Experimental evaluation on noise reduction performance of a motorcycle helmet

Ozer M. S., Terzioglu F., Ozturk S.

International Journal of Automotive Engineering and Technologies, cilt.8, sa.3, ss.125-133, 2019 (TRDizin)

Özet

Motorcycle helmets are generally thought to be only protection of motorcycledrivers against head injuries as well as loud noise in traffic. While there havebeen several papers on noise elimination capabilities of motorcycle helmets, nocontrolled study has been reported to compare different types of test conditionsin literature. The purpose of this study is to assess noise reduction capacities ofa motorcycle helmet under different types of acoustical loadings as well asenvironments and to identify better test condition. Firstly, a Head & Torsosimulator with and without the motorcycle helmet in a built acoustical cabinetwas exposed to digitally generated sound to investigate insertion loss values.Besides, the Head & Torso simulator was fixed onto a motorcycle to simulateactual driving conditions. Sound pressure levels were captured at the ear level toobtain insertion loss values in case of motorcycle noise for different enginespeeds. By comparing calculated insertion losses, it was revealed thatconsiderable differences existed between tests for different conditions.Beneficial interpretations were deduced and thus, a practical solution waspresented for accurate measurements acoustic performance of the motorcyclehelmets in laboratory conditions.