Buckling of sandwich columns reinforced by triaxial weave fabric composite skin-sheets

This paper investigates computationally the buckling of simply supported sandwich columns constructed using elastic cores reinforced by skin-sheets of triaxial weave fabric (TWF) composites. A novel computationally cheap volume segmentation based thin plate model for the elastic properties of TWF is first developed. The predicted elastic properties of TWF exhibit quasi-isotropic behavior and correlate well with published numerical and measured results. Having demonstrated strong agreement with established results, these properties are then employed in the use of a plate on elastic foundation concept to study the stability of sandwich columns under a uniaxially compressed load environment. The parametric study comprises the effects of thickness, aspect ratio, and modulus of the sandwich core (treated as an elastic foundation), as well as the inclusion of the effects of the initial in-plane and out-of-plane imperfections of the skin-sheets on the critical buckling load. Remarkable dependencies of the critical buckling load on these parameters are demonstrated, due to both independent and wedding actions, noting that a perturbation due to out-of-plane imperfections has been observed to be the most significant contributor to reduction in compressive resistance.