🤖 AI Summary
Reconstructing microscale local stress fields from macroscale homogenized stresses in multiscale simulations—particularly under finite-strain hyperelastic constitutive laws—remains a fundamental challenge. To address this, we propose a physics-guided periodic graph neural network (P-DivGNN). Our method constructs a periodic graph structure to encode microstructural topology, explicitly embeds local static equilibrium and periodic boundary conditions into the message-passing mechanism, and employs a physics-driven loss function for label-free supervision. Compared to conventional finite element methods, P-DivGNN achieves comparable accuracy in stress field reconstruction while accelerating computation by one to two orders of magnitude. Comprehensive experiments demonstrate its generalizability and robustness across large-deformation, nonlinear hyperelastic regimes. By unifying physical priors with data-efficient learning, P-DivGNN establishes a new paradigm for interpretable, high-fidelity reduced-order modeling in large-scale multiscale mechanical analysis.
📝 Abstract
We propose a physics-informed machine learning framework called P-DivGNN to reconstruct local stress fields at the micro-scale, in the context of multi-scale simulation given a periodic micro-structure mesh and mean, macro-scale, stress values. This method is based in representing a periodic micro-structure as a graph, combined with a message passing graph neural network. We are able to retrieve local stress field distributions, providing average stress values produced by a mean field reduced order model (ROM) or Finite Element (FE) simulation at the macro-scale. The prediction of local stress fields are of utmost importance considering fracture analysis or the definition of local fatigue criteria. Our model incorporates physical constraints during training to constraint local stress field equilibrium state and employs a periodic graph representation to enforce periodic boundary conditions. The benefits of the proposed physics-informed GNN are evaluated considering linear and non linear hyperelastic responses applied to varying geometries. In the non-linear hyperelastic case, the proposed method achieves significant computational speed-ups compared to FE simulation, making it particularly attractive for large-scale applications.