Measurement of Noise in Armoured Personnel Carriers

摘要

The Mobile Tracked Vehicle, Engineering (MTVE) is one of the armoured personnel carrier variants being produced in Canada under the M113 life extension program. M113A2s, from which the MTVE has evolved, are undergoing an extensive rebuild with lengthened hulls, upgraded power packs, new suspensions for increased vehicle weight and modified running gears with one additional road-wheel per track system. As a result of the high noise levels within the vehicle during user trials of the MTVE, a program was initiated to evaluate the interior sound levels present in this vehicle under representative operating conditions. Noise was measured in the MTVE and compared to the M113A2 at all operating speeds on both pavement and gravel. The noise data indicated that the MTVE was quieter than the M113A2 at low operating speed but may be noisier at moderate and maximum speed depending on the position in the vehicle. Measured noise levels were compared to the Canadian Standard as provided by the Canada Labour Code, Part II, of the Canada Occupational Safety and Health Regulations to provide an indication of the level of hearing protection required depending on vehicle operating scenario and duration. Assessment of the source of the noise -- in particular the fan and vehicle track -- were conducted. Recommendations to reduce the levels using insulating panels or active control techniques were suggested. As a result, the vehicle intercom headsets used by the driver and crew commander currently use an active noise control system. For passengers, double hearing protection is required. Full details of the test results and analysis are provided in the paper.