Modeling and Experimental Validation of Composite Stiffened Panels under Uniaxial Tension

Abstract

A finite element model implemented with a progressive damage propagation mechanism was generated to study the mechanical behavior of stiffened composite panels under uniaxial tension. Typical damage modes including fiber breakage, matrix crushing and delamination were considered in the model. Failure criteria with corresponding stiffness degradation technologies was used to predict the initiation and evolution of intra-laminar damage modes by a user-defined subroutine. Cohesive elements with thickness of 0.01mm were defined along the interface areas between the filler and the adjacent laminate layers for predicting the initiation and propagation of delamination. Corresponding tests on composite stiffened panel with a web cut-out were conducted. A good correlation between the numerical results and test data was obtained, which validated the finite element models. Both the numerical and experimental results conclude that the delamination in the flange around the cut-out region is the most critical failure mode for the composite stiffened panel under the uniaxial tensile load.