bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of cable tension force in pedestrian suspension bridge short hangers based on finite element model updating
Authors: Ereiz Suzana , Duvnjak Ivan , Pajan Jurica , Bartolac Marko , Damjanović Domagoj 
Published: June 2024

Abstract
The hangers are the important element on suspension bridges that transfer the forces from the deck to the main cable. To verify their capacity and identify possible risks, the forces transferred by the hangers and the corresponding tension must be determined. However, this is often done using standard equations for determining cable forces. Due to the different lengths of the hangers and the way in which their tensioning is achieved, the effects of boundary conditions occur that need to be considered and that require an update of the finite element model at the local level (when the whole bridge structure is observed). This paper presents a method for determining the cable tension of hangers that combines the experimentally determined dynamic properties (natural frequencies and mode shapes) and the numerical model updating. In addition to the usual approach based on the determination of the natural frequency of hangers, this paper presents an approach based on the mode shapes of the hangers. Special attention is paid to the boundary conditions coefficient. The method is applied on suspension bridge case study.
Evaluation of Evacuation Possibility During Earthquake based on Seismic Response Analysis Model of Human Body Considering Walking and Falling
Authors: Sakuma Haruki , Hida Takenori 
Published: June 2024

Abstract
In the past massive earthquakes, many people suffered severe damage. Among them, not a few people suffered fall-induced injury because of evacuation actions during the shaking. Therefore, it is important to estimate the human response to shaking and the possibility of evacuation to evaluate human injury during an earthquake. Considering these background, this study proposes the evaluation method of fall and walking difficulty during an earthquake considering human behavior by constructing the seismic response analysis model of human body. First, the shaking table tests with human subject were conducted to observe the human behavior under strong motion excitation. Then the human body model considering walking and falling was developed based on a cart-type double inverted pendulum with feedback control system. In order to set appropriate feedback gains of the control system, the displacement and velocity of head of the human body model was compared to those of the human subject of the shaking table test. Then, the behavior and mechanism of falling of the human due to walking during shaking was investigated by inputting the strong motion record, which observed during 1995 Hyogo-ken Nanbu earthquake, to the human body model. Next, sinusoidal waves of various amplitudes and periods were input to the human body model to clarify the relationship between the vibration characteristics of the input motion and the response of the human body. Then, the evaluation method for evacuation possibility during an earthquake was proposed. Finally, the validity of the proposed method was investigated by comparing the behavior of the human body excited by sinusoidal wave with that excited by an earthquake shaking.
Structural assessment of a half-built building by vibration tests
Authors: He H , Meijers W 
Published: June 2024

Abstract
Structural quality of a half-built building was investigated by different experimental approaches. Vibration test was specially employed as it is a non-destructive method, which can be performed without the interruption of the construction. The principle of the tests is identifying the dynamic behaviour of the structural element by the measurement of structure response (acceleration or velocity) under certain excitations. Various floor locations are chosen for the evaluation of specific structural elements. For the comparison and verification purpose, numerical and analytical methods are also used for structural analysis. By the comparison between theoretical estimations and tested results on a reference structure, different methods are verified. It shows the eigenfrequency of (complex) structural elements/systems can be estimated accurately with relatively simple analytical formulas. Therefore, the analytical method was further used for the comparison with the vibration tests and the assessment of structural quality.
Dynamic amplifications in railway transition zones: investigation of key phenomena
Authors: Jain A. , van Dalen K.N. , Steenbergen M.J.M.M. , Metrikine A.V. 
Published: June 2024

Abstract
The railway transition zone where the track transitions from a ballasted track to a slab track, is a crucial area that can experience amplified dynamic responses. This work aims to develop a deeper insight into the mechanisms leading to the amplified dynamic response in railway transition zones. The study employs a finite element model to investigate the amplification of total strain energy due to the phenomena of reflection and redistribution of energy close to the transition interface. The results of the study are obtained for three case studies involving non-reflecting boundary (representing an energy sink) and homogeneous material along the vertical direction of the track, and the responses are studied for individual and combined effects in comparison to a benchmark case. The findings of the study show that eliminating the phenomena results in no dynamic amplification in total strain energy in railway transition zones. The conclusion highlights the importance of understanding these phenomena in order to design an efficient railway transition structure.
Active mitigation of self-excited vibrations of a magnetic track brake
Authors: Ebner Bernhard , Tippelt Daniel , Edelmann Johannes , Plöchl Manfred 
Published: June 2024

