International Journal of Aerospace and Lightweight Structures (IJALS)Volume 1 Number 2 (2011)
Impact Resistant Behaviour of Lightweight Structural Elements
This paper presents findings from an experimental investigation undertaken by the authors on the generic impact resistant behaviour of lightweight structural elements. Given that the main thrusts of the research were on the fundamentals of impact actions the investigation considered only common timber materials (as opposed to innovative proprietary made lightweight products). The effects of a cushion and a dummy mass interface in mitigating impact actions are first demonstrated by observations from laboratory experimentations which involved impacting a timber beam at its mid-span position by a fallen object. Importantly, these mitigating effects have been quantified systematically by making comparisons between experiments featuring the use of different combinations of materials as interface. The use of hand calculation methods based on equal momentum and equal energy principles to constrain displacement demand estimates have also been presented. Good agreement between the predicted and observed displacement values have been found across all the experiments in order that the presented calculation method can be generalised. Meanwhile, limitations with the use of the conventional quasi-static approach in the analysis of impact actions are highlighted. Significantly, the revealed phenomena have important implications in the design of innovative light weight products that are potentially exposed to the hazards of impact.
Keywords: Cushion, Fallen object, Impact.