Interfacing AceGEN and FEniCS for advanced constitutive models

There are two main difficulties related to FE analysis: (i) the necessity to provide effective FE procedures for complex constitutive models or advanced FE formulations, and (ii) the need to solve big problems. Up to date, no single environment exists to fully tackle both. In the present contribution we combine two existing systems: AceGen and FEniCS. AceGen is an advanced automatic differentiation (AD) system, capable to derive highly efficient low-level computer code for characteristic FE quantities (gradients, tangent operators, sensitivity vectors, etc) for complex FE formulations. FEniCS is a flexible open-source FE framework, designed to perform large-scale analyses on high-performance computer architectures.

The proposed hybrid approach relies on new developments of FEniCSx project, which allows to incorporate external FE code to the environment. As examples, we have generated FE routines for two representative FE formulations: hyperelesticity and non-linear elasto-plasticity with hardening. The former formulation can be also generated by the FEniCS Form Compiler (FFC), thus allows to quantitively show the runtime speedup of the FE procedures generated by AceGEN w.r.t. FEniCS/FFC. The latter formulation shows the dominance of the hybrid approach over AceGen/AceFem or FEniCS alone, which is the ability to solve complex FE formulations within the HPC-ready framework.