Multilayer Woven Fabrics Research Articles

The influences of ply interference on ballistic impact response and energy absorption behavior of multilayered woven fabrics

This paper presents a detailed experimental and numerical analysis aiming to investigate the ballistic impact response and energy absorption behavior of multilayered woven fabrics with different ply interference. Different levels of ply interference are provided by controlling the influencing factors such as angle-plying, stitching the constituent plies and spacing the adjacent plies. The three aforementioned designs were evaluated for their energy absorption capacity against ballistic impact with the impact velocities ranging from 300∼400 m/s. The energy absorption mechanism was studied through the combination of high-speed camera and numerical simulations in terms of fabric deformation, and evolution of energy absorption for each ply at different impact velocity. It was found that stitching the aligned systems showed the most pronounced beneficial effect on energy absorption, showing approximate 50 % ∼ 110 % increase than the quasi-isotropic system with a mismatched lay-up angle of 22.5º.This is probably because that thread stitching enables the panel to be more efficient in spreading energy to a more global extent, involving a more defined transverse deformation and a larger area of stress distribution, which is beneficial for energy absorption.

Incorporating Variable Porosity into the Determination of Effective Permeability in Interchanging Double Cloth Woven Fabrics Using Darcy's Law.

Woven fabrics are widely used for thermal protection due to their porosity, which provides thermal insulation and breathability. This research focuses on investigating the influential parameters in the thermal protective properties of layer interchanging double cloth, including the woven structure and varying yarn fineness. The properties affecting the protective properties and comfort of multilayered woven fabrics include the fabric thickness, fabric porosity, and air permeability. Darcy's law is applicable for determining the effective air permeability of woven fabrics. By understanding and controlling fabric porosity, it becomes possible to develop thermal protective clothing that combines improved comfort, cost-efficiency, and effectiveness. This study represents a novel approach for the clarification of airflow permeability behavior in complex structures of elastic multilayer woven fabrics using Darcy's law. This innovative approach expands the understanding of permeability in fabrics beyond single-layer fabrics with vertical pores or 3D fabrics used in resin injection processes.

General method to digitalize multi-layer woven structure

As an advanced composite reinforcement, multi-layer woven fabrics are widely used in industries. However, for most nonprofessional engineers and researchers, the complexity of the spatial architecture of multi-layer woven structure (MLWS) makes it difficult to understand and apply. In order to fully utilize the advantage of the designability of MLWS, a digitalization expression is used to define the design variable of MLWS by 8 parameters. This expression has wide universality and practicability, which can parametrize all kinds of MLWSs, and characterize full-scale complex preforms. Based on this expression, a general method and process for constructing novel and complex MLWS architectures are also proposed and developed. Furthermore, a method to generate the preform jacquard pattern for the electronic jacquard system is also developed to demonstrate the application in manufacturing. This digitalization expression can be considered as the key point to connect the material design and automatic manufacturing, which can improve the design technology of multi-layer woven composite material.

An experimental investigation into ballistic performance of woven fabrics with single and multiple layers

One of the challenges in improving the protective performance of flexible body armor is optimizing woven fabric, so it is critical to understand how different fabrics and fabric arrangements with the same areal density affect their ballistic resistance. An object of this article is to comparatively investigate the ballistic resistance of single-layer and multi-layer woven fabrics with the same areal density. Four single-layer fabrics with areal densities of 70, 125, 200, and 280 g/m2 were selected, and multi-layer fabrics (comprising two, three, and four layers) were assembled by folding a single-layer fabric with an areal density of 70 g/m2. Ballistic impact tests were carried out on the single-layer and multi-layer fabrics to compare their ballistic resistance. The results show that the specific energy absorption of the multi-layer fabric assembly is more than 7% higher than that of the single layer fabric; the multi-layer fabric mainly improves the ballistic resistance by increasing dynamic in-plane force, while the single-layer fabric does so by increasing the maximum transverse deflection. Moreover, from the perspective of fabric application in the flexible body armor, the energy absorption at ballistic limit of the single-layer and multi-layer fabrics was transformed into energy absorption per unit transverse displacement, and the index of the multi-layer fabric is obviously better than that of the single-layer fabric.

The Influence of Structure of Multilayer Woven Fabrics on Their Mechanical Properties

Multilayer woven fabrics used for conveyor belts must be characterized by high mechanical strength. The design process of multilayer woven fabrics for such application requires taking into account the structural characteristics of the fabric, which allows to adjust the final product properties to the dedicated use. The geometry of warp threads—means stuffer and binding is the decisive aspect, which influences the strength properties of multilayer woven fabrics and materials made with their use as well. The aim of this work was to examine the possibility of shaping mechanical strength and bending rigidity of multilayer woven fabrics by changing the order of introducing weft threads into individual layers. The eight variants of multilayer woven fabrics were manufactured using laboratory harness loom. They were produced using different structural models in two weft variants, then tested. The mechanical features were determined, such as breaking force, recovered and unrecovered elongations in cyclic tensile test, stiffness rigidity. The analysis of the obtained results confirmed, that both the model and the order in which the weft threads were introduced into individual layers influence the mechanical strength and bending rigidity of multilayer woven. It was found, that the strength properties characterized by the above mentioned indicators are influenced by the number of threads weaved as both the stuffer and binding warp.

