Structural Engineering and Mechanics

  • 제50권5호
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  • Pages.589-603
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  • 2014
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  • 1225-4568(pISSN)
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  • 1598-6217(eISSN)
테크노프레스 (Techno-Press)
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DOI QR코드

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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
⟨ 이전 논문 다음 논문 ⟩

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

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  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