PSI - Issue 41

Andrea Pranno et al. / Procedia Structural Integrity 41 (2022) 618–630 Author name / Structural Integrity Procedia 00 (2019) 000–000

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simulate the nonlinear phenomena of diffuse propagation of multiple cracks incorporating other nonlinearities of the materials constitutive laws to model the plasticity and heterogeneity of the materials and the adhesion between steel reinforcement and concrete. Then, in the present study, an advanced and innovative finite element model was developed to investigate how the diffuse cracking phenomenon affects vibration characteristics in reinforced concrete beams. Specifically, with the developed numerical formulation, the damage phenomena caused by quasi-static monotonic and cyclic loadings was determined and the evolution of the dynamic properties of reinforced concrete beams was investigated. The deduced vibration characteristics of the investigated beams highlighted that diffuse damage plays a large role on their dynamic behavior, even at low frequencies. Natural vibration frequency variation is strictly correlated, in addition to damage assessment, with modal deformations resulting from the most damaged system components. Natural vibration frequency is highly sensitive to damage evolution in reinforced concrete structures. Therefore, the frequency-based damage identification parameters can be used even when load and, as a consequence, the damage are moderate. Additionally, numerical results have established that the use of advance damage indicators, such as those based on modal curvature, allows for realistic detection of the extent and location of the damage. In particular, the CDF indicator has shown to be particularly effective in locating and assessing damage, but there are advantages and disadvantages to the above damage detection technique, including the fact that it requires more measurements than damage detection based on modal deformations, but they are more effective because modal curvature appears to be more influenced by damage phenomena than mode shape deformations. We can conclude from the numerical outcomes that the proposed model can effectively be applied to damage detection procedures in reinforced concrete structures, thanks to its accuracy and completeness, in conjunction with mathematical models and experimental results. References Abdel Wahab , M.M., De Roeck, G., 1999. DAMAGE DETECTION IN BRIDGES USING MODAL CURVATURES: APPLICATION TO A REAL DAMAGE SCENARIO. Journal of Sound and Vibration 226, 217–235. https://doi.org/10.1006/jsvi.1999.2295 Abdel Wahab, M.M., De Roeck, G., Peeters, B., 1999. 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