Damage mechanism characterization of ±35° and ±55° FW composite tubes using acoustic emission method

The focus of this study is to investigate the mechanical properties, of +/- 35 degrees and +/- 55 degrees filament wound (FW) composite tubes under axial compression loading using the acoustic emission technique. For this purpose, material failure, crashworthiness characteristics, and the effect of each mechanism on the energy absorption capacity were studied using numerical and experimental approaches. Also, to identify and estimate the contribution percentage of damage mechanisms as well as how the damage grows in the specimens, the analysis of acoustic emission signals recorded during loading was performed. Digital image correlation was additionally used to capture displacement/strain contour maps. Finally, to analyze the effect of the winding pattern in the experimental test, the tubes were simulated using finite element analysis (FEA). For modeling of damage mechanisms, a 3D continuum damage model was used. The results of signal processing showed that by increasing the weaving angle of fibers from +/- 35 degrees to +/- 55 degrees, the separation of fibers from the matrix decreases, and the percentage of matrix crushing and fiber failure increases. The assessment of damage percentages showed that the reason for the large drop in force at +/- 55 degrees compared to +/- 35 degrees is the increase in matrix crushing. Furthermore, the failure behavior of FW tubes appeared to be dominated by local buckling, and the FEA effectively predicted the linear behavior and maximum load value of the composite tubes.

Automated summary

This study investigates the mechanical properties of filament wound composite tubes at +/-35 degrees and +/-55 degrees under axial compression loading using acoustic emission technique. The analysis shows that increasing the weaving angle of fibers leads to decreased separation of fibers from the matrix and increased percentage of matrix crushing and fiber failure.