Advertisement

Experimental Modal Analysis Study of a Standing Soldier and Rifle System

  • Razvan Rusovici
  • Joshua Drew
  • Brian Fischer
  • George Kontis
  • Terrence F. Rice
  • Francis J. Battersby
  • Michael Pavlisak
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)

Abstract

The response of the human body to shock and vibration has been a subject of interest to many researchers in the aerospace and automotive industry. In a new study, an experimental modal analysis of a rifle-armed, standing soldier in a standard firing position was performed. The purpose of the study was to determine the modes of vibration of the soldier-weapon system in order to gain an understanding of its response during the firing event. The weapon firing accuracy, especially during closely-repeated semi-automatic or fully-automatic fire, as well as the energy transmitted to the body of the soldier depend not only on the weapon itself but also on the soldier body’s dynamic characteristics. Rapid weapon fire does not allow a soldier to consciously control muscles needed to bring back the weapon to its original position, so the weapon location after each fire is influenced more by the dynamic characteristics of the human-rifle system. The experimental modal analyses were performed using multi-averaged, impact-force and electrodynamic shaker force excitation (mainly sine sweeps) and roving triaxial acceleration response at various locations on the body. It was observed that testing of human subjects poses significant difficulties since an increasing number of measurement averages could lead to muscle fatigue and ensuing tremors that could negatively influence coherence. The soldier stance during the tests could also change due to the unconscious need to adjust to a more comfortable body position. The positioning of the accelerometers was difficult since attachment could be made to skin only. While there was in general large variability in soldier size, mass and body strength, the study allowed the identification of some lower modes of interest which appeared to have the same mode shape, albeit at different frequencies, for all the various individuals tested. The signals were acquired with a National Instruments hardware and processed using ModalView software. For an average size soldier the first mode occurred at approximately 2 Hz. The first mode shape exhibited combined bending (backward) and twisting characteristics which are generally seen in a “up and to the right” motion of a right-shoulder held weapon during firing. More modes in the 0–20 Hz range were identified.

Keywords

Human vibration Experimental modal analysis LSCF Weapon Impact hammer 

References

  1. 1.
    Piersol, A.G., Paez, T.L. (eds.): Harris’ Shock and Vibration Handbook, 6th edn. McGraw Hill Publications (2010)Google Scholar
  2. 2.
    Adewusi, S., Thomas, M., Vu, V., Li, W.: Modal parameters of the human hand-arm using finite element and operational modal analysis. Mech. Ind. 15, 541–549 (2014)CrossRefGoogle Scholar
  3. 3.
    Hostens, I., Ramon, H.: Descriptive analysis of combine cabin vibrations and their effect on the human body. J. Sound Vib. 266, 453–464 (2003)CrossRefGoogle Scholar
  4. 4.
    Kitazaki, S., Griffin, M.J.: Resonance behaviour of the seated human body and effects of posture. J. Biomech. 31, 143–149 (1998)CrossRefGoogle Scholar
  5. 5.
    Hobatho, M.C., Darmana, R., Pastor, P., Barrau, J.J., Laroze, S., Morucci, J.P.: Development of a three-dimensional finite element model of a human tibia using experimental modal analysis. J. Biomech. 24, 371–383 (1991)CrossRefGoogle Scholar
  6. 6.
    Munera, M., Chiementin, X., Murer, S., Bertucci, W.: Model of the risk assessment of hand-arm system vibrations in cycling: case of cobblestone road. Proc. Inst. Mech. Eng. Part P. 229, 231–238 (2015)Google Scholar
  7. 7.
    Thuong, O., Griffin, M.J.: The vibration discomfort of standing persons: 0.5–16 Hz fore-and-aft, lateral, and vertical vibration. J. Sound Vib. 330, 816–826 (2011)CrossRefGoogle Scholar
  8. 8.
    Phillips, A.W., Allemang, R.J.: The Complex Mode Indicator Function (CMIF) as a parameter estimation method. In: Proceedings, International Modal Analysis Conference, pp. 705–710 (1998)Google Scholar
  9. 9.
    Barrett, K.E., Barman, S.M., Boitano, S., Brooks, H.L.: Ganong’s Review of Medical Physiology, 23rd edn. McGraw-Hill Medical (2010)Google Scholar

Copyright information

© The Society for Experimental Mechanics, Inc. 2019

Authors and Affiliations

  • Razvan Rusovici
    • 1
  • Joshua Drew
    • 2
  • Brian Fischer
    • 2
  • George Kontis
    • 2
  • Terrence F. Rice
    • 3
  • Francis J. Battersby
    • 3
  • Michael Pavlisak
    • 3
  1. 1.Florida Institute of TechnologyMelbourneUSA
  2. 2.Knights Armament CompanyTitusvilleUSA
  3. 3.US ARMY ARDECPicatinny ArsenalUSA

Personalised recommendations