59
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
L. Lamberson et al. (eds.), Dynamic Behavior of Materials, Volume 1, Conference Proceedings of the Society
for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59947-8_11
Chapter 11
Developing a Methodology for Testing of Hearing Protection
Systems
S. de Oliveira, C. Mullins, J. Purutyan, L. Reiniger, B. Reymann, J. J. Rosowski, J. T. Cheng, and C. Furlong
Abstract Every day, individuals around the globe are exposed to noises that have devastating long-term effects on their hearing. Noise-Induced Hearing Loss (NIHL) is the second most common form of sensorineural hearing decline behind the agerelated loss. NIHL can result from continuous exposure to high-intensity sounds such as heavy machinery or instantaneous
exposure to extremely loud sounds, like gunshots and explosions. While passive hearing protection currently exists, the characterization and testing are limited mainly to pressure attenuation levels. There is limited research and information as to the
frequency damping characteristics along with the linear and nonlinear performance. Further, the measure of these protections
is quantified after creation, with limited criteria on how to design earplugs with desired characteristics. Here, we describe our
progress in the development of methods to characterize the linear and nonlinear performance, frequency response, and damping characteristics, as well as investigating the correlation between material properties and performance.
Keywords Acoustic attenuation · Frequency · Noise-induced hearing loss · Passive hearing protection
11.1 Introduction
Hearing loss affects the quality of life of millions of people. In the United States alone, 15% of adults have reported that they
experience some form of trouble hearing. While hearing loss can be a result of a variety of different factors, as many as 40
million adults have hearing loss in one or both ears that is consistent with exposure to loud sounds, or Noise-Induced Hearing
Loss (NIHL). If the exposure is short but intense, the sound needs to be around 130 dB SPL to cause damage. If the exposure
is over a long period of time, a sound level as low as 85 dB SPL can cause NIHL [1]. Pressure attenuation values of earplugs
are generally well characterized; however, the frequency response and correlation to material properties are far underexplored. Though there has been research on hearing protection, little has linked the microscale structure with the macro performance of the earplug. Our work aims at understanding how microstructure can impact the performance of earplugs
through testing methods and computational analyses that we are developing for both, linear and nonlinear regimes.
S. de Oliveira · C. Mullins (*) · J. Purutyan · L. Reiniger · B. Reymann
Center for Holographic Studies and Laser micro-mechaTronics (CHSLT) and Mechanical Engineering Department,
Worcester Polytechnic Institute, Worcester, MA, USA
e-mail: spdeoliveira@wpi.edu; cemullins@wpi.edu; jhpurutyan@wpi.edu; ldreiniger@wpi.edu; bwreymann@wpi.edu
J. J. Rosowski · J. T. Cheng
Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, MA, USA
e-mail: tao_cheng@meei.harvard.edu
C. Furlong
Center for Holographic Studies and Laser micro-mechaTronics (CHSLT) and Mechanical Engineering Department,
Worcester Polytechnic Institute, Worcester, MA, USA
Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, MA, USA
e-mail: cfurlong@wpi.edu
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
L. Lamberson et al. (eds.), Dynamic Behavior of Materials, Volume 1, Conference Proceedings of the Society
for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59947-8_11
Chapter 11
Developing a Methodology for Testing of Hearing Protection
Systems
S. de Oliveira, C. Mullins, J. Purutyan, L. Reiniger, B. Reymann, J. J. Rosowski, J. T. Cheng, and C. Furlong
Abstract Every day, individuals around the globe are exposed to noises that have devastating long-term effects on their hearing. Noise-Induced Hearing Loss (NIHL) is the second most common form of sensorineural hearing decline behind the agerelated loss. NIHL can result from continuous exposure to high-intensity sounds such as heavy machinery or instantaneous
exposure to extremely loud sounds, like gunshots and explosions. While passive hearing protection currently exists, the characterization and testing are limited mainly to pressure attenuation levels. There is limited research and information as to the
frequency damping characteristics along with the linear and nonlinear performance. Further, the measure of these protections
is quantified after creation, with limited criteria on how to design earplugs with desired characteristics. Here, we describe our
progress in the development of methods to characterize the linear and nonlinear performance, frequency response, and damping characteristics, as well as investigating the correlation between material properties and performance.
Keywords Acoustic attenuation · Frequency · Noise-induced hearing loss · Passive hearing protection
11.1 Introduction
Hearing loss affects the quality of life of millions of people. In the United States alone, 15% of adults have reported that they
experience some form of trouble hearing. While hearing loss can be a result of a variety of different factors, as many as 40
million adults have hearing loss in one or both ears that is consistent with exposure to loud sounds, or Noise-Induced Hearing
Loss (NIHL). If the exposure is short but intense, the sound needs to be around 130 dB SPL to cause damage. If the exposure
is over a long period of time, a sound level as low as 85 dB SPL can cause NIHL [1]. Pressure attenuation values of earplugs
are generally well characterized; however, the frequency response and correlation to material properties are far underexplored. Though there has been research on hearing protection, little has linked the microscale structure with the macro performance of the earplug. Our work aims at understanding how microstructure can impact the performance of earplugs
through testing methods and computational analyses that we are developing for both, linear and nonlinear regimes.
S. de Oliveira · C. Mullins (*) · J. Purutyan · L. Reiniger · B. Reymann
Center for Holographic Studies and Laser micro-mechaTronics (CHSLT) and Mechanical Engineering Department,
Worcester Polytechnic Institute, Worcester, MA, USA
e-mail: spdeoliveira@wpi.edu; cemullins@wpi.edu; jhpurutyan@wpi.edu; ldreiniger@wpi.edu; bwreymann@wpi.edu
J. J. Rosowski · J. T. Cheng
Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, MA, USA
e-mail: tao_cheng@meei.harvard.edu
C. Furlong
Center for Holographic Studies and Laser micro-mechaTronics (CHSLT) and Mechanical Engineering Department,
Worcester Polytechnic Institute, Worcester, MA, USA
Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
Department of Otolaryngology—Head and Neck Surgery, Harvard Medical School, Boston, MA, USA
e-mail: cfurlong@wpi.edu