Fracture analysis of cracked metallic plate repaired with adhesive bonding composite patch

Fatigue crack growth test of cracked metallic plate repaired with adhesive bonding composite patch was conducted to study the fracture behavior of crack patching. The failure mode was that crack grows along with adhesive debonding. The crack length and debonding area were measured at different numbers of cycles. The nonlinear three- dimensional(3D)finite element(FE)model considering adhesive debonding and crack growth simultaneously was developed. The experimental and analytical results were in good agreement with each other.

Material parameter modeling and solution technique using birth–death element for notched metallic panel repaired with bonded composite patch

This paper seeks to outline a novel three-layer model and a new birth-dteath element solution technique to evaluate static strength of notched metallic panel repaired with bonded com- posite patch and to optimize material parameters. The higher order 3D, 8-node isotropic solid ele- ment and 8-node anisotropic layered solid element with three degrees of freedom per node are respectively implemented to model substrate panel, adhesive layer and composite patch to establish three-layer model of repaired panel. The new solving technique based on birth-death element is developed to allow solution of the stress pattern of repaired panel for identifying failure mode. The new model and its solution are used to model failure mode and residual strength of repaired panel, and the obtained results have a good agreement with the experimental findings. Finally, the influences of material parameter of adhesive layer and composite patch on the residual strength of repaired panel are investigated for optimizing material properties to meet operational and envi- ronmental constraints.

Dynamic analysis of the composite laminated repaired perforated plates by using multi-patch IGA method

The bonded repair techniques seem to be the most frequent procedures in the aviation maintenance.The achieved composite repaired perforated thin-walled plate is a complex geometry with high numerical analysis cost.The NURBS-based Isogeometric Analysis(IGA)proposes a sensible and affordable tool to carry out such geometry analysis.In this context,a well-known technique is to divide the original geometry assembly into number of simple neighbors connected geometries.In the present study the free vibration analysis of the perforated plates repaired on one side with an external bonded composite laminated patch is investigated.A multi-patch geometry modeling approach is implemented in line with the first order shear deformation theory of plates.In order to hold the geometry integrity and uniformity,all the degrees of freedom between adjacent geometry patches are completely tied through implementing a Nitsche method.To show the effectiveness and accuracy of the developed formulation,some representative results are extracted and compared with those from literature.The effects of geometrical as well as material parameters including boundary condition,cutout shape,and repair layup on the dynamic response of the repaired perforated plates are then investigated.