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• A new locally-strengthened method was developed for steel tube. • Impact tests were conducted on the locally-strengthened steel tube. • The failure mode, impact force, displacement and energy absorption were studied. • Analytical model was proposed to predict impact force and displacement responses. This paper proposes a novel stainless-steel tube locally strengthened by a concrete-filled steel tube to resist impact loads. A drop hammer impact test system was used to determine the failure modes, impact forces, and displacement responses of the strengthened tubes under an impact load. The effects of the strengthening length and thickness of the concrete and outer steel tubes on the impact responses of the strengthened tubes were investigated. The impact resistance was found to improve with an increase in the thickness of the concrete and outer steel thickness. The test results also indicated that the strengthened tubes exhibited a flexural failure mode with a combination of local and global deformations. An analytical model for predicting the dynamic responses of the locally strengthened tubes was established based on an equivalent two-degree-of-freedom (TDOF) model. The analytically predicted results were compared with the experimental results, and the good consistency between these two results demonstrated the accuracy of the established analytical model. [ABSTRACT FROM AUTHOR]

In this paper, the drop-weight impact loading tests were conducted to study the dynamic crushing behaviors of the proposed energy absorption connectors with curved plate and aluminum foam as energy absorber. The dynamic collapse modes of the connectors were obtained from the tests and three deformation processes were identified. The effects of loading rate, filled aluminum foam, curved plate thickness and radius on the energy absorption performances of the connectors were quantitatively evaluated, which showed that filling the connector with aluminum foam as well as increasing loading rate, curved plate thickness and radius generally led to increase of energy absorption capacity of the connector. Besides the experimental works, the numerical and analytical models were also developed to predict the force–displacement responses of the connectors and the accuracies of the two models were validated against the test results. The developed analytical model could be utilized as a convenient tool to quickly evaluate the energy absorption performances of such connectors under impact loading. [ABSTRACT FROM AUTHOR]

In this paper, the energy absorption performances of the aluminum foam filled connectors under drop-weight impact loading were first evaluated via using experimental method. The dynamic crushing behaviors of the connectors were examined and three deformation processes were identified from the experiments. The effects of loading rate, filled aluminum foam, pleated plate thickness and angle θ o (the angle between flat plate and pleated plate) on the energy absorption performances of the connectors were experimentally investigated, which showed that the energy absorption capacity was improved by filling the connector with aluminum foam as well as increasing loading rate, pleated plate thickness and angle θ o . Moreover, the numerical and analytical models were also developed to predict the force–displacement responses of the connectors, which showed good agreement with the test results. The developed analytical model could be used as a convenient tool to quickly evaluate the energy absorption performances of such connectors under impact loading. [ABSTRACT FROM AUTHOR]

New steel-concrete-steel sandwich beams with interlocked angle connectors (SCSSB-IACs) were first proposed, and their static behaviours were studied via conducting two-point loading tests. The failure mode, load–displacement response, resistance, and stiffness of the SCSSB-IACs were obtained. Moreover, the influences of thickness of steel faceplate, spacing of IACs, thickness of concrete core, shear-span ratio and interlocking bolts on static performances of the SCSSB-IACs were discussed. Two failure modes of the SCSSB-IACs were observed from the static tests, including flexural and shear failure. Moreover, test results indicated that the resistance and stiffness of the SCSSB-IACs were significantly affected by the thickness of steel faceplate, spacing of IACs and thickness of concrete core. In addition, the load–strain curves and deformation shapes of the SCSSB-IACs were obtained and discussed. Finally, analytical models were developed for predicting elastic stiffness and resistance of the SCSSB-IACs. The analytical models were also validated against the test data. • A steel-concrete-steel (SCS) sandwich beam with novel interlocked angle connectors (IACs) was proposed. • Two-point loading tests were conducted on the SCS sandwich beams with IACs (SCSSB-IACs). • The failure mode, load–displacement response, resistance, and stiffness of SCSSB-IACs were studied. • Analytical models were proposed to predict elastic stiffness and resistance of the SCSSB-IACs. [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]

A novel multi-functional water façade system with the combined function of energy saving and blast resisting is presented in this paper. The façade system utilizes water confined in a thin tank to harness the solar thermal energy and to shield the building from solar radiation. It is particularly suitable for hot climate regions near the Equator due to the constant high dense solar radiation throughout the year. The energy saving performance of the water façade in terms of harnessing the solar thermal energy and reducing space cooling load was evaluated by conducting temperature monitoring tests. As for its potential as a protective layer against blast loading, the water façade was tested under simulated blast loading through dropping projectile on an inflated high pressure airbag. The addition of water was shown to reduce the displacement of water façade and improve the blast resistant capacity through comparing the maximum displacements of the water façades with and without infilled water. An analytical model incorporating varying dynamic increase factor and coupled deflection mode shapes was developed to predict the displacement response of water façade under blast loading and the analytical predictions on maximum displacement were conservative as compared to those from finite element analyses. [ABSTRACT FROM AUTHOR]

