Complex fibre analysis using X-ray imaging

ROCKWOOL International A/S is part of the ROCKWOOL Group which is the world´s leading supplier of innovative products and systems based on stone wool. To characterize complex fibre materials, ROCKWOOL collaborated with the 3D Imaging Centre at DTU. By performing micro X-ray computed tomography, the internal fibre structure of the stone wool samples was visualized. Tools for automatic characterization of the fibre networks were developed in close collaboration between the 3D Imaging Centre at DTU and ROCKWOOL. The explorative analysis offered the company novel knowledge about their material properties.
ROCKWOOL’s insulation material
3D rendering showing the orientations of the fibres in a high resolution X-ray CT scan after orientation analysis
3D rendering showing the orientations of the fibres in a high resolution X-ray CT scan after orientation analysis

ROCKWOOL

ROCKWOOL is the world’s leading manufacturer of stone wool insulation. The company produces and supplies a full range of smart and sustainable insulation products for the construction industry based on innovative stone wool technology.

Challenge

Mineral wool consists of fibers arranged in a complex network. The fibers can vary in diameter, length, orientation and curvature. All these parameters influence the final material properties, hence characterizing them helps to understand and thereby tune the material properties.

Collaboration

Through the collaboration between ROCKWOOL and the 3D Imaging Centre at DTU, the material was characterized using micro X-ray computed tomography scans and an analysis toolbox was developed in-house. This collaboration was part of the LINX project in which researchers at leading Danish universities collaborate with scientists in industry to solve industry relevant problems using advanced neutron and X-ray techniques.

Results

By performing several high resolution scans along the assumed dominating fibre direction, a large field of view was analyzed without compromising visibility of individual fibers. The developed analysis is based on the estimation of local orientations which are used to track and characterize individual fibers. It involves handling large amounts of data, detailed visualizations of the inner structure of mineral wool, and an analysis of material parameters such as orientation and diameters.

Perspectives

By this characterization of the fibers, ROCKWOOL could gain valuable input for simulations. Having this analysis toolbox enables similar analyses of future products.

3D-rendering of the insulation material. The image is set together from 6 individual scans in order to probe a long part of the sample while at the same time keeping a high resolution with a voxel size of 4.95 µm3. The inspection from this perspective only gives a glimpse of the complex structure of the material with tightly packed non-oriented fibres of different diameters.
3D-rendering of the insulation material. The image is set together from 6 individual scans in order to probe a long part of the sample while at the same time keeping a high resolution with a voxel size of 4.95 µm3. The inspection from this perspective only gives a glimpse of the complex structure of the material with tightly packed non-oriented fibres of different diameters.
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