In-plane and through-thickness properties, failure modes, damage and delamination in 3D woven carbon fibre composites subjected to impact loading (original) (raw)
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Incremental Damage Development in a 3D Woven Carbon Fibre Composite
Polymers and Polymer Composites, 2007
Interest in 3D woven carbon fibre composites has increased within industries such as aerospace, automotive and marine, due to their high strength to weight ratio, their increased tailorability and their capacity to be manufactured into near net shape preforms, thereby reducing parts count, assembly time, labour intensity and costs. It is vital that critical areas of concern such as damage (and in particular damage initiation and development) are studied and understood, thereby reducing the limiting factors to their acceptance. The damage initiation and subsequent intervals of development for ILSS (Interlaminar Shear Strength) were determined experimentally. Particular focus is paid to the significance of binder edge and binder middle testing and the influence of through-the-thickness (T-T-T) reinforcement in relation to damage types and development. Control samples for binder edge and binder middle loading locations were tested to failure as a means of determining an average point o...
Internal strain measurement and impact response of 3D woven carbon fibre composites
Extrinsic Fabry Perot Interferometer (EFPI) fibre optic sensors have been utilised to measure the internal matrix strain in a three dimensionally woven carbon fibre reinforced polymer composite. EFPI sensors were embedded at two levels within a four layer 3D woven composite, and comparison surface measurements were provided through resistive strain gauging and biaxial extensometry. A variation in tensile modulus of as much as 24% was found from internal measurement compared with the material surface. Through correlation with micro-graphical analysis, a link between the variations in mechanical performance and localised variations in fibre volume fraction could be established. Furthermore, the impact performance was measured.
Numerical predictions of damage initiation in 3D woven composites under various loading conditions
The strength of three-dimensional woven composites is determined by their reinforcement configuration and the strength of their constituents. In the present work, we consider several criteria to predict initiation of damage in matrix of carbon/epoxy composites subjected to uniform temperature drop and uniaxial tension. The matrix is modeled as the isotropic material with temperature dependence of elastic properties and thermal expansion coefficient. The dilatational strain energy density, the parabolic stress and the Drucker-Prager yield criteria are implemented as a custom subroutine in commercial finite element software package MSC Marc/Mentat. The predicted damage locations are compared with the computed microtomography observations.
Assessment of the mechanical properties of a new 3D woven fibre composite material
Composites Science and Technology, 2009
Fully interlaced 3D fabric is produced by a new weaving technology, and it is here utilised to produce woven carbon fibre preforms, which are then used as reinforcement in composite materials. The purpose of this study is to assess the mechanical performance of this new type of composite material. A prototype loom was used to weave preforms with a rectangular cross section where all warp and weft yarns were fully interlaced in plain weave. Tensile, compressive, out-of-plane, shear and flexural properties of the composite flat-beam specimens were tested. The in-plane stiffness and strength were found to be lower, while the out-of-plane properties were higher compared to conventional 2D laminates. In terms of strength, it was not possible to quantify the difference, since the specimens with 3D woven material exhibited other failure modes than those tested for.
Evaluation of damage initiation models for 3D-woven fibre composites
2019
Three dimensional (3D) fibre-reinforced composites have shown weight efficient strength and stiffness characteristics as well as promising energy absorption capabilities. In the considered class of 3D-reinforcement, vertical and horizontal weft yarns interlace warp yarns. The through-thickness reinforcements suppress delamination and allow for stable and progressive damage growth in a quasi-ductile manner. With the ultimate goal of developing a homogenised computational model to predict how the material will deform and eventually fail under loading, this work proposes candidates for failure initiation criteria. The criteria are evaluated numerically for tensile, compressive and shear tests. The extension of the LaRC05 stress based failure criteria to this class of 3D-woven composites is one possibility. This however, presents a number of challenges which are discussed. These challenges are related to the relative high stiffness in all directions, which produce excessively high shear...
