bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a new vibroacoustic superelement for heavy-fluid cavities
Authors: Buron G , Thouverez F , Jézéquel L , Beley A , Thévenon F 
Published: June 2024

Abstract
We propose a Reduced Order Model (ROM) of heavy-fluid cavities with the objective to build a superelement in a finite element substructuring context. We consider the non-symmetric displacement-pressure finite element formulation. While there are numerous fluid-structure ROM in the literature, few are generalized to superelements. Typical vibroacoustic substructuring methods involve modal synthesis using uncoupled rigid-wall fluid modes and in vacuo structure modes. Vibroacoustic domains are composed of a structural domain and a fluid domain coupled on a fluid-structure boundary. Each domain can be modeled by symmetric monophysics formulations. Only the fluid-structure boundary requires a non-symmetric multiphysics formulation. Being defined on a submanifold, this subproblem is typically significantly smaller than the other subproblems. We propose to condense the uncoupled subdomains onto the fluid-structure boundary and use a Petrov-Galerkin procedure to obtain a reduced order representation of this loaded boundary. The captured boundary dynamics is then propagated to each uncoupled subdomain. Galerkin procedures are also applied to the uncoupled subproblems to increase the reduction bases. At the end, a Petrov-Galerkin procedure is applied to the full order model to build the superelement. The proposed superelement generation strategy is used to study an industrial water tank in a seismic analysis context. Results show a significant improvement over typical uncoupled superelements at the same reduction basis size. While the uncoupled superelements cannot describe the dynamics of the model beyond the weakly-coupled sloshing regime, the proposed superelement accurately captures the strongly-coupled dynamics in the studied frequency bandwidth.
Rrecommendations for Full Long-Term Analysis of Long-Span Bridges
Authors: Castellon Dario , Fenerci Aksel , Øiseth Ole A. 
Published: June 2024

Abstract
Investigations of extreme buffeting responses on long-span bridges suggest revisiting the current design guidelines as these might be non-conservative. For such purposes, the full long-term analysis is the most accurate methodology. Despite its well-known advantages, the method is not the standard practice in bridge design, mainly due its high computational demand. Recent studies have contributed to make the analysis feasible by employing enhancing strate-gies such as machine learning and efficient simulation techniques. The results are promising, and the computational effort can be reduced to a fraction of the original formulation. It’s necessary that the more accurate long-term methods are included in the design guidelines for long-span bridges. In the Norwegian Handbook for bridge design, only a simplified methodology is recommended, which exposes a gap between research and engineering practice that must be fulfilled. Therefore, this paper presents a set of recommendations for implementing the full long-term analysis based on our experience with the calculations from the Sulafjord bridge, a 2800m single span suspension bridge currently in design and feasibility stage. The objective is to provide recommendations to back-up the abovementioned regulating effort and contribute to close the gap between academia and engineering practice.
Example of bispectral analysis of a transmission line pylon
Authors: Esposito Marzino M. , Bastin T. , Duchene Y. , Denoël V. 
Published: June 2024

Abstract
It is common practice to tackle buffeting analysis by means of spectral analysis, assuming a Gaussian context. However, natural actions, as wind, or wave loading, might sometimes show important non-Gaussian behaviour. This is known to have an important impact on the extreme values of such random processes. In this context, a non-Gaussian bispectral turbulent wind analysis has been conducted on a transmission line pylon model. The non-Gaussian nature of the wind load is the result of the adoption of a nonlinear polynomial wind model applied to the Gaussian wind turbulent velocity components. Results of a stochastic dynamic analysis are compared with respect to their Gaussian counterpart, as well as to the Eurocode approach based on the equivalent static loads, which was also object of comparison of engineers in the original computation with respect to turbulent wind dynamic analysis. Importance of non-Gaussian nature of wind loading is highlighted, and considerations on why and when it should not be underestimated are discussed.
A frequency-time domain approach for soil-structure interaction involving embedded structures
Authors: Barbosa J , Aukselis A , Goulas E , Meijers SJH 
Published: June 2024

