The impact behavior of PVC foam sandwiches have been investigated by experimental tests and analytical approach, based on the energy balance model. The experimental results were compared to the AFS (Aluminium Foam Sandwich) impact response in terms of energy absorption and failure mode. The results of the low-velocity impact tests reveal that PVC foam sandwiches require a higher energy amount to produce complete failure with respect to the AFS panels, but different failure modes were observed. The AFS specimens experienced ductile fracture with large out-of-plane displacement compared to the predominantly elastic failure mode of the PVC foam sandwiches and this makes the damage detection procedure easier for sandwich structures. Moreover, the AFS structures are relatively intact compared to the more catastrophic and localized fracture of the polymeric sandwiches and, in consequence, they exhibit a better post-impact strength. The experimental results suggest that the AFS panels are a better choice compared to the sandwich panels to realize progressive energy absorbers. The failure mode and the damage have been investigated by two experimental techniques: the thermography and the tomography. The investigation of the aluminum foams by means of the 3D CT (Computed Tomography) is very useful to check their quality in terms of porosity distribution, that influence the mechanical properties of the foams. The thermographic images of the damaged specimens show a rapid crushing of the PVC core and a more uniform crushing of the aluminum foam cells. The obtained results have particular importance for applications that require lightweight structures with a high capacity of energy dissipation, such as the transport industry, where problems of collision and crash have increased in the last years. This study is the first step of a research aimed at introducing the aluminum foam sandwiches into the ship construction. On the basis of information obtained from the experimental tests, will be selected some ship components to be realized along with the investigated materials. The use of these sandwich structures can lead to a weight reduction of the ships, providing an adequate structural strength under operating conditions.
Low-velocity impact strength of sandwich materials
Schlagfestigkeit von Sandwich-Werkstoffen bei niedrigen Geschwindigkeiten
Journal of Sandwich Structures and Materials ; 13 , 4 ; 409-426
2011
18 Seiten, 15 Bilder, 5 Tabellen, 17 Quellen
Aufsatz (Zeitschrift)
Englisch
Low velocity impact of sandwich composites
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