• Journal of Welding and Joining
• /
• 제24권5호
• /
• pp.43-48
• /
• 2006

This paper is concerned with a fracture strength study of composite adhesive lap joints. The tests were carried out on specimen joints manufactured hybrid stacked composites such as the polyester and bamboo natural fiber layer. The main objective of the work was to test the fracture strength using hybrid stacked composites with a polyester and bamboo natural fiber layer. Tensile and peel strength of hybrid stacked composites are tested before appling adhesive bonding. From results, Natural fiber reinforced composites have lower tensile strength than the original polyester. and The load directional orientation and small amount and low thickness of bamboo natural fiber layer have a good effect on the tensile and peel strength of natural fiber reinforced composites. The failure strength of these materials applied adhesive bonding is also affected by fiber orientation and thickness of bamboo natural fiber layer. There for, Fiber orientation of bamboo natural fiber layer have a great effect on the tensile-shear strength of natural fiber reinforced composites including adhesive bonded joints.

• Elastomers and Composites
• /
• 제46권3호
• /
• pp.186-194
• /
• 2011

셀룰로오스계 천연섬유인 kenaf를 천연고무와 함께 균일하게 배합한 후 압축성형 방법을 사용하여 천연섬유/천연고무 복합재료를 제조하였으며, 이들의 가황거동, 경도, 인장특성, 인열강도 및 정적, 동적 특성에 미치는 kenaf 섬유함량의 영향을 조사하였다. 복합재료를 구성하는 천연섬유의 함량은 천연고무 및 배합제 대비 0, 5, 10, 15, 20 phr이었다. 실험결과 천연고무의 여러 가지 특성이 kenaf 섬유의 함량에 의존한다는 것을 나타내었다. Kenaf 섬유함량이 증가함에 따라 천연고무의 가황에 요구되는 토크는 높아진 반면 가황시간은 감소되었다. Kenaf/천연고무 복합재료의 경도, 인장탄성률과 인열강도는 섬유함량이 증가할수록 점차적으로 증가한 반면, 인장강도와 파단신장률 은 감소하는 경향을 보여주었다. 또한 kenaf 섬유함량이 증가함에 따라 천연고무의 정적 특성보다는 동적 특성의 변화가 더욱 크게 나타났다. 고무에 가해지는 에너지의 감쇄 또는 흡수와 밀접한 관계가 있는 손실인자도 섬유함량에 비례하여 증가하였다.

• Journal of Welding and Joining
• /
• 제23권6호
• /
• pp.67-71
• /
• 2005

This paper is concerned with a study on fracture strength of composites in an adhesive single lap joint. The tests were carried out on joint specimens made with hybrid stacked composites consisting of the polyester and bamboo natural fiber layer. The main objective of this work was to evaluate the fracture properties adjacent to adhesive bonded joint of natural fiber reinforced composite specimens. From the results, natural fiber reinforced composites have lower tensile strength than the original polyester. But tensile-shear strength of natural fiber reinforced composites with bamboo layer far from adhesive bond is as high as that of the original polyester adhesive bonded joints. Spew filet at the end of the overlap reduced the stress concentration at the bonded area. Spew fillet and position of bamboo natural fiber layer have a peat effect on the tensile-shear strength of natural fiber reinforced composites including adhesive bonded joints.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2005년도 추계학술발표대회 개요집
• /
• pp.94-96
• /
• 2005

This paper is concerned with a fracture strength study of composite adhesive lap joints. The tensile and peel tests were carried out on specimen manufactured hybrid stacked composites such as the polyester and bamboo natural fiber layer. The main objective of the work was to test the failure strength of adhesive bonded joints using hybrid stacked composites with a polyester and bamboo natural fiber layer adjacent to the fiber orientation. From results, the load directional orientation, small amount and low thickness of bamboo natural fiber layer have a good effect on the tensile and peel strength of natural fiber reinforced composites. and these characters are have a great influence on fracture strength and failure shape of adhesive bonded joints using hybrid stacked composites in the difference of fiber orientation.

• KIEAE Journal
• /
• 제10권6호
• /
• pp.153-158
• /
• 2010

The objective of this study was to investigate the strength characteristics of mortar with lime composites using natural fiber or superplasticizer. Lime composites consist of lime and pozzolan materials. Flow according to adding natural fiber decreased and mortar proportion added cellulose fiber showed a higher strength characterisitics than other natural fiber. but compressive and shear strength in use of superplasticizer is not effective largely. In addition, lime composites, as an environment-friendly material, may help reduse $CO_2$, and save the energy. also this materials can be recycled in environmental aspects. afterwards, further in-depth studies will be necessary for cracks and durability with respect to its wide different applications, in applying it as a construction material.