Abstract
The design of structures to seismic excitation in which soil-structure interaction (SSI) is not considered with enough detail can lead to overdesigned solutions and, in the case of large structures, lead to significant increases in the overall budget of the project. For such large structures, spending more effort in modelling SSI to derive less conservative solutions (yet, solutions that satisfy the seismic demand) can be advantageous. In this work, we report on the method recently developed at Royal HaskoningDHV (RHDHV) to assess the seismic response of a large building, which is partly deeply embedded in soil and partly founded on piles. Due to the critical nature of the project, SSI is not just of financial interest, but also a requirement from the relevant authorities.
The method described in this work consists of a substructuring technique, where the structure is decoupled from soil. This enables each part to be analyzed with the most suitable domain: frequency for soil and time for the structure. The two parts are thereafter re-coupled in a time-implicit FEM solver. The division between substructures is made at the edges of the floors and walls in contact with soil (for the embedded parts of the structure) and at the foundation beams for the more superficial parts of the buildings. Piles are included in the part containing soil.
For the soil part (and piles), a frequency-domain FEM strategy is adopted. This limits the analysis to linear elasticity. Nevertheless, the soil properties can be made linearly equivalent based on the non-linear ‘freefield’ response (i.e., without the presence of the building), as specified in some standards, e.g., ASCE-4-16. In order to consider appropriate reflection-free boundaries and radiation of waves, perfectly matched layers (PML’s) are used at the edges of the FEM model. A Python program has been developed for this purpose, and parallel computing was used to take advantage of the multiple cores available at calculation servers.
For the upper structure, an implicit time stepping scheme is used, in which structural non-linearities (e.g., sliding between components) can be modelled. The structural model is created and solved using ABAQUS software. The coupling between the upper structure and soil is done after transforming the soil response to the time-domain. This results in time convolutions at the interaction surfaces, which in turn can lead to an unstable stepping algorithm. Therefore, one must be critical and careful when deciding the time-step to use in the simulation.
In this work, we further present our approach to analyze the stability of the system (without having to solve it in its entirety, which is a time-consuming task), and present a strategy/simplification which showed to improve the convergence of the coupled algorithm.
Dynamical behaviour and Control of a Magnetic structure, composed by a Shape Memory spring driven by a DC motor with limited power supply to harvesting energy
Authors: Ribeiro M A , Balthazar J M , Daum H H , Tusset A M 
Published: June 2024

AbstractIn this work, we explore a non-linear dynamic mathematical model containing Shape Memory Alloy (SMA) and a non-ideal engine for energy production. However, numerical analyzes of the device showed chaotic behavior for a given set of parameters. Thus, we used the classical tools of non-linear dynamics (Lyapunov Maximum Exponent, bifurcation diagrams, phase maps, and Poincaré maps) that corroborated to determine the regions of chaos. However, to produce energy, the chaotic behavior makes the production of unpredictable electric current that compromises the operation of the device. Therefore, we apply two control techniques to suppress the chaotic behavior for a desired periodic orbit. The first is the State-Dependent Riccati Equation (SDRE) which considers the non-linearities of the system and Optimal Linear Feedback Control (OLFC) which employs a linear methodology to control the device. The results were promising due to the trajectory errors between the controllers that show that chaos was suppressed, and the current produced by the system became periodic.
Effects of wind-induced vibrations in tall buildings on human balance and risk of falls
Authors: Rouzegari Keynaz , Shahabpoor Erfan , Heshmati Kaveh 
Published: June 2024

Abstract
The rise in demand for housing in large cities has resulted in the construction of increasingly tall and slender buildings which are susceptible to wind-induced vibrations. Such vibrations may affect human balance and even put vulnerable occupants at risk of falls. Issues such as these are not currently considered in design guidelines, which could result in drastic social and economic consequences. To address this concern, a pilot study was conducted at the University of Bath’s VSimulator facility to experimentally investigate the impact of wind-induced vibrations in tall buildings on human balance. Four young and healthy adults were exposed to synthesised bi-directional ‘wind-induced’ vibrations with a building natural frequency of 0.2-0.5Hz, peak factor of 3.5 and peak acceleration magnitudes of 0, 5 and 10 milli-g, while performing various tasks. Their performance was assessed by a test administrator, and they were also asked to carry out a self-reflection questionnaire to assess their level of motion sickness and general discomfort after each round of testing. Results from the study showed a consistent positive correlation between increasing acceleration magnitude and loss of balance in participants. An increase in effort required to maintain balance was observed, as well as a slight increase in motion sickness and general discomfort at 10 milli-g. It was also found that factors such as fatigue and practice/learning significantly affect the performance of occupants. By extending this study, a ‘risk’ threshold of vibration could be established, contributing to the development of guidelines that enable the design of safer and more suitable tall buildings for individuals susceptible to falls.
Statistics of wind-induced vibrations for a flexible roof
Authors: Rizzo F , Pistol A , Kłaput R , Mansour S , Sabbà M F , La Scala A , Flaga Ł 
Published: June 2024

