Yarn Orientation Research Articles

The comparative analysis of energy dissipation behaviour of woven and UD para-aramid fabrics

This research examines how impact energy spreads across para-aramid fabrics, comparing woven and unidirectional types, using 2-D Thin Plate Spline analysis. The experiment involved dropping a weighted hemisphere onto fabric samples and measuring their deformation across different layer counts. To assess how yarn orientation affects energy dispersion, panels with 0º/90º and 0º/90º/±45º configurations were tested. By analysing the fabric's shape changes under impact, the study revealed patterns of energy propagation. Calculations of bending energy and expansion factors provided insights into this behaviour. The findings indicate that unidirectional fabrics outperform woven structures in distributing impact energy across their surface. Moreover, incorporating ±45º fibre reinforcements in both fabric types enhances energy dispersion and mitigates impact effects.

Structure Design on Thermoplastic Composites Considering Forming Effects.

Carbon fiber reinforced polypropylene (CF/PP) thermoplastics integrate the superior formability of fabrics with the recoverable characteristics of polypropylene, making them a pivotal solution for achieving lightweight designs in new energy vehicles. However, the prevailing methodologies for designing the structural performance of CF/PP vehicular components often omit the constraints imposed by the manufacturing process, thereby compromising product quality and reliability. This research presents a novel approach for developing a stamping-bending coupled finite element model (FEM) utilizing ABAQUS/Explicit. Initially, the hot stamping simulation is implemented, followed by the transmission of stamping information, including fiber yarn orientation and fiber yarn angle, to the follow-up step for updating the material properties of the cured specimen. Then, the structural performance analysis is conducted, accounting for the stamping effects. Furthermore, the parametric study reveals that the shape and length of the blank holding ring exerted minimal influence on the maximum fiber angle characteristic. However, it is noted that the energy absorption and crushing force efficiency metrics of the CF/PP specimens can be enhanced by increasing the length of the blank holding ring. Finally, a discrete optimization design is implemented to enhance the bending performance of the CF/PP specimen, accounting for the constraint of the maximum shear angle resulting from the stamping process. The optimized design resulted in a mass reduction of 14.3% and an improvement in specific energy absorption (SEA) by 17.5% compared to the baseline sample.

Damage and fracture studies of continuous flax fiber-reinforced composites 3D printed by in-nozzle impregnation additive manufacturing

Additive manufacturing (AM) of continuous yarn-reinforced biobased composites presents multi-functional properties and low environmental impact of this technology. Few studies focused on the mechanical damage mechanisms of continuous biobased composites obtained by AM processes, while it is a topic of high interest for the mastery of mechanical behaviors and optimization of the materials for high requirement applications. This study aims to assess the damage and fracture modes of continuous flax yarn-reinforced PLA manufactured by AM, with different yarn orientations. The additively manufactured biobased composites were characterized by tensile test, 3D microscopy and micro-tomography to link the process-structure-properties relationships regarding the damage and fracture modes. The results showed that the 0° manufactured composite had a significant enhancement of tensile properties compared to other configurations. The damage mechanism presented fiber rupture with polymer transverse cracks at 0°, while the 45° and 90°-oriented composites showed premature fiber/matrix interface debonding. This study aims to find the relationship between damage mechanisms, deposition strategy, and anisotropy of the additively manufactured long vegetal fibers-reinforced biobased composite materials. The results bring a new understanding of the anisotropy and defects in printed composite materials regarding their mechanical behaviors during damage.

Effect of fiber orientation on the mechanical properties of a biodegradable composite made from lyocell‐fiber reinforced polybutylene adipate terephthalate

AbstractPolymer waste in the environment is a more and more serious problem for nature. Therefore, the industry is increasingly interested in the use of materials that are biodegradable. Polybutylene adipate terephthalate (PBAT) belongs to the group of biodegradable polymers, but this polymer often does not have the desired properties for many uses. Therefore, this polymer is often mixed with other biodegradable polymers to form blends with suitable properties. An alternative is, to change the polymer's properties with the addition of fibers. The aim of the present work is to use lyocell fibers to improve the mechanical properties of PBAT. Lyocell is an eco‐friendly cellulose fiber that is biodegradable. The lyocell fibers were embedded into a PBAT matrix in the form of a woven fabric, with different orientations of the fabric warp yarns to the long axis of composites. Consequently, composites with a warp yarn orientation of 0°, ±22.5°, ±45°, ±67.5°, and 90° were prepared. The mechanical properties were characterized by quasi‐static tensile testing and also by dynamic mechanical analysis. The elastic modulus as a function of warp yarn orientation was modeled with the modified rule‐of‐mixture theory and with the theory of elasticity.

