This study investigates the multifunctional potential of metallized polyphenylene sulfide (PPS) nonwovens integrated as electrically conductive interlayers in glass fiber-reinforced polymer (GFRP) composites. The PPS nonwovens were coated with a nickel–phosphorus layer via electroless plating and embedded between the laminate plies. The system was evaluated both as an electrothermal heating element for de-icing and as a sensing layer for non-destructive testing. For de-icing applications, icing wind tunnel tests were conducted under glaze-ice and mixed-ice conditions. The integrated heating layer enabled complete ice removal within approximately 120 s for both icing regimes, while the distributed Joule-heating mechanism ensured stable and spatially uniform surface temperatures. Furthermore, the metallized nonwovens were successfully applied as an internal thermal excitation source in shearography, allowing clear identification of impact-induced damage, including delamination. The incorporation of the metallized PPS interlayer also enhanced the mechanical performance of the GFRP composite, with flexural strength increasing from 944 MPa (reference) to approximately 1164 MPa. Dynamic mechanical analysis indicated a slight increase in glass transition temperature from 132 °C to 141 °C. These findings demonstrate that metallized thermoplastic nonwovens provide an effective approach to designing multifunctional composites for advanced engineering applications.

This research presents a set of methods for obtaining measurable data on yarns in historical textiles, addressing a gap in conservation and conservation science. A systematic analysis was conducted on 26 specimens, primarily from historical paintings of known provenance, all including a selvedge. Techniques for measuring crimp, twist, yarn width and yarn thickness were developed. Methods for the measurement of thread count, fabric thickness, weight, and pH are also discussed. By quantifying these characteristics, this study enhances our understanding of traditional textile production. Numerical data enable direct comparisons between different fabric structures and allow correlations with the tensile properties of historical textiles. Correlations have been established between the measured characteristics of the interlaced yarns and the warp and weft directions, which appear to be uncontroversial within this group of samples. This improves the ability to distinguish warp and weft in a textile when a selvedge is not available. The set of methods is largely non-destructive, as only a few yarns need to be extracted to measure their crimp and thickness. The data needed for textile engineering research are made available for historical woven structures, providing new opportunities for their analysis and for predictive digital simulation. The next steps in this ongoing research are to explore correlations between the measured characteristics and the tensile response of the analysed textiles, and to extend the study to a wider range of historical fabrics to obtain more broadly representative data.

The objective of this work is to study defect detection efficacy using embedded carbon nanotube (CNT) fibers as heaters for shearography and thermography. For that, GFRP laminates with various amounts of CNT-doped strips embedded at different layers have been manufactured. Impact tests are performed to create realistic damage in the GFRP specimens for inspection. Shearography and thermography non-destructive testing of the GFRP laminates are performed simultaneously with embedded CNT strips as heating sources before and after the impact test. This research was performed as part of the Horizon Europe COMP-ECO project (grant agreement 101079250). In the future, we aim at developing a novel demonstrator of a composite aerospace structure with integrated CNT-doped sensors that support NDT and enable self-sensing and in-situ SHM capabilities.

Twin matrix composites (TMC) are novel composite architectures where reinforcing composite elements are embedded in a secondary resin to address various mechanical functions suited for diverse engineering applications such as morphing wings. Here, for the first time, a recyclable twin matrix composite using micro-pultruded rods as reinforcements will be manufactured. Within the scope of the work, the design of the TMC mould which allows 0°/90°/0° reinforced layup will be discussed and created through additive manufacturing. Recycling and remanufacturing TMC will be conducted up to 4 times, and surface characteristics of the rods will be examined to monitor the effect of recycling. Interlaminar shear strength of TMC made from fresh and recycled rods will be investigated comparatively.

Hydrogen is being investigated as aviation fuel, with the objective to achieve an energy transition for the aviation sector. Effective storage solutions are crucial to mitigate the aerodynamic penalty caused by its low volumetric energy density. The focus of this study is the integration of a cryo-compressed vacuum-insulated storage vessel into the primary structure of aircraft, aiming to enhance structural efficiency. This is achieved by implementing analytical methods to analyse the thermo-mechanical loading of the inner and outer walls of the fuel tank. It is envisioned that the inner wall rather than the outer wall is more suitable to sustain additional loads. However, it is unclear how the cryogenic environment affects the stress state of the composite material.

