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• A steel–concrete-steel sandwich panel with energy absorbing supports (SSP-EAS) was developed for impact resisting. • The impact resistant performances of the SSP-EAS were experimentally and numerically investigated. • Impact response modes and failure modes of the SSP-EAS were studied. • The effects of crushing force of EAS and initial impact momentum on impact behaviors of the SSP-EAS were analyzed. A new steel–concrete-steel sandwich panel with energy absorbing supports (SSP-EAS) was firstly proposed, and its dynamic responses under impact loading were investigated through conducting impact tests and numerical simulations. Three types of impact response modes of SSP-EASs were categorized according to the different crushing magnitudes of energy absorbing supports (EASs). In addition, the steel–concrete-steel sandwich panel (SSP) exhibited the combination of the global flexural deformation, local indentation and local bulging during the impact. The EAS could effectively absorb impact energy through the plastic bending of steel plates and the crushing of aluminum foam blocks, except for the response mode I with insignificant crushing of EASs. Moreover, the effects of crushing force of EASs and initial impact momentum on the dynamic responses of SSP-EAS were numerically analyzed. The impact resistance of the SSP-EAS could be improved through properly designing the EAS and assuring its maximum displacement slightly smaller than the compaction displacement during impact. In addition, the crushing force of EAS should not exceed the ultimate resistance of the SSP to assure the EAS being triggered to crush. Moreover, the SSP-EAS exhibited enhanced impact performances under higher initial impact momentum. [ABSTRACT FROM AUTHOR]

A novel energy absorption connector with pleated plate and aluminum foam as energy absorber was proposed to be inserted between the blast resistant façade and building to absorb blast energy and reduce blast load transferred to the building. The energy absorption performance of the connector under quasi-static compression loading was first studied by using experimental method. The deformation mechanisms were observed from the experiment and three different deformation processes were also identified. The effects of aluminum foam, pleated plate thickness and angle θ o (the angle between flat plate and pleated plate) as well as pleat number on the energy absorption performance of the connector were experimentally investigated, which showed that the energy absorption capacity could be improved by filling the connector with aluminum foam and increasing the pleated plate thickness, angle θ o and pleat number. Moreover, an analytical model for determining the load–displacement curve of the energy absorption connector was also developed and the predictions by the analytical model were proven to be reasonable by comparing with the experimental data. [ABSTRACT FROM AUTHOR]

The response behavior of steel–concrete–steel (SCS) sandwich panels without shear connectors was experimentally studied under lateral pressure loading in this paper. The loading was applied by a hydraulic actuator on an inflated airbag to assert lateral pressure on the SCS panels. The failure modes and maximum resistance of the SCS panels were obtained from the test and compared with the numerical analysis results. It was found from the experimental and numerical studies that the end plates could function as shear connectors to achieve the composite action between face plates and concrete core. Based on the experimental and numerical observations, the formulae to predict the bending resistance and transverse shear resistance of SCS panel without shear connectors were developed and the accuracy of the proposed formulae was verified by comparing with the experimental and numerical results. [ABSTRACT FROM AUTHOR]

• A steel-polyurethane foam-steel–concrete-steel (SPUFSCS) composite structure is proposed. • Low-velocity impact test on SPUFSCS panel is conducted, and local indentation and global deformation is observed. • The panel with polyurethane foam (PUF) layer exhibits better impact resistant performance than traditional steel–concrete-steel (SCS) panel. • Impact energy dissipated by the PUF layer is more than that of SCS layer. This paper presents a study on the low-velocity impact response of a new steel-polyurethane foam-steel–concrete-steel (SPUFSCS) panel. The SPUFSCS composite panel consisted of a steel faceplate and polyurethane foam (PUF) with a density of 193 kg/m3 that were attached to the front of the traditional steel–concrete-steel (SCS) panel. Low-velocity impact tests on the SPUFSCS panels were conducted by employing an instrumented drop hammer impact test system, and the failure modes of the SPUFSCS panels were found to consist of local indentation and global deformation. The impact process of the panels can be divided into three stages: PUF crushing, loading, and unloading. The impact force, displacement histories, and permanent deformation of the SPUFSCS panels were recorded and discussed in detail. The effects of concrete thickness and ratio of the thickness of the middle plate to that of the bottom plate on the impact responses of the SPUFSCS panels were experimentally studied. The finite element method was employed to predict the behavior of the SPUFSCS panel under impact loading, and good agreement was observed between the experimental and numerical results. Moreover, a parametric study was conducted to reveal the influence of the thickness of the PUF and top steel plate on the dynamic response of the SPUFSCS composite panels. [ABSTRACT FROM AUTHOR]