Influence of Textile Architecture on the Mechanical Properties of 3D Woven Carbon Composites
Influence of Textile Architecture on the Mechanical Properties of 3D Woven Carbon Composites, 2019
The application of 3D woven composites in advanced structural components is limited by a lack of understanding of the influence of weaving parameters on the final architecture and mechanical properties of composites. This paper investigates the effect of fundamental and easily adjustable weave parameters (pick density and float length) on the mechanical properties (tension, compression and flexure) in 3D woven warp interlock layer-to-layer carbon/epoxy composite structures. The purpose of this paper is to establish a link between the textile and composite performance within this 3D weave architecture. The 3D fabrics, manufactured using a Jacquard loom, are fabricated in three different pick densities: 4, 10 & 16 wefts/cm, with a constant end density of 12 warps/cm from T700S-50C-12k carbon fibre. The pick density with the best mechanical properties is then used for the float length change iteration. The aim is to keep end and pick densities constant in the two float length variation specimens. The mechanical properties of the specimens are affected by the fibre content, tow waviness, misalignment of the load carrying tows and the distribution/size of resin rich areas. This paper depicts a link between the pick density/float length, mechanical properties and failure mechanisms in 3D woven layer-to-layer carbon/epoxy composites.
Polymers & Polymer Composites, 2009
This paper presents a study into the infl uence of the Through-The-Thickness (T-T-T) binder yarn count on the fi bre volume fraction (V f), crimp and damage tolerance within 3D woven carbon fi bre composites. Three fabrics were woven with varying binder yarn counts; the fi rst had 1x12k binders, the second had 2x6k binders (two individual 6k tows laid on top of one another into the structure to form one tow) and the third had 1x6k binder tows. Dry fabric compress tests conducted on the three 3D woven fabrics showed that a power law can be successful utilised to predict V f and identify the required pressure to achieve a specifi c V f. All three fabrics achieved V f 's in the range of 45-47% however the 2x6k binder fabric had higher %CV's compared to the other fabrics. The degree of crimp within the three 3D woven fabrics was shown to be highest within the 1x12k binder fabric followed by the 1x6k binder fabric with the 2x6k binder fabric having the lowest percentage crimp. Compression after Impact (CAI) tests were conducted and showed that impact depth was signifi cantly infl uenced by impact location on the T-T-T binders with impact depth differences up to 97% observed. It was shown that impact location and depth played no major role in the CAI strength of the composite. CAI strength was observed to be highest within the 2x6 k binder composite followed by the 1x6k binder composite with the 1x12k composite having the lowest CAI values.
Mechanical characterisation of composite materials with 3D woven reinforcement architectures
2016
The use of traditional two-dimensional (2D) fibre preforms can be associated with poor outof-plane and interlaminar mechanical performance, particularly in response to impact loads. Such preforms comprise multiple plies which necessitate labour-intensive ply cutting and assembly steps. 3D woven textiles, due to the incorporation of through-thickness yarns, have been found to exhibit superior out-of-plane mechanical properties whilst simultaneously reducing ply-assembly time and cost (single-piece preform construction). Their delamination resistance and damage tolerance have been extensively investigated over the last number of years; however, there is a paucity of published work on their inplane and out-of-plane mechanical properties when compared to their 2D counterparts. Thus, this research details a comprehensive mechanical characterisation of an orthogonal 3D woven composite in comparison with a suitable 2D laminate. Composite panels have been manufactured with Henkel’s Loctite ...
Damage Tolerance of 3D Woven Composites with Weft Binders
2014
3D woven composites, due to the presence of through-thickness fibre bridging, have the potential to improve damage tolerance and at the same time to reduce the manufacturing costs. However, the ability to withstand damage depends on weave architecture as well as the geometry of individual tows. A substantial amount of research has been performed to understand in-plane properties as well as the performance of 3D woven composites exposed to impact loads, but there is limited research on the damage tolerance and notch sensitivity of 3D weaves and no work is reported on the damage tolerance of 3D weaves with a weft binding pattern. In view of the recent interest in 3D woven composites, the influence of weft binder on the tensile, open hole tensile, impact resistance and subsequent residual compressive strength properties and failure mechanisms of 3D woven composites was investigated against equivalent UD cross-ply laminate. Four different 3D woven architectures; layer-to-layer, angle in...