A FACTBOOK OF THE MECHANICAL PR0PERTIE:S OF THE COMPONENTS FOR SINGLE-UNIT AND ARTICULATED HEAVY TRUCKS Paul S. Fancher Robert D. Ervin Christopher B. Winkler Thomas D. Gillespie The University of Michigan 'I'rmsportation Research Institute Ann Arbor, Michigan 48 109 December 1986 The University of Michigan UM:TRI Transportation Research Institute 1. Report No. 2. GO**-t Acces~ionNo. 3. Recipimt's Catalog No. 4. fitlo md Subtitle 5. Rmtt OC. A FACTSOOK OF THE MECHANICAL PROPERTiES OF THE December 1.986 COMPONENTS FOR SINGLE-UNlT AND ARTICULATED HEAVY '6. pufamino Orponizotion code TRUCKS 8. Pwfoming Orgmizotion Report No. 7. P,!;. Fancher, R.D. trvin, C.B. wlnk ler, and T.D. Gillespie UMTRI-86- 12 9. P.rfarming Orgmixotion Nme md Address 10. Wad Unit No. The University of Michigan Transportation Research Institute 11. Contract or Cront NO. Ann Arbor, Michi gan 4e8109 DTNH22-83-C-07187 '3- TIP. of R.port and Period Covered 12. honsaring Agmcy Nme md Address National Highway Traffic Safety Administration PHASE I FINAL REPORT Department of Transportation 9/30/83 - 3/31/86 400 Seventh Street, S.W. 14. %ensoring Agency cod. Waqhington. D.C. 20 590 15. Supplemontay Notes Contract Technical Manager: Mr. Wi 1 liam Leasure la. Ahstroo This factbook provides a compilation of the mechanical properties of the components used in heavy trucks. It contains sections describing and discussing geometric layout, mass distribution, tires , suspensions, steering sys tems, brakes, frames, and hitches. Parametric data on heavy truck components are presented in a form suitable for use in analyzing the braking and steering performance of heavy trucks including combination vehicles. The influences of component properties on maneuvering performance are discussed. 17. Key Words 18. Distribution Statmmmt Heavy truck components, Geometric layout, Inertial properties, Unlimited Steering, Braking, Suspensions, Ti res 19. SIcurity Clwssif. (of this reput) 23. Lcurity Clwssif. (of chis pw) 21. No. of Popes 22 Price None None 190 TABLE OF CONTENTS Section Page ... LIST OF' FIGURES ....................................................................... u LIST OF TABLES ........................................................................ v ACKNOWLEDGEMENT'S.............................................................. vi DISCLAIMER CONCERNING THE MENTIONING OF INDIVIDUAL MANUFACTURERS .................................................. vii 1.0 INTRODUCTION......................................................................... 1 1.1 Background.......................................................................... 1 1.2 Scope................................................................................. 1 1.3 Organization of the IDiscussions................................................... 2 2.0 BASIC COMPONENTS................................................................. 7 2.1 Tires .................................................................................. 7 2.2 Suspensions ......................................................................... 37 2.3 Steering Systems .....................................................................68 2.4 Brstkes ................................................................................ 87 2.5 Frames ............................................................................... 100 2.6 Hitches ...............................................................................108 3.0 GEOME'IlUC LAYOUTS AND MASS DISTRIBUTIONS OF MAJOR UNITS ......................................................................................110 ................................................................... 3.1 Geometric .Layout . 110 3.2 Mass Distribution .................................................................. 128 APPENDIX A: DATA SEiTS FOR BENCHMARK VEHICLES.. ................. 154 LIST OF FIGURES Figure Page 1.1 Overall information .flow............................................................. 3 1.2 Co~nponentsdescribed in section 2 ................................................. 4 2.1.1 Definition of primary cornering and braking force and moments ............... 8 2.1.2 Factors influencing the pertinent mechanical properties of truck tires .......... 9 2.1.3 The: tire operating at a slip angle (i,e., "pure cornering") ......................... 11 2.1.4 Lateral force vs. slip angle, illustrating cornering stiffness property, C, ...... 12 2.1.5 Aligning moment vs . slip angle, illustrating aligning stiffness, CMz........... 14 2.1.6 Lorlgitudinal force vs . longitudinal slip. illustrating peak and slide measures. FVeak and Fxslide ....................................................... 2.1.7 The: cross-influence of lateral and longitudinal tire forces such as accrue during combined braking and cornering .......................................... 