Impact Of Fiber Orientation Research Articles

Impact of fiber orientation on cutting forces and surface quality in flax/epoxy composite machining

Impact of fiber orientation on cutting forces and surface quality in flax/epoxy composite machining

3D printed carbon fiber reinforced carbon as an energy efficient alternative to graphite for EFAS tooling

As Electric Field Assisted Sintering (EFAS) gains more industrial acceptance and use, it becomes more important to develop more efficient means to implement this technology. To this aim, 3D printed continuous carbon fiber reinforced carbon (CCC) was manufactured and fabricated into tooling for EFAS systems as an alternative to traditional graphite tooling. The impact of fiber orientation on the thermal and electrical properties of the CCC was characterized. Sample material was sintered in Tokai G535 graphite tooling, under common processing conditions and compared with CCC tooling. There was nearly 50 % energy savings compared to graphite while maintaining equivalent sample density and microstructure plus keeping ram temperatures 39 % cooler. This is due to spatial control of generated heat and thermal diffusivity within the molds, by means of fiber orientation anisotropy. Finite element modeling of the tooling design supported the experimental results as well as displays the effect of optimization of this 3D printed CCC material.

Effect of fiber orientation-based composite lamina on mitigation of stress intensity factor for a repaired plate: a finite element study

The bonded composite repair has proven to be an effective method for addressing crack damage propagation. Numerous studies have employed experimental and simulation techniques to demonstrate the repair performance through the composites. These studies have explored various parameters related to bonded composites, such as size and properties, to enhance repair effectiveness. However, one aspect that has not been thoroughly investigated is the impact of fiber orientation within the composites. Therefore, the current work investigates the effect of the fiber direction of the composite patch bonded on a thin plate under plane stress conditions. Three types of fiber orientation of composite patch have been considered. In this investigation, the finite element method was used to determine the stress intensity factor using the ANSYS commercial code. The research findings showed that the fiber direction influenced the mitigation of stress intensity factor. This study is particularly important for designing the composite patch based on the fiber direction.

Characterization, quantitative evaluation, and formation mechanism of surface damage in ultrasonic vibration assisted scratching of Cf/SiC composites

Carbon fiber reinforced silicon carbide ceramic matrix composites (Cf/SiC composites) have a wide range of applications in aerospace, nuclear energy, braking systems owing to its excellent mechanical performance. Nevertheless, the hardness, brittleness, heterogeneity, and anisotropy of Cf/SiC composites give rise to difficulties in machining them. In addition, the characterization and formation mechanism of surface damage in the grinding of Cf/SiC composites have not been fully elucidated. The purpose of this paper is to provide a characterization method for surface damage of Cf/SiC composites and an evaluation index for surface edge chipping damage (SECD) through conventional scratching (CS) / ultrasonic vibration assisted scratching (UVAS) tests with single abrasive. Towards revealing the surface damage behavior of Cf/SiC composites during scratching, as well as the impact of fiber orientation on surface damage. The findings indicate that main forms of surface damage of Cf/SiC composites in single abrasive scratching are fiber breakage, fiber fracture-shedding, fiber fracture, fiber-matrix interface debonding, interface fragmentation, matrix cracking, and matrix microcracks. Further, ultrasonic vibration could help to suppress the SECD, and the SECD factor was smallest when scratching along the perpendicular fiber. Furthermore, the fiber orientation can significantly affect the scratching force and cross-sectional area of scratches on Cf/SiC composites via single abrasive scratching. The tangential scratching force was usually smaller as compared to the normal scratching force, and the cross-sectional area of scratches in UVAS is smaller than that in CS. Based on the above findings, this study elucidates the formation and evolution of surface damage after scratching under different fiber orientations, filling the research gap in surface damage under ultrasonic assisted machining of Cf/SiC composites and providing technical guidance for the machining.

