Failure analysis methods for corrugated-core sandwich cylinders based on identified composite parameters and modified failure criteria

Composite structures have high sensitivity to inaccuracy of material parameters and geometry imperfections from making process, which greatly affect the accuracy of the ultimate load prediction. Three methods were proposed to enhance the accuracy of the ultimate load prediction of corrugated-core sandwich cylinders, including the finite element modelling (FEM) method based on parameter identification by vibration correlation technique (VCT), the failure map method based on multi-failure theory, and the knockdown factor (KDF) method based on imperfection sensitivity analysis. Traditional composite failure criteria were modified by the identified mechanical parameters. Adopting standard composite parameters, the FEM prediction error for the ultimate load is 50.5 %, and reduced to 20.9 %, 12.14 %, and 4.54 % by these three proposed methods based on identified parameters and modified failure criteria. Considering imperfections, the KDF method based on imperfection sensitivity analysis could suggest the most consistent ultimate load prediction with the experiment.