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

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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

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Explicit FE model, taking into account surface between components – matrix, weft and warp yarns Voxel FE model: regular meshing of material volume into elements with isotropic (matrix) and anisotropic (yarn) properties Quantification of the geometry:

• Anisotropy type
• Angle of fibers
• rientation
• Density
• Yarns shape

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Structure tensor

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CT image I window, defined by w(r)

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Structure tensor method

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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)

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Degree of anisotropy (beta)

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Beta is the ratio of eigenvalues: → anisotropic → isotropic

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Experimental part

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Sample materials, equipment and parameters of micro-CT acquisition

Material Equipment Reso- lution, mkm Vol- tage, kV Cur- rent, mkA Proje- ctions number 2.5 4.2 4.4 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 Tomohawk Unidirectional steel fiber reinforced polymer 85 413 633

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Micro-CT data

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Knitted glass fiber reinforced composite, resolution 4 μm, 3D view Woven CFRP, resolution 2.5 μm, cross-section

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Results: orientation fields

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Computed orientation fields Knitted glass fiber composite Resolution: 4 μm

isotropic anisotropic (orientation)

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Results: orientation fields

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Computed orientation fields Woven carbon fiber reinforced polymer Resolution: 2.5 μm

isotropic anisotropic (orientation)

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Image segmentation

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Anisotropy

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Density

130 135 140 145 150 155 160 165 1 10

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matrix yarns

Anisotropy Density Orientation vectors

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Voxel-based Abaqus model

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VoxTex software

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TexComp (KUL)