Yuqiu Yang

Application of FRP in a vehicle for Student Formula SAE Competition of Japan

Although it is only from around the late 1970s onwards that researchers have turned their attention to the energy absorption properties of fibre reinforced plastics (FRPs), it is proved that the energy absorption capability of a given FRP can be altered quite significantly by varying its material and geometric parameters. With further investigation into the behaviour with respect to energy absorption, attempts on applying FRPs as the real structure materials typically used for vehicle construction have been made. In Japan, there is a Student Formula SAE Competition of JAPAN that gives students an opportunity to develop skills for object creation ‘Mono-Zukuri’ and contributes to the expansion of the Japanese automotive industry as well. Since 2007, the students and their advisers of Kyoto Institute of Technology formed a team with a hand-made formula car named ‘Grandelfino’ to take part in this competition. Based on more than 20 years of research on the energy management capability of FRP tubes, in 2009, more than 10 wt% FRP was applied into manufacture of members of ‘Grandelfino-4’ for weight reduction and high fuel economy. As a result, in competition, ‘Grandelfino-4’ got the best ranking in the history – 13th among 80 teams, which performed much better than the previous two versions: ‘Grandelfino-3’ (34th in 2008) and ‘Grandelfino-2’ (52nd in 2007). In this paper, the crushing behaviour and energy absorbing mechanism of braided FRP tubes with flexible resin were investigated, and additionally the design of tubular braided composites for the components in ‘Grandelfino-4’, like suspension arm and impact attenuator, were mainly introduced.

Physical-mechanical and Morphological Properties of Cellulose Reinforced Composites from Recycled Jute Woven Cloth

In this study, the jute cloth from recycled coffee bags was used to fabricate ecologically friendly composites by hand lay up molding technique. As the primal investigation, the effect of moisture contents of the jute cloth on the mechanical properties of the composites was discussed based on the results of 3 point bending and Izod impact tests. Additionally, The Dynamic mechanical analysis (DMA), and the thermogravimetric (TGA) were also performed to investigate the thermal properties of the composites. The results suggested that the moisture content of jute cloth did not affect significantly on the thermal behaviors. However bending and Izod impact tests’ results showed that the mechanical properties of composites deceased with the decrease of the moisture content. On the other hand, the composite with low moisture content had relative higher initial fracture stress which was considered affected by better interfacial between natural fiber and polymer.

Mechanical Properties of Jute/PLA Injection Molded Products-All Natural Composites

Natural composites have been important materials system due to preservation of earth environments. Natural fibers such as jute, hemp, bagasse and so on are very good candidate of natural composites as reinforcements. On the other hand regarding matrix parts thermosetting polymer and thermoplastic polymer deriver form petrochemical products are not environmental friendly material, even if thermoplastic polymer can be recycled. In order to create fully environmental friendly material (FEFM) biodegradable polymer which can be deriver from natural resources is needed. Therefore poly(lactic acid) (PLA) polymer is very good material for the FEFM. However, PLA is very brittle polymer, so that polymer chemists have been made the efforts to make tough PLA. In this paper Jute/PLA composites was fabricated by injection moldings and mechanical properties were measured. It is believable that industries will have much attention to FEFM, so that injection molding was adopted to fabricate the composites. Long fiber pellet pultrusion technique was adopted to prepare jute fiber-PLA pellet (Jute/PLA). Because it is a new method which is able to fabricate composite pellets with relative long length fibers for injection molding process, where, jute yarns were continuously pulled and coated with PLA resin. Here two kinds of PLA materials were used including the one with mold releasing agent and the other is without it. After pass through a heated die whereby PLA resin impregnates into the jute yarns and sufficient cooling, the impregnated jute yarns were cut into pellets. Then Jute/PLA pellets were fed into injection machine to make dumbbell shape specimens. In current study, the effects of temperature of heat die i.e. impregnation temperature and the kind of PLA were focused to get optimum molding condition. The volume fractions of jute fiber in pellet were measured by several measuring method including image analyzing, density measurement and dissolution methods. And the mechanical property were investigated by tensile and Izod testing. It is found that 250 degree is much suitable for Jute/PLA long fiber pultrusion process. Additionally the jute fibers seem much effective to increase the tensile modulus and the Izod strength. That is to say, the addition of Jute fiber in PLA, the brittle property can be improved.Copyright

Fracture Behavior of Long Glass Fiber Reinforced PP Sheets With Hole

Recently, owning to the increasing concerns on the environment, lightweight materials representative by composite are being considered to be used in primary structure components in particular in vehicle instead of metal. In order to enhance the mechanical property in particularly tensile property, at current study, stampable sheets (glass mat which were fabricated by punch knitted technology) were adopt to make glass mat reinforced thermoplastic PP (GMT). In the paper, three kinds of specimens including two GMT which have glass fiber weight percent 40 and 20 wt% respectively and a LFT (normal long fiber reinforced thermoplastics PP) which has glass fiber 40wt% were fabricated and tensile tested. The mean fiber length of GMT and LFT were 6.67 and 1.37 mm, respectively. For tensile test, it was observed that the modulus of 40GMT and 40LFT were similar. However, it was found that 40GMT specimens have better tensile strength than 40LFT specimens. In the case of different glass fiber content, 40GMT had more than two times higher value than 20GMT in both tensile modulus and tensile strength. Referring to the effect of hole on the tensile property of GMT and LFT, it was found that the notched tensile strength of both GMT and LFT decrease when W/d equal to 2.0. On the other hand, for W/d equal to 2.5 and 3.0 have no effect to tensile strength.Copyright

