A Physics-Based Terrain Model for Off-Road Vehicle Simulations

2012 ◽  
Author(s):  
Justin Madsen ◽  
Paul Ayers ◽  
Alexander Reid ◽  
Andrew Seidl ◽  
George Bozdech ◽  
...  
Keyword(s):  
Soil Compaction ◽  
Three Dimensional ◽  
Interaction Model ◽  
Simulation Software ◽  
Governing Equations ◽  
Terrain Model ◽  
Vehicle Mobility ◽  
Terrain Representation ◽  
Tire Forces ◽  
Power And Energy

We present the development of a three-dimensional Vehicle/Tire/Terrain Interaction Model (VTTIM) consisting of a general 3D tire-terrain traction model which operates on a novel deformable terrain representation that utilizes a soil compaction model. Rather than utilizing popular empirical terramechanics models that only consider the pressure/sinkage directly under the tire, the governing equations of the terrain are based on i) the propagation of subsoil stresses due to vehicular loads, and ii) the resulting stress/strain which is based on a visco-elastic-plastic soil model developed by Ayers and Bozdech. The implementation of the terrain model is modularized in the form of an API, as the vehicle and tire are assumed to be contained in commercial simulation software as to focus on the implementation of the deformable terrain model. A number of test simulations are run using a rigid tire with and without grousers to show the capability of the VTTIM to predict tire forces for use in vehicle mobility and traction performance simulations. Power and energy required to deform the terrain will also be presented with the simulation results, which allows the prediction of the extra power required by a vehicle traveling on off-road, deformable soil.

Off-Road Vehicle Dynamics Mobility Simulation With a Compaction Based Deformable Terrain Model

2013 ◽  
Author(s):  
Justin Madsen ◽  
Andrew Seidl ◽  
Dan Negrut
Keyword(s):  
Vehicle Dynamics ◽  
Transfer Functions ◽  
Soil Mechanics ◽  
Three Dimensional ◽  
Interaction Model ◽  
Simulation Software ◽  
Repeated Loading ◽  
Model Parameters ◽  
Vehicle Simulation ◽  
Terrain Model

This paper discusses the terramechanics models developed to incorporate a physics-based, three dimensional deformable terrain database model with vehicle dynamics mobility simulation software. The vehicle model is contained in Chrono, a research-grade C++ based Application Programming Interface (API) that enables accurate multibody simulations. The terrain database is also contained in a C++ based API, and includes a general tire-terrain interaction model which is modular to allow for any tire model that supports the Standard Tire Interface (STI) to operate on the terrain. Furthermore, the ability to handle arbitrary, three dimensional traction element geometry allows for tracked vehicles (or vehicle hulls) to also interact with the deformable terrain. The governing equations of the terrain are based on a soil compaction model that includes both the propagation of subsoil stresses due to vehicular loads, and the resulting visco-elastic-plastic stress/strain on the affected soil volume. Non-flat, non-homogenous and non-uniform soil densities, rutting, repeated loading and strain hardening effects are all captured in the vehicle mobility response as a result of the general 3-D tire/terrain model developed. Pedo-transfer functions allow for the calculation of the soil mechanics model parameters from existing soil measurements. This terrain model runs at near real-time speed, due to parallel CPU and GPU implementation. Results that exercise the force models developed with the 3-D tire geometry are presented and discussed for a kinematically driven tire and a full vehicle simulation.

Analysis of Tire Models for Rolling on a Deformable Substrate

2002 ◽  
Vol 30 (3) ◽  
pp. 180-197 ◽  
Author(s):  
S. Shoop ◽  
I. Darnell ◽  
K. Kestler
Keyword(s):  
Finite Element ◽  
Vehicle Dynamics ◽  
Three Dimensional ◽  
Element Model ◽  
Tire Model ◽  
Terrain Model ◽  
Vehicle Mobility ◽  
Conventional Models ◽  
Dynamics Simulations ◽  
Tire Models

Abstract The objective of this research is to produce a finite element model of tire-terrain interaction that can be used to explore the effects of tire and terrain variables on vehicle mobility and terrain deformation. Such a model would need to account for the deformable nature of both the tire and the terrain and be fully three-dimensional. Thus, it is important that the tire model be very efficient at rolling yet retain realistic surface contact and deformation related to contact. A promising methodology was developed by Darnell for efficiently modeling a tire for vehicle dynamics simulations. The performance of the Darnell model was examined with respect to measured tire deformation as well as to conventional models of the same tire. The Darnell tire model was then rolled across a soil simulating the sand used in off-road vehicle experiments. The combined tire-terrain model presented is fully operational, but optimization and validation are in progress.

