Papers by Keyword: Fiber Orientation

Abstract: Additive manufacturing provides the ability to produce structural components featuring complex shapes in one step, compared to traditional methods of production. Therefore, additive manufacturing has recently gained attention for the direct production of parts. Using fibre reinforced filaments offers the opportunity to improve the mechanical properties of FFF printed components. In order to dimension them correctly, the mechanical properties of additive manufactured samples based on glass fibre reinforced filaments were determined. Additionally, the influence of extrusion paths resulting in a distinct fibre orientation were taken into account. Samples were produces by FFF-method (Fused Filament Fabrication) from three materials: Bulk ABS and short glass fibre reinforced ABS featuring 5 wt% and 10 wt% fibre content. Additionally, samples were printed in two different raster orientations of 0° and 90°. Three different sample types were manufactured in order to perform tension, flexural and impact tests. Prior to printing the samples, the slicer parameters were optimized for usage with the fibre reinforced filament. To determine the FOD (Fibre Orientation Distribution) and FLD (Fibre Length Distribution), the samples were scanned using a CT. Results show that fibre reinforced filaments used in this contribution can increase stiffness to 150 % of the bulk material in printing direction with a fibre weight content of 10 %. CT investigations have shown that the orientation of fibres is primary aligned to the printing path.

Abstract: In this study, it was tried to develop a process chain for ceramic injection molding of Al₂O₃-chopped-fiber reinforced oxide-ceramic-matrix-composite. The feedstocks are compounded at 50 Vol. % filling degree of solid (Al₂O₃ μ-powder (Taimei Chemicals Co. Ltd.) and 3,2 mm chopped fibers (3M)), in which fiber content varies from 0 Vol. % to 100 Vol. %. As binder system, PE + Paraffin Wax + Stearic Acid are used. The ingredients are compounded in a kneader (Brabender) at 125°C and after the viscosity measurement in the high pressure capillary rheometer at 160°C and certain shear rates, the feedstock is injection molded (Battenfeld) at 160°C, which is followed by debinding process, including chemical (in n-Hexane) and thermal steps, and 2h sintering at different temperatures. Flow paths in the machinery parts, rheological properties of binding system, fiber content and the fiber orientation have significant effect on the flow behavior of the feedstock, fiber -orientation, -distribution & -length, which are crucial to understand the properties of end-parts like mechanical reinforcement of the fibers. The fibers in the sintered parts are ca. 200 μm in average length. The fibers in the feedstock show different orientations depending on the part-geometry and the green bodies have different densities depending on sintering temperature, amount of dispersant and fiber orientation.

Abstract: In this work, experiments were conducted to examine the impact of fiber orientation of self-reinforced polypropylene on wrinkling phenomenon. Defects due to wrinkling are major quality issues in rapid forming of sheet materials. This article examines the influence of two fiber orientations [0°/90° and 45°/-45°] on wrinkling initiation of a self-reinforced polypropylene composite (Curv®) material system. It was found that 45°/-45° specimen wrinkles at smaller axial displacement compared to 0°/90° specimen. In both specimens, there was an abrupt change in strain increment ratio that corresponded to the onset of wrinkling. This phenomenon validates the robustness of the wrinkling indictor based on strain increment ratio concept.

