Compressive bearing capacity and failure mechanism of CFRP-aluminum laminate column with single-channel cross section

The axial compressive bearing capacity, failure modes, and failure mechanisms of carbon fiber-reinforced aluminum laminate (CARALL) columns with single-channel cross sections were studied in detail. In this study, two types of short CARALL specimens with a 5/4 configuration were first fabricated using 2024-T3 aluminum alloy and different fiber orientations ([0 degrees/90 degrees/0 degrees](3), [45 degrees/0 degrees/-45 degrees](3)) via a pressure-molding thermal-curing forming process. The short CARALL columns were then subjected to static loading tests to determine their axial compressive behaviors in terms of ultimate bearing capacity and failure modes. Thereafter, the user-defined FORTRAN subroutineVUMAT, which is based on ABAQUS, was used to investigate the failure mechanism of the proposed CARALL columns. Meanwhile, based on the classic laminated panel mechanics theory, a theoretical method was proposed to predict the safe bearing capacity of the designed compressive CARALL columns. The results indicated that the ultimate failure of both types of short CARALL columns was a strength failure caused by the delamination of the layers. When the short CARALL columns were subjected to an axial compressive load, the fiber spread angle of the carbon fiber-reinforced polymer prepregs in the laminate panels had a significant influence on the resistance to interlaminar delamination. A smaller fiber layer angle resulted in greater resistance to interlaminar delamination. Setting a certain number of fiber layers with angles between 0 degrees and 45 degrees could increase the toughness of the compression column member against interlaminar shear delamination at the initial stage. Comparisons of the experimental, numerical, and theoretical results demonstrated good agreement, indicating that the proposed theoretical method is feasible for predicting the safe bearing capacity of CARALL columns with a single-channel cross section and can be applied to the design of compressive laminate pillar components.

Automated summary

The study investigated the axial compressive bearing capacity, failure modes, and failure mechanisms of CARALL columns with a single-channel cross section. It was found that the ultimate failure of short CARALL columns was due to delamination, and the fiber layer angle had a significant impact on interlaminar delamination resistance. A smaller fiber layer angle resulted in greater resistance against delamination, indicating the feasibility of the proposed theoretical method for predicting safe bearing capacity.