Papers by Keyword: Fiber Orientation

Abstract: To describe vibration characteristic of composite laminated plates with various fiber orientations, a composite laminated finite element, which follows classical lamination theory, was constructed. In each ply of rectangular composite laminated plates, the fiber orientation changes with respect to the horizontal coordinate. Natural frequencies and mode shapes of composite laminated plates were studied. The first six natural frequencies and mode shapes of composite laminated plates with various fiber orientations are obtained. The accuracy of this composite laminated element is verified by comparing numerical and theoretical results. The results show that the changes of fiber orientation bring a greater degree of flexibility for structure design of composite laminated plates, which can be used to adjust frequencies and mode shapes of composite laminated plates according to practical engineering need.

Abstract: In this study, the influence of fiber orientation on the flexural strength of ultra-high-performance fiber-reinforced concrete (UHPFRC) was examined. To this end, a circular UHPFRC panel measuring φ1,200 × 50 mm was cast from its center, and test specimens measuring 50 × 50 × 200 mm with 10 mm notches for three-point bending tests were cut from it with angles of 0, 30, 60 and 90° between the specimen axis and the radial direction of the panel. After the bending test, fiber orientation on the ruptured surfaces of the specimens was observed. The flexural strengths of the specimens cut at angles of 60, 30 and 0° were 80, 40 and 10% of that for the specimen cut at an angle of 90°. It was also found that the flexural strength of specimens cut from a rectangular panel cast from its center point depended on their original positions and orientation within the panel. Similar fiber orientation characteristics were found in the circular and rectangular panels.

Abstract: This paper is focused on behavior of fiber reinforced cement composites (FRC) and ultrahigh-performance fiber reinforced cement composites (UHPFRC) in dependence on the direction of casting. Almost fifty prismatic samples of size of 400 x 100 x 100 mm were cast into horizontal and vertical moulds. Forty of them with most corresponding results were used in this paper – twenty for FRC and twenty for UHPFRC. In each mixture three samples of both series were cast in the common horizontal direction and the other three in the vertical way. It was found that specific fracture energy of horizontally cast prisms was approximately four and half times higher for both materials than the vertically cast ones. The peak loads of FRC were very similar for both ways of casting. On the other hand the UHPFRC behaved differently, the peak load of horizontally cast prisms was approximately three times higher than the vertically cast ones. It was demonstrated that these differences are caused by the way of casting and vibration.

Abstract: The developments in the field of composite materials are growing tremendously day by day. One such development is the use of natural fibers as reinforcement in the composite material. This is attributed to the fact that natural fibers are environmental friendly, economical, easily available and non-abrasive. Mixing of natural fiber with Glass Fibers is finding increased applications. In this present investigation Banana – Bamboo – Glass fiber reinforced natural fiber composites is fabricated by Hand – Layup technique with varying fiber orientation such as [0°_G, 90°_BM, 0°_BN, 0°_G], [0°_G, 0°_BM, +45°_BN, 0°_G] and [0°_G, 0°_BM, 90°_BN, 0°_G] and are tested for its tensile strength. The tensile strength of the fabricated composites is evaluated. The results indicated that the natural fiber composite with the fiber orientation of [0°_G, 0°_BM, 90°_BN, 0°_G] can withstand more load when compared to the samples with other fiber orientation. Nomenclature Used : BN – Banana fiber BM – Bamboo fiber G – Glass fiber

Abstract: This work is focused on the study of orthogonal cutting of carbon fiber reinforced composite. A model based on finite element was developed. Through defining ultimate stresses of fiber tension cracking and fiber compression bucking, ultimate stresses of matrix longitudinal tensile and shear damage. Cutting forces obtained from the FE simulation matches well with the experimental observations. Than analysis cracking and crushing phenomenon of matrix in different fiber orientation, the influence of fiber orientation on sub-surface damage was studied, it shows that the cracking of sub-surface damage value increased with the increase of fiber orientation angle.

Abstract: FRCMCs have potential applications in aerospace and other high-tech fields. According to FRCMCs anisotropic and non-homogeneous structure, the composites surface characteristics are different from metal material. Fiber orientations play the decisive role in grinding surface quality of woven ceramic matrix composites. This paper investigates the relationship between fiber orientations and grinding surface quality. Using a non-contact optical measurement instrument, the method was developed on 2.5D SiO2/SiO2 composite. Through a series of measuring experiments, it was found that greater grinding surface quality occurred at a fiber orientation 90, but poorer grinding surface took place at a fiber orientation 0. Meanwhile there were less surface defects at acute fiber orientation angle than at obtuse angle. The research obtained will be an important technical support on improving the processing quality of FRCMC.

Abstract: Based on fiber length, fiber orientation distribution and fraction volume, the Halpin-Tsai’ elasticity modulus prediction equation were modified and the elasticity modulus of SGF/TPU composites was experimentally studied. The relationship between the structure and elasticity modulus of SGF/TPU composites was discussed. Results showed that the elasticity modulus of GF-TPU composite rapidly increased as the increasing of fiber volume fraction () and the increasing of the fiber length at the range of 0%-20%. The modified prediction equation of the elasticity modulus fits the test result quite well.

Abstract: The use of laminated composites in aircraft structures is not totally new. However, the idea of using woven fiber glass as reinforcement in primary structural members is not widely addressed as compared to unidirectional fibers. In an effort to characterize the dynamic behavior of a woven laminated composite subject to dynamic loads, modal testing is performed experimentally on a cantilevered laminated woven glass fiber/epoxy composite flat plate which resembles an aircraft wing with aspect ratio of 5. To that end, the effect of stacking sequence and fiber orientation of the laminated composite plate on the modal properties is assessed. 6-layer laminated composite configurations with various stacking sequence and fiber orientation are fabricated so as to generate variable stiffness plates. The modal test employs the single roving hammer technique to obtain the frequency response of the plate and the results of the first five modes against the fiber orientation and stacking sequence are analyzed.

Abstract: Based on generalized non-Newtonian fluid with seven parameters Cross-WLF viscosity model and modified 2-domain Tait model, the injection process of short glass fiber-reinforced polypropylene is simulated with a true 3D model. The effects of gate location on clamp force, fiber orientation and parts deformation are investigated. The results show that: (1) Clamp force of the 3^rd scheme that gate location is set on the center of long-side is the largest and that of the 1^st scheme that gate location is set on the center of top is the smallest. (2)Because of shear stress, in the direction of thickness, the distributions of fiber orientation are layered orderly, namely, the degree of fiber orientation in core layer is the lowest, but that in subsurface layer is the highest. While perpendicular to the shear flow, the layering distribution isn’t obvious. (3) Compared the three schemes in respect of clamp force and parts deflection, the 3^rd scheme is the poorest, which should not be adopted as can as possible, while the 1^st scheme and 2^nd scheme are reasonable.

Abstract: The process of short fiber reinforced injection molding is a typical multi-scale problem, it has become a cutting-edge issue of the field of polymer molding to study clearly the mesoscopic structure changing rules in the whole molding processing. Aiming at the processing of glass fiber reinforced polypropylene injection, basing on the foundation of macro continuum medium model, approximated short fiber reinforced injection molding process as macro-mesoscopic double scale problem composed by macro-flow and small-scale short fiber movement, establish the double scale model, which couple Mesoscopic fiber orientation. And the cooling crystallization model was established by learning from multi-scale simulation of liquid metal crystallization method.