Roadside Measurement of Truck Noise Source Distributions Paul - PowerPoint PPT Presentation

Roadside Measurement of Truck Noise Source Distributions Paul Donavan Bruce Rymer ADC40 Summer Meeting San Luis Obispo, CA July 22-25, 2007

Beam Forming Applied to Trucks Test Track Environment

50 mph Cruise 5900 Truck 10 10 9 10 8 10 10 dB 7 10 6 10 1 2 3 4 10 10 10 10 10 100 1000 10000 Frequency, Hz

5900 Truck 50 mph Cruise – 416 Hz 10 10 10 10 10 10 9 9 9 10 10 10 ~6ft ~6ft 8 8 8 10 10 10 7 7 7 ~4-5.2 m ~4-5.2 m 10 10 10 say 4.6m say 4.6m 6 6 6 10 10 10 1 1 1 2 2 2 3 3 3 4 4 4 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 100 100 100 1000 1000 1000 10000 10000 10000 Frequency, Hz Frequency, Hz Engine Noise from Underneath Tire Tread Passing Cab Frequency

5900 Truck 50 mph Engine Noise from Underneath Cruise – 884 Hz Cab (note lower level compared to next slide) 10 10 10 10 10 10 (103)Spectral Density re 20 muPa in 1 Hz Band at Time of Max OASPL 10 10 9 9 9 10 10 10 9 10 8 8 8 10 10 10 8 10 ~6ft ~6ft 7 7 7 10 10 10 7 10 6 6 6 10 10 10 6 10 1 1 1 2 2 2 3 3 3 4 4 4 ~4-5.2 m ~4-5.2 m 10 10 10 1 10 10 10 2 3 10 10 10 4 10 10 10 10 10 10 10 100 100 100 10 10 1000 1000 1000 10 10000 10000 10000 frequency say 4.6m say 4.6m Frequency, Hz Frequency, Hz Engine Noise from wheel well Reflection of Engine Noise

5900 Truck 50 mph 1 st Harmonic of tread passage frequency for Cruise – 960 Hz G167 drive axle tire 10 10 10 10 10 10 9 9 9 10 10 10 8 8 8 10 10 10 7 7 7 10 10 10 ~6ft ~6ft 6 6 6 10 10 10 1 1 1 2 2 2 3 3 3 4 4 4 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 100 100 100 1000 1000 1000 10000 10000 10000 ~4-5.2 m ~4-5.2 m Frequency, Hz Frequency, Hz say 4.6m say 4.6m

Beam Forming Applied to Trucks Roadside Environment

Test Site Layout Photo Cells Photo Cells 44 ft (0.5 sec @ 60 mph) 44 ft (0.5 sec @ 60 mph) 12 ft 12 ft V~ 50-60 mph V~ 50-60 mph 25 ft 25 ft 25 ft 25 ft 4 ft 4 ft Radar Gun Radar Gun w/operator w/operator Mic 1 Mic 1 (spotter) (spotter) Still Camera Still Camera Array Array w/operator w/operator 50 ft 50 ft Video Camera Video Camera unattended unattended Mic 2 Mic 2 Array Operator Array Operator Microphone Operator Microphone Operator

Veolia Test Site 101.4 dBA

Papas Taverna Site 103.9 dBA

Rockin H Ranch Site 99.1 dBA

Measurements • Controlled passbys & OBSI • Conventional statistcal passbys at 25 & 50 ft • Beam-forming of passby – heavy trucks � 56 at Veolia site � 59 at Papas site � 95 at Rockin H site � + Some medium trucks & cars at each

OBSI & 25 ft Controlled Passby 100 Papas 25 ft 95 Veolia 25 ft Rockin H 25 ft Papas OBSI 90 Veolia OBSI Rockin H OBSI 85 Noise Level, dBA 80 75 70 65 60 55 50 45 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 1/3 Octave Band Center Frequncy, Hz

Overall OBSI & Passby Levels 110 Veolia 105 Papas Rockin H 100 Noise Level, dBA 95 90 85 80 75 70 65 OBSI PBY 25 ft PBY 50 ft

