Short Fiber Mat Research Articles

Fatigue resistance of randomly oriented short glass fiber reinforced polyester composite materials immersed in seawater environment

Randomly oriented short fiber mat reinforced polyester composite laminates immersed in natural seawater for various periods were tested in static and cyclic fatigue loading under three-point bending conditions. Water absorption increased the weight of the specimen while the extraction of soluble compounds induces a weak weight loss. Wohler curves carried out from repetitive fatigue tests were drawn for the different periods of immersion time. These curves, which are characterized by an important and a significant scatter in their lifetime, were modeled by straight lines. These glass-polyester laminates deteriorate in fatigue tests at a constant rate by cycle decade. This rate increases with increasing immersion time in seawater at a constant speed. A comparison between different mathematical models of endurance curves shows that Wohler's equation gives a good representation of the average part of the curve.

Implications of fiber characteristics and mat densification on permeability, compaction and properties of kenaf fiber panels

In the manufacturing of medium density and high density fiberboards the fiber characteristics and mat density substantially influence mat permeability, compaction pressure and panel's physicomechanical properties. In this paper, the permeability and compaction response of kenaf bast fiber mats are experimentally determined at three fiber lengths for both dry and resinated fiber mats with various levels of mat densification. The mats of long fibers have demonstrated higher permeability and require higher compaction pressure than short fiber mats at the same level of densification. Furthermore, kenaf panels in the density range of 800kg/m3 to 1100kg/m3 are manufactured with commercial melamine urea formaldehyde resin and three fiber categories. The panels are evaluated to demonstrate the effects of these factors on a panel's physicomechanical properties. The higher compaction pressure and good stress distribution with long fibers have resulted in higher mechanical properties than those of short fiber panels. On the other hand, a decrease in fiber length has lowered the mat permeability, resulting in significant improvements in dimensional properties. The panel physicomechanical properties can also significantly improve by increasing the panel density. The high density kenaf panels have shown excellent mechanical properties which are well above the standard requirements of MDF and HDF panels according to (ANSI, A208.2: 2009) and (ANSI, A135.4-2012) standards.

Application of Multilayered Paper Processing to Hybrid Random Natural Fiber Mat

Fiber reinforced plastic composite (FRP) has gained remarkable development because of its excellent properties, such as low density, high stiffness, high strength, corrosion resistance, long fatigue life, and so on. However, as more and more products made of FRP, the rubbish of FRP is also increasing which has become an important problem to the environment. Recycling and reusing is a noticeable method to reduce trash discharge and to save resource. Although it is a more challenging work for FRP, many researchers have report their scores in this area, such as the group from The University of Nottingham who have developed a new technology to recycle the carbon fiber. The objective of this research is to make short fiber mat from recycled carbon fiber by paperboard making method. In this method the fiber can be made into very thin layers and be laid into mat. After that the mats were used to fabricate FRP and the tensile property of the materials was investigated. The property was evaluated between recycled carbon fiber and jute fiber as well as hybrid one. It was found that the hybrid one has better performance.

2918 風車用GFRP材の機械的特性と成形性の評価(S27-1 複合材料の動向とその加工技術(1),S27 複合材料の動向とその加工技術)

GFRP with a higher specific strength is generally used for wind turbine blades. For blade molding, the RTM method is commonly employed. This method requires sufficient resin fluidity to ensure stable molding quality. Insufficient resin fluidity can cause problems, such as the inability to achieve the expected material strength. Regarding the effect of fiber specifications on the mechanical strength of molded parts and the effect of using the RTM method on resin fluidity, the following conclusions have been reached. (1) GFRP made by adding a short fiber mat to the material has a higher mechanical strength than that of material without the mat. (2) When the material with the mat is used, the RTM method results in lower resin fluidity. (3) With the molding of larger parts on the horizon, material selection that takes into consideration mechanical strength and formability will be increasingly important.

MECHANICAL PROPERTIES OF HYBRID CARBON/GLASS FIBER COMPOSITES

Hybrid composites were prepared by impregnating epoxy resin into the short fiber mat consisting of carbon and glass fibers. The effect of the mix ratio of the reinforcing fibers (hybrid ratio) on the mechanical properties of the hybrid composites and the temperature dependence of the mechanical properties were studied.As the hybrid ratio of carbon fibers decreases, Young's modulus decreases almost linearly, the tensile strength remains almost constant, and the impact fracture energy increases almost linearly. It is possible to estimate Young's modulus, the tensile strength, and the impact fracture energy of the composites with various hybrid ratios from an additive rule.Young's modulus and tensile strength decreases with increasing temperature. The impact fracture energy increases as the temperature rises. The hybrid ratio-temperature superposition holds for each mechanical property.