المؤلفون: La Paglia, Ivano, Rapino, Luca, Ripamonti, Francesco, Baro, Simone, Corradi, Roberto

المساهمون: La Paglia, Ivano, Rapino, Luca, Ripamonti, Francesco, Baro, Simone, Corradi, Roberto

مصطلحات موضوعية: Rolling tyre dynamics, Experimental cleat test, Wave propagation solution, Identification algorithm, Structure-borne noise

الوصف: Road vehicle NVH performances can be improved acting on tyres, which play a fundamental role in the transmission of structure-borne noise and vibration into the cabin, up to 500 Hz. This paper aims at investigating the in-plane dynamics of a rolling tyre in this frequency range. Tyre radial vibration measurements are carried out through a dedicated experimental setup, based on a laser triangulation sensor scanning the tread of a rolling tyre. The experimental data are collected during cleat tests, considering different rolling speeds and inflation pressures, to investigate their influence on tyre dynamics. Then, a data processing algorithm is proposed with the aim of identifying the progressive and regressive waves propagating along the tyre circumference after the cleat impact. Finally, to interpret the results, the identified tyre response has been compared to the analytical results obtained through a simplified in-plane tyre model.

العلاقة: volume:211; firstpage:1; lastpage:13; numberofpages:13; journal:MECHANICAL SYSTEMS AND SIGNAL PROCESSING; https://hdl.handle.net/11311/1260644Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85184498922; https://www.sciencedirect.com/science/article/pii/S0888327024000797Test

الإتاحة: https://doi.org/10.1016/j.ymssp.2024.111181Test
https://hdl.handle.net/11311/1260644Test
https://www.sciencedirect.com/science/article/pii/S0888327024000797Test

المؤلفون: Riccardo Bonomelli, Gabriele Farina, Marco Pilotti, Daniela Molinari, Francesco Ballio

المساهمون: Bonomelli, Riccardo, Farina, Gabriele, Pilotti, Marco, Molinari, Daniela, Ballio, Francesco

مصطلحات موضوعية: Dam break wave propagation, Shallow water equations, Flood vulnerability and damage

الوصف: Study region: Valle Camonica basin and Lake Iseo in the Italian pre-alpine and alpine region. Study focus: This paper provides the first hydraulic reconstruction of the terminal part of the Gleno dam break with the propagation of the flood wave along a wide pre-alpine valley. The reconstruction of this part of the event, accomplished with a new 2D Shallow Water Equations solver, provides the occasion to tackle some important issues related to the computation of flood damage, a topic of paramount practical importance for which there is no widely accepted procedure in the literature. New hydrological insights for the region: The hydraulic reconstruction provides insights into the propagation of the flood through the floodplain as far as the inlet of Lake Iseo. A methodology for damage computation is presented that considers a physically based criterion for the vulnerability of human life, with significant implications with respect to the use of simpler approaches based only on the density of the population. The economic evaluation of the damage to the built environment and to agricultural activities is included through a comprehensive recent approach. We discuss the variations of the expected damage due to the hydraulic works accomplished over the last 100 years to decrease the flood hazard, showing that its reduction has been followed by an increase in the expected damage in the surrounding areas.

وصف الملف: ELETTRONICO

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:001054953900001; volume:48; firstpage:1; lastpage:15; numberofpages:15; journal:JOURNAL OF HYDROLOGY. REGIONAL STUDIES; https://hdl.handle.net/11311/1251617Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85165357955; https://authors.elsevier.com/sd/article/S2214-5818Test(23)00154-4

الإتاحة: https://doi.org/10.1016/j.ejrh.2023.101467Test
https://hdl.handle.net/11311/1251617Test
https://authors.elsevier.com/sd/article/S2214-5818Test(23)00154-4

المؤلفون: Bonetti, Stefano, Botti, Michele, Mazzieri, Ilario, Antonietti, Paola F.

المساهمون: Bonetti, Stefano, Botti, Michele, Mazzieri, Ilario, Antonietti, Paola F.

مصطلحات موضوعية: Discontinuous Galerkin method, Thermo-poroelasticity, Wave propagation, Polygonal and polyhedral meshes

الوصف: We present and analyze a high-order discontinuous Galerkin method for the space discretization of the wave propagation model in thermo-poroelastic media. The proposed scheme supports general polytopal grids. Stability analysis and hp-version error estimates in suitable energy norms are derived for the semi-discrete problem. The fully-discrete scheme is then obtained based on employing an implicit Newmark-β time integration scheme. A wide set of numerical simulations is reported, both for the verification of the theoretical estimates and for examples of physical interest. A comparison with the results of the poroelastic model is provided too, highlighting the differences between the predictive capabilities of the two models.