• 접착 및 계면
• /
• 제9권4호
• /
• pp.24-29
• /
• 2008

두 종류의 천연섬유, 즉 면섬유와 목분을 이용하여 폴리프로필렌 - 천연섬유 복합재료를 제조하고 혼합가공시 유변학적 특성과 열적특성을 고찰하였다. PP/천연섬유 복합재료에서 천연섬유의 함량이 증가함에 따라 토오크 값이 상승하였고, 면섬유의 경우 낮은 체적 밀도로 인해 목분 복합재료보다 높은 토오크값을 나타내었다. PP의 MI에 따라서는 낮은 MI의 PP/천연섬유 복합재료에서 더 높은 토오크값이 관찰되었다. X-선 회절분석과 시차주사열분석을 통해 천연섬유의 함량이 증가될수록 PP/천연섬유 복합재료의 결정화온도는 상승하나 결정화도는 감소함이 확인되었다.

• Composites Research
• /
• 제20권2호
• /
• pp.32-38
• /
• 2007

Natural fibers can refer to all types of fibres only produced by nature. Their lengths vary from particles to long strands. Natural fibers are categorized roughly by six types, depending on the types of sources; base, leaf, seed, grasses, fruit and wood. Of these fibers, jute, flax, sisal and ramie are the most commonly used as reinforced materials in preparing polymer composites. In development and improvement of these composites, many studies have been implemented to overcome the drawbacks such as incompatibility, moisture problems and so on. The range of industry sectors of natural fiber-reinforced polymer composites becomes more extensive gradually and many of the companies all over the world are engaged in fabrications or applications. This paper mainly discussed the recent status of the domestic/overseas market and research issues of natural fiber-reinforced polymer composites. We made an exception of wood-polymer composites market which have played a great role because they had been often dealt with.

• Advanced Composite Materials
• /
• 제16권4호
• /
• pp.299-314
• /
• 2007

In the present study, natural fibers (jute, kenaf and henequen) reinforced thermoplastic (poly(lactic acid) and polypropylene) and thermosetting (unsaturated polyester) matrix composites were well fabricated by a compression molding technique using all chopped natural fibers of about 10 mm long, respectively. Prior to green composite fabrication, natural fiber bundles were surface-treated with tap water by static soaking and dynamic ultrasonication methods, respectively. The interfacial shear strength, flexural properties, and dynamic mechanical properties of each green composite system were investigated by means of single fiber microbonding test, 3-point flexural test, and dynamic mechanical analysis, respectively. The result indicated that the properties of the polymeric resins were significantly improved by incorporating the natural fibers into the resin matrix and also the properties of untreated green composites were further improved by the water treatment done to the natural fibers used. Also, the property improvement of natural fiber-reinforced green composites strongly depended on the treatment method. The interfacial and mechanical results agreed with each other.

• 한국생산제조학회지
• /
• 제19권1호
• /
• pp.140-144
• /
• 2010

In recent years there has been a growing interest for the use of natural fibers in composite applications due to their low cost, environmental friendliness, and good mechanical properties. The purpose of this study is to determine the characteristic of bending strength on bamboo fiber reinforced polymer composites. The parameters of RTM process depend on the weight ratio of bamboo fiber and resin, the number of bamboo ply and amount of hardening agent. Besides the existence of pore in composites according to vacuum time investigated a effect on mechanical properties of reinforced polymer composites. Test result shows that compressive strength was a maximum(approximately 1,840kgf/$cm^2$) value when weight ratio of resin was 12%.

• 대한기계학회논문집A
• /
• 제30권8호
• /
• pp.916-922
• /
• 2006

In recent years there has been a growing interest for the use of natural fibers in composite applications due to their low cost, environmental friendliness, and good mechanical properties. The purpose of this study is to determine the characteristic of bending strength on bamboo fiber reinforced polymer composites. The parameters of RTM process depend on the weight ratio of bamboo fiber and resin, the number of bamboo ply and amount of hardening agent. Mechanical properties was investigated for each process factor of polymer composites. Test result shows that bending strength was a maximum(approximately 85MPa) value when composite thickness was 6mm and weight ratio of resin was 13%.