This book will be of great interest to any professional engineer or automotive engineering student working on off-road vehicles. Reflecting the increase in off-road vehicle production and development-recreational, agricultural, construction, military-this book equips readers with all of the necessary knowledge to successfully design and model off-road vehicle systems, and provides a comprehensive introduction to terramechanics, the mechanics of vehicle/terrain interaction. The only book to cover the principles of off-road vehicle and terrain engineering, a rapidly developing sector that includes SUVs, tractors and agricultural vehicles, military vehicles, and construction equipmentCovers the latest developments in the field, including the latest computer-aided methods employed in the development of new generation of high-mobility off-road vehicles in Europe, North America and Asia.Ideal for professional reference and course reference by students, with new detailed worked design examples, case studies, and accompanying problems and solutions.
Author(s): J.Y. Wong
Edition: 2
Year: 2009
Language: English
Pages: 488
cover......Page 1
Copyright......Page 2
Preface to the Second Edition......Page 3
Preface to the First Edition......Page 5
Conversion Factors......Page 8
Nomenclature......Page 9
Introduction......Page 14
Role of Terramechanics......Page 15
Some Basic Issues in Terramechanics......Page 19
Modelling of Terrain Behaviour......Page 20
Measurement and Characterization of Terrain Properties......Page 21
Cone penetrometer technique......Page 22
Bevameter technique......Page 23
Modelling of Vehicle–Terrain Interaction......Page 25
Empirical Methods......Page 28
Computational Methods......Page 29
Methods for Parametric Analysis......Page 30
Modelling of Terrain Behaviour......Page 33
Modelling Terrain as an Elastic Medium......Page 34
Example 2.1......Page 41
Solution......Page 42
Modelling Terrain as a Plastic Medium......Page 43
Solution......Page 45
Solution......Page 49
Solution......Page 52
Modelling Terrain Behaviour based on the Critical State Soil Mechanics......Page 57
Modelling Terrain using the Finite Element Method (FEM)......Page 60
Modelling Terrain Behaviour using the Discrete (Distinct) Element Method (DEM)......Page 67
PROBLEMS......Page 74
Cone Penetrometer Technique......Page 76
Bevameter Technique......Page 79
Basic Features of the Bevameter......Page 80
A Portable Automatic Data Acquisition and Processing System......Page 83
Characterization of the Response
of Terrains to Normal and Repetitive Loadings......Page 86
Pressure–Sinkage Relationship......Page 87
Response to Repetitive Loading......Page 96
Physical Features of the Muskegs Tested......Page 99
Pressure–Sinkage Relationship......Page 101
Response to Repetitive Loading......Page 111
Response of Snow Covers......Page 113
Bearing Capacity of an Ice Layer in a Snow Cover......Page 115
Pressure–Sinkage Relationship of Snow Covers with a Significant Ice Layer......Page 121
Response to Repetitive Loading......Page 123
Characterization of the Shear Stress–Displacement Relationships......Page 125
Behaviour of Terrain under Repetitive Shear Loading......Page 133
Factors Affecting Off-Road Vehicle Performance......Page 139
Aerodynamic Resistance......Page 140
Internal resistance of the running gear......Page 141
Thrust (Tractive Effort or Propelling Force)......Page 142
Drawbar Pull Coefficient and Drawbar Power......Page 143
Tractive (Drawbar) Efficiency......Page 145
Four-Wheel-Drive......Page 149
Transport Productivity and Transport Efficiency......Page 157
Mobility Map and Mobility Profile......Page 159
Problems......Page 161
Empirical Methods......Page 164
Methods for Parametric Analysis......Page 172
Methods for Predicting Static Pressure Distributions beneath Tracks......Page 180
Problems......Page 184
Computer-Aided Method NTVPM for Evaluating the Performance of Vehicles with Flexible Tracks......Page 186
Basic Approach to the Prediction of Normal Pressure Distribution under a Flexible Track......Page 187
Prediction of Shear Stress Distribution under a Flexible Track......Page 197
Effects of Shear Stresses on the Normal Pressure Distribution......Page 200
Prediction of Motion Resistance and Drawbar Pull......Page 202
Experimental Substantiation......Page 204
