bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal design of pendulum-tuned mass damper for the vibration control of offshore wind turbines with a flexible monopile foundation
Authors: Colherinhas G B , Petrini F , de Morais M V G 
Published: June 2024

Abstract
This paper presents an optimal design of a passive-adaptive Pendulum-Tuned Mass Damper (PTMD) to mitigate the structural vibrations of an Offshore Wind Turbine (OWT) with a flexible monopile foundation considering the Pile-Soil Interaction (PSI). The OWT is based on the 5-MW baseline proposed by the National Renewable Energy Lab. The PSI is designed by a pile modeled as beam-column elements supported by nonlinear springs for lateral loads (p-y curves) and axial loads (t-z and Q-z curves), applied at the nodal points between the elements. The estimation of wind and wave spectra, as well as the hydrodynamic and aerodynamic loads, are conducted by using an in-house built MATLAB® routine working together with an ANSYS® 3-D finite element global model for evaluating the resultant peak displacement response at the OWT hub by a power spectral density analysis. Optimum design cases of PTMD parameters are obtained by a parametric analysis evaluating the dynamic response along and across directions at the hub and the resultant stress at the base of the tower. These responses and stress are evaluated as a function of the wind velocity at the hub.
Frequency-amplitude decoupling in the Gentle Driving of Piles (GDP) method: shaker design and experiments
Authors: Gómez Sergio S. , Tsetas Athanasios , Middelplaats Lennart N. M. , Metrikine Andrei 
Published: June 2024

Abstract
This paper presents a new shaker design for the Gentle Driving of Piles method. Specifically, a lab-scale vibratory device has been developed that can simultaneously apply axial and torsional vibrations, both possessing frequency-amplitude decoupling. This design was implemented and tested in a lab-scale experimental campaign, where both pile and soil were extensively instrumented. The monitoring of the dynamic pile and soil behaviours during driving with various installation settings is of utmost importance to comprehend the governing mechanisms of the process. In that manner, the optimization of pile installation may be realized both for axial vibratory driving and GDP. In this work, the frequency-amplitude decoupling is pivotal, as it is showcased that both enhanced installation performance and reduced power consumption can be attained with proper selection of the installation settings and exploitation of high-frequency torsion.
Optimization Problem of the size-scale for a Foldable Chain Scissors Structure based on Stress Analysis
Authors: Yoshida Keigo , Ario Ichiro , Zawidzki Machi , Hama Yuta 
Published: June 2024

Abstract
Emergency bridges are used to restore the lifeline of damaged bridges after disasters. However, the design specification of existing emergency bridges do not afford rapid bridging. Therefore, a trial deployable bridge (Scissors Bridge) using a scissors structure that folds compactly has been experimentally produced. But, the assembly process for the bridge has not been considered and there are no practical design examples or design methods for scissors bridges. In this paper, as for existing bridges, we established a design method of scissors bridges when considering the live load. In addition, a general-purpose member cross-sectional dimension optimization method, aimed at minimizing weight, was developed and proposed. Considering the problem of insufficient strength of the scissors bridge, the optimum reinforcing pattern and its cross-sectional dimensions were determined through two methods of reinforcement and optimization of the cross-sectional dimension of the member. Finally, a trial of practical design calculation was performed using the results of the study to determine whether a scissors bridge satisfying the standard of the Specifications for Highway Bridges can be designed.
mechanical bridge machineries: phenomenological modelling and experiments
Authors: Sektani K. , Tsouvalas A. , Metrikine A. 
Published: June 2024

Abstract
The reassessment of existing mechanical bridge machineries in The Netherlands has prompted the development of acceptance/rejection criteria for evaluating their structural safety. The current design code in The Netherlands [1, 2] establishes an ultimate limit state, primarily intended for the design of new machineries, employing a conservative approach with upper bounds on maximum loads. However, to reassess existing bridges and prevent unnecessary replacements, a more accurate prediction of the dynamic response is essential. The current code relies on a linear single degree of freedom (SDOF) dynamical system [3], which is found to inadequately predict the dynamic response of existing machineries across all load cases [4]. This discrepancy can be attributed to, for instance, the neglect of time-dependent and discontinuous model parameters of the machineries [5, 6, 7].
Given that each movable bridge possesses a unique set of fixed parameters, on-site measurements of a single bridge do not provide the generic information required for the design and/or reassessment of existing structures in general terms. In this paper, a novel experimental setup is presented which allows the investigation of a wide range of variations in order to capture the dynamics of the powertrain in a class of bridge machineries. Additionally, a modelling methodology is developed to overcome the limitations of existing calculation rules, by incorporating base excitations, damping, and other relevant variables of the physical system, which are currently neglected by the code. A subsequent comparison with measured data, demonstrating the accuracy of the proposed methodology for different driveline compositions, machinery configurations and braking systems is included in the thesis of this research, due to page limitations.
Quantified effects of barriers and terrain elevations on design of buildings exposed to hemispherical open-air explosions
Authors: Flink PJ , Meijers SJH 
Published: June 2024

