Simulation And Analysis Of Edge Impact And Compression-after-impact On Stiffened Composite Panels

For composite stiffened plates,the low speed edge impact damage modes are complicated and may result in severe strength drop problems that threaten the structural safety.Based on the experimental analysis,this paper presents a finite element simulation method for predicting the impact damage and compressive residual strength of T-shaped composite bars.The main contents of this article include:(1)The damage resistance and damage tolerance of stiffened plates at different impact positions are analyzed.It is pointed out that the in-plane impact is more serious than the out-of-plane impact.The failure mechanism of compression after impact on stiffened plate is analyzed.The edge damage of rib is the key factor to control the residual strength of stiffened plate.(2)The discrete ply model of composite laminates was established.Considering the delamination between layers,fiber tension damage,fiber compression failure,matrix tension damage,matrix compression failure and separation of matrix,the bilinear continuum damage model was adopted to simulate the process of edge impact on the laminated plate.The damage morphology,impact response and damage parameters similar to the experiment are obtained,and the data comparison with the experiment proves the validity of the model.(3)Based on the whole process analysis of impact-compression after impact,a simplified model for predicting the edges impact damage on T-rib is established.The damage morphology,residual strength and failure strain predicted by the finite element model are in good agreement with the experimental values,indicating that the delamination propagation and sub-layer buckling are the important reasons for the failure of stiffened plates with impact damage.