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13th World Conference on Timber engineering: Timber for a Livable Future, WCTE 2023

作者： Gubana, Alessandra Melotto, Massimo De Cillia, Luca Mazelli, Alessandro DPIA Polytechnic Department of Engineering and Architecture University of Udine Italy

ISBN: (纸本)9781713873297

Self-tapping screws are an interesting solution for timber-to-timber shear connections due to their performance, their economic advantages and their ease of use. The screws are preferably used inclined with respect to the shear flow direction, to improve the stiffness and the strength of the connection. The shear transfer mechanism is influenced also by the withdrawal capacity of the screw and by friction between timber elements. These connections are useful for the bending reinforcement of existing timber floors, but the design of these composite-sections requires the knowledge of the connection behaviour. However, very few data are available on the long-term behaviour. An experimental campaign to follow the connection behaviour during time has been performed. The results of a first group of twenty-four identic specimens were already presented. The last results of another group of sixty-three specimens are here reported. One half of the specimens was stored in a controlled environment, one half was stored in a not-controlled environment. Air temperature and humidity were regularly recorded. Push-out tests (as soon as built and after 6, 12 and 24 months) were performed and the main mechanical parameters of the connections as strength, stiffness and ductility at different ages are here compared. © 2023 13th World Conference on Timber engineering, WCTE 2023. All rights reserved.

关键词： Timber

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EVALUATION OF THE BEHAVIOUR FACTOR BY INCREMENTAL DYNAMIC ANALYSES FOR THE SEISMIC DESIGN OF LIGHT-FRAME TIMBER BUILDINGS 13

EVALUATION OF THE BEHAVIOUR FACTOR BY INCREMENTAL DYNAMIC AN...

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13th World Conference on Timber engineering: Timber for a Livable Future, WCTE 2023

作者： Gubana, Alessandra Mazelli, Alessandro DPIA Polytechnic Department of Engineering and Architecture University of Udine Italy

ISBN: (纸本)9781713873297

Light Frame Wood structures are today a valid alternative to Cross Laminated Timber structures for low and medium height buildings, both in terms of performance and environmental impact, given the lower volume of wood used. Light wood frames demonstrate a ductile behavior under seismic actions, linked to the plastic deformation of the connections, but uncertainties still regard the value of the behaviour factor associated to these types of structures. This paper presents the evaluation of the behaviour factor ‘q’, used for the seismic design, based on Incremental Dynamic Analyses for Light-Frame Timber Buildings. Papers in literature regarding its evaluation are mostly based on static nonlinear pushover analyses. Example buildings with 2, 3 and 4 storeys, were designed according to capacity design and then analysed by varying the displacement-ductility of the sheathing-to-frame connection. The results are then compared with the requirements provided by codes. © WCTE *** rights reserved

关键词： Seismic design

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Influence of structural irregularity on the q-behaviour factor of light-frame timber buildings by means of incremental dynamic analysis 64

Influence of structural irregularity on the q-behaviour fact...

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64th International Conference on Vibroengineering

作者： Mazelli, Alessandro Bedon, Chiara Morassi, Antonino DPIA Polytechnic Department of Engineering and Architecture University of Udine Udine Italy DIA Department of Engineering and Architecture University of Trieste Trieste Italy

This paper investigates the role of sheathing-to-framing connection ductility in the evaluation of the structural q-behaviour factor for Light-Frame Timber (LFT) buildings, by means of Incremental Dynamic Analyses (IDA). This approach allows to consider nonlinear cyclic behaviour of the walls, which cannot be taken into account with the static approaches used in most of the available literature on LFT buildings. To this aim, Finite Element wall models, preliminary calibrated towards a cyclic full-scale experimental test, are built to study six case-study buildings, both regular and non-regular, with 2, 3 or 4 storeys, which were designed according to Eurocode and Capacity Design provisions. Parametric analyses are performed by varying the displacement-ductility of the panel. Finally, numerical results are discussed in terms of q-behaviour factor, and its sensitivity to structural irregularities, with respect to existing code provisions for timber buildings. © 2023 JVE International. All rights reserved.

关键词： Factor analysis

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Laterally vibrating lithium niobate MEMS resonators with 30% electromechanical coupling coefficient 30

Laterally vibrating lithium niobate MEMS resonators with 30%...

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30th IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2017

作者： Pop, Flavius V. Kochhar, Abhay S. Vidal-Álvarez, Gabriel Piazza, Gianluca Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh United States DPIA Polytechnic Department of Engineering and Architecture University of Udine Italy

ISBN: (纸本)9781509050789

This paper demonstrates laterally vibrating lithium niobate (LN) microelectromechanical (MEMS) resonators operating at 500 MHz with an electromechanical coupling coefficient (kt2) around 30% - the highest ever attained for this class of resonators. This accomplishment is made possible by the use of direct bonding of bulk X-cut LN wafers to high resistivity silicon and a resonator electrode layout that permits harnessing the full capabilities of the film. © 2017 IEEE.

