Robust evaluation of flow front data for in-plane permeability characterization by radial flow experiments

Abstract

b department of Polymer Materials and Plastics engineering, clausthal university of technology, clausthal-Zellerfeld, germany; c institut für verbundwerkstoffe gmbH, Kaiserslautern, germany ABSTRACT A novel approach is presented for modeling the temporally advancing fluid flow front in radial flow experiments for in-plane permeability characterization of reinforcing fabrics. The method is based on fitting an elliptic paraboloid to the flow front data collected throughout such an experiment. This "paraboloid" approach is compared to the conventional "ellipse" method and validated by means of data sets of optically tracked experiments from two different research institutions. A detailed discussion of the results reveals the benefits of the "paraboloid" method in terms of numerical efficiency as well robustness against temporal or local data variations. The "paraboloid" method is tested on temporally and spatially limited data sets from a testrig involving linear capacitive sensors. There, the method shows advantages over the conventional approach as it incorporates the entirety of available measurement data, particularly in the last stages of the experiments which are most characteristic for the material under test.

In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise

“…In order to estimate the magnitude of variations induced by analysis it was decided to recalculate some of the results using a unified analysis approach. For this, the data sets (fluid injection pressure, dynamic fluid viscosity, flow front data) originally used in step (2) and (3) were collected and evaluated according to an uniform procedure: For step (2), the elliptic paraboloid fitting method introduced by Fauster et al [9] was applied to all of the collected data sets, and for step (3), the Adams/Rebenfeld algorithm was used. As the paraboloid method allows fitting an elliptic paraboloid to the entire set of flow front data acquired during the radial flow experiments in a single step, it is a global method.…”

Inferring material properties from CFRP processes via Sim-to-Real learning

“…4): (i) The images were rotated to align them with the images created by the simulation, (ii) empty zones outside the fabric were removed, (iii) image areas showing the stiffing frame of the mechanical setup were removed and (iv) parts of the flow front, occluded by the stiffening frame, were supplemented by a specifically developed, automated mechanism. The latter involves fitting an elliptical geometry model to selected data points along the fluid flow front [16] and extrapolating parabolic models for the major and minor ellipse axis length [17], respectively.…”

An overview on current manufacturing technologies: Processing continuous rovings impregnated with thermoset resin

“…Common products manufactured with this technology are tubes and reinforcements rods, that have a core made of linear filaments and a braided cover. [ 13,128–134 ]…”

“…The most common model to describe fluid flow through a porous material is Darcy's law; it correlates the volume‐averaged flow rate ν with permeability K , pressure gradient ∇P , and viscosity η – see Equation (). [ 10,131,205–207 ] Viscosity can be defined as the fluid's resistance to flow. [ 208 ] A permeability equation based on the research of Kozeny and Carman [ 184,209–211 ] (Equation ()) allows to estimate the permeability in longitudinal direction via the fiber volume ratio ( e F ), the fiber radius ( r F ), and the Kozeny constant k , a geometric factor. …”