SEMINARIO - TOPIC Tyre- Contact Stresses Prof Morris De Beer CSIR Built Environment Pretoria, South Africa (http://www.csir.co.za) Road s:, design performance
Layout of Presentation Background South African road situation ; Increase in inflation pressures over time; Research with Accelerated Testing (APT) Devices; R&D on tyre-pavement contact stresses, using Stress-In-Motion (SIM) technology; damage & Analyses in SA context; The way forward; Conclusions en Recommendations Road s:, design performance
STRESS-IN IN-MOTION (SIM) TECHNOLOGY Since the 1990s improvement necessary in tyrepavement interaction model; Uniform & Circular shape not representative - studying road surface failures with HVS; Stress-In-Motion (SIM) devices developed; New 3D shapes sizes of tyre-pavement contact stress regimes measured; Implementation in linear non-linear pavement models (new challenge); Road s:, design performance
Heavy Vehicle Simulator (HVS) testing since 1975 PRACTICAL SOLUTIONS NEEDED!! Road s:, design performance
Total - all Roads in SA ~ 750 000 km Road s:, design performance
Thinly Surfaced ( 12 mm -50 mm) Flexible s - Road s:, design performance
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Typical Heavy Vehicles (HVs) Road s:, design performance
Fatigue Cracking aging Delamination.. EXAMPLES OF ROAD SURFACE FAILURES.. Road s:, design performance
Damage. Road Road s:, design performance
Tyre Types on Steering Axles - Recently: Road s:, design performance
Truck Tire Inflation Pressure in South Africa: ~ 20 % Increase in 20 Years Road s:, design performance
H:\CAPSA04\[Tyre Inflation Pressure Information-MORTON-MDB- N3 TCC - SELECTED HEAVY VEHICLE (HV) TRUCK TYRE PRESSURE DATA (26 Feb 2003-06 March 2003) LEFT-FRONT-(225 tyres) RIGHT-FRONT-(225 tyres) REST-LEFT-(845) REST-RIGHT-(845) Normalised Frequency 1.2 1 0.8 0.6 0.4 0.2 Trailing Tyres: Ave: 800 kpa; ~116 PSI Steering Tyres : Ave: 900 kpa; ~130 PSI 0 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 TYRE INFLATION PRESSURE (kpa) Road s:, design performance
Tyre Weight (Mass) Distribution - 2003 H:\ICAP-2006 Summary N3 TCC-FINAL-4-B-ICAP-2006.xls TYRES-1-2 -Histogram-Paper (2) ALL TYRES MEASURED: n = 45 227 (This Study) - N3 -TCC-2003 All Other Tyres Axle 1 Left Axle 1 Right 1600 1400 All other Tyers: 1.9 Tonne Steering Tyres: 2.95 Tonne 120 100 1200 Number of Tyres 1000 800 600 400 200 80 60 40 20 0 0.050 0.300 0.550 0.800 1.050 1.300 1.550 1.800 2.050 2.300 2.550 2.800 3.050 3.300 Bin: Tyre Mass Weight [Tonne] 3.550 3.800 4.050 4.300 4.550 4.800 0 Road s:, design performance
HVS Mk IV+ Test Tyres DUAL: 12R22.5 SINGLE: 315/80 R22.5 Road s:, design performance
425/65 R22.5 tyre in South Africa Road s:, design performance
Vehicle-Tyre Tyre- Interaction: Stress-In-Motion (SIM) Technology Road s:, design performance
Assumption of Tyre Loading - Modeling: Tyre Loading, P (kn) - Circular; - Variable load; - Variable pressure, but Uniform.. Uniform Contact Stress, q (kpa) Road s:, design performance
Stress In Motion (SIM) Technology The measurement of 3D tyre/pavement contact stresses from moving vehicles Road s:, design performance
Stress In Motion (SIM) SIM Mk II Device: CSIR : 93-95 315/80 HVS TYRE ON SIM Mk II SYSTEM Road s:, design performance
Dual Tyre: 3D-Contact Stresses (Pressure) 80 kn Single Axle (..ESAL) Stress Ratio: 10:3:1 Road s:, design performance
Sectometer S. Eckels, 1928 Road Truck Tyres. Modern Tyre science Road s:, design performance
