Papers by Keyword: Fibre Orientation

Abstract: The paper investigates the influence of fibre orientation on the mechanical characteristics of PETG plastic products manufactured by FDM printing (Fused Deposition Modelling). Three groups of experimental samples were made with different fibre orientation: along the load axis, perpendicular to it, and at an angle of 45 °. Experimental tensile and compression tests, including the stages of elastic deformation, structure strengthening, and local fracture, were performed to study the mechanical characteristics of the material. It is established that the orientation of the fibres is a determining factor of strength and deformation behaviour of products: samples with fibres along the load axis are characterized by increased plasticity and strength, while the transverse orientation reduces mechanical resistance due to interlayer destruction. Samples with fibre orientation at an angle of 45° demonstrated an optimal combination of strength and deformation capacity. The results of the study confirm the need to consider the fibre orientation when designing PETG plastic products to ensure optimal performance.

Abstract: Carbon fibre reinforced plastics (CRFP) are high performance materials with an outstanding lightweight potential. Recycling applications for production waste though, are still scarce and not fully established. In the CaroLIn (carbon fibre nonwovens optimised for aircraft interior components) research project a novel aerodynamic textile process is developed, in order to produce highly orientated non-wovens form recycled carbon fibres. In the first stage of the project a laboratory plant for the orientation of fibres has been constructed and implemented. Afterwards a process window has been defined and a number of process parameters identified. The influence of those parameters was then investigated, using the statistical design of experiment (DOE) method.

Abstract: Sustaining the shelf life of fresh food remains a herculean task to most farmers as cold chain must remain unbroken in order to maintain the quality of fresh food. The concept of this research is to reduce energy consumption in refrigerated vehicles through light weight insulated panel as this medium could effectively reduce the payload of the entire vehicle. Part of the progress made in this work, is to develop five different composite cover sheet for insulated panel using fibre loading and orientation as manufacturing parameters and results show that oriented reinforced composite materials offer significant weight reduction compared to un-oriented composite cover sheet. The panel weight of these new materials were estimated using all the conceptual parameters of a refrigerated vehicle and the results indicate that composite reinforced with 10%wt. of fibre at 30^o orientation in the matrix, offers the best panel weight reduction with 5.2380Kg/m² and 6.7380Kg/m² for 50mm and 100mm insulation thicknesses, respectively.

Abstract: In the present scenario, composites are beginning to play a major role in day to day applications. Suitable properties can be imparted by selection or orientation of fibers during the manufacturing process. This paper demonstrates the natural composites made up of Manila as reinforcing agent with epoxy resin as matrix enclosed between glass fibers. Glass fibers, also known as woven rovings, are used to improve the surface finish and provide better strength and rigidity to the composite. Using hand lay-up method, fibers of Manila are arranged in alternate layers. The strength of composites depends on the fiber-matrix interfacial bonding. Three composite samples are prepared and mechanical stability of the composite is determined by tensile test. It is seen that there is not much variation in the ultimate strength of the three samples. On an average, it is found that average break load of the composite is 4.8 KN and the corresponding displacement is 9.08 mm. All the three samples exhibit almost similar elongation of about 18 % and the average ultimate tensile strength is 31.66 MPa. The reason for uniform tensile properties is due to a homogeneous distribution of fibers in all the three samples.

Abstract: Several analytical, numerical and experimental techniques are available to study the stress concentration around the notches. The stress distribution in a rectangular composite laminated plate with a central notch was studied using the finite element method. The objective of this study is to analyze the fibre orientation effect on the variation of stress concentrations at the notch root and the J-integral at the crack-tip emanating from this notch in a plate subjected to tensile loading. The results show that the anisotropic stress concentration factor can be higher or lower than that of a homogeneous material. The area of maximum normal and tangential stresses could shift with fibre orientation with respect to the loading axis. The interaction effect between a crack located on the ligament of the plate and the circular notch of radius is considered.The results indicate that fold sequence influences appreciably the acceleration or the retardation of the crack propagation.

