Shape-informed surrogate models based on signed distance function domain encoding

TL;DR

This paper introduces a novel, meshless surrogate modeling approach that uses shape-informed neural networks with signed distance functions to efficiently approximate PDE solutions on arbitrary, changing geometries.

Contribution

It combines shape encoding via signed distance functions with neural networks to create a flexible, low-dimensional, and accurate surrogate model for parameterized PDEs without explicit geometric parametrization.

Findings

Achieves high accuracy in fluid dynamics and solid mechanics simulations.

Handles geometries with topology changes without manual intervention.

Offers computational efficiency and flexibility over traditional methods.

Abstract

We propose a non-intrusive method to build surrogate models that approximate the solution of parameterized partial differential equations (PDEs), capable of taking into account the dependence of the solution on the shape of the computational domain. Our approach is based on the combination of two neural networks (NNs). The first NN, conditioned on a latent code, provides an implicit representation of geometry variability through signed distance functions. This automated shape encoding technique generates compact, low-dimensional representations of geometries within a latent space, without requiring the explicit construction of an encoder. The second NN reconstructs the output physical fields independently for each spatial point, thus avoiding the computational burden typically associated with high-dimensional discretizations like computational meshes. Furthermore, we show that accuracy in geometrical characterization can be further enhanced by employing Fourier feature mapping as input feature of the NN. The meshless nature of the proposed method, combined with the dimensionality reduction achieved through automatic feature extraction in latent space, makes it highly flexible and computationally efficient. This strategy eliminates the need for manual intervention in extracting geometric parameters, and can even be applied in cases where geometries undergo changes in their topology. Numerical tests in the field of fluid dynamics and solid mechanics demonstrate the effectiveness of the proposed method in accurately predict the solution of PDEs in domains of arbitrary shape. Remarkably, the results show that it achieves accuracy comparable to the best-case scenarios where an explicit parametrization of the computational domain is available.