PSI - Issue 60

Anupoju Rajeev et al. / Procedia Structural Integrity 60 (2024) 222–232 Author name / StructuralIntegrity Procedia 00 (2019) 000–000

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Fig. 4. Response spectra of an SDOF system having bilinear resistance function

Finite element simulations are conducted at extreme load combinations. The peak deflection from numerical analysis is compared with the deflection values from analytical model in Table 6.

Fig. 5. Displacement-time history profile from analytical and numerical models

4. Conclusion In conclusion, this study focused on developing response spectra for Single Degree of Freedom (SDOF) systems with a bilinear resistance function. It was observed that the response spectra for bilinear resistance differed slightly from the conventional linear-perfectly plastic response spectra, such as those found in UFC-340 [23]. The continuous tangent hyperbolic relation proposed by Stochino and Carta [8] was explored to account for the complete non-linearity of the resistance function, resulting in a computationally expensive yet smooth response curve. The analysis was primarily limited to bilinear systems, and while the proposed framework was validated for one-way elements, its application to two-way elements required certain assumptions. The Finite Element (FE) model results exhibited good agreement with the analytical model in the impulsive region, but discrepancies emerged in cases of high loads. The FE model was used to estimate damping through log decrement analysis and integrated into the theoretical model. Displacement histories from both analytical and numerical models were compared. However, it is crucial to acknowledge that the analytical model comes with several assumptions, and it may not accurately predict the structure's response under extreme load conditions. In such cases, the FE model provides valuable insights. A significant limitation of this study lies in the absence of experimental validation for both the numerical and SDOF models. Future work should encompass full-scale experimental investigations on RC