Angle-interlock Woven Research Articles

An experimental–numerical study on 3D angle-interlock woven composite under transverse impact at subzero temperatures

Three-dimensional (3D) angle-interlock woven composite may possess different impact properties at subzero temperatures compared with that at room temperatures due to its rate- and temperature-dependent resin. The purpose of this work is to investigate the impact damage behaviors of a 3D angle-interlock woven composite undergoing transverse impact tests at subzero temperatures. The experimental data and high-speed photography obtained from the tests have been compared with numerical results to explore the damage development and temperature rise. A coupled thermo-mechanical constitutive model has been developed to capture the effects of increase in temperature, strain rate sensitivity and fragmentation of the composite material. The proposed model is based on the decomposition of the compliance matrix into elastic and plastic parts. Thermo-mechanical coupling has been considered where temperature rises as a result of plastic work. The proposed model has been implemented in the explicit coupled thermo-mechanical finite element code. The numerical results were compared with transverse impact experiments at room and subzero temperatures.

Elevated temperature effect on tension fatigue behavior and failure mechanism of carbon/epoxy 3D angle-interlock woven composites

This paper reported elevated temperature effect on tension fatigue behavior and failure mechanism of carbon/epoxy 3D angle-interlock woven composites. The S-N curve shows that the composite has good fatigue properties, and the fatigue properties decrease to a certain extent at elevated temperature. The tensile fatigue limit of composite is 38% and 30% stress level at 25 °C and 100 °C, respectively. Tensile modulus-fatigue life curve shows that the composite has obvious three-stage cumulative damage development, while the high temperature increases the material’s viscoelasticity and toughness. Fracture morphologies indicate that the composite exhibits jagged inclined fracture. The main fatigue failure mechanism is matrix microcracks propagate and expand inside the material along warp and weft direction. The microcracks propagate to the fiber/matrix interface, resulting in stress concentration and debonding of the interface. And the fracture of a large number of warp fibers and fiber bundles eventually causes the composite to fail. At high temperatures, the material softens, the interface bonding strength becomes worse, leading to more serious fiber pullout and breakage, and the brittleness of the material weakens.

Elastic and fracture behavior of three-dimensional ply-to-ply angle interlock woven composites: Through-thickness, size effect, and multiaxial tests

This work presents a comprehensive investigation of the elastic and fracture behavior of ply-to-ply angle interlock three-dimensional woven composites. The research investigated novel splitting and wedge-driven out-of-plane fracture tests to shed light on the tensile fracture behavior in the thickness direction and to provide estimates of the out-of-plane tensile strength and fracture energy. In addition, size effect tests on geometrically-scaled Single Edge Notch Tension (SENT) specimens were performed to fully characterize the intra-laminar fracture energy of the material and to study the scaling of structural strength in this type of three-dimensional composites. The results confirmed that size effect in the structural strength of these materials is significant. In fact, even if the range of sizes investigated was broader than in any previous size effect study on traditional laminated composites and two-dimensional textile composites, all the experimental data fell in the transition zone between quasi-ductile and brittle behavior. This implies strong damage tolerance of the investigated three-dimensional composites. The analysis of the data via Bažant’s Type II Size Effect Law (SEL) enabled the objective characterization of the intra-laminar fracture energy of three-dimensional composites for the first time. Finally, Arcan rig tests combined with X-ray micro-computed tomography allowed unprecedented insights on the different damage mechanisms under multi-axial nominal loading conditions, particularly tension-dominated and shear-dominated conditions.

Mode-I fracture crack growth behaviors of 3-D angle interlock woven composites under low-velocity wedge-loaded impact

We report Mode-I low-velocity impact fracture behaviors of 3-D angle interlock woven carbon fiber/epoxy composites. The wedge-loaded compact tension (WLCT) specimen was used to test Mode-I fracture behaviors. The crack initiation and propagation were photographed with a high-speed camera. We found that the crack initiated from resin-rich zone and then propagated along yarn / resin interface. The crack propagation direction changed along the crimped yarn orientations. A finite element analysis (FEA) model was established to simulate internal crack propagation behaviors. The FEA results indicated that the crack propagation path depends on the weaving architecture of the 3-D woven composites.

