Response of energy absorbing connector with polyurethane foam and multiple pleated plates under impact loading

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 θ₀ (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.