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1

Laboratory measurements of electromagnetic field inside motorcycle helmet with installed Bluetooth communicator

Gombarska Daniela, Psenakova Zuzana, Carnecka Lucia

Przegląd Elektrotechniczny

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2021

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R. 97, nr 6

56--59

EN

The main objective of the paper is to evaluate the electromagnetic field (EMF) within the motorcycle helmet with a Bluetooth communicator. Under laboratory conditions, the measurement was carried out using two helmets with integrated Bluetooth communicator set in intercom mode. The distance of the helmet was set to 500 mm without communication, the same distance with communication and the distance set to 2500 mm with continuous communication and BK PRECISION 2650A spectral analyzer together with Rohde & Schwarz used as a measurement set-up.

PL

Głównym celem pracy jest ocena pola elektromagnetycznego wewnątrz kasku motocyklowego z komunikatorem Bluetooth. W warunkach laboratoryjnych pomiar przeprowadzono z wykorzystaniem dwóch kasków z wbudowanym komunikatorem Bluetooth ustawionym w trybie interkomu. Odległość pomiaru ustawiono na 500 mm bez komunikacji z kasku, taką samą odległość z komunikacją z kasku oraz odległość ustawioną na 2500 mm z komunikacją ciągłą. Jako stanowisko pomiarowe wykorzystano analizator widma BK PRECISION 2650A firmy Rohde & Schwarz.

2

Numerical analysis of the drag coefficient of a motorcycle helmet

Czyż Z., Karpiński P., Sevdim T.

Applied Computer Science

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2018

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Vol. 14, no 1

16--26

EN

The paper discusses a numerical investigation, using a CFD tool, ANSYS FLUENT, of drag acting on a motorcycle helmet. The simulations were performed on a model of a helmet downloaded from a free CAD model library. A solid model enabled us to generate a mesh, to define boundary conditions and to specify a model of turbulence. Accordingly, the values of forces acting on individual sections of the helmet were obtained and the coefficients of aerodynamic drag were calculated. The test results can be used to optimize the shape of the existing motorcycle helmet construction and to study the impact of generated drag forces on reaction forces affecting a motorcyclist’s body.

3

Attenuation of Noise by Motorcycle Safety Helmets

Młyński R., Kozłowski E., Żera J.

International Journal of Occupational Safety and Ergonomics

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2009

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Vol. 15, No. 3

287--293

EN

For workers such as police motorcyclists or couriers, traffic and engine noise reaching the ears is an important factor contributing to the overall condition of their work. This noise can be reduced with motorcycle helmets. In this study, insertion loss of motorcycle helmets was measured with the microphone-in-real-ear technique and sound attenuation with the real-ear-at-threshold method. Results for 3 Nolan helmets show essentially no protection against external noise in the frequency range <250 Hz. In the frequency range >500 Hz, attenuation increases linearly at a rate of 8–9 dB per octave, to ~30 dB at 8 kHz. Lack of attenuation in the low-frequency range may cause annoying effects. In addition, high attenuation in the high-frequency range may decrease intelligibility of speech signals for a rider in a helmet. Attenuation measured in this study does not take into account noise generated by turbulent wind around the helmet. Thus, the measured values of attenuation represent a motorcycle rider’s best conditions of hearing.