The EU is a world leader in the development and manufacturing of structural products for the transport, energy, and construction industries that generate an annual income of €1tn (10.8% in gross value) for the European economy. The European “Green Deal” sets an ambitious target of rendering Europe climate neutral by 2050. The recently approved Circular Economy Action Plan brings forward the requirement for delivering sustainable and resilient end-products across the entire industrial ecosystem. Hence the question on how to maximize the operational life-cycle of critical complex structures, e.g. airplanes, wind-turbines, bridges while drastically reducing manufacturing and and maintenance costs becomes seminal. Additively Manufactured fibre reinforced composite (AMC) components built via fused deposition modelling rapidly find applications within the European aerospace and transport industry as they are prone to, less machine, material, and labour costs, less manufacturing waste, and usage of more efficient materials. A drawback of AMC components is their typically complex and in cases tessellated geometry; this gives rise to combined damage mechanisms that deviate from the usual “high strength and ductile metal” paradigm. This “complexity”, if controlled, can result in components of tailored properties, e.g. of increased fracture toughness and pseudo-ductile post fracture response. Unfortunately, current analysis and design methods lack the necessary level of refinement, or the underlying theoretical framework indeed, to address this critical issue.
The overarching aim of AI2AM is to provide an integrated design framework to address this challenge by greatly advancing the current state-of-the-art by employing a truly cross-disciplinary research methodology. On the modelling side, this project is designed to develop a novel, rapid and high-fidelity physics-based method custom fit for the analysis of such complex structures. On the design side, this research will deliver the first ever AI driven topology optimisation framework for AMC components of increased fractured toughness.
To this end, over a period of two years (2021-2023), AI2AM delivered novel numerical methods and tools for the damage analysis and topology optimisation analysis of fibre reinforced 3D printed domains. The main conclusions of the project are:
1) Cohesive phase field models provide a versatile paradigm for the damage analysis of 3D printed composites. Our results demonstrate that the numerical predictions match experimental results when the pertinent material parameters, i.e. fracture toughness per material orientation and critical stress per material orientation are well-defined.
2) Both Scaled Boundary Finite Element and Virtual Element methods provide well-behaved fracture simulations of increased computational efficiency when compared to standard finite element solvers. This is mainly due to the ability of the methods to solve over complex discretization topologies without the need for local mesh refinement.
3) Fusing topology optimisation with machine learning surrogate models succeeds in providing designs of increased fracture toughness compared to conventional designs. However, further research is required for the results to be generalizable.
4) Deploying highly-parallelized solvers for coupled field problems along-side with discrete methods that can operate over quad-tree meshes is necessary for rendering phase field methods applicable to optimisation problems. As a side-project we were also able to apply similar algorithms to fluid-structure interaction problems achieving 50x speed-ups when operating in multi-core servers.
