Recent advancements in mechanical characterisation of 3D woven composites

Abstract

Three dimensional (3D) woven composites have attracted the interest of academia and industry thanks to their damage tolerance characteristics and automated fabric manufacturing. Although much research has been conducted to investigate their out-of-plane "through thickness" properties, still their in-plane properties are not fully understood and rely on extensive experimentation. To date, the literature lacks an inclusive summary of the mechanical characterisation for 3D woven composites. Therefore, the objective of this paper is to provide a comprehensive review of the available research studies on 3D woven composites mechanical characterisation, with less emphasis on the outof-plane response, but an in-depth review of the in-plane response "un-notched vs. notched". The paper highlights the knowledge gap in the literature of 3D woven composites, suggesting opportunities for future research in this field and a room for improvement in utilising Non-Destructive Techniques (NDT), such as Digital Image Correlation (DIC), Acoustic Emission (AE) and X-ray Computed Tomography (CT), for observing damage initiation and evolution in 3D woven composites that could be used to calibrate and evaluate analytical and numerical models.

The effect of z-binding yarns on the electrical properties of 3D woven composites

“…Due to the high stress concentration at the interlacement points between z-binding yarns and in-plane yarns, localised damage occurs at those locations. Furthermore, the progression of delamination is also controlled by the architecture of z-binding yarns in 3D composites [23,25,26]. Having a reliable real-time damage detection technique is essential for monitoring the integrity of 2D laminated and 3D woven composites in service especially for the non-visible damage that may lead to catastrophic failure.…”

Tailored fibre placement of commingled carbon-thermoplastic fibres for notch-insensitive composites

“…Creating notches/holes in CFRP laminates with machining/drilling has been extensively studied in the literature and as reported in the introduction, it significantly reduces the tensile modulus and strength of the laminates due to the damage induced during the machining process [4][5][6][7][8][9]. Thus, it would have made a reasonable sense if the machined-hole specimens had the least tensile modulus and strength compared to the tailored-hole specimens.…”

“…This helps in reducing the size of the resin rich region introduced around the notch/hole which represents a critical/weak point in the design of tailored-hole-1 specimens. From the hole-creation process point of view, no delamination or matrix cracking is introduced due to the notch creation such as the ones experienced in the machined-hole specimens [4][5][6][7][8][9]. This all leads to the relatively superior notch-insensitive behaviour of the tailored-hole-2 compared to the tailored-hole-1 and the machined-hole specimens.…”

“…The connections however, require introduction of holes and notches, which are generally drilled into the composites. Such machined-holes can introduce micro to macro scale defects leading to delamination and de-bonding between the reinforcement and matrix, which can significantly reduce the mechanical performance of the composite [4][5][6][7][8][9].…”

Effect of reinforcement architecture on the macroscopic mechanical properties of fiberous polymer composites: A review

“…Further, interlocking of the third directional yarn can be through thickness or layer by layer. [ 19 ] The mechanical behavior of orthogonal interlocked 3D woven textile reinforced composite material is substantially different than angular interlocked preform reinforced composites due to the placement of third fiber. Braided, knitted, and needle punched fabrics are also being used as reinforcement in polymer composite materials to fabricate various components.…”