Recycling is essential for sustainable development and the transition to a circular economy. One of the key challenges in mechanical recycling is the effective liberation of materials from multi-material structures during shredding. This thesis addresses this previously underexplored aspect by applying the finite element method (FEM) to simulate the shredding process in a rotary shredder. The aim was to develop a simulation-based methodology for predicting shredding performance with respect to the metrics liberation degree, specific mechanical energy consumption, and fragment size distribution.

A numerical model for shredding in a rotary shredder was developed based on experimental trials, using single-specimen tests with hybrid profiles and plates composed of steel and glass fiber-reinforced polymers, primarily joined by adhesion. The simulations successfully replicate the complex loading conditions as well as the material-specific fracture and deformation behavior. In addition, an automated post-processing method was developed to efficiently characterize simulated fragments and quantify mechanical energy consumption. The results demonstrate that FEM-based shredding simulations are a promising tool for predicting shredding performance and represent a novel contribution to the recyclability assessment of multi-material structures.