Notched Strength and Fractures Behavior of Chopped Glass Mat Reinforced Unsaturated Plastics

Glass chopped fiber mats have been used as traditional reinforcements for fiber reinforced plastics. However, the literature is found limited even it has a long history. However short fiber mats is considered to be suitable reinforcement configuration for natural fiber or filled composites because the natural fiber is inherently short fiber. Various fiber textile technologies are available to be used to fabricate the fiber mats structure, for example needle punching process. Therefore the relation between different textile manufacturing techniques (the fiber mat structure) and the composites properties is considered necessary to be should be fully understood. Chopped glass mat reinforced composite was used as experimental materials and the fracture behavior of the specimens with drill-hole was investigated. Acoustic emission (AE) measurement was carried out by using Dual AE measurement system with both 140 KHz and 1 MHz sensors to understand the fiber and matrix fracture behaviors simultaneously. Also the characteristic distance was calculated experimentally and was compared theoretically with the values obtained from finite element stress analysis. It is found that the notched strength decrease by drilling a hole in the center. While regarding to the effect of w/d ratio i.e. the ratio of width to the diameter of the drill-hole, w/d of 3 specimens seems to have relative higher notched strength as compared to 2 or 5 w/d specimens. During the tensile test AE signals which detected by both 140 kHz and 1MHz are found to be generated almost at the same time. Additionally, the white area before the final broken seems to relative to the characteristic distance calculated by finite element stress analysis.Copyright

Effect of Hot Water Immersion on the Mechanical Properties of Jute and Jute Hybrid Reinforced Composites

As well known, the corrosion resistance and durability of the material are always considered in the safety design of the materials. In this study, the jute fabric from recycled coffee bags was used to fabricate ecologically friendly composites. Jute fabrics with two kinds of different moisture contents were used to fabricate the natural fiber reinforced composites, and the hot water immersion properties have been evaluated. Additionally, the effects of the hybridization with glass woven fabric laminated structures were also investigated. Jute/Jute laminated composite, Jute/Jute/Glass, and Glass/Jute/Glass laminated hybrid composites had been fabricated by hand lay up method. A preliminary investigation on the effect of moisture contents of the jute fabric on the mechanical properties of the jute and jute/glass hybrid composites was discussed based on the results of 3 point bending test. Moreover, the durability of the composites in the hot water immersion was also evaluated. The effects of hot water immersion on the mechanical properties were investigated by the way of 3 point bending test. The specimens were immersed in hot water maintained at 80°C with the immersion time of 24, 120 and 240 hours. Specimens were taken out from the hot water at the same time and repeated the 3 point bending test after each immersion time and the weight changes had been measured. Results showed that the Jute/Jute composite absorbed water easily, and it could be noted that all of the natural dried composites showed comparable higher water absorbed value to the deeply dried ones. The bending strength after aging decreased remarkably. In particularly, all of the natural dried composites showed higher bending strength than the deeply dried one before aging. However, after 120 hours aging, on the contrary, almost the deeply dried composites showed comparable higher value to the natural dried ones. That could be due to the better bonding between fiber and matrix for the deeply dried composites which decreased the water absorption of the composites. Additionally, the hybrid structure is effective in protecting the composites from water absorbing especially for the Glass/Jute/Glass hybrid one.Copyright

Design of Fiber-Reinforced Composite Tubes as Energy Absorption Element

As an energy absorption member, fiber-reinforced composites (FRPs) are more favorable because they are light in weight and possess better energy absorption capabilities as compared to their metal counterparts. However, the energy absorbing mechanisms of FRP are complicated owning to the multi-micro fractures. Therefore, in this study, the designs of FRP tubes were carried out with considerations directed at the energy absorbing mechanisms. Two methods based on the design of the energy absorbed by bending of the fronds (Ubend ) and the energy absorbed by fiber fractures (Uff ) are concentrated. Here the bending behavior of frond can be considered as the bending beam by an external force. And it is found that Ubend is affected directly by the inertia moment I, which is affect by the geometry. Therefore, FRP tubes were fabricated to have a geometry combined with a bigger I. Additional, in order to get more fiber fractures to get an increased Uff , the design of bending stress, σ, was carried out. FRP tubes bending towards one side only rather than two sides are proposed to get bending fronds with a double thicker thickness, which in turn led to high stresses, many fiber fractures and high energy absorption.Copyright