July 10, 2007: 14h15: - Session 2c - Infrastructure

Transcription

1 July 10, 2007: 14h15: - Session 2c - Infrastructure Comparison of Contact Stresses of the test tyres used by the 1/3 rd scale Model Mobile Load Simulator (MMLS3) and the full scale tyres of the Heavy Vehicle Simulator (HVS) - A Summary - Morris De Beer CSIR Built Environment, Elzbieta S Sadzik, GDPTRW

2 Project Background: Project initiated by Gauteng Department of Public Transport, Roads and Works (GDPTRW); Accelerated Pavement Testing (APT) Strategy of 2004; Full Scale Testing vs 1/3 rd Scale Testing; Heavy Vehicle Simulator (HVS), and 1/3 rd Scale Model Mobile Load Simulator (MMLS3).

3 Project Objectives: Quantification of the 3D tyre-pavement contact stresses: HVS and MMLS3 test tyres (using SIM) 4 Studies; Comparison with similar previous Stress-In- Motion (SIM) studies on various HVS tyres Z Vertical Stress only - in this paper; Recommendations for tyre load and inflation pressures of future Accelerated Pavement Testing (APT) on Hot Mix Asphalt (HMA) rutting tests (MMLS3 and HVS);

4 Heavy Vehicle Simulator (HVS) of Gautrans (GDPTRW) Full Scale

5 Model Mobile Load Simulator (MMLS3) 1/3 rd Scale

6 Oct HVS SIM TESTS

7 Truck Tyres Usage on N3 (2003) LEFT STEERING TYRES (N3-26/02/ /03/2003) Other 12.9 % 12R % 47.1 % 315/80 R22.5 (Mostly Steering Axle)

8 HVS Mk IV+ Full Scale Test Tyres DUAL: 12R22.5 SINGLE: 315/80 R22.5 (Steering Axle)

9 SAE sign convention used during SIM measurements. X-Longitudinal, Y-Lateral and Z -Vertical loads/stresses. Tyre Rotation +X +Z +Y

10 Oct 2004 Preparation of Test Gautrans- KoedoesPoort

11 September mm Concrete Gautrans- KoedoesPoort

12 Dual SIM system during HVS tyre Gautrans

13 MMLS3 Test Tyres

14 Model Mobile Load Simulator (MMLS3) 1/3rd Scale Tyre Tyre 1: 2: Diamond Tyre 2: Tyre Diamond 1: Diamond CRANK FOR HEIGHT SETTING ADJUSTMENT 300 PNEUMATIC TYRE DRIVE MOTOR 300 Tyre 3: Longitudinal 1260 Tyre 4: Longitudinal LONGITUDINAL SECTION CROSS SECTION

15 Characteristics of MMLS3 (highway applications) and HVS Mk IV+ Characteristic Nominal Constant Tyre Loading Range (kn) Footprint area (approximately), depending on tyre type, loading and inflation pressure (cm 2 ) MMLS3 (1/3 rd Scale) 1.9 to 2.9 HVS (Full Scale) 30 to 205 (Dual, Single, Aircraft) 34 to to 881 Inflation pressure 25 C 560 to to Nominal Speed Ranges: (km/h) Approx. wheel load repetitions per hour (rep/hr) Simulated: 3 to 26 (Actual 1 to 8.67) to 12 Uni-directional: 660, and Bi-directional: 1 300

16 SIM-HVS TEST MATRIX 12R22.5 TYRES

17 Model Mobile Load Simulator (MMLS3) 1/3 rd Scale 1.8 kn, 2.7 kn, and 2.9 kn; For tyre inflation pressures between 400 to 860 kpa, all 4 x tyres loaded and inflated to same values by MMLS3 Team; MMLS3 Speeds: 3 km/h, 13 km/h and 26 km/h.

18 Test Matrices: SIM-MMLS3MMLS3 Total of Tests (S1/S2) MMLS3 Load 1.8 kn m/s m/s m/s MMLS3 Load 2.7 kn m/s m/s m/s MMLS3 Load 2.9 kn m/s m/s m/s Inflation Pressure (kpa) (S1/S2) 27/26 3* /520 27/ /700 27/ /800 27/ / Grand total of number of tests completed (S1 & S2) Grand total of number of tests processed (S1 & S2) (Total of all tests on all 4 tyres)

19 STATIC TYRE PRINTS (12R22.5)

20 MMLS3 TYRE PRINTS 10 to 26 times smaller than 12R22.5 Full Scale Tyre Prints depending on load and inflation pressure level.