Rockin H Site – Heavy Trucks at 25ft 96 94 M easured Sound Pressure Level, dBA Curve Fit (Only) 92 90 88 86 84 82 80 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 Speed, m ph

Heavy Truck Curve Fits – 25 ft 96 Rockin H 94 Papas Sound Pressure Level, dBA Veolia 92 90 88 86 84 82 80 40 45 50 55 60 65 70 Speed, m ph

Truck REMELs at 50 ft 94 REM ELS Data Base Rockin H 92 Veolia Sound Pressure Level, dBA Papas 90 88 86 84 82 80 78 40 45 50 55 60 65 70 Speed, m ph

OBSI, Passby Levels & Truck Levels 110 Veolia 105 Papas Rockin H 100 Noise Level, dBA 95 90 85 80 75 70 65 OBSI PBY 25 ft PBY 50 ft Truck Curve Fit Truck "REMELS" at 25 ft

Loudspeaker Spatial Calibration 3 ft Loudspeaker

Speaker at 1000 Hz C/L 4m 3m 2m 1m 0m -1m -7m +7m Apparent Ground Plane

Speaker at 2500 Hz Apparent Ground Plane

Speaker at 500 Hz Apparent Ground Plane

Speaker at 315 Hz Apparent Ground Plane

Passby Array Processing • Determined time of maximum A-weighted passby • Centered analysis at – 0.1 to +0.1 second about time of maximum • Analysis window of 0.2 seconds or about 16ft (5m) of movement at 55 mph

Passenger Car – 400 Hz 63

Passenger Car – 400 Hz 63

Passenger Car – 800 Hz 70

Passenger Car – 800 Hz 70

Passenger Car – 2000 Hz 56

Passenger Car – 2000 Hz 56

Truck at Veolia Site – 400 Hz 72

Truck at Veolia Site – 400 Hz 72

Truck at Veolia Site – 800 Hz 72

Truck at Veolia Site – 800 Hz 72

Truck at Veolia Site – 1600 Hz 64

Truck at Veolia Site – 1600 Hz 64

Truck at Veolia Site – 400 Hz 80

Truck at Veolia Site – 400 Hz 80

Truck at Veolia Site – 800 Hz 72

Truck at Veolia Site – 800 Hz 72

Truck at Veolia Site – 1600 Hz 61

Truck at Veolia Site – 1600 Hz 61

Truck at Veolia Site – 400 Hz 65

Truck at Veolia Site – 400 Hz 65

Truck at Veolia Site – 500 Hz 77

Truck at Veolia Site – 500 Hz 77

Truck at Veolia Site – 1600 Hz 64

Truck at Veolia Site – 1600 Hz 64

Truck at Veolia Site – 2500 Hz 71

Truck at Veolia Site – 2500 Hz 71

Summary • Reviewed over 45 passbys to date � Almost universally show loudest sources at the ground or within 1m � Drive axle tire noise appears to dominate � Engine noise at high frequency • Next steps � Analyze in more detail interesting cases – higher up source regions � Develop method for quantifying source vertical distributions

Veolia Site – Heavy Trucks at 25ft 96 Measured 94 Sound Pressure Level, dBA Curve Fit (Only) 92 90 88 86 84 82 80 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 Speed, m ph

Papas Site – Heavy Trucks at 25ft 96 M easured 94 Sound Pressure Level, dBA Curve Fit (O nly) 92 90 88 86 84 82 80 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 Speed, m ph

Oldest AC Potential Test Sites Brown Lane 101.4 dBA Brazil Lakeville Hwy Veolia Older AC Rt 116 103.9 dBA Field Gate Papa’s Lakeville Rd New AC 99.1 dBA 6220 Lakeville Pegasus Rockin H Newer AC Vineyard

OBSI & 50 ft Controlled Passby 100 Papas 50 ft 95 Veolia 50 ft Rockin H 50 ft Papas OBSI 90 Veolia OBSI Rockin H OBSI 85 Noise Level, dBA 80 75 70 65 60 55 50 45 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 1/3 Octave Band Center Frequncy, Hz