Evaluation of Dynamic Scaling Factor by Correlating Quasi-static and Impact Behavior of Sandwich Structures

Abstract

Composite sandwich materials are commonplace in the aerospace, marine, automotive, civil and other industries, but their susceptibility to dynamic impact and quasi-static concentrated loadings is still a concern. This work has two aims; (i) to perform Quasi-static (QS) and Low-velocity impact (LVI) tests to calculate a novel predictive parameter, the Dynamic scaling factor (DSF), defined as the ratio of LVI to QS results. The DSF allows the prediction of the impact behaviour by easier and lower-cost quasi-static tests. (ii) to evaluate the feasibility of Aluminium honeycomb sandwich (AHS) as a new sustainable alternative to composite sandwich. The mechanical tests were carried out using two different tups, hemispherical and conical, and damage detection employed Non-destructive techniques (NDT), specifically x-ray digital radiography. Two ‘traditional’ composite sandwich solutions, a thinner, lighter GFRP/PVC laminate and a thicker, heavier GFRP/balsa one, were compared with two AHS panels of equivalent bending stiffness to the composite sandwiches. For the perforation of the upper face only, results indicated that AHS absorbed more energy. If the complete perforation of the whole sandwich is considered, GFRP/PVC and GFRP/balsa sandwich composites absorbed more energy. The DSF was found to be greater than or equal to unity, varying between 1 and 2, depending on laminate thickness, material, tup geometry, and damage level considered. When perforation of the first skin is important, AHS can provide a new viable high-performance lightweight alternative to ‘traditional’ composites in terms of impact strength whilst providing a more sustainable alternative. This makes AHS a valuable new material choice in marine applications that emphasises weight reduction, energy efficiency and recyclability.