bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterisation of the damping performance of a Stockbridge damper from laboratory tests of an overhead high-voltage transmission line conductor
Authors: Mendonça Raphael , Caetano Elsa , Moutinho Carlos , Rodrigues João , Saadi Omar 
Published: June 2024

Abstract
This paper presents a study to evaluate the damping effectiveness of Stockbridge dampers on an overhead high-voltage transmission line conductor and their effects on estimating the corresponding fatigue lifetime. To increase the understanding of the dynamic behaviour of Stockbridge dampers, a test setup was designed and constructed to accommodate a segment of a conductor following the normative prescriptions of CIGRÉ. A classical modal identification was initially conducted to characterise the corresponding dynamic behaviour without and with an added Stockbridge damper. The Power Method was used to assess the conductor self-damping at different vibration amplitudes and excitation frequencies. Furthermore, a set of sensors was installed on the conductor, close to the anchorage, to simulate the VIBREC device and permit the analysis of the damper’s influence in estimating the conductor’s lifetime. Through the analysis of the database collected with the tests, it was possible to assess the dynamic properties of the conductor, identify the reduction of the vibration amplitudes enabled by the Stockbridge damper, and characterise the consequent increase in the conductor’s lifetime.
Elastic waves in periodically anisotropic heterogeneous media: bridge the gap between rigorous and phenomenological approaches
Authors: Andrianov I. , Danishevskyy V. , Kaplunov J. , Kirichek Y. 
Published: June 2024

Abstract
Despite the growing capacity of computer codes, analytical solutions are still of great interest. As a rule, they are based on certain asymptotic approximations. In our work, we use a two-scale asymptotic procedure. Anti-plane shear waves in a layered medium are studied. To clarify the basics of the methodology, we restrict ourselves with a layered membrane. For long-wave case we obtained solutions for periodic and anti-periodic modes. We analyse them in the low- and high-contrast cases. The results obtained can be generalized for complex multiscale heterogeneous media and structures. They are useful for bridging the gap between mathematically rigorous and phenomenological approaches in dynamics of heterogeneous materials. They also can be implicated as benchmarks for numerical modelling.
Control of Flexible Structures Using Model Predictive Control and Gaussian Processes
Authors: AlQahtani N. A. , Rogers T. J. , Sims N. D. 
Published: June 2024

Abstract
There is a recognised need to address issues of vibration control by making use of recent developments in data-driven modelling. The present study considers the difficulties imposed by the limitations of the actuator in the range of active vibration control. The paper proposes and examines a data-based Gaussian process (GP) model of a proof mass actuator in a flexible structural framework, aiming to improve control performance. This requires incorporating an inverse GP of static nonlinearity within the Wiener-Hammerstein model. The model starts with designing model predictive control (MPC) for a cantilever beam, in which the aim is to identify the optimal control force. Utilising the GP is the second step towards quantifying the uncertainty and limitation of the proof mass actuator by designing an inverse GP for the static nonlinearity. This quantification forwards to an MPC controller using a steady-state target optimisation tracking approach, in which this controller provides the optimal voltage required to eliminate vibration within the controller’s limitations. The numerical outcome shows that the proposed scheme was capable of supplying the necessary voltage, which eliminated the structure’s vibration within an actuator’s limits. The results of this work encourage additional research into the developed strategy, particularly in the context of experimental real-time implementation.
Observer based pitch control for load mitigation and power regulation of floating offshore wind turbines
Authors: Fitzgerald Breiffni , Sarkar Saptarshi 
Published: June 2024