Abstract: –The behaviour of extruded glass fibre reinforced thermoplastic pipe under axial crushing load was investigated experimentally. It was envisaged that the difference between the axial and hoop moduli and strengths as well as the volume fraction would influence the mode of collapses and energy absorption. The moduli could be varied using a new extrusion technology, which controls the fibre orientation pattern, hence, the mechanical properties. The ability to vary the moduli and the fibre volume fraction provide means of controlling the collapse mode in order to optimise specific energy absorption. Axial compression tests were performed on glass filled Polypropylene and Polyethylene composite pipes. The samples were chosen with a variety of fibre volume fraction, V_f = 5% to 20% and average angle of orientation, θ = 50^o to 80^o to evaluate the effect of anisotropy and V_f on the energy absorption capacity and collapse modes. The observations indicate that, the samples containing of higher V_f and θ, collapsed in brittle failure mode (fragmentation), while those with less V_f and θ angle collapsed in non-axis-symmetric (diamond) mode with local fracture. The galss fillet with polypropylene-60^o (GPP-60) displayed the highest specific energy absorption (E_s) compared to the other GPE, MDPE and LDPE pipe samples. However, the glass fillet polyethylene – 75^o (GPE-75) displayed the highest E_s and the glass fillet polyethylene – 65^o (GPE-65) displayed the lowest E_s compared with in the GPE pipes. The specific energy absorption of GPP-70 pipe (24 kJ/kg) and GPE-75 pipe (12 kJ/kg) is almost 50 % and 25% of the amount of specific energy absorption of aluminium tubes (60 kJ/kg), respectively. Moreover, it is close to the specific energy absorption of glass-epoxy 15^o (GE-15) / which is 30 kJ/kg, and much higher than aramid-epoxy-15^o (AE-15)/ which is 9 kJ/kg.

Abstract: In this study, the focus was on the optimum design of laminate stacking sequences (LSS) of basalt fiber reinforced composite (BFRP) structure. Eleven rectangular composite panels with different stacking sequences and fiber orientations were analyzed. A three-point flexural test according to ASTM D790 was carried out in ANSYS to simulate the basalt fiber reinforced composite layup flexural strength. From the results, it was found that the composite structure layup of [0/0/45/0/0]_s has the highest strength among all samples.

Abstract: The entire simulation process for long fiber reinforced thermoplastics is examined to determine the effective mechanical properties which are influenced by the microstructural fiber orientation state. Therefore, flow and fiber orientation simulations are conducted and the obtained fiber orientation tensors are used in two-scale structural simulations. The fiber orientation distributions as well as the mechanical properties are compared with micro-computed tomography data and results from threepoint bending tests performed by dynamical mechanical analysis (DMA), respectively. The validated results show that prediction of the essential mechanical properties is possible with the applied combinated methods and that the knowledge of the fiber orientation and its gradients is of crucial importance for the entire simulation process.

Abstract: The hygrothermal effect is introduced by using empirical relations for degrading the material stiffness properties of the matrix. A parametric study is conducted by varying the fiber volume fraction and the fiber orientation of the angle plies in the laminate. It is possible to minimize the environmental effect by judiciously selecting the laminate configuration.

Abstract: The developments in the field of composite materials are phenomenal. The use of natural fibers in the field of composite material is gaining importance. This is due to the advantages of natural fibers: they are eco-friendly, easily available, non-abrasive and cost effective. The combination of natural fiber with Glass fibers is used widely in many applications. In the current investigation Banana – Bamboo – Glass fiber reinforced composites is fabricated by Hand – Layup technique with varying fiber orientation and is tested for its tensile strength and the combination that would yield the best tensile strength is identified by using Taguchi Method.

Abstract: Fiber reinforced polymer composites are common materials used to produce parts for structural applications. The attractiveness of these materials is a result of the combined advantages of the fiber reinforcing effect and the high production rates achievable by technologies such as injection molding. The fiber orientation in short fiber reinforced thermoplastics depends on injection moulding technology parameters. The aim of this paper is to propose possibilities for comparing fiber orientation of the real sample and the result from simulation software.

Abstract: Understanding rules of the distribution of fiber is important to control the mechanical properties of composite material performance. Fiber orientation in dumbbell-shaped injection cavity is different from that in regular cuboids because of its complex shape. Fiber orientation equation, Fokker - Planck equation was solved by the finite volume method and the errors brought by approximate method were avoided. The calculation results verified demonstrated that the shape of injection cavity affected the fiber orientation. In the flow direction, fiber of the shrinkage zone oriented along the flow direction and of the dilation zone oriented along tensile direction which is vertical to the flow. In cavity thickness direction, fiber orientation was layered.