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Item type:Publication, Access status: without files , Data-driven modeling of structural dynamics: improving measurement noise robustness with Augmented Dynamic Mode Decomposition(Institute of Structural Analysis and Antiseismic Research National Technical University of Athens, 2025-06); ; ; Accurate modeling of structural dynamics is essential for designing effective vibration control strategies in earthquake engineering. Traditional system identification techniques often struggle to distinguish intrinsic structural behavior from external forces, particularly in the presence of measurement noise. Dynamic Mode Decomposition with Control (DMDc) offers a data-driven approach to extracting system dynamics while accounting for external inputs. However, its performance degrades significantly in noisy environments, leading to inaccurate mode identification and misrepresented damping characteristics. To address this challenge, we introduce Augmented Dynamic Mode Decomposition with Control (AugDMDc), a novel extension that incorporates time-delay coordinates into DMDc to enhance noise robustness. By embedding past measurements into the state-space representation, AugDMDc effectively reduces the impact of sensor noise while preserving the ability to separate a structure’s natural response from external excitations. We validate this approach using a structural dynamic system equipped with an Active Mass Damper (AMD), comparing the performance of DMDc and AugDMDc under various conditions.Publicationtype: Conference Paper30 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Selective mass scaling for Timoshenko beam and Mindlin plate elements based on the discrete strain gap method(Institute of Structural Analysis and Antiseismic Research National Technical University of Athens, 2025-06); ; ; The conditional stability of explicit time integration algorithms limits the critical time step size, which depends on the highest natural frequency of the discretized problem. For shear deformable structural finite element formulations, efficiency is typically limited by the highest transverse shear frequencies. Selective mass scaling (SMS) methods aim at selectively scaling the high frequencies while preserving the important low frequency content. In particular, recent SMS concepts, which are inspired by the discrete strain gap (DSG) method [1] and, thus, are denoted as DSGSMS concepts, result in effective and accurate methods, which naturally preserve both linear and angular momentum. In this contribution, we extend previous work on DSGSMS for shear deformable element formulations [2] with respect to several aspects. First, we perform a theoretical analysis of the DSGSMS method that provides new insight into spectral properties and analytical time step estimates. Second, we extend the DSGSMS method from Timoshenko beam elements to Mindlin plate elements. Third, we test the extended concept with respect to spectral accuracy and the transient behavior in explicit time integration.Publicationtype: Conference Paper52 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Physics-based wireless structural health monitoring and control using temporal finite elements(Institute of Structural Analysis and Antiseismic Research National Technical University of Athens, 2025-06); ; ; Integrating structural control into wireless structural health monitoring systems typically entails implementing control algorithms that predict counteracting forces for keeping the structural response within acceptable bounds. Control algorithms usually involve data-driven analysis, implemented in wireless sensor networks as feedback-loop systems. Although effective, data-driven analysis for structural control hardly accounts for the physics underlying the structural behavior. In an attempt to implement structural control in an intuitive manner for engineers, this work suggests an embedded structural control method that builds upon physics-based modeling, using the finite element method for analysis. In particular, the proposed physics-based wireless structural health monitoring and control (SHMC) method bases the prediction of control forces on temporal finite elements (TFE), which integrate the time dimension into the well-known FE spatial shape functions. Prior to embedment, the TFE models are reduced to (i) decrease the computational burden on the sensor nodes and (ii) match the discretization of the TFE models with the degrees of freedom measured by the SHMC system. The proposed SHMC method is implemented in a prototype wireless SHMC system and validated in laboratory tests on a model frame structure mounted on a shake table. The results showcase the capability of the physics-based wireless SHMC method to retain the structural response within previously defined bounds.Publicationtype: Conference Paper28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Numerical study of the installation of piles combining the zipper and CEL methods(Institute of Structural Analysis and Antiseismic Research National Technical University of Athens, 2025-06); Simulating the installation effects of piles in numerical finite element models is often neglected due to the complexities of modeling large soil displacements under dynamic loads. This study presents a novel combined modelling approach that integrates two distinct numerical techniques: the zipper method for vibratory driving and the Coupled Eulerian-Lagrangian (CEL) approach for impact driving. This comprehensive simulation captures the complete installation process of a king pile (I-profile). Three-dimensional finite element models in Abaqus are employed to simulate the initial vibratory phase, followed by a seamless transfer of stress states and solution-dependent variables to the CEL model with nearly similar geometry for impact driving simulation. The numerical results reveal significant installation-induced changes in soil state, including void ratio distribution and effective stress patterns, consistent with existing literature. Subsequent static load tests indicate that considering both vibratory and impact driving phases results in notably different predictions of axial capacity. Specifically, simulations that include the vibratory phase show a 14% increase in skin friction and a 13% increase in compressive resistance compared to those that neglect it. This study proposes a promising numerical framework for modeling complex pile installation processes and their effects on soil-structure interaction. The findings provide valuable insights for designing efficient pile foundation systems.Publicationtype: Conference Paper22 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 37 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Selective mass scaling for Timoshenko beam and Mindlin plate elements based on the discrete strain gap methodPublicationtype: Conference Paper40