Numerical analysis of L-shaped wrinkling behavior of 3D woven preforms based on a novel hybrid element yarn model

Numerical simulation is a key means to evaluate the forming performance of 3D woven preforms (3DWPs). However, the macroscopic continuous model of 3DWPs cannot predict the orientation and deformation of yarns, while the microscopic discrete model is unsuitable for large-size samples forming simulation due to computational constraints. A novel mesoscopic hybrid element yarn model is thus proposed to establish a large-size 3D woven virtual yarn preform (VYP) model and the L-shaped virtual forming simulation model. The L-shaped forming experiment of the 3DWP is designed and executed, and the accuracy of the numerical simulation models is verified from three aspects: the mechanical curve, the sample's macroscopic morphology, and the local meso-structure features. Subsequently, the deformation behavior of the yarn structure inside the 3DWP during the L-shaped forming process is analyzed by combining experimental and simulation results. Furthermore, the effects of the L-shaped angle and chamfer radius on the deformation behavior of the 3DWP are studied, which helps guide the structural design of 3DWPs.

Single Curvature Bending Results of Structural Stitched Textile Reinforcements Part II: Quantitative Analysis Using Taguchi Method

A Novel non-crimp dry thick fabric was manufactured at the University of Ottawa advanced preforming technology (uOttawa fabric) to cover the growing need for such thick preforms in the aerospace applications. The bending behavior was investigated using significant numbers of tests performed with a new bending apparatus designed and manufactured at University of Ottawa.This research paper was aimed to analyze the bending results obtained for samples made from the new uOttawa fabric and samples made from an industrial fabric using a statistical method celled Taguchi method. The Taguchi analysis highlights the most parameters having the stronger effects on testing. The main parameters investigated in bending were the type of fabric, the thickness, yarn orientations, fibre volume fraction and bending cycles. Two plans were used to investigate which parameters have strong effect on bending moment. The Taguchi analysis revealed that the type of fabric, number of cycles and fibre volume fraction have the largest effect on bending behavior of these fabrics.

Simulation of failure behavior of 2.5D SiC/SiC variable thickness dovetail joint structures based on mesoscale model

The application of ceramic matrix composites plays an important role in improving the performance of aero engines. However, mesoscopic aperiodicity causes excellent challenges for the performance analysis of ceramic matrix composite structures. It is no longer applicable to obtain the macroscopic properties of materials through experiments or RVE simulations for structural performance analysis. Here an attempt is made to develop a performance analysis method for mesoscopic aperiodic ceramic matrix composite structures based on mesoscale models and apply the method to the strength calculation of 2.5D SiC/SiC variable thickness dovetail joint structures. The established model reasonably approximates and accurately describes the structure’s real yarn geometries and orientations, reflecting the differences of yarn architectures in different regions. The yarn stress–strain curve is obtained through experiments, and the yarn constitutive model is established. The failure behavior of the 2.5D woven dovetail joint structure is simulated using the progressive damage analysis method and taking the yarn as the basic load-bearing unit. The simulated results are in good agreement with the experimental data in terms of failure load, load–displacement responses, macroscopic damage evolutions, and failure modes.

Impact of Fiber Characteristics on the Interfacial Interaction of Mammalian Cells and Bacteria

An imperative requisite of tissue-engineered scaffolds is to promote host cell regeneration and concomitantly thwart microbial growth. Antibacterial agents are often added to prevent implant-related infections, which, however, aggravates the risk of bacterial resistance. For the first time, we report a fiber-based platform that selectively promotes the growth of mammalian cells and alleviates bacteria by varying fiber size, orientation, and material of polymeric yarns. The interactions of Gram-positive and -negative bacterial species with mammalian mesenchymal stem cells (MSC) were investigated on poly-€-caprolactone (PCL) yarns, polyethylene terephthalate (PET), poly-L-lactic acid (PLLA), and cotton. Various yarn configurations were studied by altering the fiber diameter (from nano- to microscale) and fiber orientations (aligned, twisted, and random) of PCL yarns. PCL nanofibrous yarn decreased the adhesion of S. aureus and E. coli, with a 2.7-fold and 1.5-fold reduction, respectively, compared to PCL microfibrous yarn. Among different fiber orientations, nanoaligned fibers resulted in an 8-fold and 30-fold reduction of S. aureus and E. coli adhesion compared to random fibers. Moreover, aligned orientation was superior in retarding the S. aureus adhesion by 14-fold compared to nanotwisted fibers. Our data demonstrate that polymeric yarns comprising fibers with nanoscale features and aligned orientation promote mammalian cell adhesion and spreading and concomitantly mitigate bacterial interaction. Moreover, we unveil the wicking of cells through polymeric yarns, facilitating early cell adhesion in fibrous scaffolds. Overall, this study provides insight to engineer scaffolds that couple superior interaction of mammalian cells with high-strength fibrous yarns for regenerative applications devoid of antibacterial agents or other surface modification strategies.

