Researchers develop model for hearing protection in high-noise environments

  • Published
  • By Maria Callier
  • Air Force Office of Scientific Research
ARLINGTON, Va. --  Researchers funded by the Air Force, Army, and Navy are investigating ways to improve communication links for people wearing headphones, helmets and other protective equipment in noisy environments. 

Their research has been an especially important collaboration for the military because many serving in the armed forces suffer from hearing impairment due to repeated exposure to aircraft engine sounds and large caliber weaponry. 

Dr. Leszek Demkowicz, an expert at constructing geometric models and the finite element codes, from the University of Texas at Austin and additional scientists who specialize in finite elements, geometry description, acoustics and hearing science, are conducting research about high noise environments. 

Despite a lack of fundamental research regarding the transmission of acoustic energy through non-airborne pathways to the cochlea, the researchers have persevered. They have created finite element code, based on earlier software that has helped them build a model of the human head. The model shows detailing of the cochlea region and its interface with the skull and air pathways. 

"To make use of the finite element codes, one needs a mathematical description of how an acoustic wave moves through the model," said Dr. Willard Larkin, program manager, AFOSR. "This aspect of the project is undertaken by a different, collaborating group of mathematicians whose efforts are absolutely essential to the project: Marek and Elizabeth Bleszynski, of Monopole Research, in Thousand Oaks, California," he said. 

Dr. Larkin also noted that even muffs or plugs and other ordinary hearing protection devices are not effective when pitted against acoustic energy. 

"Acoustic energy can reach the cochlea via non-airborne pathways and the amount of acoustic energy reaching the cochlea in this way can be significant and can interfere with and degrade the ability to localize the directions of sound sources and can also impede voice communications," he said. 

The U.T. project about hearing protection in high noise environments has been built on two decades of research on higher order finite elements for wave propagation problems documented in a two-volume book, authored by Dr. Demkowicz, "Computing with hp-Adaptive Finite Elements" and over 45 additional publications.