Comparisons of Predictions by NTVPM with Test Data......Page 216
Applications of the Computer-Aided Method NTVPM to Parametric Analysis of Vehicles with Flexible Tracks......Page 219
Effects of Initial Track Tension and Track System Configuration......Page 222
Effects of Suspension Setting......Page 247
Effects of Longitudinal Location of the Centre of Gravity......Page 255
Effects of Vehicle Total Weight......Page 265
Effects of Track Width......Page 276
Effects of Sprocket Location......Page 289
Concept of a High-Mobility Tracked Vehicle for Operation on Soft Ground......Page 301
Effects of Design Features on the Performance of Two-Unit Articulated Vehicles......Page 303
Analysis and Evaluation of Detracking Risks......Page 313
The Necessary Condition for Detracking......Page 314
Detracking Risk Indicators for Track Drive Lugs/Track Guides Overriding the Sprocket/Idler......Page 316
Risk Indicators for Disengagement of the Leading Track Drive Lug/Track Guide with the Sprocket/Idler......Page 318
Basic Features of the Module DETRACK for Evaluating Detracking Risks......Page 320
Applications of DETRACK to Evaluating Detracking Risks of Track Systems......Page 321
When a braking torque is applied......Page 322
Summary......Page 325
Applications of NTVPM to Product Development in the Off-Road Vehicle Industry......Page 327
Concluding Remarks......Page 333
Basic Approach to the Development of the Computer-Aided Method RTVPM......Page 340
Analysis of the Upper Run of the Track......Page 341
Analysis of the Lower Run of the Track in Contact with the Terrain......Page 346
Analysis of the Links in Contact with the Idler......Page 350
Analysis of the Links in Contact with the Sprocket......Page 354
Analysis of the Complete Track System with Rigid Links......Page 355
Experimental Substantiation......Page 356
Applications of the Computer-Aided Method RTVPM to Parametric Analysis......Page 360
Effects of the Ratio of Roadwheel Spacing to Track Pitch......Page 362
Effects of Initial Track Tension......Page 371
Concept of a Vehicle with Enhanced Performance on Soft Ground......Page 373
Concluding Remarks......Page 375
Methods for Evaluating Wheeled Vehicle Performance......Page 377
Empirical Methods......Page 378
Methods for Parametric Analysis......Page 384
Rigid Wheel–Terrain Interaction......Page 385
Compaction Resistance of Rigid Wheels......Page 386
Stress Distributions on the Contact Patch of Driven Rigid Wheels......Page 391
Stress Distributions on the Contact Patch of Towed Rigid Wheels......Page 392
Solution......Page 389
Compaction Resistance of a Flexible Tyre......Page 397
Prediction of the Operating Mode of a Pneumatic Tyre......Page 399
Resistance Due to Tyre Flexing......Page 403
Thrust–Slip Relationship of a Flexible Tyre......Page 405
Solution......Page 404
Problems......Page 407
Basic Features of NWVPM for Evaluating Tyre Performance......Page 408
Normal Pressure Distributions......Page 409
Shear Stress Distributions......Page 411
Example 12.1......Page 413
For a Tyre in the Rigid Operating Mode......Page 414
For a Tyre in the Elastic Operating Mode......Page 415
For a Tyre in the Rigid Operating Mode......Page 417
For a Tyre in the Elastic Operating Mode......Page 418
Basic Features of NWVPM for Evaluating Wheeled Vehicle Performance......Page 419
Experimental Substantiation......Page 422
Applications of NWVPM to Parametric Analysis of Wheeled Vehicle Performance......Page 424
Applications of NWVPM to the Evaluation of Lunar Vehicle Wheels......Page 429
Lunar Vehicle Wheels......Page 430
Procedures and Soil Conditions for Testing Lunar Vehicle Wheels......Page 431
Boeing-GM IV and VI Wheels......Page 433
Bendix 1 Wheel......Page 435
Concluding Remarks......Page 436
Applications of the Finite Element Technique to Tyre Modelling in the Analysis of Tyre–Terrain Interaction......Page 437
Modelling Tyre Behavior using the Finite Element Technique......Page 439
Analysis of Tyre–Terrain Interaction using the Tyre Model......Page 441
Wheeled Vehicles vs Tracked Vehicles from the Traction Perspective......Page 444
General Analysis of Wheeled Vehicles vs Tracked Vehicles......Page 445
Using Computer-Aided Methods for the Analysis of Wheeled Vehicles vs Tracked Vehicles......Page 451
Problems......Page 455
References......Page 456
E......Page 466
S......Page 467
W......Page 468
