DOI QR코드

DOI QR Code

Contact forces generated by fallen debris

  • Sun, Jing (Department of Infrastructure Engineering, University of Melbourne) ;
  • Lam, Nelson (Department of Infrastructure Engineering, University of Melbourne) ;
  • Zhang, Lihai (Department of Infrastructure Engineering, University of Melbourne) ;
  • Gad, Emad (Faculty of Engineering & Industrial Sciences, Swinburne University of Technology) ;
  • Ruan, Dong (Faculty of Engineering & Industrial Sciences, Swinburne University of Technology)
  • 투고 : 2014.01.16
  • 심사 : 2014.03.03
  • 발행 : 2014.06.10

초록

Expressions for determining the value of the impact force as reported in the literature and incorporated into code provisions are essentially quasi-static forces for emulating deflection. Quasi-static forces are not to be confused with contact force which is generated in the vicinity of the point of contact between the impactor and target, and contact force is responsible for damage featuring perforation and denting. The distinction between the two types of forces in the context of impact actions is not widely understood and few guidelines have been developed for their estimation. The value of the contact force can be many times higher than that of the quasi-static force and lasts for a matter of a few milli-seconds whereas the deflection of the target can evolve over a much longer time span. The stiffer the impactor the shorter the period of time to deliver the impulsive action onto the target and consequently the higher the peak value of the contact force. This phenomenon is not taken into account by any contemporary codified method of modelling impact actions which are mostly based on the considerations of momentum and energy principles. Computer software such as LS-DYNA has the capability of predicting contact force but the dynamic stiffness parameters of the impactor material which is required for input into the program has not been documented for debris materials. The alternative, direct, approach for an accurate evaluation of the damage potential of an impact scenario is by physical experimentation. However, it can be difficult to extrapolate observations from laboratory testings to behaviour in real scenarios when the underlying principles have not been established. Contact force is also difficult to measure. Thus, the amount of useful information that can be retrieved from isolated impact experiments to guide design and to quantify risk is very limited. In this paper, practical methods for estimating the amount of contact force that can be generated by the impact of a fallen debris object are introduced along with the governing principles. An experimental-calibration procedure forming part of the assessment procedure has also been verified.

키워드

참고문헌

  1. British Standard Institute (2008), Eurocode 1 - Actions on structures - Part 1 - 7: General actions - accidental 602 actions (S.P. Committee, Ed.), European Committee for Standardization, London.
  2. Ali, M., Sun, J., Lam, N.T.K., Zhang, L.H. and Gad, E.F., "Estimation of impact generated deflection of beam by hand calculation method", Aus. J. Struct. Eng., Article No.S-13-006.
  3. Lam, N.T.K., Tsang, H.H. and Gad, E.F. (2010), "Simulations of response to low velocity impact by spreadsheet", Int. J. Struct. Stab. Dyn., 10(3), 483-499. https://doi.org/10.1142/S0219455410003580
  4. Mark, A.L. and Stephen, J.S. (2011), Applications of Spreadsheets in Education-the Amazing Power of a Simple Tool, Bentham Science Publishers, Sharjah, United Arab Emirates
  5. Yang, Y., Lam, N.T.K. and Zhang, L.H. (2012a), "Estimation of response of plate structure subject to low velocity impact by a solid object", Int. J. Struct. Stab. Dyn., 12(6), 1250053. https://doi.org/10.1142/S0219455412500538
  6. Yang, Y., Lam, N.T.K. and Zhang, L.H. (2012b), "Evaluation of simplified methods of estimating beam responses to impact", Int. J. Struct. Stab. Dyn., 12(3), 1250016. https://doi.org/10.1142/S0219455412500162
  7. Nguyen, M.Q., Jacombs, S.S., Thomson, R.S., Hachenberg, D. and Scott, M.L. (2005), "Simulation of impact on sandwich structures", Compos. Struct., 62(2), 217-227.
  8. Heimbs, S., Heller, S., Middendorf, P., Hahnel, F. and Weisse, J. (2009), "Low velocity impact on CFRP plates with compressive preload: Test and modelling", Int. J. Impact Eng., 36(10-11), 1182-1193. https://doi.org/10.1016/j.ijimpeng.2009.04.006
  9. Sjoblom, P.O., Hartness, J.T. and Cordell, T.M. (1988), "On low-velocity impact testing of composite materials", J. Compos. Mater., 22(1), 30-52. https://doi.org/10.1177/002199838802200103
  10. Zineddin, M. and Krauthammer, T. (2007), "Dynamic response and behavior of reinforced concrete slabs under impact loading", Int. J. Impact Eng., 34(9), 1517-1534. https://doi.org/10.1016/j.ijimpeng.2006.10.012
  11. Crisco, J.J., Hendee, S.P. and Greenwald, R.M. (1997), "The influence of baseball modulus and mass on head and chest impacts: a theoretical study", Med. Sci. Sport. Exer., 29(1), 26-36.
  12. Smith, L.V. (2001), "Evaluating baseball bat performance", Sport. Eng., 4(4), 205-214. https://doi.org/10.1046/j.1460-2687.2001.00087.x
  13. Nicholls, R.L., Miller, K. and Elliott, B.C. (2006), "Numerical analysis of maximal bat performance in baseball", J. Biomech., 39(6), 1001-1009. https://doi.org/10.1016/j.jbiomech.2005.02.020
  14. Cheng, N., Takla, M. and Subic, A. (2011), "Development of an FE model of a cricket ball", Procedia Eng., 13, 238-245. https://doi.org/10.1016/j.proeng.2011.05.079
  15. Day, J. and Bala, S. (2006), General guidlines for crash analysis in LS-DYNA, Livermore Software Technology Corporation.
  16. Yang, Y. (2013), "Modelling impact actions of spherical objects", PhD thesis, Infrastructure Engineering, School of Engineering, University of Melbourne.
  17. Machado, M., Moreira, P., Flores, P. and Lankarani, H.M. (2012) "Compliant contact force models in multibody dynamics: Evolution of the Hertz contact theory", Mech. Mach. Theo., 53, 99-121. https://doi.org/10.1016/j.mechmachtheory.2012.02.010

피인용 문헌

  1. Contact forces generated by hailstone impact vol.84, 2015, https://doi.org/10.1016/j.ijimpeng.2015.05.015
  2. Computer Simulation of Contact Forces Generated by Impact vol.17, pp.01, 2017, https://doi.org/10.1142/S0219455417500055
  3. Damage modelling of aluminium panels impacted by windborne debris vol.165, 2017, https://doi.org/10.1016/j.jweia.2017.02.014
  4. Deterministic solutions for contact force generated by impact of windborne debris vol.91, 2016, https://doi.org/10.1016/j.ijimpeng.2016.01.002
  5. Overturning stability of L-shaped rigid barriers subjected to rockfall impacts vol.15, pp.7, 2018, https://doi.org/10.1007/s10346-018-0957-5
  6. Experimental and Analytical Assessment of Flexural Behavior of Cantilevered RC Walls Subjected to Impact Actions vol.146, pp.4, 2020, https://doi.org/10.1061/(asce)st.1943-541x.0002578