Damage Tolerance of Sandwich Foam Cores: Experimental Characterization and Numerical Modelling

Abstract

In this paper, a novel analytical model for predicting the post-crushing compressive response of crushable foams is presented. The calibration of the model is performed using experimental measurements obtained exclusively from standard monotonic compressive tests. Therefore, the need of performing time-consuming compressive tests including multiple unloading-reloading cycles is avoided. Model predictions have been validated against experimental measurements available for three different foam materials. The model is shown to accurately predict the thickness of the crushed material layer during progressive crushing and the residual after-crushing strain (with a maximum error of about 12%). When compared to existing models, whose calibrations require the same experimental measurements of the present model, the latter is capable to predict the residual after-crushing strain with a significantly smaller error (error reduction over 56%). Furthermore, it is shown that the proposed model is able to accurately capture the characteristic features of the post-crushing compressive response of crushable foams. The results presented in this work demonstrate the relevance of the proposed model for a damage-tolerant design of foam-cored composite sandwich structures.