Abstract
The blast-resistant design of buildings has been of interest for decades, in petrochemical industry, military, legal courts, nuclear reactors, embassies and other vital facilities. Reliable analysis procedures have been established to determine the response of those buildings to a well-defined blast load. The overpressure caused by a hemispherical open-air explosion of a certain amount of TNT equivalents can be readily determined from literature. The reflected and side-on pressure and impulse are primary inputs for the blast-resistant design of buildings. That design can be more economical if barriers and terrain elevations are accounted for or provided. However, the effects of barriers and terrain elevations are not easily accessible in literature and consequently it is difficult to include in analyses. The influence must be estimated in practice, computed numerically, or neglected. In this present paper a series of hemispherical open-air explosions in geometrical configurations with barriers and elevations is addressed computationally with dedicated CFD software. Investigation of the results leads to a straightforward dependency of blast design parameters on geometrical parameters such as the scaled distances from the blast source to the obstacle or elevation and the building, as well as the height of the obstacle. The blast parameters can then be determined for future analyses based on the dependencies determined for this study. This can be considered as a practical supplement to the existing literature about open-air explosions, as it reduces the need for numerical analysis to determine the blast parameters in a range of configurations with barriers and terrain elevations.
Nonparametric ground motion models of arias intensity and significant duration for the Italian dataset
Authors: Hussaini Sayed Mohammad Sajad , Caicedo Daniel , Mohammadi Amirhossein , Karimzadeh Shaghayegh , Lourenço Paulo B 
Published: June 2024

Abstract
In the field of ground motion simulation, the stochastic site-based methodology relies on the existing database of ground shaking. Based on these methodologies, several properties of seismic signals are used to simulate seismic waves. These parameters could be evaluated either parametrically via linear or nonlinear regression techniques or non-parametrically via sophisticated machine-learning algorithms. Nonetheless, parametric models, which consist of a particular mathematical formulation, can be a source of large bias. In this study, machine learning techniques are employed to develop predictive models for two main input parameters of a stochastic site-based ground motion model: Arias intensity and significant duration, which control the time variation of the simulated ground shakings. The Arias intensity, defined by the integral of the square of the acceleration time series, and the significant duration, which is related to the strong shaking phase of an earthquake, are also of particular interest in structural and geotechnical engineering fields. For this purpose, the random forest approach is employed to develop prediction models for the Italian database. To guarantee the prediction accuracy of the models also for unseen future data, only 80 percent of the data is used for training, and the rest is reserved for testing the trained model. The model hyperparameters are tuned to control bias and variance trade-offs by k-fold cross-validation. For each model, a set of hyperparameters is selected, and a possible range is given. Then, a Bayesian optimization technique is implemented to find the best set of these hyperparameters among the given range. All these models provided promising results compared to the prior models in the literature.
Efficient time-dependent reliability analysis for a railway bridge model
Authors: Bittner M , Fritsch L , Hirzinger B , Broggi M , Beer M 
Published: June 2024

Abstract
This paper proposes a framework for efficient time-dependent reliability analysis for a parametrized stochastic dynamic system, namely a train bridge load model with uncertain design properties. The Probability Density Evolution Method is utilized to explore the multidimensional random space, identify specific failure paths contributing to the failure region, and provide a full probabilistic output of the desired target quantity. The framework is tested on an uncertain railway bridge subjected to train transit (moving loads). The peak acceleration as a function of the train speed in a certain interval is analysed and utilised as performance criteria. The main sources of uncertainties are the damping and the bridge’s moment of inertia. The full evolutionary Probability Density Function of the bridge’s maximum deck acceleration is obtained, the reliability is assessed and a probability of failure estimated. The results show that in the considered speed intervals, the velocities contributing to the failure region are depending on the underlying sampling method. The Probability Density Evolution Method offers additional insight on the evolution of the critical peak accelerations while at the same time performing a reasonable amount of full model evaluations. The study concludes that further discussion is needed to determine the appropriate prediction of the train speeds that may or may not significantly contribute to the probability of failure in this bridge train model.
Data-driven system identification of unknown systems utilising sparse identification of nonlinear dynamics (SINDy)
Authors: Pandey P , Haddad Khodaparast H , Friswell M I , Chatterjee T , Jamia N , Deighan T 
Published: June 2024