关键词： Resonators

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Technicians and Interventions Scheduling for the Maintenance Service of Container Ships

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Procedia CIRP 2016年 47卷 216-221页

作者： Antonella Meneghetti Elisa De Zan DPIA - Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 206 Udine 33100 Italy

The problem of personnel and interventions scheduling faced by a container ship maintenance service provider (MSPC), commonly the manufacturer of a main ship subsystem such as engines, is analysed. Clients can make a request for a maintenance service of a containership at a given harbour with a given number of days in advance to the desired date, as established in the service contract. The MSPC is allowed to delay the intervention to any future stop of the route within a specified time window depending on its urgency, as set in the contract. The MSPC technicians can be divided into different categories of skills and further distinguished as belonging to the MSPC main company, to the MSP network of subsidiaries, or hired on demand, with different availability constraints, personnel costs, and transport costs in relation to harbour proximity. Delays on planned arrival dates to harbours as well as changes in the duration of stay are common due to bad meteorological conditions, congestions at harbours, or other issues arisen during sailing or previous stops, so a rolling planning horizon should be adopted to face such a dynamic environment. A Constraint Programming optimisation model hybridized with Large Neighborhood Search is proposed in order to address the problem and its performance compared to actual plans from a world-wide known MSPC. The model has been developed to perform also as a decision making tool; a factorial design of experiment is adopted in order to analyse the impact of a change in some contractual features, such as the minimum time allowed to clients for requiring a service, or the maximum delay allowed to the MSPC to satisfy a service request. How granting clients more flexibility while preserving efficacy and efficiency of the service can so be investigated.

关键词： maintenance service container ships technicians scheduling service contracts Constraint Programming Large Neighborhood Search

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Morphodynamic numerical modelling of bridge pier erosion induced by downstream check-dam partial collapse

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Procedia Structural Integrity 2024年 62卷 601-608页

作者： Matteo Nicolini Polytechnic Department of Engineering and Architecture (DPIA) University of Udine via del Cotonificio 114 Udine 33100 Italy

The paper presents a case study in which a severe bridge pier erosion effect was triggered by a partial collapse of a downstream check-dam, due to a flood event in June 2020. The area under study is about 30 km east from the city of Udine (Italy), along the river Torre, which is the main tributary of the river Isonzo. In particular, it is 1 km downstream of the confluence between river Torre and its main tributary, river Natisone. The hydrodynamic complexity of the reach is further exacerbated by the presence of two bridges, close to each other and almost parallel (the new one is just upstream and it is under construction, although almost finished, while the old one is still in service). The result is that there are many bridge piers in the riverbed, determining some interference effects also increasing local erosion. The presence of a check-dam 600 m downstream of the old bridge had a stabilizing effect in this sense, although it was originally designed as a grade control structure of the river. The flood event determined a partial collapse of such structure, whose central portion was progressively excised by tipping. The backward propagation of the erosion reached the area of the bridges, determining a progressive general lowering of the river bed. As a consequence, many bridge piers of the old bridge were excavated, determining severe conditions for the stability of the structure (the traffic was interrupted). The paper presents the methodology adopted and the main results obtained by hydrodynamic and morphodynamic numerical analyses, which were conducted through a two-dimensional, finite volume, shallow water model able to determine the hydrodynamic fields (water depth and flow velocity) and the evolutionary trends of the river bed, allowing to identify the best retrofitting strategy for the design phase.

关键词： river flood two-dimensional models BASEMENT software case study

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Comparison of model order reduction techniques for flexible multibody dynamics using an equivalent rigid-link system approach 8

Comparison of model order reduction techniques for flexible ...

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8th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS, MBD 2017

作者： Vidoni, Renato Scalera, Lorenzo Gasparetto, Alessandro Giovagnoni, Marco Faculty of Science and Technology Free University of Bozen-Bolzano piazza Università 5 Bolzano39100 Italy DPIA Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 208 Udine33100 Italy

ISBN: (纸本)9788001061749

In this paper we present a comparison of different model order reduction techniques for flexible multibody dynamics. In particular, we adopt a formulation based on a Equivalent Rigid-Link System (ERLS). This approach is suitable in the case of large displacements and small elastic deformations and it allows the kinematic equations of motion to be decoupled from the compatibility equations of the displacements at the joints. The ERLS approach, recently extended through a modal formulation, is here implemented in combination with different reduction techniques, i.e. Craig- Bampton, Interior Mode Ranking (IMR), Guyan, Least Square Model Reduction (LSMR) and Mode Displacement Method (MDM). In order to assess the advantages and disadvantages of the different methodologies, these techniques are applied to a benchmark mechanism under different input conditions, i.e. gravitational force and step torque input. The accuracy of each reduced model is numerically evaluated through the comparison of computational time, the behaviour in frequency domain and by means of vector correlation methods, i.e. Modal Assurance Criterion (MAC), Cross-Orthogonality (CO) and Normalized Cross-Orthogonality (NCO). © 2017 International Center for Numerical Methods in engineering. All rights reserved.

关键词： Equations of motion

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Geomatic 3D modeling of a statue (ALSO) for structural analysis & risk evaluation: The example of San Giovannino Martelli in florence 1

Geomatic 3D modeling of a statue (ALSO) for structural analy...

