INFLUENCE OF BRAZIER EFFECT ON THE FAILURE BEHAVIOR OF A GFRP THIN CIRCULAR CYLINDER - AN EXPERIMENTAL AND NUMERICAL STUDY

Abstract

The observed ovalization phenomenon (flattening of a circular cross-section) under the applied bending loads in the thin-walled long-length cylinder-like structures, such as wind turbine rotor blades has been referred to as the Brazier effect. The Brazier forces tend to reduce the second area moment of the cylinder, and eventually lead to structural collapse. To understand the detailed effect of the Brazier forces on the damage initiation and propagation in composite structures, in the current research work, a GFRP thin cylinder (sub-component level) was manufactured and tested under a compression load to induce the ovalization effect. To predict the stiffness and strength degradation of the cylindrical cross-section caused by transverse loads, along with the ply level strength properties, required mode I and mode II strength and fracture energy values are obtained from experimental coupon level testing. Besides, numerical simulations are accomplished at the coupon level to calibrate the implemented material models. Finally, the obtained load vs. displacement curve from experimental testing of the cylinder was used to validate the results predicted by the detailed FE model. © 2022 Yakanna et al.