MODELING TIRE-SOIL INTERACTION USING FINITE ELEMENT ANALYSIS AND SMOOTH PARTICLE HYDRODYNAMICS

计算机建模极大地改变了设计过程和收集实验信息的方式。传统的设计和开发过程涉及各种简化假设的物理模型公式，在某些情况下，这些模型不能有效地用于原型设计和实验评估。这些进程的持续设置、运行和信息收集可能很快就会变得非常昂贵。随着计算机建模的出现，与基于物理模型的实验相比，可以在更短的时间内以更低的成本进行广泛的虚拟实验。此外，虚拟模型可以更真实地反映物理系统，并可以提供更准确的系统动态性能估计。所提出的研究的长期目标是开发有效的充气轮胎及其与刚性和可变形地形表面相互作用的虚拟模型。随着计算机建模方法的进步，开发全面的充气轮胎模型已经成为可能，该模型可以确定其各种特性，包括轮胎-道路相互作用参数，这些参数要么是昂贵的，要么是几乎不可能从物理模型中测量。因此，虚拟轮胎模型可以作为先进轮胎设计的重要和有效的工具，增强车辆的动态性能，包括燃油效率、机动性、方向动力学，从而提高车辆和驾驶员的安全性。轮胎与软土相互作用的建模仍然是实现资源部门和军用车辆轮胎改进设计的最大挑战。尽管最近的一些研究提供了一系列描述轮胎与软土相互作用的新参数，但由于缺乏准确的土本构方程，这些参数的有效性尚未得到证实。这些研究通常采用土壤的有限元模型，其中材料模型需要大量的校准和验证。拟议的研究将旨在开发虚拟轮胎模型，该模型可应用于涉及不可变形和可变形地形表面的公路和越野商用车。将强调模型的准确性和效率，以促进高性能轮胎设计的应用，特别是在可变形地形上运行的高速和高负载能力资源部门车辆。为此，将探索光滑颗粒流体动力学（SPH）的无网格建模方法，以更准确地模拟大变形和复杂的轮胎-土壤相互作用。

Computerized modeling has greatly changed both the design process and the way in which experimental information is gathered. Traditional design and development processes involved formulations of physical models with various simplifying assumptions and, in some cases, these models could not be effectively employed for prototyping and experimental evaluations. The continuous setup, running, and information gathering of these processes could quickly become very expensive. With the advent of computerized modeling, a wide range of virtual experiments could be performed in less time and at substantially lower cost than those based on the physical models. Furthermore, the virtual models could be far more realistic of the physical systems and could provide more accurate estimations of the system dynamic performance.  The longterm objective of the proposed research is to develop effective virtual models of pneumatic tires and their interactions with rigid as well as deformable terrain surfaces. With the advancements in the computerized modeling methods, it has become feasible to develop comprehensive pneumatic tire models, which could permit the determination of its various properties including the tire-road interaction parameters, which are either prohibitively expensive to measure or nearly impossible from the physical models. The virtual tire models could thus serve as important and efficient tools for designs of advance tires with enhanced dynamic performance of the vehicles including the fuel efficiency, mobility, directional dynamics and thereby the safety of the vehicle and the driver. The modeling of tire interactions with soft soils continues to be the greatest challenge for realizing improved designs for resource sectors and military vehicles tires. Although a few recent works have provided an array of new parameters describing the tire interactions with soft soils, their effectiveness is not yet proven mostly due to lack of accurate soil constitutive equations. These studies generally employ Finite Element models of the soil, where the material models requiring extensive calibrations and validation.  The proposed study will aim at developments of virtual tire models that could be applied to on-road and off-road commercial vehicles involving non-deformable and deformable terrain surfaces. The accuracy and efficiency of the model will be emphasized to facilitate applications towards designs of high performance tires particularly for high-speed and high load capacity resource sector vehicles operating on deformable terrains. For this purpose, the meshless modeling method of Smooth Particle Hydrodynamics (SPH) would be explored for more accurately simulations of large soil deformations and complex tire-soil interactions.