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Item type:Publication, Access status: without files , Water imbibition in nanoporous Vycor glass : X-ray tomography-based Lattice-Boltzmann simulations and their validation by optical and gravimetric experiments(InterPore2023, 2023-05); ; ; ; Capillary rise dynamics of molecular liquids in nanoporous solid is governed by the interplay of liquid’s viscosity, the liquid-solid interaction and permeability of the porous medium. Classical hydrodynamics provides a square-root-of-time dependent law to describe the liquid front advancement during imbibition, also known as Lucas-Washburn law (L-W). Although the validity of the L-W law down to the single digit nm scale has been proven [1], complex dynamics and broadening of the imbibition front arise in connection to the pore size distribution of the solid and its tortuosity. To address this problem we present Lattice-Boltzmann computer simulations (L-B) of water imbibition in nanoporous Vycor glass. X-ray-based tomography of a 400 porous Vycor reveals the geometry of the pore space from the single-pore up to the Darcy scale. The scale invariant spinodal demixing-based pore formation in controlled pore glass allows us to re-scale such geometry 100 times down. Thus we complement the L-B simulations with optical imaging experiment for water imbibition in Vycor with poresizes of 4 . At this scale, changes in the refractive index of the solid upon filling provide for direct observation of the rise dynamics and the broadening of the filling front. The latter is visible via intense light scattering at this region induced by the coexistence of liquid-gas phases at length scales comparable to the light characteristic wavelengths.Publicationtype: Conference Poster35 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Workshop GRK 2462 "Processes in Natural and Technical Particle-Fluid-Systems" (PintPFS) : 26th & 27th of September 2022, Hamburg, Germany : conference proceedings(2022-09-26); ; ; ; In the framework of Research Training Group GRK 2462 “Processes in Natural and Technical Particle-Fluid-Systems” (PintPFS), funded by the German Research Foundation (DFG), researchers from the fields of civil engineering, mechanical engineering, process engineering, and materials sciences investigate natural and technical Particle-Fluid-Systems (PFS) in an interdisciplinary approach. As PFS are ubiquitous in everyday life and relevant for many processes in industry, pharmacy, and food production, they represent a fascinating field of research with potential for promising and useful discoveries in many aspects.Publicationtype: Conference Proceedings409 2186 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Strain sensing in GFRP via fully integrated carbon nanotube epoxy film sensors(Elsevier, 2021-10); ; ; ; Structural health monitoring of composite structures enables early damage detection to prevent critical component failure. Surface-mounted strain gauges are commonly applied to monitor the integrity of composite structures in highly loaded areas. However, strain gauges can only measure strain on the structure's surface and are exposed to environmental influences. Within this paper, fully integrated carbon nanotube thin-film sensors for strain and damage sensing in glass fibre reinforced polymers (GFRP) via electrical resistance measurements are presented. Single wall carbon nanotube epoxy thin-films were manufactured using a manual film applicator, partially pre-cured, placed on dry glass fabrics and infused in a resin transfer moulding process. The mechanical properties of the composites and strain sensing capabilities of the integrated sensors were studied for various load cases and different laminate lay-ups. Results of quasi-static and step-wise three-point bending and tensile tests show that the integrated films allow for localised strain measurements in GFRP without significant loss of mechanical properties. Open hole tensile tests proof the ability to monitor local strain and damage in highly loaded areas enabling failure prediction via threshold resistance change values. The proposed thin-films enable a tailored strain and damage monitoring of GFRP offering the possibility for measurements at different material depths, over large sections or selectively in highly loaded areas. The manufacturing process is easily automatable and suitable for large scale manufacturing.Publicationtype: Journal ArticleScopus© Citations 7 83 277