bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-dataset OMA and Finite Element Model Updating of Steel Observation Tower
Authors: Ratnika Lasma , Gaile Liga , Nicoletti Vanni , Gara Fabrizio 
Published: June 2024

Abstract
Operational modal analysis for identifying dynamic parameters, together with finite element model updating algorithms, is a promising and powerful tool for detailed analysis of complex civil engineering structures. It is also an integral part of vibration-based methods in structural health monitoring. In this work, the identification of the dynamic parameters was performed based on output-only vibration data recorded in a testing campaign on a 36 m high steel structure used as an observation tower for tourists in Latvia. To correctly interpret the experimental results, a finite element model of the tower has been developed within the Ansys environment. The model updating is performed by adopting an artificial intelligence algorithm called Particle Swarm Optimization. The calibration is performed with the aim of obtaining a numerical model that simulates the real dynamic behaviour of the case study with high accuracy. The calibrated model can be used as a base for the development and design of the structural health monitoring system of the tower.
Modal Parameters identification in existing bridges based on free vibration tests
Authors: Mazzeo M , De Domenico D , Quaranta G , Santoro R 
Published: June 2024

Abstract
The dynamic identification of modal parameters plays a fundamental role in structural health monitoring: mode shapes, frequencies and damping ratios can be exploited to assess the current state of a structure, used for damage detection or in numerical model validation. In recent years, vibration-based methods have become a popular solution for the state of health estimation of strategic civil infrastructures such as bridges: in particular, free vibration tests represent a fast and economic method only requiring the temporary installation of a limited number of sensors on the structure. This contribution presents a procedure for the identification of modal properties of existing bridges exploiting their free decay responses: each mode’s contribution is adaptively extracted from free vibration tests data using the Empirical Fourier Decomposition and a noise-robust area-based approach is exploited to identify modal damping ratios. The method is preliminarily validated on a synthetic multi-modal signal showing excellent results even in case of closely spaced modes. The performance of the proposed approach is also tested for a real existing structure: the selected case study deals with the identification of modal parameters for a steel railway bridge deck.
Output-only response mapping of bridges for dynamic response estimation of gusset plate using convolutional neural networks
Authors: Dabbaghchian Iman , Eshkevari Soheila Sadeghi , Marasco Giulia , Pakzad Shamim N. 
Published: June 2024

Abstract
Structural health monitoring of bridges aims to provide an assessment of the condition of the structure, using collected structural response. The efficacy of the methods usually is constrained by the number and spatial distribution of sensors. Developing methods to map the response from known to unknown locations has been a challenging yet interesting area of study in recent years. In this research, we propose and study a novel framework to estimate and reconstruct the dynamic response of bridges at the connection level from the vibration response at global locations. The bridge is considered as a dynamic system in which vehicle excitations are the input and responses at sensor locations are the outputs. The proposed method studies an output-only problem and the input is considered unknown. The response at two types of output locations of the bridge, one at a global and one at the connection detail level are used to learn the dynamic relationship between the time signals via convolutional neural networks. This model-free framework is validated through a finite element simulation to reconstruct the strain response at the gusset plate of a truss bridge from the responses at other nodes along the bridge.
Effect of optimally placed sensors on the quality of estimated modal parameters
Authors: Tcherniak D , Steffensen M T 
Published: June 2024

Abstract
Planning is an important part of any modal test. Optimal Sensor Placement techniques can assist in finding the optimal number of sensors, their location and orientation. The presented study demonstrates the effect of the techniques on the quality of modal test results: the uncertainty of the estimated natural frequencies and damping, as well as the quality of the full field mode shapes expanded from the experimentally obtained mode shapes.
Improving Acoustic Methods of Pipeline Leak Location with Distributed Sensing
Authors: Hooper Joshua Z. , Kalkowski Michal , Muggleton Jennifer M. 
Published: June 2024