For pick-and-place processes to become widely implemented in industry a consistent and acceptable product quality needs to be achieved. In the state of the art it is assumed that reinforcements will be in perfect condition at the start of forming or draping. In reality the handling process can already result in undesired deformations. The current work will look at fiber angle deviations that occur during this process due to in-plane shear. It is shown that bounds can be set for these fiber angle deviations based on experimental work. Periodic representative volume element homogenization is used to obtain homogenized material properties for a bi-axial non-crimp fabric with a specific construction. With these material properties the in-plane shear strain, and thus the fiber angle deviations, can be predicted. The presented methodology and results obtained using it can be a basis in the design process for automated handling of reinforcements and for in-situ quality control of the pick-and-place process.

A realistic wear test was developed for porous thermal insulation systems exposed to high temperature turbulent gas flow, because it is essential for the development of existing and new concepts of such insulation and therefore also for the performance of processes that depend on such insulation. Wear is crucial and often dominant for the long-term performance of thermal insulation and, because of the complex nature of insulation wear under exposure of high-temperature turbulent flow, realistic testing capability is a necessary tool for improvement. A test rig was developed to subject fibrous ceramic insulation, the most encountered type of thermal insulation, to conditions representative for in-service use and to enable investigation of the occurring phenomena and behaviour. This rig can accommodate a range of different insulation configurations and is compatible with many turbulent flow sources. This test rig, its components, the experimental procedure, its accuracy and representative results are presented.

The purpose of this work is to experimentally establish the combined influence on the flow and thermal resistance of an exhaust pipe wall formed by a porous, compliant layer with overlying discrete roughness elements exposed to the pulsating exhaust gas flow of a combustion engine. Through measuring the streamwise pressure drop over and radial temperature differences in different pipe samples for a range of flow states with different Reynolds numbers and non-dimensional pulsation frequencies, the effects were discerned. The configurations of the sample walls covered a range of mesh pitches, compliant-layer densities, and compliant-layer compression ratios. The (non-sinusoidally) pulsating exhaust gas flow spanned the following range: Re_b (= u_bD/ν_b) = 1⋅ 10⁴ - 3⋅ 10⁴, T_b = 500 - 800 ^∘C, ω⁺(= ωνb/uτ2) = 0.003 - 0.040. The friction factors were found to be effectively constant with Reynolds number and non-dimensional pulsation frequency while the variation with insulation density/compression was not significant. Additionally, for both mesh pitches, the measured friction factors were in line with those reported in literature for similar geometries with steady flow and solid walls. Together this indicates that neither compliance nor the pulsations in the exhaust gas flow significantly affect the friction for this configuration. Comparison of the samples based on the derived thermal resistance showed a similar influence of the fluid-wall interface as for the friction. Additionally a distinct influence of compression, independent of the insulation density, was observed that increases with increasing temperature. It was concluded that the increased resistance was due to additional radiation resistance because of fibre reorientation due to compression.

Tubular adhesive joints, used in truss structures to join pultruded carbon fibre-reinforced polymer members to aluminium nodes, are modelled with varying dimensions. The numerical model uses a Cohesive Zone Modelling formulation with a trapezoidal traction-separation law for the adhesive layer, and experimental tests are carried to validate it. The results showed that the joint strength increases significantly with the bonding area, with a limit on the overlap length above which it stops increasing. This upper limit is affected by the thickness and tapering angle of the adherends, due to their influence on the shear stress distribution along the overlap. On the other hand, the adhesive thickness has only a marginal influence on the joint strength.

For the application of composite materials to become more widespread and replace traditional materials their manufacturing processes and final products will need to be competitive and be e.g. lighter, stronger or stiffer and quicker, easier or more cost-efficient to produce than traditional materials. The state of the art for pick-and-place operations for the manufacturing of composite parts focuses on handling single lab-sized layers at undisclosed speeds. The process could however be more competitive by being able to handle more and larger layers in a faster manner than currently presented in research. The aim of the paper is to evaluate the existing pick-and-place strategies on their suitability for the swift automated handling of multiple large-sized layers of reinforcement. The review shows that many of the existing techniques could be suitable for different scenario’s and discusses which factors are to be taken into account when dealing with large layers, more than one layer or rapid handling. (Figure presented.).