Damage initiation and propagation mechanisms of 3-D angle-interlock woven composites under thermo-oxidative aging

The thermo-oxidative aging behavior of carbon/matrix composite material reinforced with 3D angle-interlock woven perform (3DAWC) was investigated experimentally and numerically. The aim is to explore the damage mechanism of thermo-oxidative aging through micro-CT 3-D reconstruction. We found that the interface between adjacent orthogonal yarns is favorable sites for crack onset. Cracks extend horizontally from four free outer surfaces to the interior of the sample. The propagation of the crack is continuously hindered by the undulating warp tows. Crack volume and maximum crack depth are positively correlated with aging day. Realistic finite element models of 3DAWC are constructed according to CT slices to detect the influence of yarn architecture on the sensitivity to damage mechanism. The results show that diamond-shaped weft is the stress concentration areas caused by a temperature drop and the shrinkage of the nearby resin region is more serious. The finite element model can predict the most likely location of the crack initiation.

Effect of bias yarn on tensile fracture mechanism of multiaxial 3D angle-interlock woven composites

A novel 3D woven structure was designed and developed in this paper, namely multiaxial 3D angle-interlock woven composites (MAWC). In order to determine the specific influence of bias yarns on the tensile properties and failure mechanisms, two MAWCs with different weave patterns and 3D angle-interlock woven composites (3DAWC) were fabricated. Based on the meso-structure characteristics of MAWC, a realistic meso-model was proposed. The tensile behavior of MAWCs and 3DAWC were experimentally characterized, and the full-field strain distributions were recorded by digital image correlation (DIC). Moreover, a progressive damage model along with the X-ray micro-computed tomography (Micro-CT) technique were applied to reveal the damage processes and failure mechanisms of composites. Results showed that the axial tensile strength of MAWCs decreased due to the change of yarn orientation. The stress-strain curves of two MAWCs presented nonlinear behavior, while those of 3DAWC could be seen as linear within the whole strain range. Stress concentration regions of two MAWCs were found to be distributed more dispersedly than those of 3DAWC. The local tow splitting, fiber slippage and interfacial debonding were the primary failure modes of bias yarn in MAWCs under tension.

Experimental and numerical study of in-plane shear properties and failure process of multiaxial 3D angle-interlock woven composites

A novel multiaxial 3D angle-interlock woven composites (MAWC) was developed in this paper. Two MAWCs with different weave patterns and 3D angle-interlock woven composites (3DAWC) were manufactured to identify the particular influence of bias yarns on the in-plane shear performance and failure mechanism of the composites. Based on the variable cross-sections, a realistic meso-model of MAWC was proposed. The in-plane shear tests were carried out and the digital image correlation (DIC) was used to record the full-field strain distribution of the specimens. Furthermore, a progressive damage model and X-ray micro-computed tomography (Micro-CT) were implemented to reveal the damage evolution and mechanisms of composites. Results indicated that all load–displacement curves presented nonlinear behavior, and the in-plane shear modulus and strength were significantly improved due to the bias yarns. The fiber slippage, tow splitting and interfacial debonding were the primary failure modes of bias yarns in MAWC architectures.

Fatigue behavior and failure mechanisms of 3D angle-interlock woven composite at room and cryogenic temperatures under bending

• Fatigue properties of 3D angle-interlock woven composite at room and cryogenics temperatures are obtained. • Fatigue failure mechanisms at room and cryogenics temperatures are presented. • The effect of temperature on fatigue performance and mechanisms is analyzed.

Multiscale modeling of mechanical behavior and failure mechanism of 3D angle-interlock woven aluminum composites subjected to warp/weft directional tension loading

The mechanical behavior and progressive damage mechanism of novel aluminum matrix composites reinforced with 3D angle-interlock woven carbon fibers were investigated using a multiscale modeling approach. The mechanical properties and failure of yarns were evaluated using a microscale model under different loading scenarios. On this basis, a mesoscale model was developed to analyze the tensile behavior and failure mechanism of the composites. The interfacial decohesion, matrix damage, and failure of fibers and yarns were incorporated into the microscopic and mesoscopic models. The stress–strain curves and fracture modes from simulation show good agreement with the experimental curves and fracture morphology. Local interface and matrix damage initiate first under warp directional tension. Thereafter, interfacial failure, weft yarn cracking, and matrix failure occur successively. Axial fracture of warp yarn, which displays a quasi-ductile fracture characteristic, dominates the ultimate composites failure. Under weft directional tension, interfacial failure and warp yarn rupture occur at the early and middle stages. Matrix failure and weft yarn fracture emerge simultaneously at the final stage, leading to the cata-strophic failure of composites. The weft directional strength and fracture strain are lower than the warp directional ones because of the lower weft density and the more serious brittle fracture of weft yarns.

