Documenti full-text disponibili:
Abstract
Understanding the interaction of sea ice with offshore structures is of primary importance for the development of technology in cold climate regions. The rheological properties of sea ice (strength, creep, viscosity) as well as the roughness of the contact surface are the main factors influencing the type of interaction with a structure.
A device was developed and designed and small scale laboratory experiments were carried out to study sea ice frictional interaction with steel material by means of a uniaxial compression rig.
Sea-ice was artificially grown between a stainless steel piston (of circular cross section) and a hollow cylinder of the same material, coaxial to the former and of the same surface roughness. Three different values for the roughness were tested: 1.2, 10 and 30 μm Ry (maximum asperities height), chosen as representative values for typical surface conditions, from smooth to normally corroded steel. Creep tests (0.2, 0.3, 0.4 and 0.6 kN) were conducted at T = -10 ºC. By pushing the piston head towards the cylinder base, three different types of relative movement were observed: 1) the piston slid through the ice, 2) the piston slid through the ice and the ice slid on the surface of the outer cylinder, 3) the ice slid only on the cylinder surface. A cyclic stick-slip motion of the piston was detected with a representative frequency of 0.1 Hz. The ratio of the mean rate of axial displacement to the frequency of the stick-slip oscillations was found to be comparable to the roughness length (Sm). The roughness is the most influential parameter affecting the amplitude of the oscillations, while the load has a relevant influence on the their frequency.
Guidelines for further investigations were recommended.
Marco Nanetti - seloselo@virgilio.it
Abstract
Understanding the interaction of sea ice with offshore structures is of primary importance for the development of technology in cold climate regions. The rheological properties of sea ice (strength, creep, viscosity) as well as the roughness of the contact surface are the main factors influencing the type of interaction with a structure.
A device was developed and designed and small scale laboratory experiments were carried out to study sea ice frictional interaction with steel material by means of a uniaxial compression rig.
Sea-ice was artificially grown between a stainless steel piston (of circular cross section) and a hollow cylinder of the same material, coaxial to the former and of the same surface roughness. Three different values for the roughness were tested: 1.2, 10 and 30 μm Ry (maximum asperities height), chosen as representative values for typical surface conditions, from smooth to normally corroded steel. Creep tests (0.2, 0.3, 0.4 and 0.6 kN) were conducted at T = -10 ºC. By pushing the piston head towards the cylinder base, three different types of relative movement were observed: 1) the piston slid through the ice, 2) the piston slid through the ice and the ice slid on the surface of the outer cylinder, 3) the ice slid only on the cylinder surface. A cyclic stick-slip motion of the piston was detected with a representative frequency of 0.1 Hz. The ratio of the mean rate of axial displacement to the frequency of the stick-slip oscillations was found to be comparable to the roughness length (Sm). The roughness is the most influential parameter affecting the amplitude of the oscillations, while the load has a relevant influence on the their frequency.
Guidelines for further investigations were recommended.
Marco Nanetti - seloselo@virgilio.it
Tipologia del documento
Tesi di laurea
(Laurea)
Autore della tesi
Nanetti, Marco
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Indirizzo
Geotecnologie
Ordinamento Cds
Ante DM509
Parole chiave
Sea ice, friction, roughness, creep, steel, adhesion, uniaxial compression.
Data di discussione della Tesi
21 Dicembre 2007
URI
Altri metadati
Tipologia del documento
Tesi di laurea
(Tesi di laurea specialistica a ciclo unico)
Autore della tesi
Nanetti, Marco
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Indirizzo
Geotecnologie
Ordinamento Cds
Ante DM509
Parole chiave
Sea ice, friction, roughness, creep, steel, adhesion, uniaxial compression.
Data di discussione della Tesi
21 Dicembre 2007
URI
Statistica sui download
Gestione del documento: