The Experts below are selected from a list of 3528 Experts worldwide ranked by ideXlab platform
Riccardo Russo - One of the best experts on this subject based on the ideXlab platform.
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On the stability of periodic motions of an unbalanced rigid rotor on lubricated journal bearings
Nonlinear Dynamics, 1996Co-Authors: Renato Brancati, Michele Russo, Riccardo RussoAbstract:A theoretical investigation is carried out on the orbital motions of a symmetrical, unbalanced, rigid rotor subjected to a Constant Vertical Load and supported on two lubricated journal bearings. In order to determine the fluid film forces, the short bearing theory is adopted. A method is illustrated that makes it possible to determine the analytical equation of the orbit as an approximated solution of the system of non-linear differential equations of motion of the journal axis. A procedure is also described for evaluating the stability of the solution found. Diagrams of the curves delimiting, in the working plane of the rotor σ-mσ, the areas of stability of the various periodic solutions determined are provided. Finally, the results obtained are compared and combined with those provided by a direct integration of the motion equation made using the Runge-Kutta method.
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On the stability of periodic motions of an unbalanced rigid rotor on lubricated journal bearings
Nonlinear Dynamics, 1996Co-Authors: Renato Brancati, Michele Russo, Riccardo RussoAbstract:A theoretical investigation is carried out on the orbital motions of a symmetrical, unbalanced, rigid rotor subjected to a Constant Vertical Load and supported on two lubricated journal bearings. In order to determine the fluid film forces, the short bearing theory is adopted.
Matija Gams - One of the best experts on this subject based on the ideXlab platform.
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Seismic behaviour of masonry buildings built of low compressive strength units
Bulletin of Earthquake Engineering, 2018Co-Authors: Petra Triller, Miha Tomaževič, Matija GamsAbstract:Seismic behaviour of masonry buildings, built of low compressive strength units, is discussed. Although such materials have already been tested and approved for use from mechanical and thermal insulation point of view, the knowledge regarding their structural behaviour is still lacking. In order to investigate the resistance and deformation capacity of this particular type of masonry construction in seismic conditions, a series of eight walls and model of a two-storey full scale confined masonry building have been tested by subjecting the specimens to cyclic shear Loads. All tests were conducted under a combination of Constant Vertical Load and quasi static, cyclically imposed horizontal Load. The behaviour of tested specimens was of typical shear type. Compared with the behaviour of plain masonry walls, the presence of tie-columns resulted into higher resistance and displacement capacity, as well as smaller lateral resistance degradation. The response of the model was determined by storey mechanism with predominant shear behaviour of the walls and failure mechanism of the same type as in the case of individual confined masonry walls. Adequate seismic behaviour of this particular masonry structural type can be expected under the condition that the buildings are built as confined masonry system with limited number of stories.
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Seismic Response of URM Walls Strengthened with FRP Reinforced Coating
Key Engineering Materials, 2017Co-Authors: Petra Triller, Miha Tomaževič, Matija GamsAbstract:A set of individual URM walls as well as an assemblage of a three-storey URM hollow clay block masonry structure composed of two shear- and two cross-walls have been tested in original and strengthened state. As a method of strengthening, the coating of the walls, consisting of glass fiber reinforced polymer (GFRP) grid laid in fiber reinforced cementitious mortar matrix (sometimes called textile reinforced mortar), anchored to the walls with glass fiber anchors, has been used. All specimens were subjected to Constant Vertical Load simulating the effect of gravity Loads and cyclic horizontal displacements with step-wise increased amplitudes, induced either at the top of the walls or at the floor levels of the assemblage, simulating the effect of seismic Loads.The observed behaviour and failure mechanisms were of the shear type. The results show that by the application of FRP reinforced coatings, the seismic performance of URM structures can be significantly improved. As the results of experiments indicate, the energy dissipation, displacement capacity and shear resistance of URM increase substantially. In this regard, adequate anchoring of coating to the masonry and into the r.c. floor structures is essential.
Renato Brancati - One of the best experts on this subject based on the ideXlab platform.
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On the stability of periodic motions of an unbalanced rigid rotor on lubricated journal bearings
Nonlinear Dynamics, 1996Co-Authors: Renato Brancati, Michele Russo, Riccardo RussoAbstract:A theoretical investigation is carried out on the orbital motions of a symmetrical, unbalanced, rigid rotor subjected to a Constant Vertical Load and supported on two lubricated journal bearings. In order to determine the fluid film forces, the short bearing theory is adopted. A method is illustrated that makes it possible to determine the analytical equation of the orbit as an approximated solution of the system of non-linear differential equations of motion of the journal axis. A procedure is also described for evaluating the stability of the solution found. Diagrams of the curves delimiting, in the working plane of the rotor σ-mσ, the areas of stability of the various periodic solutions determined are provided. Finally, the results obtained are compared and combined with those provided by a direct integration of the motion equation made using the Runge-Kutta method.
