Geometrical modelling of 3D woven reinforcements for polymer composites: Prediction of fabric permeability and composite mechanical properties

Abstract

For a 3D orthogonal carbon fibre weave, geometrical parameters characterising the unit cell were quantified using micro-Computed Tomography and image analysis. Novel procedures for generation of unit cell models, reflecting systematic local variations in yarn paths and yarn cross-sections, and discretisation into voxels for numerical analysis were implemented in TexGen. Resin flow during reinforcement impregnation was simulated usingComputational Fluid Dynamics to predict the in-plane permeability. With increasing degree of local refinement of the geometrical models, agreement of the predicted permeabilities with experimental data improved significantly. A significant effect of the binder configuration at the fabric surfaces on the permeability was observed. In-plane tensile properties of composites predicted using mechanical finite element analysis showed good quantitative agreement with experimental results. Accurate modelling of the fabric surface layers predicted a reduction of the composite strength, particularly in the direction of yarns with crimp caused by compression at binder cross-over points.

Numerical and experimental investigation of saturated transverse permeability of 2D woven glass fabrics based on material twins

“…Since the simulations are conducted in representative regions extracted from the material twins created with 10 fabric layers, five combinations of layers for NOL = 6 and three for NOL = 8 have been studied, so that error bars can be provided for simulation results along the x and y axes. Thus, numerical predictions can also illustrate the variability of the material much like experiments, which was generally not possible in previous studies . Meanwhile, differently from other investigations that assume a uniform distribution of fiber volume content in one fabric stack, the geometric models used in numerical simulation are constructed from real fabrics so that the nesting and distortion between fabric layers can be precisely described without any particular assumption.…”

“…This is possible, thanks to microtomographic observations of the material structure and to the micro‐CT AGM methodology devised to construct a detailed and structured geometric model of textile architecture. The structured voxel file created allows a thorough analysis of the geometric features of the fiber tows contained in the specimen. Material variability: Lower resolution micro‐CT scans enable to model larger specimens that are more representative of material variability than single unit cells like in most previous investigations (). Numerical simulations: Because the structure of the material has been identified and all the tows numbered, it is possible to create finite element meshes of the fibers and/or of the mesopores between the tows. Hence, numerical simulations can be carried out to predict the mechanical or flow behavior of engineering textiles, thus establishing a connection between material properties and the geometric features of fibrous reinforcements.…”

Experimental investigation of the mechanical properties of neoprene coated nylon woven reinforced composites

“…Hence, composites are reported to generally show better axial mechanical properties when made with uniaxially strained fabrics than crimped yarns in most 2D reinforcements [6,9].…”

Automated tool to determine geometric measurements of woven textiles using digital image analysis techniques

“…[2][3][4] Textile modeling processes require the generation of a representative model. This model can be used in simulations to predict the physical and mechanical material properties.…”