Keywords: nonlinear behaviour, numerical modelling, impact load, reinforced concrete panels.

Impact and blast events resulting from traffic, industrial and domestic accidents in addition to terrorist attacks have frequently occurred on buildings and structures. Buildings capable of sustaining impact and blast loads have gained significant attention, especially, after the World Trade Centre 9/11 attack. How the building facade responds to this loading significantly affects the behaviour of the structure and the safety of its occupants. The objective of this research is to develop a numerical model capable of simulating the effect of shock and impact loads on building façade components.

The velocity of the impact governs the response of the structure. Low-velocity impacts may cause quasi-static response, while hyper-velocity impacts can cause the properties of the material to change [1]. Impact load is a relatively large dynamic load applied to the structure or part of the structure in a comparatively short period of time.

With the advancement of computational techniques and nonlinear analysis software, it becomes more efficient to carry out simulation of the complex responses of structural components subjected to severe shock and impact loads [2]. In this research the façade panel is modelled as a continuous system with distributed mass and stiffness. A nonlinear numerical simulation is performed to analyze reinforced concrete panels using the ANSYS/LS-DYNA finite element software. The model developed is validated using the results of experimental impact tests on reinforced concrete beams conducted at the American University in Cairo [3]. The validated model can be used for a parametric study for the design optimization of building components subjected to impact loads.

The model response in terms of acceleration response at three different locations on the beam, and the values of reactions at the support are compared with the corresponding values from the test. The developed models showed good correlation with the experimental test results and the impact phenomena could be modelled numerically with reasonable accuracy. The observed small differences between the numerical and experimental models are explained by the factors not considered in the model. Those include the contact modelling between the impact head and the specimens, as well as the specimen and the support. The dynamic response of the supporting frame is also not considered in the model which will affect the supporting conditions. Also not considered in the analysis is the damage state of the beam due to several previous impact tests.

1

N. Jones, "Structural Impact", Cambridge University Press, Cambridge, 1989.

2

Z. Tu, Y. Lu, "Evaluation of typical concrete material models used in hydrocodes for high dynamic response simulations", International Journal of Impact Engineering, 36(1), 132-146, January 2009. doi:10.1016/j.ijimpeng.2007.12.010

3

H. Cherif, "Experimental investigation of building components response to impact and short duration loads", M.Sc. Thesis, The American university in Cairo, 2009.

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