Numerical analysis of singly curved shallow composite panels under three-point bend load

Abstract The experimental methodology to test curved panels under three-point bend (3PB) load is assessed. The problem arises when mechanical and strength characterization of pipe material systems is required. Test specimens cut out from pipe samples oriented in the tangential direction were used to measure hoop modulus and strength. In this procedure singly curved beams with the same radius as the pipe are obtained. The present assessment was made using three different approaches: Finite Element Method (FEM) with nonlinear geometrical analysis, curved beam theory and an approximate 2D elasticity solution. It was verified that for some cases the nonlinear effect becomes important. Furthermore the maximum span achievable, which is limited by the specimen’s geometry, can prevent the use of appropriate span/thickness ratios to avoid significant shear effects. However it was concluded that for typical GRP shell panels, with internal radius between 150 and 250 mm and a wall thickness of 12 mm, the 3PB tests display an almost linear relationship between applied load and maximum deflection. Moreover, reasonable accurate results, with an error lower than 5%, can be expected using the curved beam theory formulas. Finally some preliminarily experimental results are presented for the 250 mm radius beams with a thickness of 12 mm.