Abstract
Most commercial wind turbines use proportional-integral (PI) collective blade-pitch control to regulate rotor speed in the above-rated wind speed regime. A significant drawback of this type of controller is that it assumes that the blades have identical structural properties and are subject to similar aerodynamic loads, which is seldom the case. Also, these controllers are designed to regulate the rotor speed and are not designed for structural vibration/load reduction. However, it is well known that blade pitch control can reduce structural loads on wind turbines. This opens up the possibility of designing controllers that use existing actuators and sensors like the blade pitch actuators to reduce structural loads/vibrations while maintaining the required rotor speed. Recent studies have investigated individual blade pitch control (IPC) to address these shortcomings. However, the vast majority of studies published in the literature depend on the availability of state measurement. Although sensors are commonly placed on all wind turbines, and some information is readily available, the measurement required by the typical state-feedback controllers is usually not available. Displacements and velocities of the blade, the tower and the floating platform are difficult to measure. This paper develops an observer-based individual blade pitch controller for load mitigation and power regulation of floating offshore wind turbines. We propose to use a Kalman filter to estimate the state from the accelerometer and strain gauge measurement for use in the state-feedback controller. The state-feedback controller was proposed previously by the authors that showed excellent performance. This paper extends the capability of the state-feedback controller by designing an observer (Kalman filter) to estimate the state from limited measurements. The proposed observer based controller is compared against a baseline proportional integral collective blade pitch controller and full state-feedback controllers to evaluate its performance. Numerical results show that the proposed output feedback controller offers performance improvements over the baseline controller, similar to the full state-feedback controller.
Experimental investigation on a passive self-tuning vibration neutraliser for two distinct frequencies
Authors: Nehemy G F , Rustighi E , Gonçalves P J P , Brennan M J 
Published: June 2024

Abstract
Tuned vibration neutralisers are used to suppress the vibration of a host structure subjected to external harmonic forces. Although they are analogous to tuned vibration absorbers, the primary difference is that while absorbers are usually designed with optimum damping to attenuate vibration in a frequency range around a resonance, neutralisers are designed with relatively low damping to act as a mechanical notch-filter. The narrow band frequency in which the conventional neutralisers are effective, and the mistuning compromising their performance, are known problems. Thus, self-tuning vibration neutralisers were introduced to make them more robust. In many cases, however, these systems need an external power source to adapt. This paper concerns an investigation into a self-tuning vibration neutraliser for two distinct frequencies, that does not need an external power source. It consists of a rectangular beam with tip masses, which is held at its centre in a roller bearing that is fixed to a host structure. The rectangular cross section has two different stiffnesses in the local coordinates that can rotate with respect to the global reference. Results from some experimental tests compare very well with time domain numerical simulations. It is shown that the coupling between two orthogonal degrees-of-freedom enables the neutraliser to passively tune to one of two tuned frequencies, depending on the frequency of the external harmonic force.
Improved fatigue life of floating offshore wind turbine towers with tuned mass damper inerters (TMDIs)
Authors: McAuliffe J , Baisthakur S , Broderick B , Fitzgerald B 
Published: June 2024

Abstract
Floating offshore wind turbines (FOWTs) are the largest rotating structures on earth. FOWTs are very flexible and dynamically sensitive, they are also installed in very harsh environments and exposed to stochastic environmental loading from wind and ocean waves. In recent years dampers have been installed in the towers of offshore wind turbines to mitigate vibrations. In this paper, structural dynamic models are used to demonstrate improvements in the fatigue life of FOWT towers when they are equipped with a new type of damper - the tuned mass damper inerter (TMDI). A multi-body dynamic approach is used to model the wind turbine and the TMDI installed in the tower. The model is subjected to stochastically generated wind and wave loads of varying magnitudes to develop wind-induced probabilistic demand models for towers of FOWTs under model and load uncertainties. Numerical simulations are carried out to determine the improvements in fatigue life of FOWT towers that can be achieved by installing TMDIs in comparison to traditional tuned mass dampers (TMDs). The results show that the TMDI outperforms the classical TMD when considering fatigue life.
Optimal tuning and assessment of non-grounded regenerative tuned mass damper inerter (RE-TMDI) configurations for concurrent motion control and energy harvesting
Authors: Rajana K , Giaralis A 
Published: June 2024