Abstract
This paper focuses on the application of experimental data-based system identification of unknown systems utilising sparse identification of nonlinear dynamics (SINDy). SINDy is used to detect the system dynamics in the three well-known nonlinear systems. Analyzed are SINDy’s abilities to accurately represent transient/steady-state behaviour, noise effect, and model structure. A sparse set of basis functions can effectively capture the dynamics of a system, according to the data-driven approach known as SINDy. The coefficients of these basis functions are determined via methods of sparse regression, and the final model is made up of a number of sparse ordinary differential equations. The findings demonstrate that SINDy, with sufficient time-series data, can capture both transient and steady-state phenomena. According to the analysis of the noise effect, SINDy’s performance declines as the system’s noise level rises. The feature library must contain the appropriate model structure in order for SINDy to function effectively. SINDy has the potential to extract unknown system dynamics from experimental data.
Comparing Open-Source BEM solvers for analysing wave energy converters
Authors: Raghavan V , Lavidas G , Metrikine A V 
Published: June 2024

Abstract
Ocean wave energy has immense potential and can provide at least twice as much electricity as globally produced now due to its high energy density. In order to efficiently extract this energy and make this commercially viable, Wave Energy Converters (WECs) need to interact with the resource in an optimized way for the expanse of sea states. This interaction is critical to power production by these devices and hence an accurate modelling of this is paramount. The Boundary element method (BEM) based on the linear potential flow theory has yielded accurate results at low computational costs when compared to complex Computational Fluid Dynamics methods. Hydrodynamic Analysis of Marine Structures (HAMS) and Capytaine are recently developed open-source BEM frequency domain solvers, originally created for large marine structures. These solvers have since been utilized for studying wave energy converters, though, for very few converter geometries. Owing to the implementation of parallelization in both HAMS and Capytaine, both these solvers could be capable for significantly lower computational costs as compared to the traditional BEM solvers such as Nemoh. This research aims to compare hydrodynamic coefficients and computational costs in Nemoh, HAMS and Capytaine for various WEC geometries.
Collective Identification of Superstructures and Dynamic Soil Springs Considering the Effects of Higher Modes Based on the MIEC Method
Authors: Tojo Takaki , Suzuki Takuya , Nakamura Naohiro , Nabeshima Kunihiko 
Published: June 2024

Abstract
The natural period and damping ratio are essential parameters that significantly impact the seismic response of buildings. Most recent seismic observation records have indicated that buildings are also affected by the dynamic soil-structure interaction (DSSI). In this study, we propose an identification method of vibration characteristics considering low-to high-order modes using the modal iterative error correction method and evaluate the influence of DSSI. First, we confirmed the validity of the proposed method using a numerical analysis model. Next, the proposed method was applied to the large shaking table test, and the stiffness and damping of the specimen were identified. The identification results for the test showed that the stiffness of the building or soil spring decreased, and the damping ratio tended to increase with the increase in the maximum deformation experienced. Upon evaluating the influence of DSSI on the foundation in the fixed condition, the effects of the first and second modes on the natural period were found to be more pronounced than the third mode. When the maximum deformation experienced increased, the natural period did not considerably change, whereas a part of modal damping ratios exhibited relatively large fluctuations.
Implementation of a Timoshenko beam within an elastodynamic halfspace modeled by the Wave Based Method
Authors: Lainer M , Müller G 
Published: June 2024

Abstract
The Wave Based Method (WBM) is an indirect Trefftz approach, which uses weighted wave functions to approximate the field response of a boundary value problem. These wave functions weakly fulfill the underlying differential equations and pass through a weighted residual approach by applying boundary conditions. This method has firstly been introduced for vibroacoustic problems to simulate excitations in the mid-frequency range. The accuracy of the WBM strongly depends on the relation between the geometrical size of a boundary value problem and the applied excitation frequency. This permits to transfer the WBM from vibroacoustic applications to soil halfspaces without significantly increasing the number of wave functions, and hence the number of unknown weighting values. Within this paper, a coupling approach between a Timoshenko beam and adjoining WBM domains is introduced as an efficient procedure for the simulation of a trench with two side walls. This trench is installed as a wave barrier against an incoming Rayleigh wave. The performance and accuracy of this coupling approach are analyzed and compared with results from literature. Moreover, different materials are tested for the side walls to assess the mitigation efficiency of the trench.
Numerical modelling of an impact resistance analysis of EN C45 steel pipe buried beneath the ground surface loaded with a detonation wave generated by an explosion of a cubic TNT charge
Authors: Olaleye Kayode , Pyka Dariusz , Bocian Mirosław , Jamroziak Krzysztof 
Published: June 2024

