## 4 Conclusions  
A degenerated plate element-based finite element model incorporating geometric nonlinearity was developed in a MATLAB environment to analyze delamination behavior in laminated composite plates under static uniform pressure loads. Geometric nonlinearity was modeled using Green-Lagrange strain components. The parametric study considered laminates with various lamina orientations, boundary conditions, damage locations, and  
Figure 11: Maximum displacement of multiple delaminated plates of various lamina sequence with simply supported boundary condition (SSSS). (**a**) Maximum displacement of plate of delamination size 0.2a and lamina sequence \((0/90/0)_{35}\). (**b**) Maximum displacement of plate of delamination size 0.5a and lamina sequence \((0/90/0)_{35}\). (**c**) Maximum displacement of plate of delamination size 0.2a and lamina sequence \((0/45/90)_{35}\). (**d**) Maximum displacement of plate of delamination size 0.5a and lamina sequence \((0/45/90)_{35}\). (**e**) Maximum displacement of plate of delamination size 0.2a and lamina sequence \((0/45/90)_{34}\). (**f**) Maximum displacement of plate of delamination size 0.5a and lamina sequence \((0/45/90)_{34}\). damage sizes to assess the efficacy of the developed algorithm. The focus was on single interface delaminations located at the mid-interface. The following conclusions can be drawn from the numerical analysis:  
* Incorporation of geometric nonlinearity significantly decreases laminate displacement compared to linear analysis, as nonlinearity stiffens the plate. * The simply supported boundary condition (SSSS) was found to be more affected by nonlinearity (around 30-40%) compared to CFFF, CCCC, and CSCS boundary conditions. * In most cases, an increase in damage size results in a greater effect of nonlinearity on the displacement response. * No significant effect of geometric nonlinearity on damage location (center, edge, corner) was observed when other parameters remained unchanged. * Lamina orientation had the greatest influence on nonlinear displacement for the CFFF boundary condition, whereas other boundary conditions showed only minor variations. The model was further validated in predicting the nonlinear response of laminates with multiple interface delaminations. Overall, the results demonstrate that geometric nonlinearity significantly influences the structural response, depending on the conditions. Therefore, incorporating geometric nonlinearity in the analysis is crucial for predicting realistic behavior, especially for delaminated composite structures, ultimately leading to safer and more reliable designs. The study also provided valuable engineering insights: boundary conditions significantly affect damage tolerance; stacking sequences influence delamination resistance; and certain delamination locations and sizes can amplify nonlinear effects. These findings will contribute to more effective damage assessment and maintenance planning. The results presented in this paper will serve as a benchmark for future researchers. Experimental validation, planned as part of future work, will further reinforce the model's credibility and reliability. In addition, this study will be extended to dynamic and buckling analyses of laminated plate and shell structures with delamination. Conceptualization, P.T. and S.K.B. ; methodology, P.T. ; validation, S.A., P.T. and H.P. ; formal analysis, S.K.B. and H.P. ; resources, C.K., S.A. and H.P. ; data curation, P.T. ; writing--original draft preparation, S.K.B. ; writing--review and editing, C.K., S.A. and H.P. ; visualization, S.K.B. and P.T. ; supervision, C.K. ; project administration, P.T. ; funding acquisition, H.P. All authors have read and agreed to the published version of the manuscript. This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea Government (MOTIE) (20224000000040).