Numerical modelling of lightweight Steel‐Concrete‐Steel sandwich composite beams subjected to impact

• Finite element model was developed to predict the drop weight impact response of SCS sandwich beams.
• A theoretical model of SCS sandwich beam under impact load was established.
• Energy balance model to predict response of sandwich slab under impact is discussed.
• Design guidelines for SCS sandwich structure have been discussed.

This paper presents the numerical and analytical models to predict the response behaviour of Steel–Concrete–Steel (SCS) sandwich composite beams subjected to drop-weight impact loading. The sandwich composite beam has an ultra-lightweight concrete core of density 1440 kg/m3 sandwiched between two thin steel face plates which are interconnected by J-hook connectors. Explicit nonlinear finite element analysis was carried out and the results obtained are verified against the impact test data to establish its accuracy in predicting the permanent deformation, vertical displacement–time history and impact force–time history of the sandwich beams. The numerical analysis also shows that the J-hook connectors are subjected to tension force during impact in addition to shear force due to flexural action in the beam. This signifies the important role of J-hook connectors in preventing tensile separation of the steel face plates when subjected to impact load. An analytical approach based on energy balance model was also developed to predict the impact response of SCS sandwich beams. A good agreement was observed between the analytical solution and the experimental data indicating that the approach provides a reasonable and conservative estimation of the impact resistance of the sandwich beams.