composites FE models I. Straumut, S.V. Lomov, M. Wevers Department - PDF document

VoxTex: new tool for transformation of micro-CT images into textile composites FE models I. Straumut, S.V. Lomov, M. Wevers Department of Materials Engineering KU Leuven, Belgium µCT -> meso-FE Voxel FE model: regular meshing of material Quantification of the volume into elements geometry: with isotropic (matrix) • Anisotropy type and anisotropic (yarn) properties • Angle of fibers orientation Explicit FE model, taking • Density into account surface between components – • matrix, weft and warp Yarns shape yarns 14/04/2014 2 1

Structure tensor CT image I window, defined by w(r) 14/04/2014 3 Structure tensor method The method includes following stages: 1. Computation of structure tensor from a region of 3D gray-value tomographic image 2. Decomposition of the tensor into eigenvalues and eigenvectors 3. Calculation of angles in spherical coordinate system 4. Calculation of the degree of anisotropy (beta) 14/04/2014 4 2

Degree of anisotropy (beta) Beta is the ratio of eigenvalues: → anisotropic → isotropic 14/04/2014 5 Experimental part Sample materials, equipment and parameters of micro-CT acquisition Reso- Vol- Cur- Proje- Material Equipment lution, tage, rent, ctions mkm kV mkA number 2.5 4.2 4.4 Unidirectional steel fiber reinforced polymer Tomohawk 85 413 633 6.4 8.3 13.6 Knitted glass fiber reinforces polymer Nanotom 4.0 58 210 2400 Woven carbon fiber reinforced polymer Nanotom 2.5 70 310 2400 Woven carbon fiber reinforced polymer Nanotom 2.7 70 570 2400 14/04/2014 6 3

Micro-CT data Knitted glass fiber Woven CFRP, resolution 2.5 μ m, cross-section reinforced composite, resolution 4 μ m, 3D view 14/04/2014 7 Results: orientation fields Computed orientation fields Knitted glass fiber composite Resolution: 4 μ m anisotropic (orientation) isotropic 14/04/2014 8 4

Results: orientation fields Computed orientation fields Woven carbon fiber reinforced polymer Resolution: 2.5 μ m anisotropic (orientation) isotropic 14/04/2014 9 Image segmentation Density 10 2 Density 165 160 yarns 155 10 150 145 140 1 matrix 135 130 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Anisotropy Anisotropy Orientation vectors 14/04/2014 10 5

Voxel-based Abaqus model 14/04/2014 11 VoxTex software TexComp (KUL) 14/04/2014 12 6