21 Relative Comparison MMLS3-Square Square Profile ( kpa) HVS 12R22.5 ( kpa)

22 Steering Tyres MMLS3-Square Square Profile ( kpa) HVS 315/80 R22.5 (Steering Tyre kpa))

23 TYRE LOAD COMPARISON HVS-SIMSIM Variation:~ +/- 5 %

24 HEAVY VEHICLE SIMULATOR (HVS) DUAL TEST TYRES (12R22.5)

25 Smooth Plates HVS Dual Tyre Tests

26 3D Contact Stresses: MMLS3 Square Tyre

27 3D Contact Stresses: MMLS3 Square Tyre

28 Typical SIM Data Z - Vertical Contact Stress-Full Scale n-shapes

29 STANDARD TYRE LOAD: 40 kn, 520 kpa

30 STANDARD TYRE LOAD: 40 kn, 720 kpa

31 STANDARD TYRE LOAD: 40 kn, 1000 kpa

32 3D Contact Stresses: HVS Extreme Loading on SIM 315/80 R22.5 Tyre

33 Typical SIM Data Z-Vertical Stress - Overloading - Full Scale m-shapes

34 TYRE LOAD FINGER PRINTING - VERTICAL CONTACT STRESS (HVS 12R22.5) INFLATION CSIR 2007 PRESSURE

35 Model Mobile Load Simulator (MMLS3) 1/3 rd Scale

36 Model Mobile Load Simulator (MMLS3) 1/3rd Scale- on SIM device

37 Close-up of Square Profile MMLS3 Test Tyre

38 Close-up of Square MMLS3 Test Tyre on SIM Textured (Rough) Surface

39 TYRE LOAD FINGER PRINTING - VERTICAL CONTACT STRESS (MMLS3) INFLATION CSIR 2007 PRESSURE

40 3D Contact Stresses: MMLS3 Square Profile Tyre

41 MMLS3 ON SIM:FAST TESTING - 26 km/h

42 3D Contact Stresses: MMLS3 Square Profile Tyre

43 3D Contact Stresses: MMLS3 SIM Device This Study

44 3D Contact Stresses: MMLS3 Square Profile Tyre SIM Textured Surface

45 Close-up of Square MMLS3 Test Tyre on SIM with plate (Smooth) Surface

46 Smooth Plates HVS Dual Tyre Tests

47 Maximum Vertical Contact Stress (MVCS) (kpa) Detail MVCS results for the HVS and the MMLS3 for both rough and smooth SIM test surface Maximum Vertical Contact Stress (MVCS) (or "PEAK STRESS") (12R22.5 and 315/80 R22.5 (HVS MK IV+) compared with MMLS3) 12R22.5-AVERAGE 315/80-R Tyre Inflation Pressure (kpa)

48 Maximum Vertical Contact Stress (MVCS) (kpa) Detail MVCS results for the HVS and the MMLS3 for both rough and smooth SIM test surface Maximum Vertical Contact Stress (MVCS) (or "PEAK STRESS") (12R22.5 and 315/80 R22.5 (HVS MK IV+) compared with MMLS3) 12R22.5-AVERAGE 315/80-R22.5 DIAMOND-2.4 m/s-sim Original SIM data - Draft CR 2005/30: y = 0.473x R2 = Tyre Inflation Pressure (kpa)

49 Maximum Vertical Contact Stress (MVCS) (kpa) Detail MVCS results for the HVS and the MMLS3 for both rough and smooth SIM test surface Maximum Vertical Contact Stress (MVCS) (or "PEAK STRESS") (12R22.5 and 315/80 R22.5 (HVS MK IV+) compared with MMLS3) 12R22.5-AVERAGE 315/80-R22.5 DIAMOND-2.4 m/s-sim FEB-2006-NEW Original SIM data - Draft CR 2005/30: y = 0.473x R2 = New Data - Feb 2006 y = x R 2 = Tyre Inflation Pressure (kpa)

50 Maximum Vertical Contact Stress (MVCS) (kpa) Detail MVCS results for the HVS and the MMLS3 for both rough and smooth SIM test surface Maximum Vertical Contact Stress (MVCS) (or "PEAK STRESS") (12R22.5 and 315/80 R22.5 (HVS MK IV+) compared with MMLS3) 12R22.5-AVERAGE 315/80-R22.5 MMLS3-WESTRACK-EPPS DIAMOND-2.4 m/s-sim FEB-2006-NEW Original SIM data - Draft CR 2005/30: y = 0.473x R2 = New Data - Feb 2006 y = x R 2 = Westrack, Hugo et al, 7/11/2006 y = x R 2 = Tyre Inflation Pressure (kpa)