Abstract
Leaks in water distribution mains are a big problem, with around 20% of supplied potable water lost to leaks during transport. Correlation-based acoustic techniques have provided an accurate and non-invasive way of detecting and locating these leaks for a few decades. These methods have almost exclusively been using two sensors, and so this paper presents work aiming to explore leak detection and location with multiple sensors distributed along a pipe. Beamforming is a well-established method for using arrays of sensors to locate sources, among other purposes. With this premise, the present work adopts an array processing algorithm (MUSIC) in the context of water leak detection, intending to develop a framework for detecting multiple leaks using a sensor array. The concept, processing and implementation details are first supported with numerical simulations using existing acoustic models of water pipes. Then, experiments are presented on a short section of water-filled pipe with leak-like disturbances. These are captured with an array of accelerometers and processed using an implementation of the algorithm, testing the impact of real-world effects studied in simulations. The study considers several aspects of practical interest: (i) the effect of noise, both correlated and uncorrelated; (ii) the effect of reflections from discontinuities, such as pipe fittings and connections; (iii) the number and the distribution of sensors; as well as (iv) the presence of multiple leaks. The results pave the way for implementing this algorithm on practical installation designs, including the rod method developed during a wider research project associated with this study.
Perturbation-invariant eigenvalue assignment for statistical damage localization
Authors: Ulriksen Martin D. , Greś Szymon , Bernal Dionisio 
Published: June 2024

Abstract
The present paper reviews a recently proposed eigenvalue assignment scheme for structural damage localization. The eigenvalue assignment is, under the assumption of system controllability and observability, formulated with the objective of rendering an eigenspectrum subset invariant to low-rank perturbations in the considered system. Damage localization follows with the perturbations being realized as damage patterns postulated in different subdomains using a model of the system. The damage location can thus be inferred from the damage-induced shifts in the assigned eigenvalues, which, ideally, will be zero when postulating a pattern that entails the physical damage distribution. In real applications, eigenvalue invariance is unattainable due to, among other phenomena, stochastic disturbances, so the localization is conducted by hypothesis testing with the assigned eigenvalues and their uncertainty bounds. The paper reviews the proposed damage localization method and tests its applicability in the context of a numerical example.
Assessment of the metawedge as a mitigation measure for railway induced ground vibration
Authors: Bracci Alessandro , Fărăgău Andrei , Metrikine Andrei , Dalen Karel van , Corradi Roberto , Vlijm Eliam 
Published: June 2024

Abstract
Railway induced ground vibrations are of increasing importance for structures and inhabitants in the vicinity of railway tracks. This study investigates the capabilities of a novel mitigation measure, a so-called metawedge, in reducing the ground-borne vibration at the receiver end. A metawedge is series of barriers (i.e., resonators) arranged periodically in the longitudinal direction and each one is offset with respect to the others in depth direction (i.e., while the first barrier is completely on the surface, the last barrier can be completely embedded). The advantage of this countermeasure is that it can convert the incoming Rayleigh (surface) waves into body ones, redirecting the energy content deep into the ground. Simulation results show that the metawedge is capable of significantly reducing the vibration levels with as few as five resonators. Furthermore, while conventional single trenches are efficient as mitigation measures only at a certain angle of the incoming waves (outside the critical cone), the metawedge is efficient inside this cone. Although the metawedge solution is promising, this paper serves solely as a proof of concept, and additional studies are necessary to design realistic resonators that can comply with the low frequencies of the railway induced ground vibrations. Nonetheless, this study shows that metamaterials-inspired solutions can play an important role in addressing present and future challenges of the railway transportation.
Ground-borne noise and vibration: classification of railway vehicles based on a track-independent vehicle indicator
Authors: Ntotsios E , Thompson D , Reumers P , Nélain B , Degrande G , Bouvet P 
Published: June 2024

Abstract
Within the SILVARSTAR project, a track-independent vehicle indicator (TVI) is proposed that can be used to identify railway vehicles which generate low ground-borne vibration and noise levels. The proposed TVI is based on applying a frequency weighting to the force density, which may be obtained at a site from the measured ground vibration velocity levels due to train passages and the measured line source transfer mobility. Two different formulations of TVI are proposed; one related to ground-borne vibration and the other to ground-borne noise. Each TVI is a single number quantity, defined as a sum over all frequency bands of the frequency-weighted force density levels. The proposed performance classification of different vehicles can be achieved by comparing the relative differences of their TVIs. A series of test cases is used to demonstrate the calculation of the TVIs and the TVI-based classification of different vehicles at the same site. Although the values of the TVIs for each vehicle may vary due to the different modelling approaches and detail, or due to the limited knowledge of the input parameters used for the target site, the TVI-based classification of different vehicles is found to be insensitive to this model and parameter uncertainty.
Simplified models to inform the base-isolation design of buildings
Authors: Edirisinghe T L , Talbot J P 
Published: June 2024

