Effect Of Fiber Orientation Research Articles

Retention force of fiber-reinforced composite resin post on resin composite for core buildup -Effects of fiber orientation, silane treatment and thermal cycling.

The purpose of this study was to investigate the effects of fiber orientation, silane treatment, and thermal cycling on the retention force of fiber-reinforced composite resin (FRC) posts on resin composite. Two types of FRC posts (linear and woven) were prepared with and without silane treatment. Pull-out test specimens were made of FRC posts and resin composite for core buildup. Specimens were either incubated in distilled water for 24 h or subjected to 10,000 thermal cycles. The maximum fracture load obtained by a pull-out test was defined as the retention force. Fracture modes were observed after the test. Fiber orientation and thermal cycling did not affect the retention force on resin composite, and the retention force was improved by silane treatment. Whereas, fiber orientation affected the fracture mode. The result showed woven fiber orientation could contribute to the mechanically interlocking with the resin composite.

A numerical investigation of the effect of fiber orientation on the natural frequency of hybrid composite laminate.

In this study, the effect of fiber orientations on the natural frequencies of the hybrid composite laminate (HCGFRE) that is consisted of sequential stacking of plain woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) fibers was investigated. A finite element approach was carried out in order to determine the natural frequencies of hybrid composite laminate. Analyzes were performed using the LS-DYNA® software. In the finite element analysis, the natural frequencies corresponding to the first three modes were determined separately for each fiber orientation (00,300,450). Besides the modal analysis of hybrid composite laminates formed by sequential stacking of the same fiber orientations, the natural frequencies of hybrid composite laminates formed by stacking in different fiber orientations were also examined within the scope of the study. The same boundary conditions were applied for all fiber orientations since it is essential to study with a similar degree of freedom. In addition, the effect of the mesh sensitivity used in the finite element approach on the natural frequency is also considered. it is seen that both the change of fiber orientation and the stacking of composite plates with different fiber orientations directly affect the natural frequency values for all modes.

Research progress on the dynamic compressive properties of ultra-high performance concrete under high strain rates

Ultra-high performance concrete (UHPC) has been accepted rapidly attributed to its superior mechanical performance and the split Hopkinson pressure bar (SHPB) is being widely utilized to evaluate the dynamic compressive properties of UHPC. Numerous studies have been performed on the dynamic behaviour of UHPC, however, a systematic summary and analysis on the dynamic compressive properties of UHPC tested by SHPB is still missing. The review starts by introducing the advantages, deficiencies and improvement methods of SHPB system. Dynamic compressive properties including dynamic compressive strength, peak strain, stress-strain relationship and dynamic elastic modulus are analyzed. The effects of steel fiber (content, type, orientations and hybrid), temperature condition, coarse aggregate, nanomaterials, size effect and loading rate on the dynamic characteristics of UHPC are comprehensively discussed. Dynamic increase factor, energy absorption characteristics and their models are summarized. Then, the dynamic constitutive model and the dynamic failure pattern are evaluated. Based on the analysis, prediction models of dynamic strength and energy absorption are proposed by considering the strain rate and volume of steel fiber, further, a new failure mechanism of UHPC under different strain rates is proposed. Finally, the topics requiring further study are highlighted. It is expected that this paper can provide references for prospective research on dynamic characteristics of UHPC.

Study on polyethylene-based carbon fibers obtained by sulfonation under hydrostatic pressure

Polyethylene based carbon fibers were studied using high density polyethylene(HDPE) fibers and linear low density polyethylene(LLDPE) fibers with various melt flow index. The draw ratio of the polyethylene fibers and the sulfonation mechanism were investigated under hydrostatic pressures of 1 and 5 bar in the first time. The influence of the melt flow index of polyethylene and types of polyethylene fibers on the sulfonation reaction was studied. Carbon fibers were prepared through the sulfonation of LLDPE fibers possessing side chains with a high melt flow index. The polyethylene fibers, which exhibited thermoplastic properties and plastic behavior, were cross-linked through the sulfonation process. Their thermal properties and mechanical properties changed to thermoset properties and elastic behavior. Although sulfonation was performed under a hydrostatic pressure of 5 bar, it was difficult to convert the highly oriented polyethylene fibers because of their high crystallinity, but partially oriented polyethylene fibers could be converted to carbon fibers. Therefore, the effect of fiber orientation on fiber crosslinking, which has not been reported in previous literature, has been studied in detail, and a new method of hydrostatic pressure sulfonation has been successful in thermally stabilizing polyethylene fiber. Hydrostatic sulfonation was performed using partially oriented LLDPE fibers with a melt flow index of 20 at 130 °C for 2.5 h under a hydrostatic pressure of 5 bar. The resulting fibers were carbonized under the following conditions: 1000 °C, 5 °C/min, and five minutes. Carbon fibers with a tensile strength of 2.03 GPa, a tensile modulus of 143.63 GPa, and an elongation at break of 1.42% were prepared.