Custom-Made Reinforcement Structures Made of Inorganic Fibers Challenges, Chances and Technical Approaches

Ceramic fibers are just as glass and basalt member of the group of inorganic fibers. Like most types of inorganic fibers ceramic fibers have a high tear resistance but a limited flexibility. [1] Ceramic fibers are characterized by their extraordinary high temperature and chemical resistance. These properties make them interesting for different high technical applications, as they occur in aerospace, chemical-and energy technology. In this field, they are applied especially as a reinforcement component in composite materials. Not only the partially high material price, but although the typical brittleness of ceramic fibers bring huge problems during the textile production chain, which limits the availability of complex textile preforms in the market. Often, a radical revision of the machine and processing concept is necessary to enable an economical production process. The Application Center for Textile Fiber Ceramics TFK at Fraunhofer-Center for High Temperature Materials and Design HTL develops and modifies textile production processes to make them suitable for the special requirements of ceramic fibers. One and multilayer woven fabrics, braids and tape structures for the winding process have already been successfully implemented. A further development complex is the intensive investigation of three-dimensional textile reinforcement structures. Regarding the high material costs, these research activities are very important. If the textile reinforcement is placed only where needed, the amount of used fiber material can be reduced significantly.

Motorized Jacquard technology for multilayer weaving damages study and reduction: Shed profile and close shed profile

Materials used for composite reinforcements usually have high mechanical performances which are linked to a very sensitive and brittle behaviour to friction. The weaving process applied to delicate yarns, like glass, carbon and some other technical yarns, generate damages which tend to reduce the performances of the final composite. Shedding may be a major weaving stage for the generation of yarn damages. Based on a specific weaving pattern, it was observed that different shedding configurations could influence yarn damages at the shedding step. The specificity of the motorized Jacquard device is used to generate different movements and geometry configurations. A particular methodology needed to be set in order to confirm these observations and bring out a clear effect of shedding parameters on yarn damages. After damages have been identified and classified, some experiments will count the damage occurrences and evolutions in time according to shedding parameters. The aim of this research is first to show a clear effect of shedding on warp damaging thanks to the quantification of damages and then to set out an optimized configuration of shedding parameters which may reduce deterioration involved in high-density multilayer woven fabrics.

Two Dimensional (2D) P-Aramid Dry Multi-Layered Woven Fabrics Deformational Behaviour for Technical Applications

In today’s scenario for the various technical applications, from composites to body armour, the material mouldability along with its mechanical property become very important. In the present study, two dimensional (2D) woven fabrics made of para-aramid high performance fibres in multi-layer dry structure were used for investigating different forming characteristics. The different layers were arranged with 0°/90° orientation for deep drawing formability test to analyse the effect of number of layers and blank-holder pressure (BHP) during the test. Specific preforming device with low speed forming process and predefined hemispherical shape of punch has been applied. Using fine photographic analysis, some important 2D multi-layer fabrics forming characteristics i.e., material drawing-in, surface shear angle etc. from the imposed deformation have been observed, measured and analysed for better understanding and co MPa rison. The result revealed that the mouldability behaviour of the multi-layered dry textile fabric preforms is directional, and closely dependent on blank-holding pressure and number of layers. This indicates both parameters should be carefully considered while material deformation to avoid the formation of wrinkling and maintain other mechanical properties on final application.

Hybrid-mesh modelling & validation of woven fabric subjected to medium velocity impact

Simulation of the ballistic impact on a woven fabric structure is known to be difficult due to their warp-weft yarn interlacing geometry, the varying cross-section of a yarn along its length, the multi-layer and direction of the fabric, and the contact between individual yarns. To account for the complex geometry and contact behaviour, fabric structures were modelled with meso‑scale (yarn level) geometrical details, which demanded a substantial amount of computational resources. In this research, a hybrid-mesh finite element modelling approach that possesses greater computational efficiency has been developed to simulate the behaviour of multi-layer woven fabrics subjected to medium velocity impact. Yarn models are developed using different mesh sizes: four, six, eight, and twelve solid elements per cross-section with one and two layer mesh arrangements. They are then used to create hybrid-mesh fabric models, in which the finest mesh yarns are placed at the impact centre, and gradually decreasing mesh densities are used towards the fabric boundaries. The FE results, including deformation, stress distribution, and wave propagation, are evaluated. The simulation indicated a significant reduction in computational resources while maintaining the necessary accuracy.

