matrix composites. Inserting flexible interphase between unsaturated polyester matrix and jute fibers leads to less number of multiple cracking as shown in the second portion of flexural stress-displacement curve. This means the number of multiple cracking are dominated by flexible interphase. The impact strength of jute cloth reinforced unsaturated polyester matrix composites with flexible interphase incremental weight ratio of 1.2% is higher than that of jute cloth reinforced unsaturated polyester matrix composites without flexible interphase by about 45%. The impact energy after maximum load has increased significantly with all flexible interphase incremental weight ratios.Copyright

The Investigation of Traditional Japanese Trowel: Part 1 — Process Analysis and Surface Observation

The purpose of this study was to study the history of traditional Japanese trowel process. The research study were conducted the trowel blade which was made from SK5 steel. Microstructure and grain sizes were accurately measured by using the optical microscope (OM). The resultant microstructures of hardening were observed as martensite. After the tempering process, the result of microstructure found the temper-martensite structure. In the hardening process was heated up 800–850°C to austenite structure and quenched in cooling oil. Moreover, in the annealing process was quenched into straw ashes for cooling after heat up until 750°C. All heat treatment temperature and surface quality were observed and controlled by eyesight and experience of Japanese expert.Copyright

Differences Among an Expert and a Non Expert in the Behavior for Chucking in the Lathe

The expert worker (85 years old) has worked for 70 years and the non expert (16 years old) has worked 1 year of experience for the lathe processing. The subjects were compared the difference in the waist, the shoulder and the fore arm movement between the two worker while they were chucking on the lathe machine. Determination used the same parts and the same type of lathe machine for investigated. There were 4 main categories that related three stances position alignment and two hands position on the key chuck.Using the 6 infrared cameras and 2 video cameras captured the position of each marker. All markers position data which synchronization was taken by a motion analysis system (sampling rate: 100Hz). As a results show the balance movement both the waist and the shoulder during the chucking that had significantly greater in the expert worker than the non expert worker.Copyright

Stepwise Comparison of Expert and Nonexpert Preparations of a Polished Metallographic Surface

The carburizing process requires metallurgical inspection by means of polished metallurgical mounts. Metallographic preparation for a metallurgical mount is an important process. The purpose of this study is to clarify the differences in ground and polished surface finishes of metallurgical mounts for carburized parts at each step of the process as executed by an expert and a nonexpert on a semi-automated grinding and polishing machine.To clarify the differences between expert and nonexpert preparations, microscopic images of the surface finish obtained at each step of grinding and polishing were compared. The surface profile of each of the final finishes was also examined with measuring device. Each inspector has either 20 (expert) or 0.5 years (nonexpert) of experience in metallographic preparation. The ground and polished finish produced by the expert was well balanced over the entire surface. In contrast, the surface finish produced by the nonexpert was dispersed. The number of scratches and edge rounding depth apparent in the final surface finish of the expert were less than those of the nonexpert.Copyright

Comparison of Different Preparation Processes and Final Surface Finishes of Metallographic Specimens

The carburizing process requires metallurgical inspection by means of polished metallurgical mounts. Metallographic preparation for a metallurgical mount is an important process. The purpose of this study is to clarify the differences between expert and nonexpert executions of the grinding and polishing process and the consequent polished surface finishes. Three inspectors with 0.5, 2 and 20 years of experience in metallographic preparation were interviewed and their processes analyzed. As a result of the process analysis, the differences between an expert and a nonexpert were determined.Copyright

The Evaluations of the Muscle Activity During “Momi” by Using the Different Immersed Bamboo in Water to Making Kyo-Uchiwa (Japanese Paper Fan)

The aim of study is to evaluate whether altering the bamboo moisture by immersed bamboo in water on 4-hour and 3 -day that would affect the muscle activity during separated bamboo by bending process. Moreover, thirteen muscles which bilateral side of Pectoralis major, Biceps brachii, Triceps brachii, Latissimus dorsi, Gluteus medius and only right side of Rectus abdominis, Extensor carpi radialis longus and Flexor carpi radialis were recorded. As a result, the bilateral side of Biceps brachii, right side of Extensor carpi radialis longus and Flexor carpi radialis, left side of Triceps brachii showed the difference quite clearly. When the craftsman was bending the bamboo he was necessary more effortful by these muscles activity on the 4-hour immersed bamboo in water than the 3-day. The scanning electron microscopy (SEM) photographs showed the fracture characteristic of 2 subjects that the adhesive of bamboo fiber decreased when increased moisture.Copyright