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1st International Conference on Geomatics and Restoration: Conservation of Cultural Heritage in the Digital Era, GeoRes 2017

作者： Spangher, Anna Visintini, Domenico Tucci, Grazia Bonora, Valentina Polytechnic Department of Engineering and Architecture University of Udine - DPIA via delle Scienze 206 Udine Italy GECO Lab. Dept. of Civil and Environmental Engineering University of Florence - DICeA via P.A. Micheli 8 Florence Italy

This work has been developed among the researches of a PhD thesis in Civil and Environmental engineering and architecture of the University of Udine in cooperation with the GECO Laboratory of the University of Florence. It focuses on the interaction between Geomatics and Structural Analysis, both applied to cultural heritage, and expressly to artefacts and structures in stone materials, like the case study of this paper, the marble statue called "San Giovannino Martelli" (Saint John the Baptist) conserved in Florence. At the beginning, some interesting examples of surveying and structural analyses on statues are reported, in order to remind the complementary tasks and requirements of geomatics and structural analysis. Current laser scanning systems can accurately survey the geometry of a statue or any cultural heritage artefact, essential to understand their structural behaviour and resilience capability. Afterwards, following the few Italian regulations in this field, the possible risks of museum goods are described: Topics of this part are more familiar for structural engineers as object classification, seismic reactions, damage mechanisms, possible movements (adherent, slipping and oscillation), dynamic domains, anyway necessary steps to evaluate the risk and so to define eventual interventions. The artistic description of the statue, its debated attribution to Donatello or/and to Desiderio da Settignano and its history is later recalled, remembering that the surveying has been done for the idea to 3D print a replica and to place it in the original place. Having used a close range laser scanner, the obtained 3D model has an impressive geometrical Level of Detail (LoD), whose geometric features are explained in the paper, underlying that such extremely detailed mesh is directly given as output from the laser scanner software. The model simplifications by four decimation are therefore explained and also changes to geometry, like shifts on centre of the mass or bary

关键词： Finite element method

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Anaerobic Digestion of Brackish and High Salinity Aquaculture Sludges

Anaerobic Digestion of Brackish and High Salinity Aquacultur...

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2021 American Society of Agricultural and Biological Engineers Annual International Meeting, ASABE 2021

作者： Chiumenti, Alessandro Owono, Bartolomè Owono Fait, Giulio Mainardis, Matia Goi, Daniele Stella, Elisa Da Borso, Francesco Department of Agricultural Food Animal and Environmental Sciences University of Udine DI4A via delle Scienze 206 Udine33100 Italy Department Polytechnic of Engineering and Architecture University of Udine Dpia Via del Cotonificio 108 Udine33100 Italy

ISBN: (纸本)9781713833536

The development of intensive fish production is facing the challenge of the sustainable management of effluents. Aquaculture reproductive sectors (i.e., hatcheries) in most cases implement water recirculation systems (RAS), which discharge a portion of the produced wastewater. Anaerobic digestion (AD) process could mitigate the environmental impact of this waste stream while producing fuel in the form of biogas. The present research represents a further development of previous tests conducted in the framework of the AdriaAquaNet Interreg Project. The anaerobic digestion tests were conducted using a pilot scale Bioreactor simulator system (BRS, Bioprocess Control, Sweden). This apparatus can operate with semi-continuous loading, simulating a full-scale reactor in order to study the optimal process layout and the optimal substrate retention time. The system was initially loaded with an inoculum derived from anaerobically treated brackish aquaculture sludges and with digestate originated from a full-scale anaerobic reactor operating with animal manure and corn silage. The incubation period lasted 20 days, and from the 21st day, aquaculture sludges were loaded with organic loading rates (OLR) varying from 0.16 to 0.64 g VS/L day, with hydraulic retention times (HRTs) shortened from 30.0 days to 12.9 days. The tests were performed with salt concentration established at 35 g/L (high salinity conditions) and 12 g/L (original brackish water conditions). Specific methane productions were fairly good (278.9 - 300.3 NL/kg VS input), resulting higher in brackish conditions than in marine conditions, and in correspondence of retention times of about 20 -30 days. © ASABE 2021. All rights reserved.

关键词： Anaerobic digestion

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Laterally vibrating lithium niobate MEMS resonators with 30% electromechanical coupling coefficient

Laterally vibrating lithium niobate MEMS resonators with 30%...

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IEEE International Conference on Micro Electro Mechanical Systems

作者： Flavius V. Pop Abhay S. Kochhar Gabriel Vidal-Alvarez Gianluca Piazza Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh USA DPIA Polytechnic Department of Engineering and Architecture University of Udine ITALY

ISBN: (纸本)9781509050796

This paper demonstrates laterally vibrating lithium niobate (LN) microelectromechanical (MEMS) resonators operating at 500 MHz with an electromechanical coupling coefficient (k t 2 ) around 30% - the highest ever attained for this class of resonators. This accomplishment is made possible by the use of direct bonding of bulk X-cut LN wafers to high resistivity silicon and a resonator electrode layout that permits harnessing the full capabilities of the film.

关键词： Electrodes Micromechanical devices Geometry Lithium niobate Couplings Films Fabrication

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