Impact of fiber orientations, stacking sequences and ageing on mechanical properties of woven jute-kevlar hybrid composites

In this study, the impact of fiber orientation towards the loading direction, and the stacking sequence of jute and Kevlar composites and hybrids on mechanical properties were investigated. A unidirectional jute fiber mat made of jute yarn was used to fabricate three different composites to explore the effect of fiber orientation. In addition, Jute-Kevlar hybrids were used with three different stacking sequences. Experimental investigations and simulation revealed the influence of fiber orientation and the stacking sequence on the mechanical properties of fabricated composites and hybrids. The long-term durability and degradation of mechanical properties in corrosive environments were also investigated and compared with the base results. It manifested that both the tensile and flexural strengths of the composites lowered significantly when they were immersed in pH 8. Furthermore, the diffusion mechanism was examined and found to be Fickian diffusion of composites and hybrids that had been immersed in pH 8.

Force and Roughness Analysis for Natural Bagasse Fiber Reinforced Composites Under Milling Machining: An Experimental Study

ABSTRACT The machining behaviour of bagasse fibre-reinforced polymer composites is investigated in terms of cutting forces and surface roughness during the milling process in this study. The impact of fibre orientation and cutting parameters is found while quantifying cutting forces. A tool dynamometer connected to the universal milling machine measures the cutting forces during the milling process. The hand lay-up method is used to create composite specimens with three different fibre orientations to the cutting direction, such as 0°, 45° and 90° (θ). Cutting forces in the X, Y, and Z directions are calculated using cutting parameters such as speed and depth of cut. Surf experiments were used to assess the surface roughness of the composite specimens. The microscopic images aid in understanding the fibre orientation and its impact on fibre damage during the milling process.

Impact of fibre orientation on mechanical properties of GFRP composites

Knowing the characteristics of a composite material under a given set of circumstances is essential for reliable structural member design. Understanding and being familiar with the stacking order of laminates organised to make a composite is essential since composites are used in an increasing number of applications. The goal of the current effort is to develop an E-glass fibre reinforced with epoxy composite by stacking the laminates of 0°, 45°, and 90° and integrating all three orientations. Different samples were compared experimentally with axial tensile and compressive loading. The specimen with a 0° orientation in the tensile test demonstrated outstanding resistance to tensile loading. It is observed that found the sample developed by different stacking sequence experiences the least strain of all the specimens with 9% elongation at break. Additionally, the sample made with fibre orientation of 450 undergo severe deformation of 20% which is considered to be largely deformed specimen compared to the rest of the combinations.

Impact of fibre orientation on the hygrothermal properties of straw bale insulation

This paper presents findings from a research project that aimed to develop the use of wheat straw bales as non-load bearing building insulation with a new prototype insulation product. Demands for more sustainable construction products, with lower net carbon emissions and improved thermal performance, have grown in recent years. There is an increasing recognition that bio-based insulation materials, including hemp, wood fibre and straw, can provide more sustainable alternatives to current insulation products. Straw bales, produced as an agricultural co-product from cereal production, can be used directly in construction. However, both the bale sizes and orientation of straw fibres in these agricultural bales are sub-optimal for most construction uses, and have become a barrier to wider adoption. This paper reports on the technical development and characterisation of a prototype insulating product produced from wheat straw, in which both the bale size and straw fibre orientation has been produced to optimise insulation performance. Thermal conductivity and hygric performance studies are presented for the prototype bales, characterising improvement in performance from optimising straw fibre orientation. Optimising orientation of the straw fibres in bales has successfully reduced thermal conductivity, compared to conventional agricultural bales, by 38%, allowing similar reductions in insulation thickness for an equivalent performance. Furthermore, by optimising the orientation of the straw fibres a reduction in water vapour permeability, moisture buffering, and moisture infiltration by as much as 76%. This research will support opportunities for greater uptake of a novel bio-based insulation materials into mainstream construction.

The Impact of Fiber Orientation on Structural Dynamics of Short-Fiber Reinforced, Thermoplastic Components—A Comparison of Simulative and Experimental Investigations

