Vibration Mitigation Analysis of a Seahawk Helicopter Seat Suspension Concept

Abstract

Recent surveys aboard rotary-wing aircraft strongly suggest that aircrew are being exposed to operational vibration associated with the potential for health risk. The objective of this study was to evaluate the effectiveness of a seat suspension concept to mitigate vertical operational vibration and minimize health risk. A Seahawk seat fitted with a magnetorheological active damper system was mounted onto the Six-Degree-of-Freedom Motion Simulator (SIXMODE) located at the Air Force Research Laboratory (AFRL). Nine military volunteers were exposed to multi-axis flight vibration recreated in the SIXMODE. Seat system configurations included LOCKED (no damper), UNLOCKED ON (damper with variable viscosity), and UNLOCKED OFF (damper with constant viscosity). Triaxial accelerations collected at the seat interfaces and subject anatomical sites were used to estimate rms spectra. The ISO 2631-1: 1997 and MIL-STD 1472 were used as guidelines for health risk assessment. The UNLOCKED ON and OFF configurations showed similar results; significant reductions in the vertical acceleration peak associated with the blade passage frequency (~17 Hz) and in the overall vertical acceleration (1-80 Hz) (P<0.05), specifically at the seat/occupant interfaces, as compared to the LOCKED configuration. The weighted seat pan vibration total values (VTVs) were substantially reduced in the vertical direction and the allowable daily exposures for minimal health risk was increased with the UNLOCKED configurations. Suspension seats can mitigate rotary-wing aircrew health risk. The specific effectiveness of variable viscosity dampers may depend on the vehicle vibration characteristics and the ability to tune the damper with respect to frequency. Additional improvement to aircrew performance may also require consideration of seat interface postural influences.

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Document Details

Document Type
Technical Report
Publication Date
Apr 30, 2019
Accession Number
AD1081874

Entities

People

  • Benjamin C. Steinhauer
  • Suzanne D. Smith
  • Wilfred H. Wells
  • William C. Glass

Organizations

  • 711th Human Performance Wing

Tags

Communities of Interest

  • Biomedical
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Air Force
  • Air Force Research Laboratories
  • Aircrafts
  • Computer Programs
  • Frequency Response
  • Government Procurement
  • Governments
  • Human Factors Engineering
  • Medical Personnel
  • Military Aircraft
  • Military Research
  • Motor Skills
  • Pain
  • Perception
  • Risk Analysis
  • Rotary Wing Aircraft
  • Tilt Rotor Aircraft

Readers

  • Aerospace Engineering
  • Control Systems Engineering.
  • Robotics and Automation.