Effect of fiber orientations and their weight percentage on banana fiber-based hybrid composite

In this era, composite materials made of natural fibers are gaining the attention and interest of researchers, scientists, and engineers due to their impeccable features in contrast to synthetic fibers. Composite materials can be easily modeled and produced in various dissimilar forms as per the need. In this study, four different composite samples were prepared using three distinct fibers; two natural-banana (B) and sisal (S) and one synthetic-glass (G), by varying the weight percentage of banana and sisal. For each sample, the stacking sequence of the fibers are (B-G-S-B), (S-B-G-S), (G-B-B-S), and (B-S-S-G), oriented at (900,+450,−450,900) and put through a uniform point load. So, a total of sixteen composite samples were evaluated for directional deformations, stresses, and rotations using ANSYS Mechanical APDL 15.0. The outcome obtained showed that the arrangement of fibers in the sequence sisal-banana-glass-sisal (S-B-G-S) at different orientations is superior in terms of toughness and distortion resistance in contrast to all the sixteen arrangements.

Structural Analysis of Chassis Frame Using CFRP and ANSYS Software

Abstract: Automotive chassis is an important part of an automobile. The chassis serves as a frame work for supporting the body and different parts of the automobile. The chassis frame has to withstand the stresses developed within a limit. Along with strength, an important consideration in chassis design is to have adequate bending stiffness for better handling characteristics. So, strength and stiffness are two important criteria for the design of the chassis. This work is aimed at work performed towards the static structural analysis of the automobile chassis in which study of the stresses developed and deformation of chassis frame of a truck has been done . The chassis is modelled in SolidWorks and finite element analysis has been done in ANSYS. a comparison of current conventional steel chassis structural Steel and Aluminum and CFRP chassis in terms of deflection and stresses must be made in order to select the best one. A discussion and analysis is also done which gives insight on various effects of unidirectional fiber orientations in the chassis on strength and stiffness. Keyword: ANSYS, SolidWorks, chassis, strength, stiffness, structural analysis.

Experimental and numerical study of catalytic combustion and pore-scale numerical study of mass diffusion in high porosity fibrous porous media

Pore structure has a significant effect on transport phenomena inside porous media. This effect can be considered in simulations by using suitable transport coefficients. Some correlations are reported in the literature, which can be applied for simple pore geometries. In the present study, a pore-scale simulation approach is presented to determine mass diffusion coefficient considering molecular and Knudsen diffusion in a fibrous porous medium as a complex porous geometry. The methodology is employed for species in catalytic combustion of Methane inside a fibrous porous structure. The effect of Solid Volume Fraction (SVF), fibers orientation, and diameter are discussed in different temperatures. It is found that SVF plays the dominant role in mass diffusion, specifically above 600K. Mass diffusion coefficients obtained in the present study and flow permeability, conduction and radiation heat transfer coefficients from the previous study are used to simulate methane combustion inside the fibrous structure on the macro scale. An experimental setup is developed for validation. The results indicated that the simulation could well predict the temperature distribution, also 6.4% error in estimating the Methane conversion rate was observed. Due to the low Peclet number, the concentration of CH4 and O2 decreased unexpectedly before entering the catalytic zone.

Fiber orientation effects on the non-linear vibrations for a microstructure-dependent tapered plate containing an arbitrarily located crack

Non-linear vibrations in a cracked orthotropic plate with non-uniform thickness as affected by the fiber orientation have been studied analytically. Linear variation in the plate thickness is assumed in one and two directions. The governing equation of the tapered orthotropic plate is derived using the equilibrium principle. The effect of microstructure is incorporated using the modified couple stress theory. The effect of partial crack on the plate dynamics is incorporated in the form of in-plane forces and bending moments. It has been found that vibration characteristics are affected by the taper parameters and fiber direction for a cracked orthotropic plate.

