Understanding Multi-Layer Composites

Many materials consist of separate layers with different properties. LINX investigates multi-layer materials to better understand their behaviour in production lines.

Multi-layer composites are laminar materials where each layer serves a particular function, interplaying with the neighbouring ones. A challenge to all layered materials is bending, since not every layer can bend to the same degree. This may result in cracks, stretches and tensions in the material, and perhaps ultimately a broken product.

To help mitigate such issues, this LINX project develops 3D X-ray imaging methods designed to monitor multi-layer composites during a bending process. A tool for movie making – obtained by recording high-precision images at different degrees of bending, each of which reveals the microstructure in every depth of the composite material. By following the individual layers, one can decode their behaviour and use it as an input for computer simulation of new products, or for trouble-shooting on existing ones. Likewise, broken products may be subjected to “live” analysis, aimed at understanding any particular fault or flaw, and whether its cause lies with the manufacturer – or with the customer.

Read the interesting one pagers from this project:

Techniques and Methods

When building a product (Ex. packaging material, window components) by creating a laminate the thickness of each individual layer, adhesion between layers, voids and fractures are key parameters to study in order to secure product performance. With x-ray scanning it is possible to observe these parameters in an non-destructive way on multi-layer (layers on top of layers) multi-material (coating/aluminum/paper) products. The output from x-ray scanning is 3D which is essential when building virtual models to describe the manufacturing process.

In this focus project different types of laminar materials have been in focus the last year. One being packaging material from Tetra Pak the other being a metal/polymer/adhesive/metal sandwich system.

For this sandwich system the interest is how does the adhesive mix with the polymer and how is it connected to the metal parts. It has been possible to visualize the mixture using X-ray tomography. The work continues in 2019 studying more samples with different production parameters.

For the packaging material, the interest have been to study how the material behave when the material is folded. A series experiment where designed, planned and executed in 2018 to study different types of folding in two different direction of the packaging material.

Project Information

Participants: Tetra Pak, VELUX, Technical University of Denmark.
Start date, end date:
April 2018 – present
Laminar materials (FP08.001, Materials at operating and processing conditions).