Multiscale Modelling and Characterization of Bonded Repaired Sandwich Composite Facing Sheet under Static Loading

Abstract

Prediction of composite materials failure is a valuable resource for ensuring structural integrity of aerospace structures. For the experimental part of the study, the sandwich specimens were fabricated using two aluminum cores, a Nomex core sandwiched between tool-facing and bag-facing sheets. A damaged slot was introduced and thereafter repaired with filler and repaired plies on the tool-facing sheet. The bonded-repaired sandwich composite facing sheet specimens were tested using a four-point bending setup under static loading conditions. A Multiscale Modelling (MSM) approach was developed to characterize the failure of a bonded-repaired sandwich composite tool-facing sheet. The MSM approach bridged three different length scales such as micro, meso and macro scales. The data processing and information transfer between the scales was facilitated by Visual Basic Applications scripts. Comparisons of micro, meso and micro-scale results were presented for both MSM and experimentation to validate the proposed MSM failure characterization approach. Numerical and fractographical results from MSM and experimentation matched very well for all three scales. In conclusion, the MSM failure characterization approach performed well against the experiment. It presents an opportunity to use an alternative composite materials failure characterization method for future research.