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:001024492000001; volume:489; firstpage:112275; lastpage:112298; numberofpages:24; journal:JOURNAL OF COMPUTATIONAL PHYSICS; https://hdl.handle.net/11311/1241137Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85162259152; https://www.sciencedirect.com/science/article/pii/S0021999123003704Test

الإتاحة: https://doi.org/10.1016/j.jcp.2023.112275Test
https://hdl.handle.net/11311/1241137Test
https://www.sciencedirect.com/science/article/pii/S0021999123003704Test

المؤلفون: Zhang, Huimin, Zhang, Runsen, Zanoni, Andrea, Xing, Yufeng, Masarati, Pierangelo

المساهمون: Zhang, Huimin, Zhang, Runsen, Zanoni, Andrea, Xing, Yufeng, Masarati, Pierangelo

مصطلحات موضوعية: Explicit, Three-sub-step, Time integration method, Wave propagation problems

الوصف: A novel explicit three-sub-step time integration method is proposed. From linear analysis, it is designed to have at least second-order accuracy, tunable stability interval, tunable algorithmic dissipation and no overshooting behaviour. A distinctive feature is that the size of its stability interval can be adjusted to control the properties of the method. With the largest stability interval, the new method has better amplitude accuracy and smaller dispersion error for wave propagation problems, compared with some existing second-order explicit methods, and as the stability interval narrows, it shows improved period accuracy and stronger algorithmic dissipation. By selecting an appropriate stability interval, the proposed method can achieve properties better than or close to existing second-order methods, and by increasing or reducing the stability interval, it can be used with higher efficiency or stronger dissipation. The new method is applied to solve some illustrative wave propagation examples, and its numerical performance is compared with those of several widely used explicit methods.

وصف الملف: ELETTRONICO

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:000743000100003; volume:92; firstpage:821; lastpage:852; numberofpages:32; journal:ARCHIVE OF APPLIED MECHANICS; http://hdl.handle.net/11311/1196974Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85123083230; https://doi.org/10.1007/s00419-021-02075-0Test

الإتاحة: https://doi.org/10.1007/s00419-021-02075-0Test
http://hdl.handle.net/11311/1196974Test

المؤلفون: Di Michele, F, May, J, Pera, D, Kastelic, V, Carafa, M, Smerzini, C, Mazzieri, I, Rubino, B, Antonietti, P F, Quarteroni, A, Aloisio, R, Marcati, P

المساهمون: Di Michele, F, May, J, Pera, D, Kastelic, V, Carafa, M, Smerzini, C, Mazzieri, I, Rubino, B, Antonietti, P F, Quarteroni, A, Aloisio, R, Marcati, P

مصطلحات موضوعية: Computational seismology, Earthquake ground motions, Earthquake hazards, Neotectonics, Site effects, Seismic wave propagation

الوصف: In this paper we simulate the earthquake that hit the city of L’Aquila on the 6th of April 2009 using SPEED (SPectral Elements in Elastodynamics with Discontinuous Galerkin), an open-source code able to simulate the propagation of seismic waves in complex three-dimensional (3D) domains. Our model includes an accurate 3D reconstruction of the Quaternary deposits, according to the most up-to-date data obtained from the Microzonation studies in Central Italy and a detailed model of the topography incorporated using a newly developed tool (May et al. 2021). The sensitivity of our results with respect to different kinematic seismic sources is investigated. The results obtained are in good agreement with the recordings at the available seismic stations at epicentral distances within a range of 20km. Finally, a blind source prediction scenario application shows a reasonably good agreement between simulations and recordings can be obtained by simulating stochastic rupture realizations with basic input data. These results, although limited to nine simulated scenarios, demonstrate that it is possible to obtain a satisfactory reconstruction of a ground shaking scenario employing a stochastic source constrained on a limited amount of ex-ante information. A similar approach can be used to model future and past earthquakes for which little or no information is typically available, with potential relevant implications for seismic risk assessment.

وصف الملف: ELETTRONICO

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:000773023400002; volume:230; issue:1; firstpage:1; lastpage:33; numberofpages:33; journal:GEOPHYSICAL JOURNAL INTERNATIONAL; http://hdl.handle.net/11311/1199593Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85127843534; https://academic.oup.com/gji/article/230/1/29/6526874Test

الإتاحة: https://doi.org/10.1093/gji/ggac042Test
http://hdl.handle.net/11311/1199593Test
https://academic.oup.com/gji/article/230/1/29/6526874Test

المؤلفون: Antonietti P. F., Facciola C., Houston P., Mazzieri I., Pennesi G., Verani M.

