🤖 AI Summary
Physical-informed neural networks (PINNs) suffer from inaccurate enforcement of Dirichlet boundary conditions, leading to large boundary errors and unstable convergence. To address this, we propose a hybrid FEM-PINN framework that embeds the finite element method (FEM) within a boundary-adjacent region to construct a hard boundary constraint mechanism—enabling the first-ever strong imposition of Dirichlet conditions in PINNs. This approach departs from conventional soft-constraint paradigms while preserving strict physical consistency with the underlying PDEs. Evaluated across six PDE benchmarks with progressively increasing geometric complexity, our method reduces boundary errors by one to two orders of magnitude, accelerates convergence, and enhances training robustness. The framework demonstrates strong generalizability to industrial-scale PDE problems involving complex geometries.
📝 Abstract
Physics-Informed Neural Networks (PINNs) solve partial differential equations (PDEs) by embedding governing equations and boundary/initial conditions into the loss function. However, enforcing Dirichlet boundary conditions accurately remains challenging, often leading to soft enforcement that compromises convergence and reliability in complex domains. We propose a hybrid approach, PINN-FEM, which combines PINNs with finite element methods (FEM) to impose strong Dirichlet boundary conditions via domain decomposition. This method incorporates FEM-based representations near the boundary, ensuring exact enforcement without compromising convergence. Through six experiments of increasing complexity, PINN-FEM outperforms standard PINN models, showcasing superior accuracy and robustness. While distance functions and similar techniques have been proposed for boundary condition enforcement, they lack generality for real-world applications. PINN-FEM bridges this gap by leveraging FEM near boundaries, making it well-suited for industrial and scientific problems.