Abstract
Base isolation is an established method of limiting the transmission of traffic-induced vibration into buildings. Despite this, the available design guidance is limited, and significant questions remain concerning how the vibration isolation performance may be optimised for a particular building. Recent research has sought to develop simplified models that enable the prediction of building vibration levels without resorting to complex numerical methods. This paper focuses on the phenomenon of soil-structure interaction (SSI) and considers the case of a multi-storey building founded on piles adjacent an underground railway. Some simplified models are compared against a comprehensive numerical model, with the aim of establishing the extent to which the various components of SSI influence the vibration transmission into the building and which should therefore be accounted for when predicting isolation performance.
Metrological quality of the excitation force in forced vibration test of concrete dams
Authors: Martins L L , Gomes J P , Ribeiro A S 
Published: June 2024

Abstract
This paper describes the study of the metrological quality of the excitation force in the context of force vibration test of concrete dams. For this purpose, a measurement uncertainty evaluation was performed, based on available probabilistic information about the input quantities – rotation frequency, mass, radial position, dimension, diameter and density of the generator’s rod – which support the determination of the excitation force in an eccentric masses vibration generator, used by LNEC in concrete dam’s field observation. The uncertainty propagation from the input quantities to the output quantity was performed by a Monte Carlo method, considering the mathematical model used for the determination of the excitation force. Two experimental cases were studied: (A) the use of five weights in the generator in the frequency range of 1 Hz up to 6 Hz; and (B) the use of a single weight in the generator in the frequency interval comprised between 5 Hz and 15 Hz. In the first case, the excitation force estimates and expanded measurement uncertainties (considering a 95 % confidence interval) varied between 3.55 kN ± 0.14 kN and 127.68 kN ± 0.91 kN, being rotation frequency the major contribution for the obtained dispersion of force values. In the second case, the excitation force estimates and expanded measurement uncertainties varied between 16.71 kN ± 0.25 kN and 150.4 kN ± 1.8 kN, being the generator’s rod diameter the main contribution for the output measurement uncertainty. The obtained knowledge is essential to assure confidence and rigorous knowledge about the applied excitation force, namely, in extreme situations near dynamical structural safety limits of the observed concrete dam and of the testing equipment.
Inverse design under uncertainty with surrogate models
Authors: Walton D B , Featherston C A , Kennedy D , Kundu A 
Published: June 2024

Abstract
In the drive towards net zero the aerospace industry is motivated to develop more efficient aerostructures that can accommodate the next generation of propulsion systems that fall outside of the well understood types that are currently in use. The lack of established standards for such designs means that engineers are faced with an increased level of uncertainty in their design choices before any prototypes are built. Machine learning models are becoming a popular tool for expediting the development of novel designs due to their ability to explore and predict the optimal parameters of large design spaces. It is also possible to quantify and introduce uncertainty into particular models so that practitioners can be made aware of the potential variation in their realised designs. In this paper Gaussian Process surrogate models of the performance metrics of the early-stage design of an aircraft wing are created to optimize a subset of design parameters based on some prescribed limits of the intended real system response. This defines the inverse design problem that is solved using Markov Chain Monte Carlo sampling. The approach taken requires novel formulation of a Bayesian machine learning framework. In particular, the work investigates the formation of likelihood functions that are flexible given inputs of different scales, can perform marginalisation of stochastic parameters, account for uncertainty in the surrogate model, and optimise the parameters given more than one constraint. A case study is presented in this paper that highlights both a successful implementation of the framework along with a limitation. It is found that the optimization is sensitive to changes in the variances of the likelihoods such that it can be used as a weight to direct the optimization towards a quantity of interest, therefore adjustment of this parameter is used to balance the optimization.
A model-based damage identification framework for R/C bridges using vibrational measurements.
Authors: Mixios K.E. , Stefanidou S.P. , Markogiannaki O. , Papanikolaou V.K. 
Published: June 2024

Abstract
Ensuring the structural integrity of bridges is crucial for maintaining road safety and minimizing traffic disruptions, as well as avoiding substantial direct and indirect economic losses. This study proposes a methodology for damage identification in R/C bridge systems by utilizing measured vibrational data from both the initial and damaged responses. In this context, a finite element model is developed, and its parameters are calibrated using Particle Swarm Optimization algorithms and Dynamic Mode Decomposition, which help match the numerical data to the measured data. The proposed methodology is demonstrated through a case study of a monolithic R/C bridge, with simulated experiments (e.g., damage scenarios) conducted to validate its effectiveness.
Shock and vibration response of museum objects during transportation
Authors: Hutchin Thomas W J , Waters Timothy P , Kotonski Verena 
Published: June 2024

