Vehicle Simulation on Soft-Soil Roads Using Altair MotionSolve
Explore the fascinating dynamics of vehicles traversing deformable roads with the new tire and soft-soil contact model now available in Altair MotionSolve.
The new Altair Soft-Soil Tire model provides a computationally efficient way to simulate tires on compressible surfaces such as clay, dry sand, and regolith. Custom and predefined shape obstacles can be added to the road, and scanned road profiles in the form of Curved Regular Grid (*.crg) files can be used to represent the deformable surface.
The soil model is based on classical and well-established principles introduced by Bekker, Wong, Janosi, Hanamoto and the current capabilities of multibody solvers. The road is modeled as a rectangular structured grid of deformable springs in the vertical direction, as illustrated in Figure 1. This approach ensures fast execution, ability to handle large road scenarios, and address challenges like multi-pass effect and track-tire combined road.
Figure 1: Road data structure, augmented with the soil properties and multi-pass parameters
The tire-soil contact model utilizes a local approximation of the terrain surface with an equivalent plane, enabling a much easier and computationally efficient way to perform the contact calculations. For this, two different strategies are employed: specifically, the Radial Basis Function (RBF) interpolation method and the 3D Enveloping contact model.
In the RBF method, the springs enclosed in the tire contact patch area are collected and their soil elevation values are utilized to generate an equivalent plane that describes the current tire-terrain interaction in a proper way, as shown in Figure 2.
Figure 2: Tire contact patch (left) and springs enclosed in the tire contact patch area (right)
The 3D Enveloping contact model employs a series of ellipses to scan the road profile and, thus, produces an effective equivalent road plane that locally approximates the irregular profile of a deformable terrain, as shown in Figure 3.
Figure 3: 3D Enveloping contact model
In the video below, the new tire and soft-soil contact model is presented, demonstrating its implementation in Altair MotionView and MotionSolve. The video showcases the comparison of experimental data with the numerical simulations of a single-wheel test bed, followed by a four-wheeled rover model and the FED-Alpha Next-Generation NATO reference mobility model (NG-NRMM). It concludes with a case study involving both wheeled and tracked vehicles using a shared road model.
https://www.youtube.com/watch?v=1B-Ry46xS38
Install HyperWork 2023 to start using the new soft soil contact model. You are encouraged to use the new tire soft-soil model for initial design study before engaging in a more complex and computationally expensive MotionSolve, EDEM, and PME FlexTire co-simulation.
For more details on this feature, please refer to Altair Soft Soil Modeling