Abstract
Magnetic track brakes (mtbs) are additional braking systems used in railway vehicles at emergency situations and low adhesion conditions. Operation at low velocities can cause harmful self-excited vibrations, which must be avoided at all circumstances. Few passive countermeasures are already published, but active vibration control of an mtb lacks in literature so far. In this paper an active vibration control to diminish self-excited vibrations, based on reducing the energy, drawn by the oscillating system, is studied. Considering a minimal model of the mtb, the energy input depends on the electromagnetic-mechanical coupling and the friction force in the mtb—rail contact. The obtained equation of this energy reveal a dependency of the phase shift, between magnetic flux and the oscillatory mechanical motion. A control law for the input voltage is obtained to reach a specific phase shift reducing the energy input and oscillating amplitudes.
Description of impact energy dissipation in fibrous composite materials using a nonlinear dynamic degenerate model
Authors: Olaleye Kayode , Pyka Dariusz , Bocian Mirosław , Jamroziak Krzysztof 
Published: June 2024

Abstract
To design effective energy-absorbing shields made of modern composite materials (e.g., fibrous composite panels), it is necessary to use deformable materials whose important feature is the largest possible dissipation of impact energy. Rheological properties of these materials differ significantly from dissipative and elastic properties described by the Hooke and Kelvin linear models. Moreover, the range of material deformation at the place of impact is so wide that the above-mentioned models are not sufficient to properly describe the process of energy dissipation. The value of dissipated energy is also important for the determination of the lifespan of dissipative and elastic elements subjected to cyclic dynamic loading and made of modern structural materials (fatigue phenomena). The authors proposed a dynamic model in which the rheological properties of the material are described by two spring parameters c, c
0 and one parameter of viscous damping k
0 in the configuration used in the so-called rheological standard model (Zener model). In addition, the model introduces the element of dry friction described by the appropriate function h(x). In addition, it was assumed that the non-linear element present in this model describes the effect of the occurrence of dry friction hSign(dx/dt) in the tested material, the value of which h is not constant but depends to some extent on the level of material deformation (variable x) is described by the relevant function. In this way, a non-linear third-order equation was obtained describing the motion of the so-called degenerate system. The developed method was tested on a computer system.
Design, build and test of packaging for vibration control of medical goods delivered by drone
Authors: Waters T P , Sherman L , Moxey H , Yang J , Court B , Chan H , Ng Y X , Cherrett T J , Oakey A , Theobald K 
Published: June 2024

Abstract
The delivery of medical products by drone is potentially game-changing and promises increased speed, particularly when trying to service hard to reach rural areas, and reduced carbon emissions. However, this raises a number of questions, including the effects of flight on the stability of medical products and how this can be mitigated through the design of appropriate packaging. The aim of this study was to design and experimentally evaluate a medical goods package capable of mitigating the vibration experienced during transportation by drone. Two proposed designs have been developed that feature coil spring and wire rope isolators. Transmission of vibration by these prototype packages, together with an industry-standard product, was measured both in the laboratory and in transportation trials. The prototype packages reduced transmitted vibration by a factor of six during drone flight tests but performed slightly worse when transported by car since road inputs occur at characteristically lower frequencies. The prototypes are significantly heavier than the standard product when empty although this is partially offset by a reduction in the number of required cool packs facilitated by the use of high performance vacuum insulation panels.
Analysis of a tendon-based deformation aggregation mechanism to host discrete vibration absorbers in continuum structures
Authors: Jayatilake S D , Woods B K S , Lowenberg M H , Titurus B 
Published: June 2024

Abstract
This paper investigates the possibility of developing a novel vibration absorber aimed towards slender continuous structures such as wings or blades. The absorber essentially consists an axially elastic tendon guided along a series of points along the span of cantilevered laboratory beam demonstrator, such that an aggregate of its induced extensional activity is observed at a specific location. The central idea is to introduce a discrete absorber at this strategically selected point, with the tendon providing the stiffness between the absorber and the primary structure. To explore the concept, the presented experiment is aimed at providing a comparison against a reduced 2 degree of freedom representation of the combined and mutually coupled absorber system. The specific focus of this arrangement is to support the interpretation of the underlying modal characteristics of the proposed concept.
A Topologically Designed Metamaterial Filter for Nonlinear-guided-wave-based Structural Health Monitoring Application
Authors: Liu Ze , Shan Shengbo , Cheng Li 
Published: June 2024