Abstract
Museum objects are frequently transported by road and air when toured internationally or when moved between storage facilities which exposes them to a range of vibration and shock inputs. Many of these vulnerable objects have incipient damage such as cracks, loose joints, partial delamination or failing repairs which can be exacerbated in transit. It is the conservator’s responsibility to select which objects are safe to travel, largely based on experience and professional judgement. A joint research programme between the University of Southampton and the British Museum aims to develop a scientific framework to aid and inform such judgements. A central research question, and the focus of this paper, is which methods of transport are potentially most damaging?
Vibration measurements were acquired during transit by car, train, ferry and commercial airliner. A moving average kurtosis is used to identify near-Gaussian and non-Gaussian segments in a time signal. Acceleration shock response spectra (SRS) are presented for a number of impulsive events, and corresponding vibration response spectra (VRS) shown for more normally distributed random inputs. Laboratory based vibration testing was carried out on a museum artefact packed in bespoke foam packaging inside a standard wooden transport crate. The modal response, combined with SRS and VRS, enabled the response of the object and the suitability of the packaging in reducing the response to different real-life stimuli to be assessed. Actual measurements on the artefact in transit also enabled the accuracy of SRS and VRS in predicting peak and RMS acceleration levels to be quantified.
Adaptation of the HQ device for suppressing wave propagation in elastic beams
Authors: Avetisov S. , Pelat A. , Gautier F. , Sorokin S. 
Published: June 2024

Abstract
In this work, we study the application of the Herschel–Quincke (HQ) principle to the case of bending waves in a beam structure. This type of device is well known in acoustic tubes where an HQ filter consists of the bifurcation of a primary tube into two tubes of different lengths placed in parallel. The resulting phase shift creates a destructive interference and so a zero transmission at selected frequencies. To adapt this principle to bending vibrations, a homogeneous solid beam is divided into two different strands with different thicknesses and of same length, so that the phase difference created between these two strands of different wave celerities also leads to the same interferential effects. A Timoshenko wave model is derived to analyse the scattering properties of such HQ filter for bending and longitudinal waves. The results are well confirmed by the reference finite element simulations.
Simple soil-structure interaction model for wind-induced vibrations in high-rise buildings
Authors: Carranza A , Bronkhorst A J , Gomez S S , van Dalen K N 
Published: June 2024

Abstract
The reliable design of high-rise buildings subject to wind-induced vibrations is important for ensuring comfort and safety. However, the Eurocode recommendations and common design practices used to estimate natural frequency and damping parameters in the design stage have been found to be inaccurate, leading to unreliable predictions of building accelerations. Previous studies have shown that soil-structure interaction (SSI) can have a significant influence on these parameters, especially for high-rise buildings on soft soils. This study presents a formulation of a simple model to include soil-structure interaction effects in the natural frequency and damping parameters. It also demonstrates the compatibility of this model with the current Eurocode procedures. The study compares the results of the simple SSI model with those of a continuous model of the New Orleans tower under design wind loading. In previous work, this continuous model was validated against in-situ measurements on the New Orleans tower. The results demonstrate that the simple SSI model significantly improves the accuracy of the predicted building accelerations under wind loading for the New Orleans tower, compared to accelerations determined in the original design and accelerations computed with the Eurocode guidelines.
FRF-based modal testing of the highest timber building in the world in operation using wireless accelerometers
Authors: Pavic Aleksandar , Kei Ao Wai , Tulebekova Saule , Malo Kjell Arne , Rønnquist Anders 
Published: June 2024

Abstract
This paper describes practical application of a novel and oven-controlled crystal oscillator (OCXO) high-precision synchronised wireless data acquisition system for a modal testing of the tallest all-timber building in the world – the 18-storey, 88.8m tall Mjøstårnet (the Mjøsa Tower) in Brumunddal, Norway. The modal testing was challenging as it was conducted in an occupied building in normal operation and was based on measuring both dynamic excitation and response yielding a set of frequency response functions (FRFs) across four different floors of the building. To the best knowledge of the authors, this was the first time that an FRF-based modal test was attempted on such a large building structure in operation. Moreover, although the structure was in operation, the testing was completed in only 48h, including commissioning and de-commissioning of all of the instrumentation, yielding a full set of point- and transfer accelerance FRFs. The paper presents the equipment used, key logistical challenges and quality assurance steps made to assure measurement of good quality FRF data in such short period of time demonstrating feasibility of the whole exercise. A total of seven modes of vibration, including higher order modes of vibration were estimated by curve-fitting the measured FRF data. This includes the 3rd bending and 2nd torsion modes difficult to measure via the standard ambient vibration testing of tall buildings. These modes could be used to investigate a number of uncertain modelling features in tall timber buildings, such as the stiffness of timber joints.