Multi-scale damage modeling and out-of-plane shear behavior of carbon/carbon honeycomb structure

In response to the demand for the ultra-high stability and light-weight optical structure in high-resolution spacecraft, the present study proposes a novel carbon/carbon (C/C) honeycomb structure which integrates the superiorities of C/C composite and honeycomb structure. The C/C honeycomb was fabricated by chemical vapor infiltration (CVI) processing with continuous carbon fiber preform, and then the L- and W-direction shear experiments were conducted. A multi-scale damage model is established to describe the mechanical and damage behavior of the C/C honeycomb, which includes the damage model and constitutive model in both meso-scale and macro-scale. The effects of yarn orientation, side length, wall thickness and height of C/C honeycomb on L- and W-direction shear characteristics as well as damage modes of the novel C/C honeycomb are comprehensively researched. The results show that the C/C honeycomb has excellent shear properties when the yarn orientation is ±45° as well as the side length and wall thickness are about l=6mm and t=0.3mm, respectively. With the yarn orientation shifts from 0°/90° to ±45°, the damage region transforms from top and bottom surfaces of the C/C honeycomb structure to honeycomb walls. As the side length increases and the wall thickness decreases, the damage region is distributed obliquely along the honeycomb wall. This research contributes to the design and optimization of optical-mechanical structures in high-resolution spacecraft.

Detect and visualize non-uniform yarn orientations on preformed CFRP parts using automatic scanning and image processing

This article presents a methodology to measure and visualize the 3D yarn orientation distribution on the surface of preformed carbon fiber reinforced polymer (CFRP) parts. An image acquisition system composing of a camera and a 6-axis robot was established to scan and capture images of a series sampling points on surface of the CFRP part. The acquired images were analyzed by an image processing algorithm based on Canny edge detector, Sobel operator and histogram analysis, to quickly determine yarn orientations at each sampling point. This method was proved to achieve <4.43° and 12.80° of average error in yarn angle and yarn orientation measurement, respectively. The measured yarn orientations and angles were visualized as color-coded maps to display the 3D yarn orientation and angle distribution on the preformed part. 2D interpolation was added to smoothen the color-coded map and accurately approximate yarn orientations and angles outside the sampling points. Compared to the existing yarn orientation/angle measurement methods based on image processing, the presented methods had following advantages: (1) successful detection on both preforms and cured parts with stable accuracy; (2) high measurement speed; (3) accurate images acquisition on severely curved surfaces; (4) economical measurement cost without requirement for customized sensors.

A 3D Anisotropic Thermomechanical Model for Thermally Induced Woven-Fabric-Reinforced Shape Memory Polymer Composites.

Soft robotic grippers offer great advantages over traditional rigid grippers with respect to grabbing objects with irregular or fragile shapes. Shape memory polymer composites are widely used as actuators and holding elements in soft robotic grippers owing to their finite strain, high specific strength, and high driving force. In this paper, a general 3D anisotropic thermomechanical model for woven fabric-reinforced shape memory polymer composites (SMPCs) is proposed based on Helmholtz free energy decomposition and the second law of thermodynamics. Furthermore, the rule of mixtures is modified to describe the stress distribution in the SMPCs, and stress concentration factors are introduced to account for the shearing interaction between the fabric and matrix and warp yarns and weft yarns. The developed model is implemented with a user material subroutine (UMAT) to simulate the shape memory behaivors of SMPCs. The good consistency between the simulation results and experimental validated the proposed model. Furthermore, a numerical investigation of the effects of yarn orientation on the shape memory behavior of the SMPC soft gripper was also performed.

3D Textiles Based on Warp Knitted Fabrics: A Review.