The quality of the fiber orientation of injection molding simulations and the transferred fiber orientation content, due to the process–structure coupling, influence the material modeling and thus the prediction of subsequently performed structural dynamics simulations of short-fiber reinforced, thermoplastic components. Existing investigations assume a reliable prediction of the fiber orientation in the injection molding simulation. The influence of the fiber orientation models and used boundary conditions of the process–structure coupling is mainly not investigated. In this research, the influence of the fiber orientation from injection molding simulations on the resulting structural dynamics simulation of short-fiber reinforced thermoplastic components is investigated. The Advani–Tucker Equation with phenomenological coefficient tensor is used in a 3- and 2.5-dimensional modeling approach for calculating the fiber orientation. The prediction quality of the simulative fiber orientations is evaluated in comparison to experiments. Depending on the material modeling and validation level, the prediction of the simulated fiber orientation differs in the range between 7.3 and 347.2% averaged deviation significantly. Furthermore, depending on the process–structure coupling and the number of layers over the thickness of the model, the Kullback–Leibner divergence differs in a range between 0.1 and 4.9%. In this context, more layers lead to higher fiber orientation content in the model and improved prediction of the structural dynamics simulation. This is significant for local and slightly for global structural dynamics phenomena regarding the mode shapes and frequency response behavior of simulative and experimental investigations. The investigations prove that the influence of the fiber orientation on the structural dynamics simulation is lower than the influence of the material modeling. With a relative average deviation of 2.8% in the frequency and 38.0% in the amplitude of the frequency response function, it can be proven that high deviations between experimental and simulative fiber orientations can lead to a sufficient prediction of the structural dynamics simulation.

Impact of fibre orientation on thickness and tensile strength of needle-punched nonwoven: Optimization of carding parameters

In this research work, the authors have investigated the influence of fibre orientation on thickness and tenacity of needle-punched nonwoven fabrics by using three-factor three-level Box–Behnken Design. Three carding parameters such as feeder speed, cylinder speed and doffer speed, which are primarily responsible for fibre orientation, were considered as three factors with three different levels. Fibre orientation was evaluated in terms of anisotropy by using tracer fibre technique. Anisotropy was measured in both un-punched and punched fibrous structure. Tenacity was measured in both machine and cross directions. It was found that the tenacity in the cross direction and thickness decreases but the tenacity in the machine direction increases with the increase of anisotropy as well as fibre orientation.

The impact of fibre orientation on T1-relaxation and apparent tissue water content in white matter.

Recent MRI studies have shown that the orientation of nerve fibres relative to the main magnetic field affects the R2*(=1/T2*) relaxation rate in white matter (WM) structures. The underlying physical causes have been discussed in several studies but are still not completely understood. However, understanding these effects in detail is of great importance since this might serve as a basis for the development of new diagnostic tools and/or improve quantitative susceptibility mapping techniques. Therefore, in addition to the known angular dependence of R2*, the current study investigates the relationship between fibre orientation and the longitudinal relaxation rate, R1 (=1/T1), as well as the apparent water content. For a group of 16 healthy subjects, a series of gradient echo, echo-planar and diffusion weighted images were acquired at 3T from which the decay rates, the apparent water content and the diffusion direction were reconstructed. The diffusion weighted data were used to determine the angle between the principle fibre direction and the main magnetic field to examine the angular dependence of R1 and apparent water content. The obtained results demonstrate that both parameters depend on the fibre orientation and exhibit a positive correlation with the angle between fibre direction and main magnetic field. These observations could be helpful to improve and/or constrain existing biophysical models of brain microstructure by imposing additional constraints resulting from the observed angular dependence R1 and apparent water content in white matter.

Effect of Fiber Orientation on the Wrinkling Behavior of Thermoplastic Composite

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.

Experimental investigation on the accuracy of plastic scintillators and of the spectrum discrimination method in small photon fields.