Abstract
Nonlinear guided waves (NGW) show great promise for structural health monitoring (SHM) due to their high sensitivity to the early detection of material micro-structural defects. In an SHM system, however, there exist inevitable non-damage-related nonlinear sources that may overwhelm the damage-induced nonlinear wave components, which in turn may jeopardize the practical implementation of the NGW-based SHM methodology. To eliminate these deceptive nonlinear interferences, this study introduces the concept of metamaterials to SHM. A wave filtering device, referred to as a meta-filter (MF), is developed to be surface-mounted on the structure under inspection under a second harmonic Lamb wave based SHM paradigm. Through a topological design, the MF enables ultra-wide stopbands to eliminate the secondary Lamb waves of the probing waves while preserving their strong fundamental wave components. The band structure, underlying wave filtering mechanism and the wave filtering function of the MF are investigated through finite element simulations. Upon tactically introducing deceptive nonlinear interferences at the actuation area, exemplified by adhesive bonding layers in a PZT-activated SHM system, the performance of the MF is examined from an SHM perspective, and finally validated experimentally using a metal specimen containing local plasticity-related incipient damage. Results demonstrate that the designed MF entails significant enhancement of the detection ability of NGW-based SHM system for incipient damages on one hand, and also allows for flexible selection of the excitation frequency on the other hand thanks to the customized band features enabled by the topological optimization.
Crack monitoring in concrete beams under bending using ultrasonic waves and coda wave interferometry: the effect of excitation frequency on coda
Authors: Knak M , Wojtczak E , Rucka M 
Published: June 2024

Abstract
Concrete is one of the most widely used construction materials in the world. In recent years, various non-destructive testing (NDT) and structural health monitoring (SHM) techniques have been investigated to improve the safety and control of the current condition of concrete structures. This study focuses on micro-crack monitoring in concrete beams. The experimental analysis was carried out on concrete elements subjected to three-point bending in a testing machine under monotonic quasi-static loading. During the tests, the fracture process was characterized using ultrasonic waves. The recorded signals were further processed by coda wave interferometry (CWI). This technique allowed the detection of cracks using the decorrelation between ultrasonic wave signals collected at different stages of degradation. Different values of excitation frequencies in the range from 100 kHz to 400 kHz were used to investigate the influence of frequency selection on the effectiveness of the damage indication based on the decorrelation of coda waves. The results obtained from the experiments were intended to highlight the effect of the applied frequencies on the coda wave interferometry.
Dynamic changes on a masonry cross vault after a forced damage
Authors: Bru D , Ivorra S , Torres B 
Published: June 2024

Abstract
This work shows the preliminary results related to the evaluation of the dynamic behavior of a 5x5 m masonry cross vault after undergoing different changes in its structural behavior. It has been built using solid clay bricks and lime and sand mortar. The cross vault has been built in the laboratory specifically for carrying out these tests and evaluating its structural behavior. A device has been designed to be able to carry out a controlled settling of one of its supports without causing an instantaneous collapse of the structure. Dynamic identification using OMA was performed by installing seismic accelerometers at several selected points on the structure, using ARTEMIS software to analyze the results. The evolution of the dynamic characteristics was carried out in four different states: (i) After construction (ii) After the generation of generalized damage through the forced settlement of one of its supports. (iii) After repair using Textile Reinforced Mortars (TRM) (iv) After generating new damage by settling one of its supports in the TRM repaired structure. After the generation of the damage in the structure, important cracks are observed in various points of the structure, although no situation was reached that would foresee a possible collapse. The repair with TRM has consisted of the introduction of fiberglass mesh bands coated in lime and sand mortar. These bands have been arranged forming a cross in the upper part of the structure and in all the edge arches of the structure. In all these phases the OMA was developed under a situation of ambient vibrations, where these vibrations levels were very low due to the situation inside of a laboratory. After each of these phases, their main frequencies, their vibration modes and the structural damping factor of each of the identified modes have been obtained. It is observed how a loss of rigidity of the vault occurs after the production of damage and how it completely recovers by means of reinforcement and repair with TRM. An increase in the damping ratio of practically all the vibration modes has been detected when the structure is damaged, although after repair with TRM these values are reduced again.
Cahora Bassa vibrations monitoring between 2010-2022. Analysis of frequencies using HST statistical models for effects separation
Authors: Oliveira S , Mendes P , Rodrigues M , Alegre A , Proença J , Carvalho E , Matsinhe B 
Published: June 2024

Abstract
Cahora Bassa dam is a 170m-high arch dam located in western Mozambique. In operation for almost 50 years, since 1974, the dam is affected by a swelling process of small/medium amplitude. Aiming to control its structural health over time, in 2010 the dam was instrumented with a continuous vibrations monitoring system, designed for Seismic and Structural Health Monitoring (SSHM), which includes 10 uniaxial accelerometers in the crest gallery and 3 triaxial accelerometers in the dam-foundation interface. The latest results on the dynamic behaviour monitoring of the dam are presented, namely the evolution of the main natural frequencies over time and the corresponding mode shapes. Then, HST statistical models for separation of effects, considering the hydrostatic pressure (H), seasonal variations (S), and time (T) dependent factors, are used to analyse the evolution of the experimental natural frequencies over the last 12 years. The achieved results show that the dynamic behaviour of the dam is mostly influenced by the water level variations. However, a very small decreasing tendency of the natural frequency values was detected, which may indicate a slight decrease of the global stiffness of the dam, possibly due to the evolution of the concrete swelling pathological process.
Data-Driven Railway Vehicle Parameter Tuning using Markov-Chain Monte Carlo Bayesian updating
Authors: Hoelzl Cyprien , Keller Lisa , Simpson Thomas , Stoura Charikleia , Kossmann Claudia , Chatzi Eleni 
Published: June 2024