Multi‐scale modeling of three‐dimensional angle interlock woven composite subjected to ballistic impact using FEM

The multi‐scale modeling and Finite element (FE) analysis of three‐dimensional angle interlock woven composites (3DAIWC) subjected to ballistic impact by conical‐cylindrical projectile have been studied in the present research. A multi‐scale modeling technique has been adopted in the Finite Element Analysis (FEA), which incorporates micro‐meso‐macro‐transition approach called macro‐homogeneous meso‐heterogeneous modeling technique. This macro‐meso‐micro‐transition approach has been implemented in the present research to develop the complex weave architecture of the target plate. A voxel‐based nonconformal mesh has been utilized to understand the behavior of the representative volume element (RVE) of the woven composite target plate. The model is validated by two dimensional weave architecture, which is analyzed for varying nose shapes (30° conical ‐ 180° flat). The macro‐homogeneous results provide the velocity variation and energy absorption of the projectile with respect to the time history.

3D angle-interlock woven structural wearable triboelectric nanogenerator fabricated with silicone rubber coated graphene oxide/cotton composite yarn

The fabric-based triboelectric nanogenerator (TENG) with flexibility, diverse structure and energy harvesting aroused widespread concern in recent years for various portable electronics. Herein, a 3D angle-interlock woven (3DAW) structural wearable TENG with high output performance was fabricated with silicone rubber coated graphene oxide/cotton composite yarn. Composite yarn acts the role of energy conversion and it was fabricated to specific 3D woven structure to further improve its electrical properties. The optimal single yarn with a diameter of 2 mm demonstrates open-circuit voltage of 30.8 V and short-circuit current of 1.1μA using constant loading force tapping (~10 N). The obtained 3DAW-TENG reveals the output power of 225 mW/m2 with the area of 5 cm×7 cm, which is more outstanding compared with those of 2D plain structure and 3D double-layer plain structure. The 3DAW-TENG also successfully shows the application in charging small electronics and triggering voltage sensors. It's suggested that the 3DAW-TENG can be a potential candidate for the filed of wearables and self-powered sensors.

Weft direction tension-tension fatigue responses of layer-to-layer 3D angle-interlock woven composites at room and elevated temperatures

Elevated fatigue behaviors of resin matrix composites are considerable key to the application of aeroengine that requires fatigue resistance at elevated temperature. However, undeniably, very few studies are focused on this issue, thereby resulting in limitation applications of resin matrix composites in aeroengine components, i.e. blades and case. In this work, the fatigue responses of layer-to-layer 3D angle-interlock woven composites (2.5DWC) were experimentally and numerically studied at room and elevated temperatures. Experimental results show that the weft direction fatigue lives at 20 °C and 180 °C experienced a relatively short cycle (less than 104 cycles) prior to the failure. But, once the stress level declined to a threshold value (dropped by 1–2%), the fatigue limitation would be activated, regardless of temperature. Moreover, the residual strength at 20 °C or 180 °C was reinforced compared to the static strength. Considering the fatigue data and fracture morphology, probable damage mechanisms corresponding to temperature-dependent weft direction fatigue behaviors of 2.5DWC were proposed. A temperature-dependent fatigue life prediction model of 2.5DWC was proposed, based on which the weft direction fatigue lives, damage propagation processes and residual stiffnesses of 2.5DWC at 20 °C and 180 °C were predicted.

