The influence of soil modeling on the prediction of vehicle dynamics and mobility – A comparison between the Finite Element Method and a Semi[1]Empirical Model

Abstract: This master's thesis investigated the influence of soil modeling on vehicle dynamics and mobility predictions with a focus on two different soil models implemented in Project Chrono: the Bekker-Wong model, and a Finite Element (FE) model. The primary objective is to provide insights for decision-making regarding the most suitable soil model under specific circumstances. The Bekker-Wong model, a semi-empirical terrain model, is straightforward to implement and provides a good baseline for simple scenarios. The FE model, on the other hand, offers greater complexity and accuracy by considering nonlinear soil properties and three-dimensional deformations. Both models were simulated using various vehicle-soil interaction scenarios to evaluate their performance and applicability. This study also analyzes the computational efficiency and resource requirements of the FE model compared to the Bekker-Wong model. The result of this thesis indicates that the FE model provides more accurate predictions of the deformations, particularly when dealing with complex soils with significant shear stresses and where time-dependent deformations are crucial. However, the computational complexity of the FE model poses a great challenge, especially for large soil patches and where fine discretization is required. This challenge could be alleviated with sophisticated solvers and adaptive mesh refinement along with running the models on powerful clusters. The limitations of the study also include the use of different input parameters for both models, making it difficult to make direct comparisons. Thus, the focus was put on performance-based comparisons of the models. Future research could focus on conducting its own soil experiments to ensure comparable soil parameter values for both models, along with validating the results with real experiments, and optimizations of the FE model.