المساهمون: Daniele Antonio Di Pietro, Luca Formaggia, Roland Masson, Antonietti, P. F., Facciola, C., Houston, P., Mazzieri, I., Pennesi, G., Verani, M.

مصطلحات موضوعية: Fast implementation, Fractured reservoir simulations, High–order Discontinuous Galerkin, Polygonal and polyhedral meshes, Quadrature free, Seismic wave propagation

الوصف: We present a comprehensive review of the current development of discontinuous Galerkin methods on polytopic grids (PolyDG) methods for geophysical applications, addressing as paradigmatic applications the numerical modeling of seismic wave propagation and fracture reservoir simulations. We first recall the theoretical background of the analysis of PolyDG methods and discuss the issue of its efficient implementation on polytopic meshes. We address in detail the issue of numerical quadrature and recall the new quadrature free algorithm for the numerical evaluation of the integrals required to assemble the mass and stiffness matrices introduced in [22]. Then we present PolyDG methods for the approximate solution of the elastodynamics equations on computational meshes consisting of polytopic elements. We review the well-posedness of the numerical formulation and hp-version a priori stability and error estimates for the semi-discrete scheme, following [10]. The computational performance of the fully-discrete approximation obtained based on employing the PolyDG method for the space discretization coupled with the leap-frog time marching scheme are demonstrated through numerical experiments. Next, we address the problem of modeling the flow in a fractured porous medium and we review the unified construction and analysis of PolyDG methods following [16]. We show, in a unified setting, the well-posedness of the numerical formulations and hp-version a priori error bounds, that are then validated through numerical tests. We also briefly discuss the extendability of our approach to handle networks of partially immersed fractures and networks of intersecting fractures, recently proposed in [15].

العلاقة: info:eu-repo/semantics/altIdentifier/isbn/978-3-030-69362-6; info:eu-repo/semantics/altIdentifier/isbn/978-3-030-69363-3; ispartofbook:SEMA SIMAI Springer Series; volume:27; firstpage:159; lastpage:225; numberofpages:67; serie:SEMA SIMAI SPRINGER SERIES; alleditors:Daniele Antonio Di Pietro, Luca Formaggia, Roland Masson; http://hdl.handle.net/11311/1193514Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85108443665

الإتاحة: https://doi.org/10.1007/978-3-030-69363-3_5Test
http://hdl.handle.net/11311/1193514Test

المؤلفون: Rakshit G., Quibus L., Vanhoenacker-Janvier D., Maitra A., Luini L.

المساهمون: Rakshit, G., Quibus, L., Vanhoenacker-Janvier, D., Maitra, A., Luini, L.

مصطلحات موضوعية: Cloud, non-rainy attenuation, oxygen, radio wave propagation, radiometers, satellite communication, water vapour

الوصف: A long-term investigation of the attenuation in non-rainy conditions has been carried out, for a tropical and a temperate location, using meteorological data and NWP (Numerical Weather Prediction) products during the period 2011-2015. The results show that ERA-5 full profiles are appropriate to estimate non-rainy attenuation in lieu of radiometric or radiosonde observations. Simpler regression-based methods are established. A new formulation for oxygen attenuation is introduced, which only requires surface temperature and pressure. Mass absorption coefficients are used for water vapour and cloud attenuation. Simpler regression-based approaches are then validated. The non-rainy attenuation at K, Ka and Q bands has been found noticeably higher in the tropics than in the temperate region. This study would facilitate the planning of global mobile satellite communication systems.

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:000678316900001; volume:9; firstpage:101311; lastpage:101320; numberofpages:10; journal:IEEE ACCESS; http://hdl.handle.net/11311/1184607Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85110924129

الإتاحة: https://doi.org/10.1109/ACCESS.2021.3096380Test
http://hdl.handle.net/11311/1184607Test

المؤلفون: Scaccabarozzi D., Saggin B.

المساهمون: Scaccabarozzi, D., Saggin, B.