Propagation and Reflection of Plane Waves in a Rotating Magneto-Elastic Fibre-Reinforced Semi Space with Surface Stress

2020 ◽  
Vol 22 (4) ◽  
pp. 939-958
Author(s):  
Indrajit Roy ◽  
D. P. Acharya ◽  
Sourav Acharya
Keyword(s):  
Surface Stress ◽  
Incident Angle ◽  
Plane Waves ◽  
Three Dimensional ◽  
Elastic Fibre ◽  
Amplitude Ratios ◽  
Governing Equations ◽  
Rotation Surface ◽  
Wave Velocities ◽  
Magnetic Field Rotation

AbstractThe present paper investigates the propagation of quasi longitudinal (qLD) and quasi transverse (qTD) waves in a magneto elastic fibre-reinforced rotating semi-infinite medium. Reflections of waves from the flat boundary with surface stress have been studied in details. The governing equations have been used to obtain the polynomial characteristic equation from which qLD and qTD wave velocities are found. It is observed that both the wave velocities depend upon the incident angle. After imposing the appropriate boundary conditions including surface stress the resultant amplitude ratios for the total displacements have been obtained. Numerically simulated results have been depicted graphically by displaying two and three dimensional graphs to highlight the influence of magnetic field, rotation, surface stress and fibre-reinforcing nature of the material medium on the propagation and reflection of plane waves.

Thermomechanical Coupling of a Hyper-viscoelastic Truck Tire and a Pavement Layer and its Impact on Three-dimensional Contact Stresses

2021 ◽  
pp. 036119812110171
Author(s):  
Angeli Jayme ◽  
Imad L. Al-Qadi
Keyword(s):  
Contact Stress ◽  
Contact Area ◽  
Three Dimensional ◽  
Interaction Model ◽  
Rolling Resistance ◽  
Contact Stresses ◽  
Thermomechanical Coupling ◽  
Temperature Profiles ◽  
Near Surface ◽  
Truck Tire

A thermomechanical coupling between a hyper-viscoelastic tire and a representative pavement layer was conducted to assess the effect of various temperature profiles on the mechanical behavior of a rolling truck tire. The two deformable bodies, namely the tire and pavement layer, were subjected to steady-state-uniform and non-uniform temperature profiles to identify the significance of considering temperature as a variable in contact-stress prediction. A myriad of ambient, internal air, and pavement-surface conditions were simulated, along with combinations of applied tire load, tire-inflation pressure, and traveling speed. Analogous to winter, the low temperature profiles induced a smaller tire-pavement contact area that resulted in stress localization. On the other hand, under high temperature conditions during the summer, higher tire deformation resulted in lower contact-stress magnitudes owing to an increase in the tire-pavement contact area. In both conditions, vertical and longitudinal contact stresses are impacted, while transverse contact stresses are relatively less affected. This behavior, however, may change under a non-free-rolling condition, such as braking, accelerating, and cornering. By incorporating temperature into the tire-pavement interaction model, changes in the magnitude and distribution of the three-dimensional contact stresses were manifested. This would have a direct implication on the rolling resistance and near-surface behavior of flexible pavements.

scholarly journals Right-sided Bochdalek hernia in an adult with hepatic malformation and intestinal malrotation

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Naoki Enomoto ◽  
Kazuhiko Yamada ◽  
Daiki Kato ◽  
Shusuke Yagi ◽  
Hitomi Wake ◽  
...  
Keyword(s):  
Elective Surgery ◽  
Abdominal Cavity ◽  
Three Dimensional ◽  
Simulation Software ◽  
3D Simulation ◽  
Diaphragmatic Defect ◽  
Intestinal Malrotation ◽  
Intestinal Loop ◽  
Bochdalek Hernia ◽  
The Right

Abstract Background Bochdalek hernia is a common congenital diaphragmatic defect that usually manifests with cardiopulmonary insufficiency in neonates. It is very rare in adults, and symptomatic cases are mostly left-sided. Diaphragmatic defects generally warrant immediate surgical intervention to reduce the risk of incarceration or strangulation of the displaced viscera. Case presentation A 47-year-old woman presented with dyspnea on exertion. Computed tomography revealed that a large part of the intestinal loop with superior mesenteric vessels and the right kidney were displaced into the right thoracic cavity. Preoperative three-dimensional (3D) simulation software visualized detailed anatomy of displaced viscera and the precise location and size of the diaphragmatic defect. She underwent elective surgery after concomitant pulmonary hypertension was stabilized preoperatively. The laparotomic approach was adopted. Malformation of the liver and the presence of intestinal malrotation were confirmed during the operation. The distal part of the duodenum, jejunum, ileum, colon, and right kidney were reduced into the abdominal cavity consecutively. A large-sized oval defect was closed with monofilament polypropylene mesh. No complications occurred postoperatively. Conclusion Symptomatic right-sided Bochdalek hernia in adults is exceedingly rare and is frequently accompanied by various visceral anomalies. Accurate diagnosis and appropriate surgical repair are crucial to prevent possible incarceration or strangulation. The preoperative 3D simulation provided comprehensive information on anatomy and concomitant anomalies and helped surgeons plan the operation meticulously and perform procedures safely.

scholarly journals Generation and Annotation of Simulation-Real Ship Images for Convolutional Neural Networks Training and Testing

