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Seminario - Numerical modelling of brittle rock deformation using the Discrete Element Method

Martedì, 8 maggio 2018 ore 16:30
Aula Arduino – Dipartimento di Geoscienze

Relatore: Steffen Abe
Institute for geothermal resource management, Mainz, Germany

Abstract

Brittle deformation processes play an important role in determining the evolution of the geometry and the mechanical behaviour of geological structures at many scales.
Numerical modelling provides a way towards a deeper understanding of the mechanisms and parameters controlling these deformation processes.
The Discrete Element Method (DEM) is a well established numerical method which enables the simulation of brittle deformation processes.
Its key advantage compared to continuum-based approaches such as the Finite Element Method (FEM) is the ability to model material discontinuities in a natural way,
even if those discontinuities are densely distributed in the model volume and emerge dynamically during the deformation process.
The open-source software package ESyS-Particle has been developed with the aim to enable the study of complex geological deformation processes using large, high-resolution DEM models exploiting
the computational power of parallel computer systems. Using this software, the mechanics of faults and fractures has been studied at a range of scales from the formation of km-scale fault systems,
the evolution of roughness on m-scale fault surfaces to granular processes in sub-mm scale fault gouge models.
The common observation between all those different model is that the way the systems behave is controlled by complex feedback mechanisms between mechanics and an evolving geometry.
This observation is perhaps most strikingly demonstrated in the simulated fault gouge where the macroscopic friction of the fault is controlled much more strongly by the shape
of the gouge grains than by the micro-scale intra-grain friction.
                                                                                            
Proponente: Prof. Matteo Massironi

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Eventi

XVI Congresso Nazionale di Planetologia Padova

Dal 3 al 7 febbraio 2020 si svolgerà a Padova, presso il Centro Culturale “San Gaetano”, il XVI Congresso Nazionale di Planetologia.

Il link dell’evento, comprensivo di form per la registrazione, è https://indico.ict.inaf.it/event/945/overview

L’indirizzo email di contatto è: CongressoPlanetologia@inaf.it

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Eventi

Cerimonia di consegna dei diplomi di dottorato. È online il video

Il giorno 30 ottobre 2019 si è svolta, presso l’Aula Magna di palazzo Bo, la cerimonia di consegna dei diplomi di dottorato (Matematica e fisica e Ingegneria).
Il video completo è disponibile al seguente link: https://mediaspace.unipd.it/playlist/dedicated/102668851/1_aej1cg4j/1_l8...

(dottorato in Scienze, Tecnologie e Misure Spaziali, 31° ciclo: 38.52)

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Eventi

Lunar cave explorer

What might look like a dangling hamster ball is actually a robotic sphere to explore the depths of lunar caves.
Designed by a team coordinated by Germany’s Julius-Maximilians-University (JMU), the Descent And Exploration in Deep Autonomy of Lunar Underground Structures, DAEDALUS, [LINK: https://www.informatik.uni-wuerzburg.de/space/mitarbeiter/nuechter/proje... ] [LINK: https://twitter.com/DaedalusSphere ]robot is being evaluated by ESA’s Concurrent Design Facility, as part of a larger study of lunar cave mission concepts [LINK: https://www.esa.int/Enabling_Support/Preparing_for_the_Future/Discovery_... ].

Lunar orbiters have mapped multiple deep pits on the surface of the Moon, believed to be ‘skylights’ into lava caves. These are of high scientific interest, offering access to pristine lunar material – perhaps even water ice deposits. Such caves might also become habitats for lunar settlers, offering natural shielding against radiation, micrometeorites and surface temperature extremes.
The 46-cm diameter DAEDALUS sphere would incorporate an immersive stereoscopic camera, a ‘laser radar’ lidar system for 3D mapping of cave interiors, temperature sensors and a radiation dosimeter, and incorporating extensible arms to help clear obstacles as well as test rock properties.

DAEDALUS would first be lowered into the cave mouth on a long tether, then disconnect to roll away autonomously under its own power. The hanging tether would then double as a Wi-Fi receiver, allowing DAEDALUS to relay its findings out of the pit.
“The design is driven by the requirement to observe the surroundings in full 360 degrees and the necessity to protect the interior from the harsh lunar environment. With the cameras acting as stereo vision system and the laser distance measurements the sphere detects obstacles during descent and navigates autonomously once reaching the pit floor.”

The consortium led by JMU has developed the robot as part of a larger Lunar Caves-System Study, carried out in response to an ESA Open Space Innovation Platform call. Partnering in this study is Germany’s Jacobs University Bremen (Germany), CISAS and the Department of Geosciences of the University of Padova, INAF-Astronomical Observatory of Padova, CIRA (Centro ItalianoRicerche Aerospaziali) and the VIGEA-Virtual Geographic Agency of Reggio Emilia, all in Italy.

The study is being evaluated along with other lunar cave exploration concepts at ESA’s Concurrent Design Facility [LINK: https://www.esa.int/Enabling_Support/Space_Engineering_Technology/20_yea... ], bringing together space engineering experts to perform rapid analysis of future mission proposals.

Infohttps://www.esa.int/ESA_Multimedia/Images/2021/03/Lunar_cave_explorer

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