Abstract: Water retted kenaf fibre reinforced epoxy laminates with five distinct fibre orientations, unidirectional, [+30/0/-30], [+45/0/-45], [+60/0/-60] and [90/] s were produced through resin infusion technique. The fibre weight fraction in each laminate was controlled and the effects of varying orientation in the resulting composite lamina were characterized through tensile and impact properties of the specimens. Superior tensile strength and modulus were observed for the unidirectional lamina while the orthogonal lamina [90/] s depicted the greatest resistance to impact. Specimen with higher proportion of fibres aligned parallel to the loading direction show greater enhancement in tensile strength while impact property of the lamina was found to be greater with increases in fibre orientation perpendicular to the direction of impact load.

Abstract: Many researches have been conducted in past decades for promoting the application of steel fibre reinforced concrete (SFRC), either conventional or self-compacting. However, the differences of post-crack behaviour and the properties of these two types of concrete remains unclear. The objective of this paper is to analyse such differences in terms of flexural behaviour, fibre orientation and contribution as well as the fibre content. For that, an extensive experimental campaign was carried out. In total 3 mixes of self-compacting and 3 mixes with traditional concrete were produced with the nominal fibre contents of 30kg/m³, 45kg/m³ and 60kg/m³. In each series, specimens were produces and characterized by three point bending test (code EN 14651) and inductive test. The results illustrate how fibre orientation and distribution justify the differences in the mechanical behaviour of the materials and the scatter of the bending test results.

Abstract: This paper reported the study of tensile properties of kenaf yarn fibre reinforced unsaturated polyester (UP) composites at different fibre orientations, i.e. 0o, ±45o and 90o. It is concluded that composites with 0o orientation show higher strength and stiffness than composites with ±45o and 90o angle fibre orientation. The highest value of stress is 29 MPa for 0^o loading direction followed by ±45^o loading direction (28 MPa) and 90^o loading direction has the lowest stress value of 6 MPa. Tensile modulus results revealed the highest value of 10.61 GPa for 0^o loading direction and the tensile modulus for 45^o orientation of loading direction is 5 GPa, followed by the modulus for 90^o of fibre loading direction of 1.2 GPa; which is the lowest.

Abstract: Superior to hardwood and softwood trees, coconut palms are able to withstand extreme weather conditions without failure. Previous studies have shown that the internal structure of coconut palm stems significantly differs from hardwood, softwood and even other palm stems, in terms of fibre orientation and density distribution, likely influencing the mechanical characteristics of the tree. This paper aims at quantifying the cocowood hierarchical structure at an integral level (stem structure). To achieved this, quantitative analysis of more than 40 senile coconut palms from Fiji and Samoa has been carried out. This paper defines and analyses the typical cocowood morphology (form-structure) in terms of such factors as characteristic radius, fibrovascular bundles orientation and density distribution. For the first time, the characteristic triple helix configuration traced out by the fibrovascular bundles within the cocowood structure is modelled for the whole coconut stem. Specific equations are proposed to determine these factors at any given position in the tree. Knowledge advanced from this study will provide a scientific basis for future cocowood biomechanics research, including finite element modelling and analysis for biomimetic engineering applications.

Abstract: The mechanical properties of E-glass/epoxy composite at high strain rates are important in evaluating this kind of composite under dynamic and impulsive loading. The in-plane and out-of-plane compressive properties at strain rates from 300 to 2500 s-1 were tested with split Hopkinson pressure bar. Samples were tested in the thickness as well as in-plane direction for seven fibre orientations: 0°, 20°, 30°, 45°, 60°, 70° and 90°. The kinetics of damage and the failure modes were identified using a high-speed photography, infrared camera, optical techniques and a scanning electron microscope. Results of the study were analyzed in terms of maximum stress, Strain at maximum stress, failure modes, damage history and fibres orientation effects. From the experimental data, the stress-strain curves, compressive stiffness, and compressive strain of the composite are rate-sensitive in in-plane and out-of-plane compressive directions. The failure and damage mechanisms are implicitly related to the rise in temperature during static and dynamic compression.