Abstract
This paper addresses the optimal tuning and numerical performance assessment of regenerative tuned mass damper inerters (RE-TMDIs) in three different configurations with non-grounded inerters attached to cantilevered primary structures under Gaussian white noise base excitation. The studied RE-TMDI configurations behave linearly and differ in the placement of the electromagnetic motor (EM), modelled as viscous damping element used for transforming kinetic energy to electricity, with respect to the inerter element. The primary structure is modelled as a linear damped generalized single-degree-of-freedom system, while a connectivity index is used to account for the location of the two RE-TMDI attachment points to the primary structure. A bi-objective optimization problem formulation is adopted and numerically solved for determining optimal RE-TMDI stiffness and EM damping coefficients that minimize primary structure displacement variance and maximize the available energy for harvesting by the EM. Parametric numerical results are reported for different RE-TMDI configurations, connectivity, inertance, secondary mass ratio and relative weighting between the two optimal design objectives. These results demonstrate that improved energy generation and vibration suppression is concurrently achieved with increasing inertance and/or increasing the distance of the host structure locations where the RE-TMDI is attached to. Recommendations are provided establishing the most advantageous RE-TMDI configuration.
Seismic assessment of an inerter-based hybrid control strategy for a base-isolated liquid storage tanks
Authors: Bajad Ketan Narayanrao , Islam Naqeeb Ul , Jangid Radhey Shyam 
Published: June 2024

Abstract
Liquid Storage tanks play a crucial role in chemical, gas, and nuclear industries, as well as public utilities such as water delivery and fire suppression. However, during earthquakes, they are susceptible to severe damage due to their base shear response and large displacement. To address this issue, a hybrid control strategy utilizing a clutched inerter (CID) has been proposed to protect base-isolated liquid storage tanks, with a bilinear lead rubber bearing (LRB) serving as the isolation device. Six actual earthquake ground motions were used to evaluate the performance of the system, and a MATLAB code utilizing the State-Space approach was developed for analysis. A parametric analysis was conducted to determine the impact of the CID’s inertance mass ratio on various responses including the total base shear response, bearing displacement, sloshing displacement, and force in the CID. The results of the time history analysis demonstrate that the hybrid control strategy effectively reduces bearing displacement response while meeting sloshing displacement demands. The optimum inertance mass ratio of the CID significantly reduces the total base shear response.
Seismic performance evaluation of adjacent structures connected with negative stiffness and inerter-based dampers
Authors: Islam Naqeeb Ul , Jangid R S 
Published: June 2024

Abstract
The seismic performance evaluation of two adjacent single-degree-of-freedom structures (SDOF) connected with a novel negative stiffness-inerter-based damper (NSID), tuned inerter damper (TID) and viscous damper (VD) is studied under base excitation. The two SDOF structures are typical of adjacent bridge structures that are vulnerable to pounding during strong seismic activity. The base excitation is modelled as a stationary white noise random process. The equations of motion are written in state space form, and optimal parameters for maximum possible response reduction are evaluated. The optimal parameters are based on minimising the total relative energy of two adjacent structures under white noise base excitations. The optimal parameters obtained for TID and NSID show that adding an inerter to a VD lowers the optimum damping ratio. Also, adding negative stiffness to TID further lowers the optimum inertance and damping ratio. The performance of optimised dampers connecting adjacent SDOF systems is then assessed under real earthquake records. Numerical results indicate that NSID and TID can achieve similar or even better response reduction than VD using a smaller damping coefficient. Among the two connected systems, more flexible ones show higher response reduction. The analytical study demonstrates that the effective damping of viscous dampers can be enhanced by adding the negative stiffness and inerter elements to the dashpot.
A full-scale numerical study on aerodynamic force conditions of high sided vehicles on the Queensferry Crossing Bridge
Authors: Zhu Licheng , McCrum Daniel , Keenahan Jennifer 
Published: June 2024

