SAFE AND SILENT ROAD TRAFFIC STIL VEILIG WEGVERKEER TIRE-ROAD NOISE This project is carried out in the framework of the innovation program GO Gebundelde Innovatiekracht, and funded by the European Regional Development Fund, Regio Twente and Provincie Overijssel. The project partners Apollo Tyres Global R&D, University of Twente (Tire-Road Consortium), Reef Infra, STEMMER IMAGING and the Provincie Gelderland are gratefully.
SILENT ROADS SOUND ABSORPTION OF POROUS ASPHALT FOR OBLIQUE INCIDENT SOUND WAVES MARIEKE BEZEMER-KRIJNEN YSBRAND WIJNANT ANDRE DE BOER This project is carried out in the framework of the innovation program GO Gebundelde Innovatiekracht, and funded by the European Regional Development Fund, Regio Twente and Provincie Overijssel. The project partners Apollo Tyres Global R&D, University of Twente (Tire-Road Consortium), Reef Infra, STEMMER IMAGING and the Provincie Gelderland are gratefully.
CONTENTS Modelling of porous asphalt concrete: Background and introduction Model approach Example and applications Test area and measurements: Airport Twente in 2013: Sound absorption and CPX Airport Twente in 2015: Design of 3 prototype roads Sound absorption, CPX, Pass-by noise Conclusions 3
BACKGROUND SOUND RADIATION FOR TIRE ROAD NOISE Tire Road Noise model: TRN model Numerical model to predict sound radiation of rolling tire sound pressure at 1 khz rotation Source: A. Schutte, eccomas, 2012 4
BACKGROUND SOUND RADIATION FOR TIRE ROAD NOISE Tire Road Noise model: TRN model Numerical model to predict sound radiation of rolling tire Structural model (FEM) Tire model Road roughness Time domain (transient) Rotating mesh Sound radiation model (BEM) Tire surface Vibrations Frequency domain Static BEM-mesh Interpolation scaled Source: A. Schutte, eccomas, 2012 5
BACKGROUND Starting point: TRN model: Only possible to implement sound absorption for normal incidence Classification of roads: Generally done by reduction of sound for normal incident sound waves But: rolling tires radiate noise in all directions Sound absorption for oblique incident sound waves should be included! 6
MODELLING OF ASPHALT CONCRETE MODEL APPROACH Modelling sound absorption for non-locally reacting porous medium Dependent on frequency and on angle of incidence Combination of scattering and sound absorption: Geometric representation of asphalt Scattering effects Air inside pores Viscothermal effects characteristic impedance: wave number: 7
MODELLING OF ASPHALT CONCRETE MODEL APPROACH Viscothermal effects Scattering effects 8
MODELLING OF ASPHALT CONCRETE SCATTERING ON STONES USING FEM MODEL Finite element model in Comsol Geometry: Air domain: Half sphere Enclosed by PML Box with spheres: Viscous properties Spheres stacked in FCC Perfectly matched layers (PML) Air domain Box with spheres 9
MODELLING OF ASPHALT CONCRETE SCATTERING ON STONES USING FEM MODEL Finite element model in Comsol Geometry: Optimise geometry for sound absorption 10
MODELLING OF ASPHALT CONCRETE MODEL APPROACH Viscothermal effects Scattering effects 11
HYBRID MODEL ANALYTICAL SOLUTION AND SCATTERING ON STONES For, and analytical solution scattering solution total solution 12
EXAMPLE OF HYBRID MODEL SOUND ABSORPTION COEFFICIENT Sound absorption coefficient: Ratio between incident and active power 13
EXAMPLE OF HYBRID MODEL OPTIMISATION Influence of angle of incidence Influence of stone size 14
CONTENTS Modelling of porous asphalt concrete: Background and introduction Model approach Example and applications Test area and measurements: Airport Twente in 2013: Sound absorption and CPX Airport Twente in 2015: Design of 3 prototype roads Sound absorption, CPX, Pass-by noise Conclusions
