Impact Analysis of Composite Repair Patches of Different Shapes at Low Velocities for Aircraft Composite Structures

The area under crack for various aircraft composite structures can be effectively repaired using composite materials. Low velocity impact can cause barely visible damage to the interior structure of laminated composite. These impacts can cause delamination in composite materials. In this study, a finite element analysis was conducted using Abaqus/Explicit and the results of the analysis were compared to the experimental data from literature. E-glass/epoxy composite laminate was subjected to a low velocity impact test. To study the effect of patch repair, a composite patch was applied on a cracked laminate and a low velocity impact was then conducted on this model. The FEA results were validated with the experimental data and an approach to model an ideal composite patch shape was conducted. Different patch shapes like square, rectangle, circle and ellipse were designed and analysed on the crack by keeping the surface area of the patch common. All these patches were compared and an ideal patch shape was found for the model based on stress concentration on the patch. Finally, a parametric study was performed considering the change in impactor speed and impactor material on impact damage. The effectiveness of finite element analysis of low velocity impact on aircraft composite structures is demonstrated.