• Four curved SCS shells subjected to concentrated load were experimentally studied. • Failure mechanism and types of curved SCS shells were summarized. • Parameters affecting strength of curved SCS shells were numerically investigated. • Analytical models of curved SCS shells subjected to concentrated load were proposed. In this study, experimental works on four curved steel-concrete-steel (C-SCS) sandwich shells were carried out to assess their behaviors when subjected to concentrated loading with a 100-mm diameter hemispherical steel hammer through analyzing the failure mode, load–displacement relationship, strain, and deformation. The influences of the concrete and steel plate thicknesses, shear connector spacing, and rise–span ratio were numerically investigated. The results showed that the ultimate strength of C-SCS shells was improved with increasing concrete and face steel plate thicknesses and with decreasing shear connector spacing. The optimal rise-span ratio was found to be between 0.25 and 0.33. Moreover, to predict the nominal yield strength and the ultimate strength of C-SCS shells, an analytical model was developed, which matched well with the experimental and FE results. This analytical model can be used as a quick method to calculate the resistances of C-SCS shells under concentrated loading by a hemispherical steel hammer. [ABSTRACT FROM AUTHOR]

• A novel energy absorption connector with PU foam and multiple pleated plates was proposed. • Energy absorption performance of the connector was experimentally studied. • PU foam filler could significantly improve the energy absorption performance. • Analytical model was proposed to predict the force-displacement response of the connector. In this study, a novel energy absorbing connector with polyurethane (PU) foam and multiple pleated (MP) plates was contrived to dissipate energy, and the energy absorbing response was experimentally, numerically and analytically examined. First, quasi-static loading tests on the connectors were performed, from which the deformation modes, force–displacement curves, and energy absorbing performances (such as specific energy absorption (SEA) and crushing force efficiency (CFE)) were obtained. In addition, a numerical method was adopted to facilitate the evaluation of energy absorbing performance of the connectors. It was found that SEA could be increased by increasing the MP plate thickness, angle between the MP plate and flat plate (θ 0), and filling PU foam. Moreover, the PU foam-filled connector was also found to be superior to the empty connector with regards to higher CFE. Finally, an energy-balance based analytical model was established to forecast the force–displacement response of the proposed connector. The experimental and analytical results were found to be similar. [ABSTRACT FROM AUTHOR]

Highlights • Shear failure mechanisms of SCS sandwich beams are explored. • Structural behaviours of SCS sandwich beams are simulated by finite element models. • Parametric studies on failure mechanisms of SCS sandwich beams are investigated. • Theoretical analysis of SCS sandwich beams is carried out considering bond-slip. Abstract The steel-concrete-steel (SCS) sandwich structure has been proposed for containment buildings in third-generation nuclear power plants. In this paper, 27 static tests on SCS sandwich beams (by the authors and others) are adopted serially to summarize the failure modes and explore the failure mechanisms of SCS sandwich beams with different bond-slip conditions between the steel plate and concrete. Further, a three-dimensional finite element (FE) model is developed to simulate the ultimate strength of SCS sandwich beams under different failure modes. The accuracy of the developed FE model in predicting ultimate strength, cracking behaviours and bond-slip behaviours is verified by static tests. Based on the validated FE model, 65 numerical cases are calculated to investigate the effects of analytical parameters on the failure mechanism and ultimate strength of SCS sandwich beams under different bond-slip conditions. The analytical parameters include the steel plate ratio, shear span to depth ratio, spacing of shear studs and shear reinforcement ratio. In addition, theoretical models are proposed to predict the ultimate strength of SCS sandwich beams under different bond-slip conditions. The accuracy of the theoretical model is verified by comparison with current design codes for SCS sandwich beams. [ABSTRACT FROM AUTHOR]