A Novel Parameters’ Identification Procedure for Aortic Walls Based on Hybrid Artificial Intelligence Approaches

Abstract

It is of great significance to have research on the deformation characteristics and stress distribution of aortic wall. Reliable prediction of constitutive parameters requires an inverse process, which possesses challenges. This work proposes an inverse procedure to identify the constitutive parameters of aortic walls, which integrates nonlinear finite element method (FEM), random forest (RF) model and hybrid Random Search (RS) and Grid Search (GS) algorithm. FEM models are first established to simulate nonlinear deformation of aortic walls subjected to uniaxial tension tests. A dataset of nonlinear relationship between the engineering stress and main stretch of aortic walls is created using FEM models and the nonlinear relationship is learned through RF model. The hybrid RS&GS algorithms are used to adjust the major hyperparameters in RF. Then the optimized RF is utilized to predict constitutive parameters of aortic walls with the help of uniaxial tension tests. The prediction results show that the RF optimized by hybrid RS&GS (RF-RS&GS) approach is an effective and accurate approach to identify the constitutive parameters of aortic walls. The present RF-RS&GS model can be further extended for the predictions of constitutive parameters of other types of nonlinear soft materials. Additionally, the relative importance of constitutive parameters of aortic walls in Gasser–Ogden–Holzapfel (GOH) strain energy function is investigated. It is found that the parameters [Formula: see text] and [Formula: see text]in GOH are most intensive to the engineering stress of aortic walls.