Microstructural Damage Characteristic of a Layer-to-Layer Three-Dimensional Angle-Interlock Woven Composite Under Quasi-Static Tensile Loading

Abstract Three-dimensional angle-interlock woven composites (3DAWCs) are widely used for their excellent mechanical properties. The most significant feature is the existence of the undulated warp yarns along the thickness direction, which makes it interesting to study the mechanical properties in the warp direction. The quasi-static tensile behavior of a layer-to-layer 3DAWC along the undulated warp direction was studied by experimental and finite element analysis (FEA) methods. Based on the experimental results, the typical failure mode involving fibers, resin, and their interfaces was found. According to the FEA results, the stress concentration effect, key structural regions, and microstructural (yarn and resin) damage mechanism were obtained, which provided effective guidance for structural optimization design of the 3DAWC with stronger tensile resistance performance. In addition, the three-step progressive failure process of the 3DAWC under quasi-static tensile load was also described at the “yarn–resin” microstructural level.

Structural Damage Characteristics of a Layer-to-Layer 3-D Angle-Interlock Woven Composite Subjected to Drop-Weight Impact

Abstract The most attractive structural feature of the three-dimensional (3D) angle-interlock woven structure is that the straight weft yarns are bundled by the undulated warp yarns, which induces the overall good structural stability and a stable fabric structure. Thus the 3-D angle-interlock woven composite (3DAWC) prepared by the vacuum-assisted resin transfer molding (VARTM) curing process has excellent mechanical properties by using the fabric and epoxy resin as the reinforcement and matrix, respectively. The low-velocity impact damage properties of the composites under different drop-weight energies (70, 80, and 100 J) were tested experimentally. The load–displacement curves, energy–time curves, and the ultimate failure modes were obtained to analyze the performance of resistance to low-velocity impact, as well as the impact energy absorption effect and failure mechanism, especially the structural damage characteristics of the 3DAWC subjected to the low-velocity impact of drop weight. By analyzing the obtained experimental results, it is found that the fabric reinforcement is the primary energy absorption component and the impact energy mainly propagates along the longitudinal direction of the yarns, especially the weft yarn system, which is arranged in a straight way. In addition, as the impact energy increases, the energy absorbed and dissipated by the composite increases simultaneously. This phenomenon is manifested in the severity of deformation and damage of the material, i.e., the amount of deformation and size of the damaged area.

Influence of fabric structure on the tensile and flexural properties of three-dimensional angle-interlock woven composites

The application of three-dimensional angle-interlock woven composites (3DAC) as structure components in aerospace field creates tremendous demands for mechanical properties. A new kind of 3DAC with bidirectional fabric structure was proposed in this paper. The tensile properties of 3DAC and 3D bidirectional angle-interlock composites (3DBAC) were conducted by quasi-static tensile tests. According to three-point bending method, the flexural properties of 3DAC and 3DBAC were experimentally tested. The load–displacement curves of specimens showed that 3DBAC presented the better stability due to the higher noncrimp rate. The stress–strain curves indicated that the tensile modulus of elasticity in 3DBAC was larger than 3DAC, and the flexural modulus of 3DBAC gained an advantage over 3DAC. Based on the mesostructure of fabrics, the failure characterizations of specimens were analyzed. Results showed that the yarns in 3DBAC bear the maximum load, and the tensile fracture was regular. Through the analysis of crack morphologies, it is found that 3DBAC exhibits better flexural properties. The results supply the theoretical support for the manufacturing of structural components in the field of lightweight design.

Temperature effects on mechanical response and failure mechanism of 3D angle-interlock woven carbon/epoxy composites

Abstract This paper reveals the fabrication of 3D angle-interlock woven carbon/epoxy composites and reports the temperature effects on their mechanical behavior and failure mechanism. The results show the temperature has a significant influence on the bending properties and failure mechanism of 3D angle-interlock woven composite. The load/deflection curves are linear elasticity, while at high temperatures showing obvious nonlinear feature and long plasticity plateau. Moreover, bending properties gradually decrease with increasing the temperature, and when the temperature exceeds 150 °C, the decrement accelerates. Macro-fracture morphology and SEM fractographs show that microcrack generation and transmission on the compression surface, fiber/matrix interface debonding, and fibers breakage are the main failure mechanisms of materials at room temperature. With increasing the temperature, the materials become more softened and achieve plasticity. The fibers breakage, matrix yielding and cracking, and interface debonding become distinguished.

