Load-carrying capacity of thin-walled composite beams subjected to pure bending

The paper deals with estimating load capacity of thin-walled composite beams with C-shaped cross-section subjected to pure bending. The discussed beams were made of eight-layer GFRP laminate. The analysis have been performed on six ply systems. To designate load capacity of analyzed structures the ANSYS® program based on finite element method were employed. The experimental tests were conducted. Estimations of load capacity were based on the following failure criteria: Inverse of Tsai-Wu, Hoffman and criterion of maximum stress reduced to fiber direction. Based on the performed experimental and numerical studies it has been concluded that the largest convergence of numerical and experimental results was obtained with the implementation of the criterion of maximum stress reduced to the fiber direction. After exceeding the compressive strength or tension strength in the direction of the fibers the composite beams were characterized by a high stiffness degradation, leading to rapid destruction of the structures.