Analysis of preconditioned glass fibre reinforced composite sandwich I-beams in bending

Abstract

The exural mechanical behaviour of various composite sandwich I-beams has been investigated under quasi-static loading. Both intact and preconditioned I-beam specimens were examined. The intact I-beams had two different support spans. The preconditions included central voids and remote debonds, both embedded at the ange-web intersections, whereas remote, barely visible impact damage (BVID) was introduced on the ange surfaces. It was found that the behaviour of the present I-beams was nearly linear until ultimate failure approached, and that the load-bearing capability exceeded the design requirement, irrespective of the preconditions. The exural rigidity of the intact I-beams calculated by using the lamination theory compared well with the experimental value. The analytical predictions for maximum de ections and maximum tensile strains were in reasonably good agreement with the respective experimental measurements. It was found that neither the central voids nor the remote debonds or BVID had a signi cant effect on the exural behaviour. The process of structural failure was extremely complex and was affected to a greater extent by the relatively low mechanical properties of the polymethacrylimide (PMC) foam core. It was shown that foam compression and local web skin wrinkling were the major failure mechanisms, irrespective of the preconditions.

Design of Lightweight Glass-Fibre-Reinforced Epoxy I-Beam for Structural Applications

“…Works [5][6][7] have been conducting detailed research of the structure and mechanical properties of composite I-beams made of carbon and glass fibers. Some authors [8][9][10] performed detailed research of the stiffness of composite I-beams in bending test. It has been found that the behavior of tested beams was practically linear until fracture, and the load-bearing capacity exceeds design requirements.…”