PSI - Issue 60

Amardeepa KCS et al. / Procedia Structural Integrity 60 (2024) 60–74 Amardeepa KCS/ StructuralIntegrity Procedia 00 (2023) 000–000

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14

th layers FI

3 rd layers FI

4

Fig. 28. Failure index values in the layer of L angle

Fig. 29. Max stress for different cases of displacement factors

7. Conclusion The global finite element analysis of the wing showed that the IS rib is critical at the stringer cut-out region when subjected to internal fuel pressure of 12.5 PSI, a requirement as per design. In the global FE model, it is impossible to model the IS ribs as per their geometrical details, including the radius and other fillet regions around the stringer cut out. The radius region at the intersection of the flange and web region is not modelled in the global wing model. Therefore, the global FE analysis showed higher stresses and failure index values at the stringer cut-out region. Hence, a standalone FE model is created, and the second level of analysis is carried out to study the critical failure issues in detail by considering an appropriate size of L angle around the stringer cut-out region. A novel finite element modelling approach is adopted for understanding and estimating the failure load at various zones of the L angle. The static analysis is carried out by enforcing the global displacement values on the L angle. The resultant shear, normal stress, and axial stress values are extracted from the region of interest and critical zones. The shear strength of matrix material (homogeneous and isotropic material) is 23 MPa, less than its transverse tensile strength of that matrix material, 53 MPa. Detailed post-processing of the analysis results is performed outside the FE