Abstract
Hazardous wind conditions can lead to critical safety problems for long-span bridges, either through dynamic oscillations or overturning of high sided vehicles. Engineers need to understand the local wind effects to ensure the safety and acceptable performance of bridge infrastructure. Traditionally, aerodynamic studies were carried out in wind tunnel facilities, however the opportunities of using computational fluid dynamics (CFD) modelling for wind assessments in place of wind tunnel tests are significant. To date, most of the existing studies are aimed at validation of wind tunnel tests and do not investigate full-scale effects. In this study, a validated full-scale 3D CFD model is developed in OpenFOAM using the k-ω-SST turbulence model for the world’s longest three-tower cable-stayed bridge: the Queensferry Crossing Bridge, which located at Edinburgh in the United Kingdom. The 3D CFD model contains details such as wind shields and wind conditions were created based on field monitoring data which was provided by Transport Scotland. The aerodynamic force conditions of the high sided vehicle on the bridge are subsequently determined and analysed. Results suggested that the truck would be more vulnerable to variations in the lift force coefficient and rolling moment coefficient than the double-decker bus.
Performance of photovoltaic systems supported by twin-hull floating structures in offshore and coastal regions
Authors: Magkouris Alexandros , Belibassakis Kostas 
Published: June 2024

Abstract
Floating photovoltaic (FPV) systems offer significant advantages over corresponding land-based ones. These include the ample surface available for arrangements in arrays, the possibility of exploiting the cooling effect of sea water on panel performance as well as the potential of integration of solar tracking techniques in a much more cost-effective way. However, application to coastal and offshore regions has proven to be a challenge, as FPV interaction with various environmental factors is not yet fully understood. In this work a twin hull floating platform is studied, featuring enhanced stability characteristics, in conjunction with lightweight structure, and quite efficient mobility. A novel Boundary Element Method developed for the hydrodynamic analysis of floating twin-hull structures is used for the calculation of responses in waves and its effect on the system power production. For the demonstration of the studied system, preliminary results - concerning the performance of a particular module in a selected coastal area of the Greek Seas - are presented and discussed. Finally, the effects of wave-induced dynamic motions on floating PV performance are presented, indicating significant variations of the performance index depending on the sea state.
Design and Modeling of Impact and Vibratory Installation of Piles in a 1g Laboratory Scale Test
Authors: Wehbe Tamara , Anoyatis George , Rattez Hadrien , François Stijn 
Published: June 2024

Abstract
The widespread deployment of offshore wind turbines requires the use of fast, low-cost, and reliable installation methods. While impact pile driving is predominantly used for offshore monopile foundations, vibratory pile driving provides an interesting alternative. The selection of a suitable installation technique is based on cost, marine environment, noise pollution, and soil conditions. To study installation effects, this research aims to develop 1g laboratory scale tests of both impact and vibratory pile driving in a sand filled and saturated container. Numerical models are employed to study the dynamic behavior of the 1g scale test, and are used to design (and optimize) the test setup. Particular attention is related to the reflection of waves at the boundary of the container and the frequency content of the vibratory and impact driving force, as to get the best correspondence with the full-scale pile installation in situ. The numerical model includes (1) a multi-body dynamic models to compute the impact or vibratory loads on the pile head, and (2) a finite element model of the sand box – pile system. This allows us to study the dynamic interaction between the pile and the soil, wave propagation in the sand box, and estimate the soil’s response. The comparison of both scales is then used to optimize the test setup, achieving a good correspondence to a full–scale test, both statically and dynamically.
Experimental and numerical assessment of soil-structure interaction effects in the case of mine-induced vibrations
Authors: Kuzniar Krystyna , Tatara Tadeusz , Zajac Maciej 
Published: June 2024