CONTENTS Modelling of porous asphalt concrete: Background and introduction Model approach Example and applications Test area and measurements: Airport Twente in 2013: Sound absorption and CPX Airport Twente in 2015: Design of 3 prototype roads Sound absorption, CPX, Pass-by noise Conclusions
TWENTE AIRPORT TEST AREA 2013 6 sections of 3x100m 17
TWENTE AIRPORT TEST AREA 2013 1: Deciville Extra Levensduur Porosity 12-13% Stone size 2/5 Stone Bestone, 100% broken surface Layer height 25mm 3: OPA 8 Porosity 20-21% Stone size 4/8 Stone Bestone, 100% broken surface Layer height 57mm 5: Stil Mastiek Porosity 6-10% Stone size 4/8 Stone Layer height Graziet kleinhammer, 100% broken surface 35mm 2: Deciville Extra Stil Porosity 15% Stone size 2/5 Stone Bestone, 100% broken surface Layer height 30mm 4: DAB Porosity 3-4% Stone size 4/8,8/11,11/16 Stone Morane, >95% broken surface Layer height 40mm 6: R117 (similar to ISO 10844:2011) Porosity 3-4% Stone size 2/6,4/8 Stone Layer height Graziet kleinhammer, 100% broken surface 35mm 18
PERFORMANCE OF ROAD 2 COMPARED TO ISO CLOSE PROXIMITY MEASUREMENTS 80 km/h: 95.3 db(a) rms 80 km/h: 91.7 db(a) rms 19
PERFORMANCE OF ROAD 2 FOR DIFFERENT TYRES CLOSE PROXIMITY MEASUREMENTS 80 km/h: 91.7 db(a) rms 80 km/h: 89.1 db(a) rms 20
DESIGN OF PROTOTYPE ROADS TEST AREA 2015 AIRPORT TWENTE 3 prototype roads, optimized for sound reduction and wet grip 2 new sections of 3x100m 21
DESIGN OF PROTOTYPE ROADS AIRPORT TWENTE Using model predictions and previous measurement results 7 8 7: Twinlay Porosity 25% (design) Stone size ~3-4mm Stone Porfier SFB 3-100 Layer height 25mm (top), 50mm 8: OPA 6 Porosity 25% (design) Stone size ~3-6mm Stone Bestone SFB 3-100 Layer height 40mm 22
SOUND ABSORPTION OF PROTOTYPE ROADS IMPEDANCE TUBE MEASUREMENTS Sound absorption for normal incidence 2 Deciville ES 6 R117/ISO 7 Twinlay 8 OPA 0/6 23
SOUND REDUCTION OF PROTOTYPE ROADS CLOSE PROXIMITY MEASUREMENTS SRTT tire Road 2, 6, 7 and 8 80 km/h rms: 91.7 db(a) rms: 95.3 db(a) rms: 90.2 db(a) rms: 90.6 db(a) 2 6 7 8 24
SOUND REDUCTION OF PROTOTYPE ROADS CLOSE PROXIMITY MEASUREMENTS SRTT tire Road 2, 6, 7 and 8 80 km/h rms: 91.7 db(a) rms: 95.3 db(a) rms: 90.2 db(a) rms: 90.6 db(a) 2 6 7 8 25
SOUND REDUCTION OF PROTOTYPE ROADS CLOSE PROXIMITY MEASUREMENTS Road 2, 6, 7 and 8 80 km/h SRTT Cento A-82 A-83 A-81 2 Deciville ES 6 R117/ISO 7 Twinlay 8 OPA 0/6 26 B-81 26
SOUND REDUCTION OF PROTOTYPE ROADS CLOSE PROXIMITY MEASUREMENTS Road 2, 6, 7 and 8 80 km/h SRTT Cento 10.00 9.00 8.00 A-82 7.00 [db(a)] 6.00 5.00 4.00 3.00 2.00 SRTT Cento Tire A-82 Tire A-83 Tire A-81 Tire B-81 A-83 A-81 1.00 0.00-1.00-2.00 Deciville ES ISO/R117 Twinlay OPA 0/6 2 6 7 8 27 27 B-81
SOUND REDUCTION OF PROTOTYPE ROADS PASS-BY MEASUREMENTS Pass by measurements with 3 microphones 28
SOUND REDUCTION OF PROTOTYPE ROADS PASS-BY MEASUREMENTS 2 6 7 8 29
CONCLUSIONS FOR SILENT ROAD TRAFFIC OPTIMAL COMBINATION OF TIRE AND ROAD Reduction using optimal combination of tire and road: Up to 9 db (compared to SRTT on ISO/R117, CPX measurements at 80 km/h) Influence of tires: Reduction up to 4.5 db at 65 km/h Reduction about 2 db at 100 km/h Important to consider combination of tire and road Important to consider angle dependent absorption behavior of porous asphalt road surfaces 30
CONCLUSIONS PHD RESEARCH Conclusions PhD research: Hybrid model approach is presented: Predict sound absorption coefficient for oblique incidence Analytically validated Hybrid model is used to optimize parameters for road design Outlook PhD research: Experimental validation of hybrid model Implement more features in hybrid model and make compatible for TRN model 31
DESIGN OF TEST ROADS AIRPORT TWENTE Measurements for oblique incident sound waves 32
THANK YOU FOR YOUR ATTENTION! M.BEZEMER@UTWENTE.NL