The mechanical behavior of complex fibrous structure of glass wool is closely related to microstructure and architecture of material. Understanding the structure and its mechanics reveals several characteristics such as fiber size, fiber distribution, junctions and contact etc. In the current study, a method is developed to describe these characteristics of the glass wool structure. The method is based on the image analysis of 3D datasets obtained by confocal microscope and numerical analysis is carried out to correlates the structure and its complex mechanical response. This also helps to understand the better thickness recovery after compression of structure which will significantly save transportation costs.
The primary objective of this project is to quantify and analyze the 3-dimensional structure of glass wool material which requires the optical imaging technique where data can be visualized in three dimensions. This is achieved by the technique of confocal optical microscopy which produce pretty impressive results compared to other techniques like Tomography. Characterization is done in the next step with the help of data acquisition which gives an enhance image and structural parameters required for modeling and analysis of the structure.​
The secondary objective is to set up a model in which these morphological parameters can be injected and perform a numerical analysis of the deformation by finite element method in order to establish a relationship between the structure and complex mechanical behavior of this material. This will help to assess the different characteristics of the structure (mechanics of fibers, stiffness of junction point, friction, rupture of fibers etc.) in the mechanical response. To perform simulation, data obtained from the data processing can be fed as inputs to a model describing the fiber structure.
Fig 1. Above images show the glass wool material and it's structure which is taken by Scanning electron microscopy. The Structure clearly shows heterogeneity of the geometry of fibers, the random distribution and contact of fibers.
The resulting images (fig 2a & 2b) from the confocal microscope have good representation of the 3D structure. Cursory inspection of the figures reveals that with the present protocol, confocal microscopy is fully able to differentiate the structures of these samples.
Fig 2a. Glass fibrous structure
Fig 2b. Glass fibrous structure
In data acquisition, the aim is to measure the objects present in the images of glass wool. The idea is to access the position (in 3D), accurate shape, size (diameter and length) of fibers and the fibers cross links which could help in performing the numerical analysis of glass wool structure. The results have shown below (fig 3 & 4).
Fig 3. Diameter distribution​
Fig 4. Skeletionisation to access the positions
Modeling and Numerical Analysis are performed in the final stage. A method is proposed to create the 3D representative volume of structure and selection of numerical parameters to simulate the compressive behavior.
Fig 5. Modeling and Simulation