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On the stability of periodic motions of an unbalanced rigid rotor on lubricated journal bearings
Nonlinear Dynamics, 1996Co-Authors: Renato Brancati, Michele Russo, Riccardo RussoAbstract:A theoretical investigation is carried out on the orbital motions of a symmetrical, unbalanced, rigid rotor subjected to a Constant Vertical Load and supported on two lubricated journal bearings. In order to determine the fluid film forces, the short bearing theory is adopted.
R. Žarnić - One of the best experts on this subject based on the ideXlab platform.
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In-situ and laboratory tests of old brick masonry strengthened with FRP in innovative configurations and design considerations
Bulletin of Earthquake Engineering, 2015Co-Authors: M. Jarc simonič, S. Gostič, V. Bosiljkov, R. ŽarnićAbstract:Worldwide cultural heritage and especially the heritage buildings in Europe are masonry buildings. Such buildings are generally capable to resist Vertical Loads but horizontal earthquake actions are often critical. The strengthening upgrade is generally required. One of the most promising methods for the strengthening of masonry walls is application of fibre reinforced polymers (FRP) to the surface of the wall. Three sets of the experimental research were performed recently with new innovative configurations of the fibre reinforcement placement on clay brick masonry. Within the framework of European FP7 research project PERPETUATE two sets of in-situ experiments were performed on 12 walls, belonging to two buildings approximately one hundred years old. Both buildings were made of solid bricks in low strength mortar. Third set of tests was performed in the laboratory on 16 specimens made of contemporary solid bricks in good lime-cement mortar. Tests were performed with different reinforcement configurations. Carbon FRP strips were epoxy-bonded horizontally, diagonally or combined (horizontally and Vertically). Glass FRP grids were placed in the modified cement mortar over the entire surface of the wall. Specimens were tested under the Constant Vertical Load and by a displacement controlled horizontal cyclic Loading. The carbon fibre reinforced polymer strengthening significantly increased the ultimate displacement capacity in case of the horizontal and combined strengthening. The diagonal strengthening was not so effective because the failure of the diagonally strengthened specimens was governed by the peeling of strips from the masonry. The GFRP grid configuration greatly increased the Load bearing capacity but not also the ultimate displacement. The shear strength of the strengthened and un-strengthened specimens was compared to the calculated values of the seismic shear Load bearing capacity. For that the Triantafillou (J Compos Constr 2(2):96–104, 1998 ), Triantafillou and Antonopoulos (J Compos Constr ASCE 4(4):198–205, 2000 ), Marcari et al. ( 2011 ) and Wang et al. (Asian J Civil Eng Build Hous 7(6): 563–580, 2006 ) calculation models and the design guides ACI 440.7R-10 ( 2010 ) and CNR-DT 200/2004 were used.
Petra Triller - One of the best experts on this subject based on the ideXlab platform.
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Seismic behaviour of masonry buildings built of low compressive strength units
Bulletin of Earthquake Engineering, 2018Co-Authors: Petra Triller, Miha Tomaževič, Matija GamsAbstract:Seismic behaviour of masonry buildings, built of low compressive strength units, is discussed. Although such materials have already been tested and approved for use from mechanical and thermal insulation point of view, the knowledge regarding their structural behaviour is still lacking. In order to investigate the resistance and deformation capacity of this particular type of masonry construction in seismic conditions, a series of eight walls and model of a two-storey full scale confined masonry building have been tested by subjecting the specimens to cyclic shear Loads. All tests were conducted under a combination of Constant Vertical Load and quasi static, cyclically imposed horizontal Load. The behaviour of tested specimens was of typical shear type. Compared with the behaviour of plain masonry walls, the presence of tie-columns resulted into higher resistance and displacement capacity, as well as smaller lateral resistance degradation. The response of the model was determined by storey mechanism with predominant shear behaviour of the walls and failure mechanism of the same type as in the case of individual confined masonry walls. Adequate seismic behaviour of this particular masonry structural type can be expected under the condition that the buildings are built as confined masonry system with limited number of stories.
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Seismic Response of URM Walls Strengthened with FRP Reinforced Coating
Key Engineering Materials, 2017Co-Authors: Petra Triller, Miha Tomaževič, Matija GamsAbstract:A set of individual URM walls as well as an assemblage of a three-storey URM hollow clay block masonry structure composed of two shear- and two cross-walls have been tested in original and strengthened state. As a method of strengthening, the coating of the walls, consisting of glass fiber reinforced polymer (GFRP) grid laid in fiber reinforced cementitious mortar matrix (sometimes called textile reinforced mortar), anchored to the walls with glass fiber anchors, has been used. All specimens were subjected to Constant Vertical Load simulating the effect of gravity Loads and cyclic horizontal displacements with step-wise increased amplitudes, induced either at the top of the walls or at the floor levels of the assemblage, simulating the effect of seismic Loads.The observed behaviour and failure mechanisms were of the shear type. The results show that by the application of FRP reinforced coatings, the seismic performance of URM structures can be significantly improved. As the results of experiments indicate, the energy dissipation, displacement capacity and shear resistance of URM increase substantially. In this regard, adequate anchoring of coating to the masonry and into the r.c. floor structures is essential.