2.1.8 Vertical load vs . vertical deflection illustrating vertical stiffness at rated load. 2.1.9 An illustration of how the curvature in (C, vs . Fz) causes a net reduction in C, due to load transfer in a turning maneuver ................................... 2.1.10 Cornering coefficient. n ................................................................. 2.1.1 1 Curvature coefficient.. .................................................................. 2.1.12 Pneumatic trail, Pt..................................................................... 2.1.13 Peak and slide traction coefficient values (wet surface).......................... 2.1.14 Peak and slide traction coefficientvalues (dry surface)........................... 2.1.15 Vertical stiffness values ............................................................. 2.2.1 Pertinent mechanica'l properties of tandem axle suspensions.................... 2.2.2 Pertinent mechanical properties of steering axle suspensions.................... 2.2.3 Pertinent mechanical properties of single (non-steering) axle suspensions.... 2.2.4 Avtxage vertical displacement vs . average vertical wheel load .................. 2.2.5 Relative vertical defl.ection vs . average vertical load per wheel.................. 2.2.6 Spring displacements in roll ......................................................... 2.2.7 Four-spring suspens.ion.............................................................. 2.2.8 Walking beam suspe.nsion ........................................................... 2.2.9 Illustration of roll center .............................................................. 2.2.10 Illustration of roll stcer............................................................... 2.2.1 1 Illustration of comm~:rcial vehicle in turn ........................................... 2.2.12 Suspension composite vertical stiffnesses......................................... 2.2.13 Suspension composj.te roll stiffnesses .............................................. 2.2.14 Suspension composite coulomb damping .......................................... 2.2.15 Suspension inter-axle load transfer................................................. 2.2.16 Suspension roll center heights ....................................................... 2.2.17 Suspension roll steel. .................................................................. 2.2.18 Suspension aligning moment compliance steer.................................... 2.3.1 Typical steering system configuration on medium and heavy trucks ........... 2.3.2 Pertinent mechanical properties of steering systems.............................. 2.3.3 Examples of steering geometry error ............................................... 2.3.4 Kingpin moment produced by lateral force........................................ iii 2.3.5 Stelcring linkages modeled as stiffnesses........................................... 2.3.6 Kingpin moment produced by tractive forces...................................... 2.3.7 Tractor front suspension roll steer coefficients.................................... 2.3.8 Efkctive cornering atiffness ratio ................................................... 2.3.9 Typical truck caster angles. .......................................................... 2.3.10 Typical tire cornering stiffness values .................... ..,....................... 2.3.1 1 Typical pneumatic trail values ....................................................... 2.3.12 Pri~narysteering stiffness values. Kss. between the steering wheel and the left road wheel ...................................................... 2.3.13 Tie rod linkage stiffness values. Ke, between left and right roadwheels ...... 2.4.1 Pertinent mechanical properties of brakes .......................................... 2.4.2 Data from a spin-down dynamometer test .......................................... 2.4.3 Brake pressures vers'us time - tractor-trailer combination........................ 2.4.4 Brake torque chracteristics........................................................... 2.4.5 Influence of velocity on average brake torque ..................................... 2.4.6 Estimates of Brake gain approximating effectiveness at high pressure and 50 mph initial ve:locity ..................................... ................... 2.5.1 Typical highway truck frame ........................................................ 2.5.2 Pertinent mechanica:l properties of frames .......................................... 2.5.3 Tractor frame torsioinal stiffness...................................................... 3.1.1 Factors influencing the pertinent mechanical properties of geometric layout... 3.1.2 Truck and tractor wheelbase........................................................