Issue 71

M. Abdulla et alii, Fracture and Structural Integrity, 71 (2025) 124-150; DOI: 10.3221/IGF-ESIS.71.10

Additionally, the current study for the unrepaired plate was validated against the numerical investigation conducted by [25] on a center-cracked rectangular aluminum 2024-T3 plate under tensile loading. The comparison with the present FE results showed good agreement as depicted in Fig. 6.

Figure 6: Validation of current results of unrepaired plate with simulation from the literature.

Mathematical Formulation for Stress Intensity Factor in Repaired Plate In this study, the SIF for the repaired centre-cracked plate was determined using a detailed formulation that accounts for the geometric and mechanical parameters of the adhesive and the composite patch. This approach is based on the Rose model, which is widely used for such analyses and provides a more accurate representation of the SIF for repaired plates compared to classic formulations for unrepaired plates. Rose Model for Stress Intensity Factor in Centre-Cracked Plate The Rose model provides a means to account for the effect of the composite patch and adhesive layer on the SIF. The SIF for a repaired centre-cracked plate can be expressed as in Equation (8) [26]:

 a

   

(8)

K

R 0

a

where σ 0 is the reduced stress in the plate at the location of the crack proportional to the applied stress, a is the crack length, and Λ is the characteristic crack length. The parameter Λ is given by Eqn. (9):

t

        S 1 1

a





E t

(9)

Λ

P P

G

A

where S is the stiffness ratio between the repaired and unrepaired sections of the plate and β is a parameter that depends on the properties and dimensions of the adhesive and the patch and is given by Eqn. (10) [27]:

  

 

G t

1

1

2

A



 

β

(10)

E t

E t

a

P P

R R

E p is the Young's modulus of the plate, t p is the thickness of the plate, E R is the Youngs modulus of reinforcement/patch, t R is the thickness of the patch, t a is the thickness of the adhesive and G A is the shear modulus of the adhesive.

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