Abstract
Earthquakes are the most intensive sources of free-field vibration. However, mine-induced rockbursts, as a result of underground exploitations in mining areas, are also a hazard to buildings. Additionally, as in the case of earthquake-induced vibrations, also in the case of mining tremors the soil-structure interaction (SSI) phenomenon is observed. In this paper, an investigation of the one of SSI effects – differences between the simultaneously recorded free-field and building foundation vibration, is performed. The research was carried out on the example of an actual, typical, masonry, low-rise office building situated in a coal basin in Poland – the Upper Silesian Coalfield (USC). Two approaches were considered in the analysis: experimental full-scale tests, and numerical assessment using Finite Element Method (FEM) modelling. A rich set of experimental data was collected from the free-field and foundation. Using the measurement data, the most important parameters that affect the SSI phenomenon were considered, e.g. magnitude of mining tremor energy, epicentre distance from mining rockburst, and peak ground acceleration of vibration. Numerical analysis of the transmission of the incident wave to the building foundation is carried out using a three-dimensional (3D) FEM model.
Comparative Study of Simplified Dynamic Soil-Structure Interaction Modelling Techniques
Authors: Bapir Baban , Abrahamczyk Lars 
Published: June 2024

Abstract
Modelling of soil-structure interaction (SSI) problem has always been a challenging topic for structural engineers. In the last half-century, several simplified modelling techniques have been proposed to consider SSI by idealizing the soil domain. The behaviour of these models is different in terms of complexity, accuracy, parameter definition and application cases. Thus, selecting a reasonably accurate and efficient model to simulate seismic soil-structure interaction is an essential issue for structural engineers. The current study makes an attempt to assess the performance of three simplified modelling techniques (Gazetas spring and dashpots, Cone model, and Beam on Nonlinear Winkler Foundation BNWF model) through a comparative study, which is conducted on nine reinforced concrete moment-resisting frame (MRF) structures with various structural height and widths supported by two different soil profiles. The seismic responses of the structures are investigated through a nonlinear time history analysis, and the performance of the models is compared in terms of capturing the period lengthening, lateral displacement, inter-story drift, and total base shear in the structures. The strengths, limitations and application cases of each model are also discussed. In addition, the influences of soil-structure interaction on the seismic response of MRF structures on soft soil deposits are investigated. Two main parameters (structure-to-soil stiffness ratio and structural slenderness ratio) are introduced, which have shown significant effects on controlling the role of SSI on building structures.
Enhancing Leak Location in Buried Water Pipes using Array Signal Processing Techniques: the Effect of Wave Velocity Variation
Authors: Matos P H , Muggleton J M , Brennan M J , Almeida F C L , Campos B C , Paupitz P J , Iwanaga M K , Karimi M , Rustighi E 
Published: June 2024

Abstract
Leakage in buried pipelines is a significant cause of water wastage in distribution systems, resulting in water losses ranging from 30% to 50% in many countries. To address this issue, techniques have been developed to detect leaks in buried pipes over the last few decades. The leak detection procedure typically involves three steps: (1) leak detection, which involves analysis of water pressure/flow measurements along the pipelines; (2) estimation of the approximate region where the leak occurred through local pressure variations; and (3) pinpointing the estimated location of the leak to perform maintenance procedures. Acoustic pinpointing techniques are among the most effective ones to deal with the latter step. These techniques exploit the delays in time of arrival of acoustic waves, caused by the leak, between different sensors placed around the suspected leak. By calculating the cross-spectral densities (CSDs) between sensors and analysing their phase difference over frequency, it is possible to infer the estimated location of the radiating source. Existing methods rely on access points to the pipeline through correlators. However, the buried pipe acts as a radiating source, and its location could also be estimated through ground vibration signals. Although array signal processing techniques applied to source localization are well-established in the acoustics field, their adaptation to the vibroacoustic field is less well developed. Among the many challenges, the identification of wave velocity is one of the most troublesome. In this paper, the effect of the wave velocity variation on the leak pinpointing is investigated and tested against numerical data. Results show that the estimation of the leak position is sensitive to the wave velocity variabilities. The pinpointing error is found to be more significant in terms of the depth of the pipe, compared to the error on the ground surface.