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Comparison of Vehicle Responses to Rumble Strip Inputs of Varying Design

SAE International Journal of Passenger Cars - Mechanical Systems

Illingworth & Rodkin Inc.-Paul R. Donavan
California Department of Transportation-Bruce Rymer
  • Journal Article
  • 2015-01-2274
Published 2015-06-15 by SAE International in United States
A measurement program was completed to assess driver input versus exterior noise generation for four vehicle designs and two different rumble strip designs. The vehicles included a small compact car, an immediate size car, a full sport utility vehicle, and a medium duty dump truck. The first rumble strip was a conventional design providing shorter wavelength input to the tire. The second was designed to provide longer wavelength, more harmonic input to the tire. The measurements included exterior pass-by noise and on-board exterior noise and interior measurements of sound pressure level and vibration level at the seat track and steering column. In general, the results indicated that the longer wavelength strips produced less overall A-weighted pass-by noise with little or no reduction in interior noise and vibration. Considerable variation in the response of the vehicles was found particularly for steering column vibration and interior noise where the overall differences ranged from about 9 to 17 decibels (dB). The exterior measures produced smaller ranges, from 2 to about 7½ dB; however, the rank ordering of vehicle…
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Parameters Affecting the Noise Performance of ASTM Standard Reference Test Tires

SAE International Journal of Passenger Cars - Mechanical Systems

Illingworth & Rodkin Inc.-Paul R. Donavan
Lodico Acoustics, LLC-Dana Lodico
  • Journal Article
  • 2013-01-1910
Published 2013-05-13 by SAE International in United States
Currently, the ASTM P225/60R 97S Radial Standard Reference Test Tire (SRTT) is used as a control test tire for calibrating test track surfaces over time and for rank ordering the noise performance of different pavement designs. As a result, variation from one SRTT to another and the effects of tire aging are important to quantify. Measurements of tire noise sound intensity on eight asphalt and two concrete test sections were conducted for eleven new and six older SRTT tires. The range in level for the new tires on each of the ten pavements was determined and was found to be 1.1 dB when averaged over all pavements compared to 0.7 dB for a single tire tested multiple times. As a group, the older tires produced levels 0.5 dB higher than the new tires when averaged for all pavements. The older tires had higher tread rubber durometer hardness values than the new tires, however, within the old and new groupings, no consistent trends could be identified. After nine months, the original 11 new tires were retested…
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Investigations of the Influence of Lower Frequency Aerodynamic Noise on Interior Cruise and Exterior Pass-By Sound Levels

SAE International Journal of Passenger Cars - Mechanical Systems

Illingworth & Rodkin Inc.-Paul R. Donavan
  • Journal Article
  • 2012-01-1554
Published 2012-06-13 by SAE International in United States
The results of a series of tests were performed that are used to investigate the contribution of aerodynamic noise to lower frequency passenger car interior and exterior cruise noise levels. Wind tunnel measurements were used to isolate aerodynamic noise from tire-pavement and engine noise and to indicate that the vehicle underbody is a significant source region for both interior and exterior noise. Comparing interior on-road measurements to the wind tunnel results, it was found that aerodynamic noise was slightly less than an equal contributor to cruise noise averaging 4.8 dB lower than the road levels between 50 and 400 Hz at a speed of 80 km/h. At 140 km/h, the difference dropped to 2.3 dB indicating that the aerodynamic noise was the major contributor. For exterior pass-by, aerodynamic noise levels were found to account for almost all of the noise measured during coast-by conditions in the frequency range from 50 to 400 Hz at 97 km/h. This finding was substantiated by additional pass-by testing using different tires on a variety of pavements. It was further…
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Challenges for Tire Noise Evaluation on Common Pavements

SAE International Journal of Passenger Cars - Mechanical Systems

Illingworth & Rodkin Inc.-Paul R. Donavan
General Motors Company-Alan Parrett, Dave Nielubowicz, Jinshuo Zhu
  • Journal Article
  • 2011-01-1582
Published 2011-05-17 by SAE International in United States
Developing common methods of noise evaluation and facilities can present a number of challenges in the area of tire/pavement noise. Some of the issues involved include the design and construction of pavements globally, the change in pavement over time, and variation in the noise produced with standard test tires used as references. To help understand and address these issues for airborne tire/pavement noise, acoustic intensity measurement methods based on the On-board Sound Intensity (OBSI) technique have been used. Initial evaluations have included measurements conducted at several different proving grounds. Also included were measurements taken on a 3m diameter tire noise dynamometer with surfaces replicating test track pavements. Variation between facilities appears to be a function of both design/construction and pavement age. Consistent with trends in the literature, for smooth asphalt surfaces, the newest surface produced levels lower than older surfaces. For more aggressive, exposed aggregate concrete surfaces, the levels produced appear to depend more on the roughness built into the surface rather than aging effects. The tire noise dynamometer produced overall levels slightly higher than…
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Contributors to Lower Frequency Pass-by Noise Levels under Cruise Conditions

SAE International Journal of Passenger Cars - Mechanical Systems

Illingworth & Rodkin Inc.-Paul R. Donavan
  • Journal Article
  • 2011-01-1613
Published 2011-05-17 by SAE International in United States
With increasing use of the constant speed pass-by conditions to capture the noise generated by this portion of the vehicle operating cycle, knowledge of the contributing sources of noise was become increasingly important. For frequencies above 400 Hz, the noise is dominated by tire/pavement noise as can be demonstrated by comparing on-board sound intensity (OBSI) measurements to constant speed pass-by noise levels. At lower frequencies, direct on-board measurements become more difficult as the tire/pavement noise source strength decreases with decreasing frequency and microphone induced wind noise increases. To investigate the contribution of sources at these lower frequencies, cruise and coast pass-by measurements were made for a number of different pavement types and two different tire designs at test speeds of 56, 72, and 97 km/h over a frequency range from 50 to 10,000 Hz. OBSI measurements were also conducted for these same conditions. From the pass-by measurements, powertrain noise was separated from “rolling” noise by comparing cruise and coast operation. For coast conditions, the noise levels below 400 Hz were found not to depend on…
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