Failure investigation of debonded sandwich columns: An experimental and numerical study

Failure of compression loaded sandwich columns with an implanted through-width face/core debond is examined.Compression tests were conducted on sandwich columns containing implemented face/core debonds.The strains and out-of-plane displacements of the debonded region were monitored using the digital image correlation technique.Finite element analysis and linear elastic fracture mechanics were employed to predict the critical instability load and compression strength of the columns.Energy release rate and mode mixity were determined and compared to fracture toughness data obtained from TSD (tilted sandwich debond) tests, predicting propagation loads.Instability loads of the columns were determined from the out-of-plane displacements using the Southwell method.The finite element estimates of debond propagation and instability loads are in overall agreement with experimental results.The proximity of the debond propagation loads and the instability loads shows the importance of instability in connection with the debond propagation of sandwich columns.