51 Maximum Vertical Contact Stress (MVCS) (kpa) Detail MVCS results for the HVS and the MMLS3 for both rough and smooth SIM test surface Maximum Vertical Contact Stress (MVCS) (or "PEAK STRESS") (12R22.5 and 315/80 R22.5 (HVS MK IV+) compared with MMLS3) 12R22.5-AVERAGE 315/80-R22.5 MMLS3-WESTRACK-EPPS DIAMOND-2.4 m/s-sim FEB-2006-NEW SMOOTH PLATE Original SIM data - Draft CR 2005/30: y = 0.473x R2 = New Data - Feb 2006 y = x R 2 = y = x R 2 = Westrack, Hugo et al, 7/11/2006 y = x R 2 = Tyre Inflation Pressure (kpa)

52 Maximum Vertical Contact Stress (MVCS) (kpa) Average MVCS results for the HVS and the MMLS3 for both rough and smooth SIM test surface HVS - 12R ROUGH SIM SURFACE 1:1 Maximum Vertical Contact Stress (MVCS) (12R22.5 of HVS MK IV+ compared with MMLS3) ROUGH AND SMOOTH TEST SURFACES HVS - 12R SMOOTH SURFACE MMLS3 - DIAMOND - ROUGH SURFACE MMLS3 - DIAMOND - SMOOTH SURFACE Tyre Inflation Pressure (kpa)

53 Maximum Vertical Contact Stress (MVCS) kpa Per centile plots: MVCS - smooth SIM surface for the MMLS3 Diamond tyres (S2 - this study) relative to three HVS test tyres. Normal Probability Plots: MMLS3 vs HVS - SMOOTH SURFACE MMLS3-DIAMOND-SMOOTH SIM-2005 HVS-12R22.5-DUAL-SMOOTH-SIM HVS-315/80-R22.5-SINGLE- SMOOTH-SIM-2006 Overlap Stress Range: 850 kpa to kpa 12R22.5 HVS Mk IV+ Dual Tyres 315/80 R22.5 HVS Single Tyre Sample Percentile (%) HVS-11R22.5-DUAL SIMULATED-SMOOTH-SIM R22.5 HVS Mk III Dual Tyres

54 Remember the 3 x Project Objectives: Quantification -3D tyre-pavement contact stresses of the HVS and MMLS3 test tyres (using SIM) 4 x Studies; Comparison - similar previous SIM studies on various HVS tyres Z Vertical Stress only in this paper; Recommendations for tyre load and inflation pressures of future Accelerated Pavement Testing (APT) on Hot Mix Asphalt (HMA) rutting tests (MMLS3 and HVS);

55 Findings: Z-Contact Stress: At Maximum - Representative Percentile Values (%) Surface Smooth Surface Rough Surface Device MMLS3-Square Square Tyre (1/3 rd Scale) 12R22.5 Tyre: %; 315/80 R22.5 Tyre: %; 11R22.5 Tyre: %. 12R22.5 Tyre: - 20 %; 315/80 R22.5 Tyre: %; 11R22.5 Tyre: %.

56 Findings: Z-Contact Stress Ranges Surface Device HVS (kpa) MMLS3 (kpa) Smooth Surface 850 to to Rough Surface (~ 30 % Lower) 700 to to 1 000

57 Recommendations (1) Table for Loading & Inflation Pressure: (See Research Report CR-2005/30)

58 Major Conclusions (1): The contact surface texture directly influences the total load and vertical stress results; and Tyre intrusion into the pin surface of the SIM occurs, which may be limited by placing smooth plates on top of the current SIM device, if so desired.

59 Major Conclusions (2): The Maximum Vertical Contact Stress (MVCS): Increase with increased tyre inflation pressure, for both the 1/3r rd scale and full- scale test tyres; Average of the HVS test tyres roughly 50 to 88 per cent higher than for the MMLS3 (rough and smooth surface); and for the relatively smooth test surface were found to be 25 to 30 per cent higher than those for both the MMLS3 (scaled) and the HVS (Full Scale) tests tyres.;

60 Major Conclusions (3): For the scaled-down down MMLS3 tyres the MVCS was roughly equal to inflation pressure, whereas for the full-scale HVS tyres the MVCS was approximately 50 per cent higher;

61 Recommendations (1): The results enables a more rational interpretation of APT test data; Further studies on different test surfaces; Critically important that loading devices such as the HVS and MMLS3 be adequately calibrated before similar studies are done in the future. Anchoring of the MMLS3 to the road pavement NB.

62 THE END THANKS FOR YOUR ATTENTION