Characterizing the thermal properties of hybrid polypropylene-steel fiber reinforced concrete under heat exposure: Insights into fiber geometry and orientation distribution

In this paper, both modeling and experimental efforts are made to characterize the effects of fiber geometry and orientation on the effective thermal conductivity of hybrid polypropylene-steel fiber reinforced concrete (HFRC) when exposed to high temperatures. Based on the Mori-Tanaka scheme, a multiscale thermal conductivity model is developed for predicting the thermal conductivity of HFRC as a function of temperature, and the aspect ratio and orientation distribution of hybrid fibers are incorporated. In what follows, one-side heating tests are conducted on composite slabs reinforced with hybrid polypropylene (PP) and steel fibers, and the thermal conductivity of slabs is obtained through the back analysis of measured temperature–time curves. It is founded that the thermal conductivity of HFRC increases with the increasing geometry of PP fibers, and the predictions are in good agreement with the experimental results at high temperatures. More importantly, microstructural analysis reveals that hybrid fibers are tightly arranged due to the weak dispersion of micro fibers, suggesting the combined effects of fiber geometry and orientation distribution on thermal conductivity. The findings provide insights into the optimal design of hybrid fibers to achieve desirable thermal properties of composite structures.

Determination of flexural properties of hybrid composite using Cowper-Symonds rate-dependent material model

This study addressed to determine the flexural properties of hybrid composite laminates (HCAFRE) under the strain rate sensitivity. The hybrid composite laminate was formed as consecutive stacking of a sequence of plain woven carbon fiber reinforced epoxy (CFRE) and a plain-woven aramid fiber reinforced epoxy (AFRE) laminates. The flexural tests were carried out at four different strain rates (0.01, 0.11, 0.55, 1.1 s−1) to determine the strain rate sensitivity of the HCAFRE. Moreover, the strain rate sensitivity of CFRE and AFRE was also determined individually. The effect of different fiber orientations (0°, 45°, and 90°) on the flexural properties of the composite laminates were also investigated at the scope of this study. In numerical analysis, composite laminates (CFRE, AFRE, and HCAFRE) were constituted in LS-DYNA finite element program using the Cowper-Symonds material model (MAT 112) which includes strain rate dependency. Consequently, it was seen that the experimental and numerical results were indicated a similar tendency to each other. Therefore, it was understood that the Cowper-Symonds material model is suited for the flexural behavior model of composite laminates under different strain rates.

Understanding the impact of fiber orientation on mechanical, interlaminar shear strength, and fracture properties of jute–banana hybrid composite laminates

AbstractJute and banana fibers are biodegradable green fibers being increasingly used to replace synthetic fibers in fiber‐reinforced polymer composites. Integration of jute and banana distinct natural fibers has the potential to improve composite performance in secondary structural applications. In this study, an equal quantity of unidirectional jute and banana fibers with four different fiber orientations [(0/0)3s, (0/45)3s, (0/90)3s, and (+45/−45)3s] was embedded in phenol formaldehyde resin to make hybrid laminates using the hot press method. Tensile, flexural, impact, interlaminar shear strength (ILSS), and single‐end notch bend tests are performed in accordance with the ASTM standards to evaluate the effect of fiber orientation on natural fiber hybrid composites (NFHCs). Experimental results revealed that changing the fiber orientations [(0/0)3s] leads to a major impact on reducing the mechanical properties of NFHC laminates to the extent of 39%. Furthermore, the tensile strength, Young's modulus, impact and ILSSs, and fracture toughness were found to be 37% higher for the (0°/0°)3s composite. Additionally, tensile, flexural, and impact fractured specimens were examined by scanning electron microscopy to understand the fiber–matrix failure behavior due to inter‐ply orientation in NFHCs.

Effect of reinforcing materials on mechanical properties of composite material using Taguchi method

The mechanical properties play an important role in the selection of suitable material in the manufacturing of boats. In this paper, the effect of glass fiber orientations and the fillers weight fraction on the mechanical properties of un saturated polyester composite material were studied. The glass fibers were used with (0/0, 0/90, 45/45) angles. The carbon filler used with (2.5%, 5%, 7.5%), while the aluminium oxide nano be used with (0%, 1%, 3%) weight fraction respectively. The standard Taguchi’s array L9 (33) was used. The signal to noise ratio and analysis of variance were introduced to analyze and estimate the optimal combination parameters. The results show that the mechanical properties improved with using the reinforcements. The glass fibers orientations angle presents the most parameter effect than the other parameters on the modulus of elasticity, tensile strength and impact strength with a contribution of 81.8%, 83.39% and 96.75% respectively. Followed by carbon and aluminium oxide nano. The optimum parameter with their levels for the highest modulus of elasticity was obtained at (0/90 fiber orientation, 5% carbon and 0% nano aluminium oxide). While the highest tensile strength and impact strength present with using (0/0 fiber orientation and 5% carbon). The experimental and expected results are very close, with an error ratio not exceeding 5%.

