Axial crushing behaviors of composite pre-folded tubes made of KFRP/CFRP hybrid laminates

In this paper, the crushing behaviors of composite pre-folded tubes made of KFRP/CFRP hybrid laminates subjected to quasi-static axial loads are investigated both experimentally and numerically. The full-diamond origami pattern and its variation forms with curved lobes are considered for the tube design. Five pre-folded tube specimens with different ply stacking sequences consisting of CFRP and KFRP woven fabrics are manufactured and tested in quasi-static axial compression tests. The finite element models for pre-folded tubes made of KFRP/CFRP hybrid laminates are developed and validated with the experimental results. A comprehensive parametric study on the energy absorption properties of CFRP/KFRP hybrid composite tubes with various geometries is performed numerically. The results show that the energy absorption performance of the composite tubes has a strong correlation with the composition of hybrid fiber and the specimen with the stacking sequence of [0(k)degrees /0(c)degrees/0(c)degrees/0 (k)degrees] has the best overall energy absorption performance among the five specimens tested. Moreover, it is found that by converting the standard full-diamond pattern to the curved variation forms, the energy absorption performance of the pre-folded tubes can be improved.