Mechanical properties prediction of 3D angle-interlock woven composites by finite element modeling method

A new 3D finite element model (FEM) is established based on the actual microstructure of 3D angle-interlock woven composites, considering the configuration of outer yarns, yarns cross-sectional deformation of and spatial orientation. A prediction of the meso-scale mechanical response and effective elastic properties of 3D angle-interlock woven composites have been presented to verify the validation of 3D FEM. The effects of woven parameters on the mechanical properties are investigated in detail. The results show that 3D FEM precisely simulates the spatial geometric characteristics of 3D angle-interlock woven composites. The reasonable overall stress fields and local stress distribution can be identified and well support the strength prediction. It is convenient to predict all the elastic constants of 3D angle-interlock woven composites with different parameters simultaneously using 3D FEM. The calculated results show that 3D angle-interlock woven composites have good mechanical properties and can be considered as anisotropy materials in a macro-scale. In addition, the warp yarn density, weft yarn density and fiber volume fraction are important factors affecting the mechanical properties of 3D angle-interlock woven composites.

A novel mesoscopic progressive damage model for 3D angle-interlock woven composites

In this paper, a novel mesoscopic progressive damage model is proposed to investigate the effective properties and damage mechanisms of 3D angle-interlock woven composites. The damage activation is based on the three-dimensional version of Puck criterion. Given that there may be multiple cracks in the transverse direction of the fiber yarns, a set of fracture angle-dependent damage variables are introduced to eliminate the stress abnormal phenomenon. In addition, an innovative exponential damage evolvement scheme, based on the equivalent displacement and stress, characteristic element length and fracture toughness, is proposed to govern the damage variables. Furthermore, a representative mesoscopic volume cell model, accounting for the fluctuation, distortion and actual cross-section size of fiber yarns, is constructed to represent the realistic interlaced architecture of the woven composites. The anisotropic damage model is applied to investigate the failure behavior of the 3D woven composites subjected to uniaxial tensile loading along the warp and weft directions. Some typical quasi-static tension experiments are performed to validate the accuracy of the simulations. The numerical predictions including failure strength and damage accumulation process are coincident with the corresponding experimental results.

3D angle-interlock woven fabric based on plain group P4mm symmetry

A unit composed of the intersected yarns was deduced by the symmetry operation which was described by the element of the plain point group 4 mm. The geometric of novel fabrics was discussed based on whole symmetries of plain group P4mm, which was analogous to the traditional angle-interlock woven fabrics. The elastic properties of this fabrics could be designed to be orthogonal isotropic. The analysis results indicated that the fiber volume fraction of the fabrics increased with the increment of the deformation coefficient of structural yarns by established its mathematical model. The feasible processing technology of novel angle-interlock woven was discussed and validated by experiment. Clearly different from traditional angle-interlock woven fabrics, the weft yarns were equally crooked as the warp yarn in these fabrics. The novel structural fabrics as a reinforced phase were beneficial to homogenize the in-plane properties of composites. The proposed fabrics were a basis in developing novel fiber reinforced composites. The mathematical model of the novel 3D angle-interlock composites was established based on point group matrix representation to predict elastic properties, the tensile modulus of elasticity was verified by experiments and its particularity was analyzed. The tensile properties of the novel 3D angle-interlock composites were compared with other three composites, the results shown that the novel 3D angle-interlock composites had stable modulus, high strength and good toughness.

X-ray tomography and numerical study on low-velocity impact damages of three-dimensional angle-interlock woven composites

Three-dimensional (3D) angle-interlock woven composites reinforced with carbon fibers were tested under low velocity impact with energies of 3 J, 9 J, 15 J, 30 J. Inner damages were photographed with Micro-CT (computer tomography). It is revealed that the damage mechanisms of samples with 3 J impact energy are matrix cracks and fiber tow splitting, while interfacial damage occurs when the impact energy reaches 9 J. The delamination, fiber tow crushing and fiber breakage will appear when the impact energy raises to a higher value such as 15 J or 30 J. Finite element analyses (FEA) results show that weft yarn is the main load carrier, and yarns at the bottom of the composite bear greater impact load than the top yarns. Both the damage morphology of experimental and numerical results demonstrate that resin cracks appear along the weft yarn on the top of the composite, and exhibit a divergence centered on the impact location at the back surface. Farther from the impact center, the delamination and matrix cracks propagate from the bottom surface to the top surface along the paths of weft yarns and epoxy resins. It is recommended that the high modulus weft yarns should be used to provide the high impact resistance performance.