A steel-concrete-steel sandwich panel with novel hybrid connectors (SCSSP-HC) was proposed in this paper, and the flexural behaviours of the SCSSP-HC were obtained via conducting four-point bending tests. All the tested SCSSP-HCs exhibited the typical flexural failure mode with three specific failure types being categorized. The typical load–displacement response of the SCSSP-HC exhibited initial elastic stage, strength hardening stage and descending stage. In addition, the effects of faceplate thickness, spacing of headed stud, shear span and loading direction on the responses of SCSSP-HCs were quantitatively studied. The results indicated that the flexural resistance and elastic stiffness of the SCSSP-HC could be significantly improved via increasing the steel faceplate thickness and decreasing the shear span. However, the spacing of headed stud and loading direction had insignificant effect on the responses of the SCSSP-HC. Moreover, an analytical model was developed to predict the elastic stiffness, yielding moment and ultimate moment of the SCSSP-HC, and the accuracy of the analytical model was validated via comparing the analytical predictions with experimental results. [Display omitted] • A novel steel-concrete-steel sandwich panel with novel hybrid connectors (SCSSP-HC) was proposed. • Four-point bending tests were conducted on the SCSSP-HC. • The failure modes and load-displacement responses of the SCSSP-HC under flexural bending were obtained. • The effects of variant parameters on the flexural behaviour of the SCSSP-HC were quantitatively studied. • An analytical model was proposed to predict the elastic stiffness and flexural resistance of the SCSSP-HC. [ABSTRACT FROM AUTHOR]

• A novel steel-PU foam-steel-concrete-steel panel was proposed for impact resisting. • Experimental tests on the proposed panels under drop weight impact loading were conducted. • More impact energy was found to be dissipated by "soft" layer of the panel. • An analytical model was proposed to predict displacement response of the panel under impact loading. A new steel-polyurethane foam-steel-concrete-steel (SPUFSCS) panel, which consists of "soft" and "stiff" layers, was proposed and its impact resistant performance was experimentally, numerically and analytically studied. The front "soft" layer, including a steel plate and polyurethane foam (PUF), was designed for dissipating impact energy and reducing peak force transmitted to the rear "stiff" layer (i.e., SCS panel). The SCS panel with high strength and ductility was employed for resisting the transmitted impact force from PUF. Experimental studies on SPUFSCS panels under impact loading were first conducted by employing an instrumented drop weight impact test system to reveal their failure modes, impact force and displacement responses. The impact energy was found to be dissipated through local indentation and global deformation of the SPUFSCS panel. The Finite Element (FE) models of the tested SPUFSCS panels under impact loading were established and validated against the experimental results. Numerical results indicated that the impact energy dissipated by "soft" layer is higher than that of "stiff" layer, which demonstrated the benefits of employing "soft" layer on improving the impact resistance of the traditional SCS panel. In addition, an analytical model was also presented for predicting the displacement response of the SPUFSCS panel under impact loading. The analytical model was proven to be reasonable in predicting the displacement response by comparing with the experimental results. [ABSTRACT FROM AUTHOR]

A new stiffener-enhanced steel–concrete–steel (SESCS) sandwich beam was proposed for impact resisting, and the dynamic response of the SESCS sandwich beam under low-velocity impact loading was experimentally, numerically and analytically studied. Drop weight impact loading tests on SESCS sandwich beams were first conducted to obtain their failure modes, impact forces and displacement responses. All the tested beams exhibited flexural failure modes, and the impact resistance was found to be significantly improved for the beam enhanced with stiffeners in the tension plate. The Finite Element (FE) model of the SESCS sandwich beam under impact loading was established and validated against the test data in terms of failure mode, impact force and displacement. In addition, an analytical model was also developed for predicting displacement response of the SESCS sandwich beam under impact loading. The analytical-predicted displacement responses were found to be well matched with the FE-predictions and test results, which demonstrated the accuracy of the proposed analytical model. • A new stiffener-enhanced steel–concrete–steel (SESCS) sandwich beam was proposed. • Drop weight impact tests on the SESCS sandwich beams were conducted. • Flexural failure mode was observed for the SESCS sandwich beams under impact load. • An analytical model was proposed for predicting displacement response of the SESCS sandwich beam under impact load. [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]

• A novel energy absorption connector with PU foam and multiple pleated plates was proposed and two deformation patterns of the connector was observed. • The proposed connector dissipated energy through plastic deformation of multiple plated plates and PU foam compression. • PU foam filler could evidently improve the energy absorption performance in terms of higher EA, SEA and CFE as well as stabilizing the deformation mode. • The developed analytical model considering the transient strain rate effect of steel and PU foam could offer acceptable predictions on the force–displacement responses of the connectors. An innovative energy absorbing connecter with polyurethane (PU) foam and multiple pleated (MP) plates was designed to be placed between blast-resistant façade and structure to absorb blast-related energy along with reducing peak blast pressure transferred to the structure. Since the energy absorbing connector usually experiences impact loading transferred from blast-resistant façade, the deformation modes, force–displacement responses and energy absorbing characteristics of the contrived connectors subjected to impact loading were evaluated via employing drop-weight impact tests and FE simulations. The energy absorption, specific energy absorption as well as crushing force efficiency of the connectors were quantitatively evaluated. The experimental results revealed that filling PU foam could evidently enhance the energy absorbing performance of the connectors via increasing energy absorption, specific energy absorption as well as crushing force efficiency. Besides, increasing angle θ 0 (angle between MP plate and flat plate) and thickness of MP plate also leaded to higher specific energy absorption and absorbed energy. Finally, an energy-balance based analytical model incorporating transient strain rate effects of both steel and PU foam was proposed, which could be employed as a simple alternative to quickly yield the force–displacement relation of the connector. The accuracy of the developed analytical model was also validated with the experimental and finite element results. [ABSTRACT FROM AUTHOR]