To investigate the accuracy of output factor measurements using a commercial (Exradin W1, SI) and a prototype, "in-house" developed, plastic scintillation dosimeter (PSD) in small photon fields. Repetitive detector-specific output factor OFdet measurements were performed in water (parallel to the CAX) using two W1 PSDs (SI), a PTW microLion, a PTW microDiamond and an unshielded diode D1V (SI) to which Monte Carlo calculated corrections factors were applied. Four sets of repetitive measurements were performed with the W1 PSD positioned parallel and perpendicular to the CAX, each set on a different day, and with analytically calculated volume averaging corrections applied. The W1 OFdet measurements were compared to measurements using an "in-house" developed PSD in water (CHUQ) and both were validated against a previously commissioned Monte Carlo beam model in small photon fields. The performance of the spectrum discrimination calibration procedure was evaluated under different fiber orientations and wavelength threshold choices and the impact on the respective OFdet was reported. For all detectors in the study an excellent agreement was observed down to a field size of 1×1 cm2 . For the smallest field size of 0.5×0.5 cm2 , the W1 PSDs presented OFdet readings higher by 3.8 to 5.0% relative to the mean corrected OFdet of the rest of the detectors and by 5.8 to 6.1% relative to the CHUQ PSD. The repetitive W1 OFdet measurements in water (parallel CAX) were higher by 3.9% relative to the OFdet measurements in Solid WaterTM (perpendicular CAX) even after volume averaging corrections were applied, indicating a potential fiber orientation dependency in small fields. Uncertainties in jaw and detector repositioning as well as source variations with time were estimated to be less than 0.9% (1 σ) for the W1 under both orientations. The CHUQ PSD agreed with the MC dose calculations in water, for the smallest field size, within 1.1-1.7% before any corrections and within 0.3-0.8% after volume averaging corrections. The spectrum discrimination method provided reproducible Cherenkov spectra under the different calibration set-ups with noisier spectra extracted if the calibration is performed in water and parallel to the CAX. The impact of fiber orientation and wavelength threshold during calibration on OFdet was in general minimal. Clinically relevant differences were observed between similar scintillator dosimeters in photon fields smaller than 1× 1 cm2 . Further research on PSDs is needed that can explain the origin of these differences especially related to the Cherenkov spectrum dependencies on the optical fiber technical characteristics.

Impact of fibre orientation in fibrous cap on the mechanical loading in human coronary atherosclerotic plaques

Impact of fibre orientation in fibrous cap on the mechanical loading in human coronary atherosclerotic plaques

LABORATORY STUDY ON THE INFLUENCE OF CASTING ON PROPERTIES OF ULTRA-HIGH PERFORMANCE FIBRE REINFORCED CONCRETE (UHPFRC) SPECIMENS

This paper presents a study on the effects of casting procedure and resulting fibre orientation on the properties of Ultra-High Performance Fibre Reinforced Concrete (UHPFRC). To investigate the impact of fibre orientation in the UHPFRC specimens, three approaches were employed. First, densities were measured from the top, middle and bottom zones of the cylinders to observe physical changes as the function of cylinder height. Secondly, two engineering fracture tests were performed in both compression and tension, and a comparison of fracture energies was conducted between different cylinder zones. While previous studies have explored the influence of steel fibres on the UHPFRC performance, the Semi-Circular Bending (SCB) and Disc Compact Tension (DCT) experimental setups have not yet been used in the UHPFRC fracture testing. Lastly, samples from different zones were scanned using X-ray computer tomography (X-ray CT). Both visual and digital image analysis of the X-ray scans were conducted in order to observe fibre orientation pattern changes within different zones. Although density calculations showed insignificant differences between different zones, fracture testing exhibited significant differences through the testing process as well as through fracture energy computations. Furthermore, X-ray CT demonstrated considerable differences in spatial fibre orientation with respect to two uniquely defined angles.

The influence of fibre orientation, extracted from different segments of the human left ventricle, on the activation and repolarization sequence: a simulation study

This computational study examined the influence of fibre orientation on the electrical processes in the heart. In contrast to similar previous studies, human diffusion tensor magnetic resonance imaging measurements were used. The fibre orientation was extracted from distinctive regions of the left ventricle. It was incorporated in a single tissue segment having a fixed geometry. The electrophysiological model applied in the computational units considered transmural heterogeneities. Excitation was computed by means of the monodomain model; the accompanying pseudo-electrocardiograms (ECGs) were calculated. The distribution of fibre orientation extracted from the same transversal section showed only small variations. The fibre information extracted from the equal circumferential but different longitudinal positions showed larger differences, mainly in the imbrication angle. Differences of the endocardial myocyte orientation mainly affected the beginning of the activation sequence. The transmural propagation was faster in areas with larger imbrication angles leading to a narrower QRS complex in pseudo-ECGs. The model can be expanded to simulate electrophysiology and contraction in the whole heart geometry. Embedded in a torso model, the impact of fibre orientation on body surface ECGs and their relation to local pseudo-ECGs can be identified.