Abstract
The wind-induced vibration of flexible structures is an important topic in the field of wind engineering in terms of human comfort and safety and of global instability of cable structures. In particular, cable structures used for roofs, for example, cable net and membrane tensile structures, are very sensitive to wind-induced vibrations because the axial force in a cable depends on its geometry. When the cable changes its geometry during the vibrations, it may either lose its tension or the cable tension may exceed the cable’s material strength. The wind-structure interaction on flexible roofs is most frequently investigated through numerical analyses using forces time-histories calculated by aerodynamic tests on rigid models. However, this approach fails to predict the effective dynamic deformation of the roof. This paper discusses results obtained from aeroelastic tests in a wind tunnel on flexible roofs. Signals were divided into slots and the statistics of peaks were estimated and discussed through the cumulative distribution function plot. Quantiles of 79%, 93% and 95% of the wind-induced acceleration were compared with the values provided in literature, codes and standards. The comparison showed that the values of accelerations provided in the literature are underestimated.
Dynamic Wind Loading of the Arnulf-Bridge in Munich
Authors: Katz Casimir 
Published: June 2024

Abstract
A very slender footbridge across the 32 rails of the central main station with a total length of 240 m had been evaluated for aeroeleastic effects. The drag and lift coefficients and the Strouhal number have been evaluated numerically with RANS. To avoid galloping effects, a certain small damping must be reached. It has been decided to measure the real damping before installing a tuned mass damper. The measurements during construction showed a sufficient damping value, but after completing the bridge better measurements showed a significant smaller value, which would trigger galloping effects. As the installation of tuned mass dampers was not only expensive, but also an issue for the interruption of railway services, a nonlinear wind history analysis has been performed, showing that the accelerations of the oscillations remain within the critical limits for a footbridge.
Assessing Seismic Vulnerability of Precast Post-Tensioned Segmental Piers
Authors: Kocakaplan Sedef , Ahmadi Ehsan , Kashani Mohammed M. 
Published: June 2024

Abstract
Precast post-tensioned segmental (PPS) bridge piers mitigate global and local damages of bridge structures through natural hinges. The application of PPS piers has increased recently in Accelerated Bridge Construction (ABC). Therefore, to increase their use in high-seismicity regions, this paper examines seismic vulnerability assessment of post-tensioned segmental bridge piers with Shape Memory Alloy (SMA) bars through a Finite Element (FE) framework. First, to investigate the energy dissipation capacity of the PPS piers with SMA, an extensive parametric study performed on the key design parameters including, (i) number of segments or aspect ratio, (ii) length, area, and post-tensioning of the SMA bars, and (ii) area and post-tensioning of the tendon. The results are also compared with the piers without SMA bars. Furthermore, an equivalent reinforced concrete (RC) pier to one of the PPS piers is also analysed. Incremental dynamic analysis (IDA) is performed, and fragility curves are generated to evaluate seismic performance of the PPS piers with and without SMA bars using a suite of 44 far-fault ground motions. The IDA results show that, slenderizing the PPS piers tends to change failure criterion from the yielding of the post-tensioning tendon to strength loss of the pier. For squat piers, the yielding of the tendon governs the failure of the pier while for very slender PPS piers, the strength of PPS piers drops due to second-order effects at small drift values prior to the yielding of the post-tensioning tendon. Furthermore, the equivalent RC pier reaches slight and medium damage states in lower intensity measures compared to the PPS piers. Finally, IDA results of PPS piers with SMA bars show that their median IDA curves for drift responses are lower than the ones without SMA bars.
Flexural Wave Control Using a Far Field Adaptive Vibration Neutraliser
Authors: Menguzzo A , Casado P M , Mace B R , Brennan M J , Rustighi E 
Published: June 2024

Abstract
The subject of this paper is the control of flexural waves on an infinite beam using a vibration neutraliser located in the far field of a forcing input. The neutraliser analytical model consists of a beam carrying three concentrated masses that can be further simplified to a mass-spring-mass system given the system symmetry. Depending on the input frequency, position and value of the masses, the neutraliser can be tuned either to maximise the power reflection or the power absorption. The bandwidth of attenuation is limited so the neutraliser may become ineffective when the forcing frequency changes. To overcome this limitation, shape memory alloy wires are used to design an adaptive beam neutraliser. The wires, made of a Nitinol alloy, exhibit a change with temperature in the elastic modulus of the material caused by a lattice structure reorganisation. This property allows adaptive tuning for different input frequencies via flexural rigidity variation. A preliminary design of the neutraliser is proposed. Analytical and experimental data are compared to assess the validity of the model.
Design and optimization of seismic metamaterials to mitigate ground vibration
Authors: Kabirian Zohre , Carneiro David , Reumers Pieter , Lombaert Geert , Degrande Geert 
Published: June 2024