مصطلحات موضوعية: Chatter vibration, Drill bit, Percussive drilling, Strain gauges, Stress wave propagation

الوصف: This work describes the results of a test campaign aimed to measure the propagation of longitudinal, torsional, and flexural stress waves on a drill bit during percussive rock drilling. Although the stress wave propagation during percussive drilling has been extensively modeled and studied in the literature, its experimental characterization is poorly documented and generally limited to the detection of the longitudinal stress waves. The activity was performed under continuous drilling while varying three parameters, the type of concrete, the operator feeding force, and the drilling hammer rotational speed. It was found that axial stress wave frequencies and spectral amplitudes depend on the investigated parameters. Moreover, a relevant coupling between axial and torsional vibrations was evidenced, while negligible contribution was found from the bending modes. A finite element model of the drill bit and percussive element was developed to simulate the impact and the coupling between axial and torsional vibrations. A strong correlation was found between computed and measured axial stress spectra, but additional studies are required to achieve a satisfactory agreement between the measured and the simulated torque vibrations.

وصف الملف: STAMPA

العلاقة: info:eu-repo/semantics/altIdentifier/pmid/34070548; info:eu-repo/semantics/altIdentifier/wos/WOS:000660663000001; volume:21; issue:11; firstpage:1; lastpage:15; numberofpages:15; journal:SENSORS; http://hdl.handle.net/11311/1175984Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85106434150

الإتاحة: https://doi.org/10.3390/s21113677Test
http://hdl.handle.net/11311/1175984Test

المؤلفون: Korai U. A., Ehsan M., Luini L., Nebuloni R.

المساهمون: Korai, U. A., Ehsan, M., Luini, L., Nebuloni, R.

مصطلحات موضوعية: 5G Networks, electromagnetic wave propagation, fog attenuation, Free space optics

الوصف: A case study for 5G/6G network free space optical (FSO) links affected by fog is reported. Twenty years of visibility data for some major cities of Pakistan were acquired from the Pakistan Meteorological Department. The visibility data consists of three daily measurements collected at 05:00, 08:00, and 17:00 Pakistan standard time (PKT). The data are used to calculate the availability of a 1550 nm FSO link, for each city. Results highlight large differences among the six locations, due to the different climatic conditions. Lahore has the worst performance: in that case, an FSO backhaul link shorter than 150 m would achieve an availability of 99.5%. Whereas, Peshawar has the best performance for the said availability.

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:001023316902078; ispartofbook:17th European Conference on Antennas and Propagation, EuCAP 2023; 17th European Conference on Antennas and Propagation, EuCAP 2023; firstpage:1; lastpage:5; numberofpages:5; https://hdl.handle.net/11311/1259472Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85162268893

الإتاحة: https://doi.org/10.23919/EuCAP57121.2023.10133451Test
https://hdl.handle.net/11311/1259472Test

المؤلفون: Zhang Z., Arosio D., Hojat A., Zanzi L.

المساهمون: Zhang, Z., Arosio, D., Hojat, A., Zanzi, L.

مصطلحات موضوعية: Inverse theory, Seismic instruments, Seismic noise, Seismic tomography, Wave propagation

الوصف: To monitor the stability of a mountain slope in northern Italy, microseismic monitoring technique has been used since 2013. Locating microseismic events is a basic step of this technique. We performed a seismic tomographic survey on the mountain surface above the rock face to obtain a reliable velocity distribution in the rock mass for the localization procedure. Seismic travel-time inversion showed high heterogeneity of the rock mass with strong contrast in velocity distribution. Low velocities were found at shallow depth on the top of the rock cliff and intermediate velocities were observed in the most critical area of the rock face corresponding to a partially detached pillar. Using the 3D velocity model obtained from inversion, localization tests were performed based on the Equal Differential Time (EDT) localization method. The results showed hypocenter misfits to be around 15 m for the five geophones of the microseismic network and the error was significantly decreased compared to the results produced by a constant velocity model. Although the localization errors are relatively large, the accuracy is sufficient to distinguish microseismic events occurring in the most critical zone of the monitored rock mass from microseismic events generated far away. Thus, the 3D velocity model will be used in future studies to improve the classification of the recorded events.

العلاقة: info:eu-repo/semantics/altIdentifier/wos/WOS:000580939500001; volume:10; issue:9; firstpage:1; lastpage:23; numberofpages:23; journal:GEOSCIENCES; http://hdl.handle.net/11311/1155291Test; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85090514726; https://www.mdpi.com/2076-3263/10/9/327Test

الإتاحة: https://doi.org/10.3390/geosciences10090327Test
http://hdl.handle.net/11311/1155291Test
https://www.mdpi.com/2076-3263/10/9/327Test