Abstract
Understanding the dynamics of the interaction between railway vehicles and tracks is essential for forecasting vehicle and track conditions and performing maintenance actions to preserve the safety of railway infrastructure. In this work, physics-based models are deployed to predict the dynamic response of railway vehicles to track alignment and irregularities. Such models comprise a large number of parameters that need to be validated and possibly tuned, a task often accomplished on the basis of expert knowledge or trial-and-error without necessarily reflecting the condition of the operating system as-is. Therefore, model uncertainties persist due to assumptions on the actual system behavior, as well as due to varying operational parameters (e.g., wheel profile, rail profile, rail moisture). To improve modelling accuracy, this study adopts a multi-body vehicle model, realized in SIMPACK software, and performs parameter tuning based on on-board measurement data (accelerations and forces) from an instrumented tilting train, which regularly traverses the Swiss Federal Railways (SBB) network. The pertinent vehicle model is optimized in terms of the interaction forces at the wheel-rail contact using a Bayesian model updating approach, relying on Markov-Chain Monte Carlo (MCMC). Specifically, the MCMC method is applied to estimate both optimal vehicle parameters and their uncertainty by minimizing the mean squared error between simulated and measured contact forces, leading to an improved vehicle twin.
A combined implicit-explicit vibration-based SHM method for damage detection of wind turbine blades
Authors: Drangsfeldt Casper Aaskov , Avendaño-Valencia Luis David 
Published: June 2024

Abstract
Today, the green transition is being pursued more than ever, leading to a significant increase in the installation of wind turbines and wind farms. Maintaining and servicing the wind turbines is accompanied by extensive expenses. Therefore, predictive maintenance techniques are in increasing demand, including the implementation of a well-functioning Structural Health Monitoring (SHM) system. In this work, physical and non-physical vibration features along with various techniques to mitigate the effect of Environmental and Operational Variability (EOV) are investigated. Vibration features originating from Vector Auto-Regressive (VAR) models are considered. Physics-domain DSFs comprise the natural frequency, while the non-physical DSFs comprise the VAR model coefficients. A challenging and inevitable aspect in SHM is the effect of EOV that can alter the DSFs so as damage does. Two mitigation approaches are considered, the first based on Bayesian non-linear regression –explicit– and the second based on Principal Component Analysis (PCA) –implicit–. Additionally, a novel combined approach is proposed, featuring regression of Principal Components (PCs). As some of the PCs will be EOV-insensitive, the specific corrected PCs are automatically selected using the F-statistic of individual regressions. A comparative analysis is carried out in a controlled experiment, featuring the vibration response of a lab-scale wind turbine blade under various temperature and damage conditions. The methods are assessed in terms of correctly detected damages from a one-class classifier based on the squared Mahalanobis distance on the EOV-corrected features, and best performing method combinations are thereby identified.
Resolving the effects of peak-splitting alike artefacts in FBG measurements for fatigue assessments of an offshore wind turbine foundation
Authors: Fallais D , Weijtjens W , Devriendt C 
Published: June 2024

Abstract
Fiber Bragg grating (FBG) based optical strain sensors have become more commonplace for fatigue monitoring applications of large structures. Despite many advantages above conventional strain gauges, in some cases FBG measurements can become corrupted by complicated failure modes, which might relate to fiber integrity or interpretation of optical signals. In this article, over one month of corrupted FBG strain data obtained from a monopile of an operational wind turbine will be assessed, with the objective to resolve the issues around the severe jump-like distortions which are present in the data. To this end, an initial working hypothesis is formulated which states that removing the jump-like distortions will improve the quality of the data and increase usability. Throughout the article this hypothesis will be tested and adjusted, as the amount of information used in the assessment will be step-wise increased. The results show that the initial goal of removing jump-like artefacts is achievable, resulting in a visually much-improved signal; however, the results obtained using the fatigue-related metrics show inconsistencies when compared with predicted fatigue quantities; these predictions are obtained using two virtual sensing methods, which extrapolate strain reference data, in terms of damage equivalent moments and time series, to the locations of the corrupted FBG sensors. Results indicate that the observed failure mode is more complex than initially expected. Finally the hypothesized failure mode is revisited, and recommendations about the usability of the data are discussed.