Heavy Vehicle Simulator (HVS) - Since 1970s Road s:, design performance
Oct 2004 - HVS SIM Tests Road s:, design performance
SINGLE SIM PAD FOR HVS TESTING Road s:, design performance
Stress In Motion (SIM) SIM Mk II: CSIR : 93-95 315/80 HVS TYRE ON SIM Mk II SYSTEM
425 /65 R22.5 HVS Tyre: Single pad SIM system (Use with HVS) Road s:, design performance
SAE sign convention:x-long,y-lateral & Z -Vertical loads/stresses Tyre Rotation +/-X +Z +X +/-Y Road s:, design performance
Tyre-Surface Interaction on textured surface - 3D Stress Regimes Road s:, design performance
Typical SIM Data Sets: Z, X, Y - Contact Stresses @ Variable loads: 315/80 R22.5 Tire Z: Vertical Stress Y: Lateral Stress X: Longitudinal Stress Road s:, design performance
STRESS-IN-MOTION TESTING USING THE HVS Road s:, design performance
(HVS) - DUAL TEST TYRES (12R22.5) Road s:, design performance
Stress-In-Motion (SIM) testing using the Heavy Vehicle Simulator (HVS)- Dual Load Configuration Twin (dual) SIM pads Road s:, design performance
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OVER-LOADING/UNDER INFLATION Road Tyre Edge Road s:, design performance
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TYRE FINGER PRINTING : VERTICAL STRESS PROFILES LOAD Road s:, design performance Lisboa, LNEC, 25 March INFLATION 2010 PRESSURE
Differential Tyre Pressure(12R22.5): 950/520 kpa @ 30 kn; 40 kn; 70 kn 100 kn 16.6 kn 11.2 kn 22.1 kn 14.8 kn 40.9 kn 61.3 kn 27.1 kn 38.2 kn Road s:, design performance
SIM systems.. Road s:, design performance
Quad Stress-In-Motion (SIM) system: Road s:, design performance
QUAD SIM PAD TESTING AT WEIGH-BRIDGE SITE: N3 NORTH TRAFFIC CONTROL CENTRE (TCC) Road s:, design performance
STRESS-IN-MOTION TESTING ON N3 NORTH (HEIDELBERG): QUAD SIM SYSTEM IN OPERATION Road s:, design performance
STRESS-IN-MOTION TESTING ON N3 NORTH (HEIDELBERG) Road s:, design performance
Example SIM testing during 2003 Road s:, design performance
Example SIM testing during 2003 Road s:, design performance
LOAD COMPARISON FIELD WITH REAL TRUCKS N3 TCC Road s:, design performance
Measured Tyre Foot Prints :Two Axle Truck Vertical Contact Stress.. Road s:, design performance
4 Axle Truck. Road s:, design performance CSIR 2008 www.csir.co.za
Road s:, design performance
5 Axle Truck. Road s:, design performance CSIR 2008 www.csir.co.za
6 Axle Truck. Road s:, design performance CSIR 2008 www.csir.co.za
Road s:, design performance
Eight (8) Axle Truck Vertical Contact Stress - Foot Prints. Road s:, design performance
TYPICAL STEERING AXLE: VERTICAL STRESS Road s:, design performance
STEERING AXLE UNEQUAL LOADING. TEST 009: KTD 904 GP 13/10/2003: AXLE 1 450 185 mm; 1.938 Ton 266 mm; 3.739 Ton 400 350 300 Counts 250 200 150 100 50 10 20 30 40 50 60 70 80 Across the SIM pads Road s:, design performance
TYRE BARELY IN CONTACT WITH SURFACE 550 500 189 mm; 0.037 Ton TEST 768-09/10/2003: DDT235N AXLE 2 297 mm; 4.312 Ton 202 mm; 1.874 Ton 194 mm; 1.223 Ton 450 400 350 Counts 300 250 200 150 100 50 10 20 30 40 50 60 70 80 Across the SIM pads Road s:, design performance
AXLE 2: MISSING TYRE.!! TEST 765: NKR 9519-09/10/2003 AXLE 2 350 244 mm; 1.782 Ton 196 mm; 1.032 Ton 195 mm; 0.661 Ton 300 250 Counts 200 150 100 50 10 20 30 40 50 60 70 80 Across the SIM pads Road s:, design performance
AXLE 2- DRIVING AXLE Road s:, design performance
Tyres Damage Road s:, design performance
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