Severo Ochoa Coffee Talk by Giacomo Rizzieri

CIMNE's Severo Ochoa Coffee Talk - "Advances in the numerical simulation of complex fluids for 3D printing applications", by Giacomo Rizzieri
📖 ABSTRACT
Additive manufacturing techniques, among which 3D Concrete Printing (3DCP) and polymer extrusion are revolutionizing the production process, offering unprecedented design freedom and efficiency. To control these technologies and fully exploit their potential it is necessary to develop efficient and reliable numerical tools.
In this talk, a general framework to simulate the extrusion and layer deposition processes of non-Newtonian fluids with the Particle Finite Element Method (PFEM) is presented. The PFEM is a mesh-based Lagrangian approach, which results to be particularly appealing for the simulation of complex fluids and free-surface flows. A PFEM 3D printing framework has been implemented in an in-house code, addressing several challenges such as the imposition of time-dependent moving boundary conditions and inter-layer contact. Moreover, an adaptive de-refinement technique is used to decrease the computational cost while preserving accuracy.
Concerning the material behaviour two rheological models are considered: a viscoplastic Bingham law and a viscoelastic Oldroyd-B law. The former model has been successfully employed for the simulation of the extrusion of cementitious materials, and it is validated by comparing the simulation results with proper experimental data. The latter is instead more representative of polymers, and it is tested on standard viscoelastic free-surface benchmarks, such as the impacting drop and the jet buckling problems.