Fibre-reinforced composites (FRCs) are already well established in several industrial sectors such as aerospace, automotive, plant engineering, shipbuilding and construction. The technical advantages of FRCs over metallic materials are well researched and proven. The key factors for an even wider industrial application of FRCs are the maximisation of resource and cost efficiency in the production and processing of the textile reinforcement materials. Due to its technology, warp knitting is the most productive and therefore cost-effective textile manufacturing process. In order to produce resource-efficient textile structures with these technologies, a high degree of prefabrication is required. This reduces costs by reducing the number of ply stacks, and by reducing the number of extra operations through final path and geometric yarn orientation of the preforms. It also reduces waste in post-processing. Furthermore, a high degree of prefabrication through functionalisation offers the potential to extend the application range of textile structures as purely mechanical reinforcements by integrating additional functions. So far, there is a gap in terms of an overview of the current state-of-the-art of relevant textile processes and products, which this work aims to fill. The focus of this work is therefore to provide an overview of warp knitted 3D structures.

Studying the geometrical models of tubular braided composite using micro computed tomography and particle swarm optimization

This paper compares the geometrical model of a 2DTBC with its actual model generated by the Micro-Computed Tomography (μCT) method. First, the geometrical models' equations are edited to simulate the manufacturing process more accurately, and the equations are incorporated into the TBC-Gen program. Then, a μ CT scan is done on a cured carbon fiber TBC, and 2D and 3D models are created. Next, two yarns of the scanned models are extracted and modelled. The segmented yarns are analyzed, and their geometrical data, including cross-section area, major and minor yarn diameters, orientation, mandrel diameter, portion angle and centre points, are extracted. Next, a yarn path simulating the scanned yarn is generated using the TBC-Gen and the extracted parameters. Then, the generated geometrical model is compared with the μCT model. To do that, a parameter named portion angle is introduced to help the geometrical model better fit the μCT model. Finally, Particle Swarm Optimization (PSO) is used to optimize the portion angle. The result of the fitting algorithm shows the accuracy of the geometrical model (less than 1% error) to simulate actual TBC. Understanding the amount of error between a geometrical model and the actual model will help to evaluate the application of geometrical models more thoroughly. Also, the more accurate geometrical model will contribute less error to the FEM simulation. The quantitative comparison between these two models can give a clear understanding of the amount of error existing in the geometrical model compared to an accurate model generated by μCT.

Mechanical and Thermal Properties of Wood-Fiber-Based All-Cellulose Composites and Cellulose-Polypropylene Biocomposites.

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova-Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH-urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova-Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340-474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

Damage behavior and removal mechanism of different yarn orientations 2.5D SiCf/SiC composites under single-abrasive scratch test

This study aims to comprehensively investigate the effects of yarn orientation and grinding depth on the damage behavior and removal mechanism of 2.5D SiCf/SiC composites via single-abrasive scratch tests. Results show that brittle matrix damage and fiber fracture are the primary removal modes of the composites. As the scratching depth increases, the fiber fracture removal modes of warp yarns are cutting fracture, cutting and shear fracture, and shear fracture, whereas those of weft yarns are cutting fracture, shear fracture, and bending fracture. The matrix is primarily removed via cracking, damage, and peeling. The resulting debris is composed of fiber segments, fiber microsegments, interface fragments, matrix fragments, and microdebris. The scratching force and cross-sectional area gradually increase with increasing scratching depth; however, the specific scratching energy decrease. This study clarifies the damage behavior and removal mechanism of 2.5D SiCf/SiC composites and provides meaningful guidance for improving processing quality.

Multi-scale and multi-step modeling of thermal conductivities of 3D braided composites

To accurately predict the Effective Thermal Conductivities (ETCs) of Three-Dimensional (3D) braided composites, this work proposes a multi-scale and multi-step Mean-Field Homogenization (MFH) method. The composites are considered as the composites with 3D multi-directional braiding yarns as inclusions at the meso-scale, and the braiding yarns are viewed as unidirectional fibers reinforced composites at the micro-scale. The ETCs of the braiding yarns are firstly determined using the MFH method at the micro-scale. According to the yarn orientation, the composites are virtually decomposed into several pseudo-grains, each of which consists of the oriented braiding yarns and matrix, and the multi-step MFH method is then developed to predict the ETCs of the pseudo-grains and the composites sequentially at the meso-scale, i.e. the MFH prediction of the ETCs of each pseudo-grain individually and the composites consisting of all the pseudo-grains in two sequential steps. The proposed multi-scale and multi-step MFH method is validated by comparing with the multi-scale FE homogenization method and the available experimental test. The modeling results show that the through-thickness and in-plane ETCs of the composites increase with the increase of fiber volume fraction and transverse ETC, and decrease and increase with the increase of interior braiding angle, respectively. The proposed multi-scale and multi-step MFH method possesses the advantages of better computational efficiency and simpler implementation compared with the multi-scale FE homogenization method.