Effect of Fibre Orientation on Novel Continuous 3D-Printed Fibre-Reinforced Composites.

Among the several additive manufacturing techniques, fused filament fabrication (FFF) is a 3D printing technique that is fast, handy, and low cost, used to produce complex-shaped parts easily and quickly. FFF adds material layer by layer, saving energy, costs, raw material costs, and waste. Nevertheless, the mechanical properties of the thermoplastic materials involved are low compared to traditional engineering materials. This paper deals with the manufacturing of composite material laminates obtained by the Markforged continuous filament fabrication (CFF) technique, using an innovative matrix infilled by carbon nanofibre (Onyx), a high-strength thermoplastic material with an excellent surface finish and high resistance to chemical agents. Three macro-categories of samples were manufactured using Onyx and continuous carbon fibre to evaluate the effect of the fibre on mechanical features of the novel composites and their influence on surface finishes. SEM (Scanning Electron Microscopy) analysis and acquisition of roughness profile by a confocal lens were conducted. Tensile and compression tests, thermogravimetric analysis and calorimetric analysis using a DSC (differential scanning calorimeter) were carried out on all specimen types to evaluate the influence of the process parameters and layup configurations on the quality and mechanical behaviour of the 3D-printed samples.

Mechanical and Water Absorption Characteristics of Jute/BasaltReinforced Laminate

To boost the output parameters, the process parameters have to be optimized; which is the aim of this project. Centered within various layers of Jute / Basalt and material orientation, the orthogonal series of various experiments are performed using the relevant Taguchi technique. The aim of these experiments is to provide a relationship between process and performance parameters to enhance the overall performance of the substance under various conditions. The effect of Basalt fibre and Jute fibre orientation during Tension and Hardness is studied in the present work. The tests are arranged according to the orthogonal array of Taguchi L9. Using ANOVA (Analysis of Variance), the experimental results are statistically analyzed to correlate the parameters and answers. It was observed from the experimental findings that orientation was perceived to be the most important element affecting the intensity of the substance proposed. By considering the optimum composition through analysis, water absorption test is performed with respect to number of days with Basalt and Jute as outer layers to study and compare the water absorption percentage of both the fibers. SEM analysis is performed to study the fiber intactness and surface morphology of the optimum sample, after every experimentation. Experimental studies have shown that hybridization of Basalt fibre jute epoxy shows greater tolerance to strength.

Effect of fiber content and fiber orientation on mechanical behavior of fused filament fabricated continuous-glass-fiber-reinforced nylon

PurposeFused filament fabrication of continuous-fiber-reinforced polymers is a promising technique to achieve customized high-performance composites. However, the off-axis tensile strength (TS) and Mode I fracture toughness of fused filament fabricated (FFFed) continuous-glass-fiber-reinforced (CGFR) nylon are unknown. The purpose of this paper is to investigate the mechanical and fracture behavior of FFFed CGFR nylon with various fiber content and off-axis fiber alignment.Design/methodology/approachTensile tests were performed on FFFed CGFR-nylon with 9.5, 18.9 and 28.4 fiber vol. %. TS was tested with fiber orientations between 0∘ and 90∘ at 15∘ intervals. Double cantilever beam tests were performed to reveal the Mode I fracture toughness of FFFed composites.FindingsTS increased with increasing fiber vol. % from 122 MPa at 9.5 vol. % to 291 MPa at 28 vol. %. FFFed nylon with a triangular infill resulted in 37 vol. % porosity and a TS of 12 MPa. Composite samples had 11–12 vol. % porosity. TS decreased by 78% from 291 MPa to 64 MPa for a change in fiber angle θ from 0∘ (parallel to the tensile stress) to 15∘. TS was between 27 and 17 MPa for 300 < θ < 900. Mode I fracture toughness of all the composites were lower than ∼332 J/m2.Practical implicationsPractical applications of FFFed continuous-fiber-reinforced (CFR) nylon should be limited to designs where tensile stresses align within 15∘ of the fiber orientation. Interlayer fracture toughness of FFFed CFR composites should be confirmed for product designs that operate under Mode I loading.Originality/valueTo the best of the authors’ knowledge, this is the first study showing the effects of fiber orientation on the mechanical behavior and effects of the fiber content on the Mode I fracture toughness of FFFed CGFR nylon.