Abstract
This paper presents a first step towards developing an optimization method to improve the vibration mitigation performance of seismic metasurfaces. Two alternative objective functions are considered in the optimization problem. First, the vibration at a single receiver due to a harmonic source is minimized. Second, the energy dissipated by the metasurface during harmonic excitation is maximized. The dynamic properties of the resonators are the design variables. Forward modelling relies on a 3D coupled finite element-boundary element method, where the resonators are modeled as single-degree-of-freedom systems on top of square concrete foundations that are positioned on a homogeneous halfspace. A local optimization method with a gradient-based algorithm is used. In both cases, significant vibration reduction is obtained at the target frequency. When the vibration amplitude is minimized, resonators with a mass equal to the maximum allowed mass are obtained, whereas resonators with a lower mass are found when the energy dissipation is maximized. Dynamic soil-structure interaction requires the natural frequency of the resonators to be slightly higher than the excitation frequency. The optimization formulation needs to be further adapted to target vibration reduction over a larger area and in a wider frequency range.
Risk mitigation/performances incrementation of an offshore wind turbine with a flexible monopile foundation by means of a pendulum-tuned mass damper
Authors: Colherinhas G B , Petrini F , de Morais M V G 
Published: June 2024

Abstract
This paper proposes a multi-level system modeling for studying the structural behavior of an Offshore Wind Turbine (OWT) with a flexible monopile foundation considering the Pile-Soil Interaction (PSI). This analysis shows that the structural response is affected by a significant uncertainty due to the randomness of the geometric and mechanical properties of the tower and foundation and by the environmental loads and rotating blades. With a Monte Carlo simulation, the sources of uncertainty of the so-called “environmental” and “exchange” zones are generated for a Performance-Based Wind Engineering (PBWE) design of OWTs. Hence, the structural response, the stresses along the foundation, and the power production are evaluated in probabilistic terms assisting the optimal design process of a Pendulum Tuned Mass Damper (PTMD) used to mitigate the structural vibration of an OWT.
Decentralized H2-Based Semi-Active Control To Suppress Transient Vibration Of Structures
Authors: Panda Jagajyoti , Adarsh S. , Chakraborty Sanjukta 
Published: June 2024

Abstract
This study presents a novel decentralized active control algorithm for vibration mitigation of structures subjected to random seismic excitations. In recent years, the applicability of decentralization technique has gained momentum in the field of control theory to overcome the complexity and computational burden of centralized system. Advancement in instrumentation scheme, i.e., sensors, actuators and computing units in the feedback loop is the reason behind the growing interest of decentralized control concept. In this case, the controller framework is designed through suboptimal H2-based proportional control algorithm. The objective of this optimal strategy is to reduce structural energy and control force simultaneously. Further, the concept of decentralized switched state-feedback control law is incorporated, and the detailed formulations are presented in digital domain for easy implementation. A set of communication channels are considered to exchange the state information between the neighbouring subcontrollers. The performance of the designed control strategy is numerically illustrated for an 8-storey building model with multiple magneto-rheological dampers. Comparative assessment with passive case and standard centralized scheme confirms better adaptiveness of the proposed control scheme.
Analysis of the dynamic properties of urban bridges with different slopes
Authors: Gómez Soberón M C , Cruz Vargas J G , Gómez J M 
Published: June 2024

Abstract
Irregular bridges present more complex behavior than regular systems. A bridge is considered irregular when there are changes in stiffness or resistance in elements of the substructure, the superstructure or both, or when the higher modes have greater participation. Most of the previous studies consider irregular bridges with different height of piers and horizontal and straight superstructure. In this work, bridges with piers of different heights are analysed due to the presence of a longitudinal slope of the deck, which is more common for urban systems. The slopes considered range from 1% to an extreme 6%. With this information, elastic and inelastic models are generated with piers whose length gradually increases to achieve the slope. The bridges have equal-length four spans, simply supported, and three axes of single piers. The superstructure consists of a concrete slab and six AASTHO type beams. Responses of these bridges are compared with a regular model, with columns of equal height and without slope. For each structure, Ruaumoko code was used to create models. Typical vehicle load for Mexico is considered and bridges are located in three characteristic soil zones of Mexico City (firm, transition and soft). Results show that bridges with regular increment of the piers length have minor higher modes participation and a more predictable response.
One-year dynamic monitoring of a steel-concrete composite overpass
Authors: Gentile Carmelo , Pirrò Marco 
Published: June 2024

Abstract
Selected results collected in the continuous dynamic monitoring of a 3-span overpass using MEMS accelerometers are reported in the paper. The investigated structure is a steel-concrete composite bridge with a trapezoidal box girder of variable height and curved cross-beams, so that the overall geometry is rather complex. The overpass has a total length of 108 m and spans of 30 m + 48 m + 30 m. The paper firstly presents the dynamic characteristics of the structure obtained from preliminary ambient vibration tests. Subsequently, the effects of environmental and operational variability during the continuous monitoring are highlighted, with the temperature significantly affecting all natural frequencies. A clear effect of changing environment is detected for torsion modes as well, whereas no remarkable changes of bending mode shapes are observed.