Characterization and modelling of the mechanical properties of mineral wool

Lucie Chapelle

    Research output: Book/ReportPh.D. thesisResearch

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    Abstract

    Mineral wool designates a highly porous network of fibres drawn by spinning molten minerals. Traditionally, mineral wool products have found application as thermal and acoustic insulation of buildings. Recent concepts where mineral wool products are subjected to higher structural loads have emerged and as a consequence focus on the mechanical properties of mineral wool has intensified. Also understanding the deformation mechanisms during compression of low density mineral wool is crucial since better thickness recovery after compression will result in significant savings on transport costs. The mechanical properties of mineral wool relate closely to the arrangement and characteristics of the fibres inside the material. Because of the complex architecture of mineral wool, the characterization and the understanding of the mechanism of deformations require a new methodology.
    In this PhD thesis, a methodology based on image analysis to characterize the 3D structure of mineral wool materials in terms of fibre orientation, fibre diameter, contacts and pore size is proposed. The method uses 3D data obtained by X-ray tomography. The measured data are fitted to probability distributions in order to facilitate the comparison of individual characteristics of different mineral wool materials and provide simple descriptors of the 3D structure. All the methods described here are applied to glass wool and stone wool.
    By developing a FEM model including the real characteristic of the mineral wool fibre structure, the effect of the structure on mechanical properties can be explored. The size of the representative volume elements for the prediction of the elastic properties is determined for two types of applied boundary conditions. For sufficiently large volumes, the predicted elastic properties are consistent with results from the literature and confirm the transverse isotropy of mineral wool.
    Finally, the overall methodology is applied to study the compression of mineral wool products. X-ray tomography and the developed image analysis techniques are employed to quantify the change of the fibre structure under compression and confirm the reorientation of the fibres. A numerical model of the cyclic compression of mineral wool is developed and reproduces successfully the hysteresis observed experimentally. The results of the modelling indicate that the size of the hysteresis is linked to the friction coefficient between the fibres.
    Elastic and compressive properties of mineral wool products can now be predicted and optimized with respect to the fibre structure, binder and fibre content using the micromechanical FEM model developed in this PhD study.
    Original languageEnglish
    PublisherTechnical University of Denmark
    Number of pages142
    Publication statusPublished - 2016

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    Cite this

    Chapelle, L. (2016). Characterization and modelling of the mechanical properties of mineral wool. Technical University of Denmark.