Numerical investigation on central tearing behaviors and propagation mechanisms of coated warp-knitted fabrics

To reveal the central tearing behaviors and propagation mechanisms of the architectural non-crimp fabric (NCF) composites with an initial crack, a microscopic finite element (FE) model was proposed and developed to simulate the tearing propagation process of materials in this paper. Firstly, the experimental program including the central crack tearing test of NCF composites and uniaxial tensile test of yarns was performed for gaining the material parameters. Secondly, a finite element (FE) model was developed and validated from the good agreement between numerical and experimental results. Furthermore, tearing damage mechanisms and failure performances of the NCF composites with an initial central crack were simulated and analyzed. Finally, the effects of initial crack length, yarn orientation, and arch curvature of weft yarn on mechanical properties were investigated in depth. The analysis and comparison results indicate that the NCF composite shows the unneglectable orthotropic characteristics, in which the initial crack length, yarn orientation, and arch curvature of weft yarn have the significant effects on the mechanical properties. This paper thus provides an adequately feasible and accurate FE model for the numerical simulation on the central tearing propagation behaviors of the NCF composites with an initial crack.

Binocular Vision-Based Yarn Orientation Measurement of Biaxial Weft-Knitted Composites.

The mechanical properties of fiber-reinforced composites are highly dependent on the local fiber orientation. In this study, a low-cost yarn orientation reconstruction approach for the composite components’ surface was built, utilizing binocular structured light detection technology to accomplish the effective fiber orientation detection of composite surfaces. It enables the quick acquisition of samples of the revolving body shape without blind spots with an electric turntable. Four collecting operations may completely cover the sample surface, the trajectory recognition coverage rate reached 80%, and the manual verification of the yarn space deviation showed good agreement with the automated technique. The results demonstrated that the developed system based on the proposed method can achieve the automatic recognition of yarn paths of views with different angles, which mostly satisfied quality control criteria in actual manufacturing processes.

Investigation the influence of spacer yarns orientation angle on the thermal behavior of 3D textile reinforced concrete (TRC)

Thermal behavior such as heat transfer is an important parameter for construction composites. Three-dimensional textile reinforced concrete (TRC) is one of the construction composites which is recently being used in the building industry. Therefore, in this study, the thermal behavior of three different TRC samples was investigated by a heat transfer test using an infrared method. The cementitious matrix was reinforced by 3D fabric with three different spacer yarn orientation angles. The cementitious matrix was fabricated by cement and waste stone powder. The TRC sample was put on the hot plate of the heat transfer apparatus and the temperature variations of the top surface of the sample were obtained. According to the test results, increasing the orientation angle of spacer yarns leads to a decrease in the thermal conductivity of the TRC sample and reduces heat transfer. On the other hand, a theoretical model was used to calculate the thermal conductivity and resistance coefficients of sandwich samples. Furthermore, a 3D finite element model was used to predict the heat transfer of TRC specimens. A unit cell of the TRC model was created in Abaqus software and finite element (FE) analysis was carried on a created model. Thermal conductivity and thermal resistance of samples according to FE results were calculated and compared with experimental results. FE results showed good agreement with the experimental data.

An integrated preforming-performance model for high-fidelity performance analysis of cured woven composite part with non-orthogonal yarn angles

Preforming process would change yarn angle and yarn orientation, its influence on the material properties and material orientations needs to be considered in the performance analysis. However, most current performance models fail to account for the preforming effect. An integrated performance model accounting for the impact of preforming has been developed. In this integrated model, part geometry, yarn angle and orientation after preforming of multiple prepreg layers are predicted by Finite Element Analysis (FEA) using a non-orthogonal constitutive law. Experiments were conducted to validate the preforming simulation for a single dome composites structure made by two prepreg layers with different initial fiber orientations. Performance analysis until failure was then conducted for the single dome structure to validate the integrated performance model. Comparison between simulation and experiment shows that not only the failure mode and failure zone, but also the force-displacement curve during compression process are captured correctly by the performance model, demonstrating the effectiveness of the newly proposed model in accounting for the impact of preforming process.