A Fatigue Damage Model for Life Prediction of Injection-Molded Short Glass Fiber-Reinforced Thermoplastic Composites.

Short glass fiber-reinforced (SGFR) thermoplastics are used in many industries manufactured by injection molding which is the most common technique for polymeric parts production. Glass fibers are commonly used as the reinforced material with thermoplastics and injection molding. In this paper, a critical plane-based fatigue damage model is proposed for tension–tension or tension–compression fatigue life prediction of SGFR thermoplastics considering fiber orientation and mean stress effects. Temperature and frequency effects were also included by applying the proposed damage model into a general fatigue model. Model predictions are presented and discussed by comparing with the experimental data from the literature.

Uniaxial tension of Kevlar-filled EPDM rubber sheet: effect of fiber orientation and distribution

Uniaxial tension of Kevlar-filled EPDM rubber sheet: effect of fiber orientation and distribution

Predicting the effect of fiber orientations and boundary conditions on the optimal placement of PZT sensor on the composite structures

In this paper, the modal-model of the composite structure is predicted and viewed to decide the optimal position of the PZT sensors on the composite structures. The novelty of this work is to systematically study the effect of fiber orientations and boundary conditions on the modal-model and the optimal location of the PZT sensors on the composite structures. The glass fibers are reinforced in a polyester matrix at different fiber orientations such as 0°, 30°, 45°, 60° and 90°. It is used for various engineering applications, especially in the aerospace and automobile sector, and it is very important to measure its dynamical response. The PZT patches can be embedded on the composite structures to measure their vibrational response. In this paper, ABAQUS software is used to build the finite element model of the PZT-composite structure. The composite structure is modeled with different boundary conditions. It is observed that the orientation of the fibers as well as the boundary condition directly put their effect on the modal-model of the composite structure and also on the selection of the optimal position of the PZT patches. It is found that the optimal position of the PZT directly depends upon the fiber orientation.

A constitutive equation for fiber suspensions in viscoelastic media

A viscosity overshoot of fibers filled in a polymer melt under a shear flow is much tougher to predict via the existing constitutive equations of suspension rheology in a viscous media, owing to the effect of fiber orientation on the viscoelastic behavior. The WMT-X (White–Metzner model eXtended by Tseng) viscoelastic fluid model coupled with the typical Dinh–Armstrong fiber suspension model, known as the suspended WMT-X model, is proposed herein. The primary procedure involves verifying the lower viscosity of the completely aligned suspension compared to that of the randomly oriented suspension. In addition, the viscosity overshoot depends on the off-diagonal orientation tensor component in the flow-gradient plane. As a validation, the numerical predictions of transient shear viscosity are in good agreement with the related experimental data.

Electrospun meshes intrinsically promote M2 polarization of microglia under hypoxia and offer protection from hypoxia-driven cell death

In this study, we offer new insights into the contrasting effects of electrospun fiber orientation on microglial polarization under normoxia and hypoxia, and establish for the first time, the intrinsically protective roles of electrospun meshes against hypoxia-induced microglial responses. First, resting microglia were cultured under normoxia on poly(caprolactone) fibers possessing two distinctly different fiber orientations. Matrix-guided differences in cell shape/orientation and differentially expressed Rho GTPases (RhoA, Rac1, Cdc42) were well-correlated with the randomly oriented fibers inducing a pro-inflammatory phenotype and the aligned fibers sustaining a resting phenotype. Upon subsequent hypoxia induction, both sets of meshes offered protection from hypoxia-induced damage by promoting a radical phenotypic switch and beneficially altering the M2/M1 ratio to different extents. Compared to 2D hypoxic controls, meshes significantly suppressed the expression of pro-inflammatory markers (IL-6, TNF-α) and induced drastically higher expression of anti-inflammatory (IL-4, IL-10, VEGF-189) and neuroprotective (Nrf-2) markers. Consistent with this M2 polarization, the expression of Rho GTPases was significantly lower in the mesh groups under hypoxia compared to normoxic culture. Moreover, meshes—particularly with aligned fibers—promoted higher cell viability, suppressed caspase 3/8 and LC-3 expression and promoted LAMP-1 and LAMP-2 expression, which suggested the mitigation of apoptotic/autophagic cell death via a lysosomal membrane-stabilization mechanism. Notably, all protective effects under hypoxia were observed in the absence of additional soluble cues. Our results offer promise for leveraging the intrinsic therapeutic potential of electrospun meshes in degenerative diseases where microglial dysfunction, hypoxia and inflammation are implicated.