Tensile behavior of Basalt/Glass single and multilayer-woven fabrics

High strength fabrics are perfect materials for use in automotive and aerospace systems, where high performance and light weight structures are demanded. Mechanical characterization under constant loading is of great importance for these materials. The purpose of this study is to analyze the tensile properties of Basalt and Glass-woven structures at different pick density, weave design, stitch distance, and number of layers. For this purpose, single and double layerwoven fabric structures have been prepared using Basalt and Glass yarns on sample weaving loom. Their uniaxial testing has been performed to analyze their tensile curves. Analysis of variance showed the statistical significance of material, pick density, direction of applied load, weave, and stitching in strength of fabric, while the effect of stitch distance was insignificant.

A numerical and experimental study of woven fabric material under ballistic impacts

The objective of this research was to use finite element modeling and simulations to evaluate the ballistic resistance of woven fabrics and soft body armor. In the work of this paper, nonlinear finite element (FE) simulations were performed to evaluate the response of single- and multi-layer woven fabrics under ballistic impacts. A shell-element based fabric material model was first validated using perforation tests performed on a single-layer fabric under high-velocity impact by a spherical steel projectile. The validated model was then used to replicate high- and low-velocity impacts by a blunt aluminum projectile on eight-layer Kevlar targets. Results from the multi-layer simulations were shown to have good agreement with experimental data. Finally, the validated fabric model was used to simulate a full-scale ballistic test on a groin protector panel of the interceptor body armor system. The simulation results of both the single- and multi-layer impacts were shown to match well with experimental data in terms of the projectile's residual velocities. This research confirms the effectiveness of the fabric model and can be extended to a wide range of applications involving soft body armors.

Three-dimensional of crinkles effects using multilayer woven fabrics containing spandex

Three-dimensional of crinkles effects using multilayer woven fabrics containing spandex

Numerical prediction of in-plane permeability for multilayer woven fabrics with manufacture-induced deformation

A unit cell based Computational Fluid Dynamics model is presented for predicting permeability of multilayer fabric structures. In Liquid Composites Moulding processes, fabric lay-ups undergo significant manufacture-induced deformation, combining compression, shear, and inter-layer nesting. Starting from the configuration of un-deformed fabric, the deformation is simulated geometrically by accounting for self-imposed kinematic constraints of interweaving yarns. The geometrical modelling approach is implemented in the open-source software TexGen. The permeability tensor is retrieved from flow analysis in ANSYS/CFX, based on TexGen voxel models. Using only measured geometrical data for un-deformed fabrics, deformed plain weave fabric and twill weave fabric lay-ups were modelled and their permeability tensors predicted. Comparison with experimental data demonstrates the generally good accuracy of predictions derived from the proposed numerical method.

Jacquard UNIVAL 100 parameters study for high-density weaving optimization

3D structures for composites, and especially 3D woven preforms use, is growing because of high-performance fibres improvements, field diversification and applications complexity. Critical industries like the air-space industry need a perfect control of processes and products’ final properties. Among other 3D weaving techniques, multilayer weaving is interesting for the diversity and complexity of possible 3D structures. A new Jacquard shedding technology called UNIVAL 100 which can be used with multilayer weaving, has appeared few years ago and uses actuators instead of the traditional Jacquard hooks. It is synonym of great improvements, as such a technology should enable controlling perfectly the way yarns are moving during shedding. The aim of this paper is first to describe their operating mode. It is our basis for a design of experiments development, the purpose of which is to experimentally determine the effects of UNIVAL parameters on process quality, in the case of high-density multilayer woven fabrics (which we will further call HDMW fabrics).

Theory of multilayer woven structures

Multilayer woven fabrics are conventionally represented with the usual weave notation of black and white squares. This notation is based on the top view of the woven fabric. Side view of multilayer woven fabrics contains more important information, namely the routes of warp yarns between layers of weft yarns. In this study, possibilities of woven structures with any numbers of layers and corresponding warp and weft yarns are described. Formulas are derived to describe horizontal, vertical, and diagonal symmetries which lead to identify the fully independent structures. The results serve as the theoretical ground to determine all the possible mechanical properties by using woven reinforcements.