Abstract
The shock wave resulting from the explosion process is the main burden on the technical infrastructure facilities or people in contact with the epicentre of the high explosive (HE). The article presents the tests of EN C45 steel pipe of 10 mm thickness buried beneath the earth as a result of the impulse load of the detonation wave of the explosive charge. This process was modelled in one way using Abaqus Explicit code software using a 75 g Tri-Nitro Toluene (TNT) position 30 mm above the steel pipe. As a result of detonation, the samples were not fragmented, but visibly deformed displaying faster travelling of the explosion wave in air than in the soil. The main purpose of the work was to verify the impact resistance of EN C45 steel, which is commonly used in technical facilities. The impact numerical model results as a result of the shock wave on the steel tested material in the areas subjected to dynamic deformation are presented. The method used in this work is Coupled Eulerian-Lagrangian Method (CEL).
A SEM/FEM weak coupling for a more accurate definition of seismic input excitation in soil-structure interaction studies: An adaptation for a massively parallel FEM resolution
Authors: Korres M , Alves Fernandes V , Zentner I , Tardieu N , Voldoire F , Gatti F , Lopez-Caballero F 
Published: June 2024

Abstract
Numerical simulation of source-to-structure wave propagation consists of a challenging and demanding task in terms of computational capabilities and resources. Some difficulties related to the multi-scale character of the numerical problem can be alleviated using a spectral element (SEM) and finite element (FEM) weak coupling, such as the one described and verified in this study. In addition, the adaptation of the FEM resolution in a domain decomposition framework is developed allowing to utilize iterative solvers and ensure the scalability of the numerical solution in a High-Performance Computing (HPC) framework more efficiently. Comparisons with solutions adopting a direct parallel solver allow to demonstrate the important acceleration of the computation chain.
Identification of Building Parameters Considering Soil-Structure Interaction Based on Observed Earthquake Records
Authors: Kitaoka Hinata , Nakamura Naohiro , Nabeshima Kunihiko 
Published: June 2024

Abstract
A typical mid-to low-rise building is subject to strong dynamic interaction effects due to its relative degree of flexibility with the soil. Thus, it is necessary to take this effect into account when evaluating the seismic performance of such buildings. In this paper, we apply the modal iterative error correction method (MIEC method) to the foreshock records of the 2011 Tohoku earthquake to identify the coupled superstructure–foundation–soil system in a real building with few observation points. For this, observations made on the first, second, fifth, and eighth floors of an eight-story steel-reinforced concrete were used for identification of building parameters. In this earthquake, the response of each part of the building is within a linear range. First, the stiffness of the superstructure is identified as a parameter in the fixed-foundation model. Next, this stiffness value is used to create a Sway-Rocking model, and the identification was performed using soil spring as a parameter. The identification results for a real building with limited number of observation points, including soil springs in a linear range, showed good correspondence with the observed values.
An efficient pile-group foundation model to deal with ground-borne vibration problems
Authors: Conto Kenny F. , Arcos Robert , Clot Arnau , Liravi Hassan 
Published: June 2024

Abstract
This paper proposes a new efficient three-dimensional approach for modelling the dynamic response of pile-group foundations due to man-made ground-borne vibration excitations. The model employs the singular boundary method to account for the soil reaction, whilst the piles are modelled as rod or Euler-Bernoulli beams to account for axial/torsional or bending motions, respectively. The model is formulated considering strong coupling conditions between the two subsystems. The robustness of the model is discussed by comparing its results with the ones obtained by a three-dimensional finite element and boundary element approach. The comparison reveals that the robustness and efficiency of the proposed methodology provide accurate results without compromising its computational efficiency. A study of the dynamic interaction factors employed for modelling large pile-group systems using the superposition method is also presented. Particularly, the influence of including neighbouring piles in the calculation of dynamic interaction factors is discussed in the context of three pile-group foundation cases. This study shows considerable discrepancies above 10 Hz in the prediction of interaction factors between systems that do not consider neighbouring piles with the ones that do.
Development of a Low-Cost Resistivity Meter for Local Groundwater Survey
Authors: Monje J C , Guico M L , Oppus C M , Retirado M G , Cuezon A R , Torres J B 
Published: June 2024

Abstract
The researchers developed a low-cost resistivity meter with a built-in data file storage system using locally available parts. This effort was done in partnership with the National Water Resources Board and the Department of Science and Technology under the Water for Tourism project for water quality monitoring in tourist areas in the Philippines such as Boracay and Caticlan. The resistivity meter system consists of a power supply module, a sensor module, and an equipment module, built using locally available materials and equipment, emulating the commercially available PASI model 16 GL-N. Due to pandemic restrictions, the developed prototype could only be tested on one soil type area. Using a Schlumberger array configuration, the results are comparably similar to the benchmark test results using the PASI. Further work will be performed on future versions of this prototype such as the possibility of multi-electrode set-ups and some user design improvements, as recommended by partner organizations.