ABSTRACT
Pultruded structural components employing unidirectional continuous fiber composites are in increasingly wide use. Often such structural members include plate components wherein one long edge is unsupported or free, e.g. channel sections and T-sections. In such cases the fibers are parallel to the long free edge while perpendicular to the free edge the material properties are matrix dominated. Localized instability (crippling) can occur at loads less than the overall buckling loads. In the following, these flange members are analyzed as long thin plates where in addition to the free edge, the other three edges are considered to be clamped or simply supported to assess that effect. Critical axial compressive buckling loads are determined using the Theory of Minimum Potential Energy. In addition, if the pultrusion process involves a chemical cleanliness or wetting defect such that when the compression flange is loaded it splits, then the buckling load is greatly reduced, increasing the possibility of unanticipated structural failure.