2021 ◽  
Vol 11 (13) ◽  
pp. 5931
Author(s):  
Ji’an You ◽  
Zhaozheng Hu ◽  
Chao Peng ◽  
Zhiqiang Wang
Keyword(s):  
Neural Networks ◽  
Convolutional Neural Networks ◽  
Image Annotation ◽  
Three Dimensional ◽  
Image Data ◽  
Detection Algorithm ◽  
Simulation Software ◽  
High Quality ◽  
Annotation Method ◽  
Detection Of Objects

Large amounts of high-quality image data are the basis and premise of the high accuracy detection of objects in the field of convolutional neural networks (CNN). It is challenging to collect various high-quality ship image data based on the marine environment. A novel method based on CNN is proposed to generate a large number of high-quality ship images to address this. We obtained ship images with different perspectives and different sizes by adjusting the ships’ postures and sizes in three-dimensional (3D) simulation software, then 3D ship data were transformed into 2D ship image according to the principle of pinhole imaging. We selected specific experimental scenes as background images, and the target ships of the 2D ship images were superimposed onto the background images to generate “Simulation–Real” ship images (named SRS images hereafter). Additionally, an image annotation method based on SRS images was designed. Finally, the target detection algorithm based on CNN was used to train and test the generated SRS images. The proposed method is suitable for generating a large number of high-quality ship image samples and annotation data of corresponding ship images quickly to significantly improve the accuracy of ship detection. The annotation method proposed is superior to the annotation methods that label images with the image annotation software of Label-me and Label-img in terms of labeling the SRS images.

scholarly journals Effect of magnetic field on nanofluid free convection in Conical Partially Annular Space

2020 ◽  
Vol 330 ◽  
pp. 01005
Author(s):  
Abderrahmane AISSA ◽  
Mohamed Amine MEDEBBER ◽  
Khaled Al-Farhany ◽  
Mohammed SAHNOUN ◽  
Ali Khaleel Kareem ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Boussinesq Approximation ◽  
Simulation Software ◽  
Comsol Multiphysics ◽  
Governing Equations ◽  
Element Analysis ◽  
Vertical Side ◽  
Side Walls

Natural convection of a magneto hydrodynamic nanofluid in a porous cavity in the presence of a magnetic field is investigated. The two vertical side walls are held isothermally at temperatures Th and Tc, while the horizontal walls of the outer cone are adiabatic. The governing equations obtained with the Boussinesq approximation are solved using Comsol Multiphysics finite element analysis and simulation software. Impact of Rayleigh number (Ra), Hartmann number (Ha) and nanofluid volume fraction (ϕ) are depicted. Results indicated that temperature gradient increases considerably with enhance of Ra and ϕ but it reduces with increases of Ha.

Application of the Mechanical Impedance of Body Arm Movement Based on the Virtual Tennis System

2013 ◽  
Vol 791-793 ◽  
pp. 1436-1440
Author(s):  
Ling Hang Yang
Keyword(s):  
Virtual Reality ◽  
Three Dimensional ◽  
Arm Movement ◽  
Mechanical Impedance ◽  
Simulation Software ◽  
Computer Hardware ◽  
Calculation Results ◽  
Virtual System ◽  
Dimensional Simulation ◽  
Theoretical Results

With the development of computer hardware and software technology, virtual reality technology of computer has been widely used in various fields. Virtual teaching process is one of the main applications of virtual reality computer technology. Tennis is one of the most common sports. Tennis process mainly includes the process of catching a ball, serving a ball and hitting a ball. Virtual process of tennis system must establish an accurate numerical simulation model to calculate the mechanical impedance during the arm movement of human. According to this, it builds a model of the mechanical impedance of human arm in tennis virtual system using three-dimensional simulation software in this paper and gets the curve of mechanical impedance through the simulation. Finally, the article compares calculation results with the theoretical results and concludes that the theoretical results and simulation results are basically consistent which provide a theoretical reference for the design of the development of virtual system for the human.

Runner Balance Design of Soap Box Compounding Cavity Based on Moldflow

2014 ◽  
Vol 941-944 ◽  
pp. 1678-1681
Author(s):  
Hong Bing Wang ◽  
Zhi Rong Li ◽  
Chun Hua Sun ◽  
Yi Ping Zhang
Keyword(s):  
Three Dimensional ◽  
Simulation Software ◽  
Injection Mold ◽  
Balance Design ◽  
Filling Time ◽  
Critical Defect ◽  
Filling Analysis ◽  
Different Dimensions ◽  
Moldflow Simulation

Filling unbalance is a critical defect for injection mould. When the upper and lower covers of soap plastic box are produced by injection mold at the same time, filling unbalance in injection would appear because of the different dimensions of the two parts. For advancing the quality of the soap plastic box, the runner system is optimized with the filling analysis module and flow runner balance module of moldflow simulation software. The three-dimensional geometrical models of the two covers are constructed using Pro/e software. In moldflow the runner balance optimization of the soap box compounding cavity is analysis. The results indicate the optimized cross section of the runners can reduce the flow unbalance ratio from 3.38% to 0.73%, and the filling time and pressure can satisfy the demands. According to the analysis results moldflow is appropriate for runner balance design of the plastic products.

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