Soft Body Armor for Law Enforcement Applications

This paper focuses on the development of a novel ballistic protection composite which can provide both cut resistance and impact protection. The ballistic shield is made by sandwiching high strength, impact resistant, multi-layered woven fabrics between a leather strike face layer and a needlepunched fabric layer that offers protection upto Level IIIA and cut resistance. The needlepunched fabric when punched into the ballistic layer(s) pushes the fibers in the Z direction providing enhanced structural coherence and strength. Three different high performance fibers (Kevlar®, Spectra® and Twaron®) were used to make the composite. Ballistic tests were performed using V50 ballistic requirement based on NIJ standard. The availability of leather layer reduces the velocity of the impact and aides with the blunting of the bullet. A new phenomenon, “mushrooming” of the bullet has been observed. Results on the ballistic protection capabilities of different strike and impact resistant composite chest shields are presented in this paper.

Development of multilayered woven panels with integrated stiffeners in the transverse and longitudinal directions for thermoplastic lightweight applications

Weaving technique offers a large potential for the highly productive manufacture of woven 3D-preform structures in lightweight applications. This research work reports on the technological modification to the construction of a double-rapier weaving machine for the low damage production of double-walled shell structures made from glass/polypropylene hybrid yarn multilayered woven fabrics. On this basis, 3D-woven preform structures with integrated stiffeners in the longitudinal and transverse directions for high composite strength and rigidity within a single weaving process were developed and implemented. Furthermore, textile engineering solutions were acquired for the required reinforcement of the gusset area between the stiffener and the skin. This broadens the range of uses for large-scale fiber-reinforced plastics with integrated stiffeners made from 3D-woven preform structures.

An analytical model for ballistic impact on textile based body armour

Polymer fibres with high tenacity and modulus such as Kevlar® are widely used in personal protection applications. Normally these fibres are manufactured into different fabric structures before being assembled layer by layer to form personal protection panels. This paper reports on an analytical model of ballistic impact of multi-layer woven fabrics developed based on the momentum theory and analytical models of single-yarn ballistic impact proposed by previous researchers. This model incorporates the effect of various intrinsic parameters such as yarn linear density and fabric thread density and the effect of various extrinsic parameters such as the projectile dimension and mass. The model also takes into account the phenomenon of strain gradient among the panel layers and its effects on the tensile strain at the edge of the projectile and the angle between the impact line and the yarn axis. In addition, possible shear failure is also considered by using shear strength together with maximum tensile strain as the failure criteria. It has been found that the results from the analytical modelling agree closely with the experimental results. Further, the analytical modelling also reveals that the model is useful in describing the strain distribution history in the primary yarns in each layer of fabric in the panel. It has been concluded here and in other published work that during the ballistic impact of multi-layer woven fabrics shear failure occurs before tensile failure for the front layers which prevents the high strength polymer fibres reaching their full energy absorption potential.

Mechanical characterization of hybrid yarn thermoplastic composites from multi-layer woven fabrics with function integration

Three dimensional (3D) spacer fabrics are constructed from two dimensional (2D) woven fabrics connected by 2D woven crosslink fabrics using thermoplastic high performance hybrid yarns. Spacer fabrics present great potential in the efficient production of fiber reinforced plastic composites with adjustable mechanical properties targeted for specific applications in Lightweight engineering. The structure of the weave and the stresses placed on the fibers during the weaving process impact the mechanical properties of the finished composite. This study shows that the mechanical properties can be significantly controlled and adjusted by pattern development of the individual 2D composite structures from the 3D spacer fabric preforms constructed of orthogonal multi-layer weaves (non-crimped fiber arrangement and a gentle weaving process). Electrically conductive fibers are woven directly into various layers of the 2D woven fabrics and are therefore successfully integrated during production. This forms the basis for function integration in the composite. The weaving technology ensures a reliable contact of the conductive fibers allowing sensor networks to be integrated into the fabric for online monitoring of the fiber reinforced plastic composite component.

A DUAL-PERMEABILITY NETWORK MODEL FOR MULTILAYER WOVEN FABRICS

An analytical permeability model is formulated for multilayer plain woven fabrics based on a network treatment. Both meso-scale flow between fibre tows and micro-scale flow within tows are taken into account, addressing the effects of meso-/micro-structures of fabrics. For a single layer fabric, open channels between adjacent fibre tows and between fibre tows and surface boundaries have a significant effect on in-plane permeability, while out-of-plane permeability is sensitive to open gaps between tows. It is shown that the permeability of multilayer woven fabrics may differ significantly from that of a single layer, depending on the meso-/micro-structures of multilayer fabrics. Two major mechanisms are found to affect the in-plane permeability of multilayer fabrics in opposite ways. As the number of layers increases, the large inter-layer open channels created after laying-up result in an increase in in-plane permeability; on the other hand, reduction of inter-layer open channels due to nesting during a compaction process leads to a decrease in in-plane permeability. In addition, reduction of trans-layer open channels due to inter-layer blocking associated with shifting also greatly reduces the out-of-plane permeability of multilayer fabrics. Predictions from the permeability model offer satisfactory agreement with the experimental data and the predictions based on finite element analysis.