STUDY OF ACTIVE VIBRATION ISOLATION SYSTEMS FOR SEVERE GROUND TRANSPORTATION ENVIRONMENTS

An investigation is conducted to evaluate the application of active mechanisms for the protection of equipment and/or personnel from the severe dynamic inputs characteristic of ground transportation vehicles. For the purposes of the study, dynamic loads and isolation system performance are defined in terms of the maximum expected vertical excitations associated with the suspension system of high speed ground transportation vehicles, and conservative levels of allowable passenger acceleration. Selected configurations employ available hardware, and consist of a static load support fluidic spring in parallel with a 0.2 Hz resonant frequency electrohydraulic isolator, which: a) provides the desired degree of isolation from both discrete frequency and broad-band vibration excitations; and b) limits the payload deflections to within plus or minus 6 inches under conditions of combined vibratory and transient dynamic loads. Rigid and flexible payloads of 1,000 3,000 and 10,000 pounds per isolator are considered. The response of the selected isolation systems is presented in terms of absolute and relative transmissibility; payload acceleration; and relative displacement between the payload and the source of excitation for the vibratory, transient, and combined excitations. In all cases the effect of increasing the payload weight by twenty percent is shown. The results indicate that the selected active isolation systems are capable of protecting a range of payloads from severe vibratory and transient dynamic loads. Systems stability, estimates of flow and power requirements, system weight, reliability, and failsafe criteria considerations are shown. Recommendations are made regarding extension of the techniques to provide isolation in the combined vertical and lateral directions. (Author)

• Supplemental Notes:
  • Prepared for National Aeronautics and Space Administration.
• Corporate Authors:

  Wright (Barry) Corporation

  Watertown, MA  United States 
• Authors:
  • Calcaterra, P C
  • Cavanaugh, R D
  • Schubert, D W
• Publication Date: 1969-11

Media Info

• Features: Appendices; References; Tables;
• Pagination: 155 p.

Subject/Index Terms

• TRT Terms: Passenger comfort; Vehicle dynamics
• Old TRIS Terms: Lading protection
• Subject Areas: Railroads;

Filing Info

• Accession Number: 00043365
• Record Type: Publication
• Source Agency: National Aeronautics and Space Administration
• Report/Paper Numbers: NASA CR-1454 Contr Rpt
• Files: TRIS
• Created Date: Apr 13 1976 12:00AM