Single Curvature Bending of Structural Stitched Textile Reinforcements Part I: Experimental Work (original) (raw)
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Literature Review on Advanced Textile Reinforcements and Preforms
AL-MUKHTAR JOURNAL OF ENGINEERING RESEARCH, 2021
This Advanced aerospace structural components and sub-assemblies are increasingly made from carbon fibre reinforcements embedded in a polymer resin matrix, often a thermosetting epoxy. Polymer matrix composites (PMCs) offer numerous advantages, foremost amongst which are their high stiffness and high strength combined with the low densities of the constituent fibre and matrix materials. As a result, PMCs enable lower fuel consumption coupled with higher payloads, providing an important economic advantage over typical metallic airframes. Manufacturing processes for advanced textile reinforcements that feature novel characteristics such as yarns oriented along the thickness, higher thicknesses that correspond to those needed for producing PMC parts from a single piece or layer of reinforcement, as well as complex shapes and near net-shape contours that correspond more or less closely to those of the PMC parts to be produced, are evolving very rapidly. Different textile solutions are being devised depending on the structural performance needed of each final PMC part, on the composite manufacturing process used for making a given PMC part, and most fundamentally on the shape of the specific part to be produced. This paper provides a review of general background literature covering the different types of 3D reinforcement textiles, along with current developments being made regarding 3D reinforcement textiles and non-crimp fabrics (NCFs).
In-plane Shear Behaviour of Novel Thick Stitched Textile Reinforcements Part I: Experimental Work
AL-MUKHTAR JOURNAL OF ENGINEERING RESEARCH, 2021
Novel thick, net-shape, drapable, high fibre volume fraction (vf) textile reinforcements used toward manufacturing aerospace polymer matrix composites (PMCs) are being developed at the University of Ottawa. The technology, referred to in this paper as University of Ottawa advanced preforming technology (uO-APT), it enables the manufacturing of flat, drapable multilayered near net-shape preforms. The in-plane shear behaviour of such novel thick reinforcement textiles was investigated to understand and define the behaviour of such thick fabric reinforcements when formed into required shapes. Wrinkling is one of the most common and critical defects that may occur during draping and forming operations performed on textile reinforcements. The behaviour of dry thick fabrics subjected to in-plane shear plays an important role, along with the bending behaviour, in the onset of wrinkles during draping and forming. Wrinkling is especially critical to single layer, thick fabrics such as uO-APT fabrics being investigated in this paper. Since the ability of biaxial stitched non-crimp reinforcement fabrics to conform to a surface featuring double curvatures depends directly on their inplane shear behaviour, that behaviour must be probed and quantified for uO-APT fabrics in order to identify their ability to deform upon draping, which is a required procedure in manufacturing processes for dry preforms used towards the production of composite parts.
IJEIT ON ENGINEERING AND INFORMATION TECHNOLOGY, 2021
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.
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The Journal of The Textile Institute, 2018
This study attempts to analyze the behavior of different types of woven composite preforms (i.e. plain, twill, and satin) under distinct loading conditions. To this end, fabric elements are modeled using discrete finite element approach. Different loading scenarios such as intra-ply shear, in-plane tension, and simultaneous intra-ply shear and in-plane tension loads are applied to the fabric elements. TexGen software is utilized to develop the geometric model of the fabric elements. Subsequently, the geometric model is exported to ABAQUS FE package and mechanistic analyses are conducted. The FE results reveal that under the same loading conditions, the in-plane tensile stress induced in plain weave elements has the minimum value compared to twill and satin elements. Having said that, the intra-ply shear resistance of the plain element is larger than the other weave types. What's more, the behavior of the fabric elements under simultaneous intra-ply shear and tension loading scenarios are studied that discloses almost the similar response for all weave types.
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Reduction of the complexity of production of articles from composite materials is largely ensured by the use of reinforcing semi-finished products in which fibers pre-form a framework. Among all the variety of reinforcing systems, woven sleeves (preforms) occupy a special place. The high degree of deformability in a nonimpregnated condition makes it possible to lay this reinforcement on any surface without folds and cuts that provide preservation of strand continuity. This advantage of woven sleeves is accompanied by a change in local reinforcement angles and, consequently, the variable nature of physical and mechanical characteristics of the curved part surface. A method for calculating physical and mechanical characteristics of the composite based on preforms at any point of the part depending on the pattern of laying strands on a curved surface has been developed. The possibility of application of the rod model of the composite to describe physical and mechanical characteristics ...
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Flexible laminates, customized for specific performance parameters, are of interest to aerospace programs such as lighter-than-air vehicles, balloon systems, decelerator systems, flexible inflatable structures and pressure vessels. The material requirements for these applications include high strength-to-weight ratio and modulus, low gas permeability, pressure retention and the capability to survive in harsh atmospheric, marine and/or stratospheric environments for extended periods of time. Non-woven multidirectional oriented composite laminates using high performance engineering fibers are produced by Cubic Tech to meet these requirements. These flexible laminates achieve a significant weight savings over woven fabrics of similar strengths by eliminating strength and modulus loss and other structural deficiencies caused by crimping of yarns during the weaving process. The absence of crimp in non-woven fabrics results in a linear elastic response that allows for ease in predicting material properties and simplification of structural models. These flexible composites afford the ability to specify structural properties, oriented to meet any design requirement. Parts can be manufactured with complex 2D and 3D geometries with integrated structures, load patches and attachment points. Structures fabricated from these laminates can be joined using standard industry seaming techniques to produce seams stronger than the base laminates. Properly designed seams hold structural loads for extended periods without failure, slip or creep.
Mechanics of Composite Materials, 2020
3D woven composites provide efficient delamination suppression, enhanced damage tolerance, superior impact, ballistic and blast performance characteristics over 2D fabric laminates. At the same time, this type of composites, having practically straight in-plane fibers, show significantly better in-plane stiffness and strength properties than respective properties of conventional composites. But, how the in-plane elastic and strength characteristics of this type of fabrics compare with respective in-plane properties of equivalent 2D woven fabrics. This paper presents a comprehensive experimental study of the comparison of in-plane tensile, bending, crimp interchange properties of UD, 2D, 3D orthogonal, 3D angle-interlock and 3D warp interlock multi-layer structures woven from E-glass tow. The results depict that the 3D woven fabrics have considerably superior mechanical properties with much lesser crimp compared to 2D fabrics.
Optimization of 3D woven preform for improved mechanical performance
Journal of Industrial Textiles, 2018
For structural design applications, through-thickness characteristics of reinforcement played a vital role, which is why 3D woven preforms are recommended for such applications. These characteristics are mainly dependent on the fiber and yarn positioning in reinforcement. Although research has been conducted for characterizing woven composites, special attention has not been made on weave pattern parameter which directly affects the mechanical performance of composites. In this research work, 3D orthogonal layer to layer and through thickness woven structures with different interlocking patterns have been thoroughly studied for their mechanical properties, thickness, air permeability and areal density. Natural fibers when used with biodegradable matrix find use in structural, as well as low to medium impact applications for automobiles. Jute yarn was used to produce four-layered 3D woven structures, as synthetic fibers will not give a biodegradable composite part. The focus of this ...