Identifying microstructural features in unidirectional composite tapes

Carbon fibre-reinforced polymer composites (CFRPs) outperform most structural engineering materials in specific stiffness and/or specific strength, especially in their unidirectional configuration. Unidirectional composites can be found as individual structural elements in cables or pin-loaded straps; they are however most commonly found in the...

The role of matrix boundary in the microstructure of unidirectional composites

Finding new ways to evaluate the variability of microstructures, and its effect on macroscopic properties such as permeability and mechanical performance [1,2] is of increasing interest in the composite field. The variability of microstructural features at a three-dimensional level is not fully understood and its effect on macroscale properties...

Method for the Microstructural Characterisation of Unidirectional Composite Tapes

The outstanding properties of carbon fibre-reinforced polymer composites are affected by the development of its microstructure during processing. This work presents a novel approach to identify microstructural features both along the tape thickness and through the thickness. Voronoi tessellation-based evaluation of the fibre volume content on...

The effect of Laser-Induced deconsolidation on the compaction behavior of thermoplastic composite tapes

The effects of laser-induced deconsolidation on the compaction process of CF/PEEK tapes were investigated. First, tapes with different degrees of deconsolidation were manufactured using a laser heater. This procedure resulted in samples with different waviness, thickness, void content and surface roughness values. Then, as-received and laser...

Deconsolidation of thermoplastic prepreg tapes during rapid laser heating

In this study, the effect of rapid laser heating, which is typical during laser-assisted fiber placement (LAFP), on the micro- and meso- structure of the thermoplastic tape was investigated. Thermoplastic tapes were heated above the melting temperature with different heated lengths (30 and 80 mm and heating times (0.2 and 0.8 s) in a dedicated...

The influence of inter-laminar thermal contact resistance on the cooling of material during laser assisted fiber placement

The effect of thermal contact resistance (TCR) correlated to the degree of intimate contact (DIC) between the incoming tape and the substrate on the temperature history during laser-assisted fiber placement (LAFP) was investigated. A novel experimental methodology was designed to understand the effect with a non-contact method which did not...

Characterising microstructural organisation in unidirectional composites

Understanding the three-dimensional variability of unidirectional composites is relevant to the material performance and the development of advanced material modelling strategies. This work proposes a new methodology for the characterization of unidirectional composites, showcased on carbon fibre/poly(ether-ether-ketone) tapes. Three...

Intimate contact development during laser assisted fiber placement: Microstructure and effect of process parameters

Intimate contact development under LAFP-specific thermal and mechanical boundary conditions/interactions and the effect of process parameters are investigated. One-layer, unidirectional strips of CF/PEKK material were placed with different process parameters on a flat tool surface to create different intimate contact conditions. The concept...