The Experts below are selected from a list of 39978 Experts worldwide ranked by ideXlab platform
Gaetano Manfredi - One of the best experts on this subject based on the ideXlab platform.
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shake table tests on standard and innovative temporary partition walls
Earthquake Engineering & Structural Dynamics, 2017Co-Authors: Crescenzo Petrone, Gennaro Magliulo, Gaetano ManfrediAbstract:Summary Shake table tests are performed on temporary internal partitions for office buildings. Four different Specimens are Tested. A steel frame is designed to exhibit relative displacements which typically occur at a given story of ordinary buildings. Four different partition walls are Tested simultaneously for each Specimen typology. This allows investigating the influence of an innovative device on the seismic performance of the Tested components. The innovative device avoids the unhooking of the panels from the supporting studs. Several shake table tests are performed subjecting the Specimens to interstory drift ratios up to 1.57%. Both the hysteretic curves and the natural frequency trend highlight that the partitions do not contribute to the lateral stiffness of the test setup. The damping ratio increases after the partition walls are installed within the test frame, causing a beneficial effect in the dynamic response. Minor damage state occurs for interstory drift ratio (IDR) in the range 0.41–0.65% in standard Specimens, whereas moderate and major damage states are attained for IDR in the range 0.51–0.95%. Significant increase of collapse IDR is recorded with the introduction of the innovative device, up to IDR larger than 1.45%. It can be therefore concluded that a simple innovative device is defined, which significantly improves the seismic performance of the Tested Specimen. Copyright © 2017 John Wiley & Sons, Ltd.
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out of plane seismic performance of plasterboard partition walls via quasi static tests
Bulletin of the New Zealand National Society for Earthquake Engineering, 2016Co-Authors: Crescenzo Petrone, Gennaro Magliulo, Pauline Lopez, Gaetano ManfrediAbstract:Internal partitions, as many nonstructural components, should be subjected to a careful and rational seismic design, as for structural elements. A quasi-static test campaign aimed at the evaluation of the out-of-plane seismic performance of Siniat plasterboard internal partitions with steel studs is conducted according to FEMA 461 testing protocol. Four tall, i.e. 5 m high, Specimens are selected from the range of internal partition developed in Europe by Siniat, a leading supplier of plasterboard components in Europe. Under the specified testing protocol, a significant nonlinear pinched behavior of the Tested Specimen is observed. The pinched behavior is caused by the damage in the screwed connections, whose cyclic behavior is strongly degrading. Both stiffness and strength of the Specimens are significantly influenced by the board typology and the amount of screwed connections. Finally, it is concluded that Eurocodes significantly underestimate the resisting bending moment of the Tested Specimens.
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shake table tests for the seismic assessment of hollow brick internal partitions
Engineering Structures, 2014Co-Authors: Crescenzo Petrone, Gennaro Magliulo, Gaetano ManfrediAbstract:The collapse of hollow brick internal partitions is one of the most widely reported nonstructural damage after an earthquake, especially in the European area. Full-scale experimental tests on standard hollow brick partitions are described in the paper. In particular, bidirectional shaking table tests are performed in order to investigate the seismic performance of hollow brick partitions, subjecting the partition simultaneously to interstorey relative displacements in their own plane and accelerations in the out of plane direction. A steel test frame is properly defined in order to simulate the seismic effects at a generic building storey. A set of five couples of accelerograms are selected matching the target response spectrum provided by the U.S. code for nonstructural components in order to investigate a wide range of seismic input. Three damage states are considered in this study and correlated to an engineering demand parameter, i.e. the interstorey drift ratio, through the use of a damage scheme. The Tested Specimen exhibits significant damage for 0.3% interstorey drift and extensive damage for drift close to 1%. The correlation between the dynamic characteristics of the test setup, in terms of damping ratio and natural frequency, and the recorded damage is shown.
Anna Hojná - One of the best experts on this subject based on the ideXlab platform.
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microstructural investigation of lme crack initiated in ferritic martensitic steel t91 loaded in liquid lead bismuth eutectic at 300 c
Materials, 2018Co-Authors: Patricie Halodová, Jan Lorinčík, Anna HojnáAbstract:Liquid lead-bismuth eutectic (LBE) is one of the candidate materials for advanced nuclear systems. The structural materials used in contact with LBE are selected according to the resistance to liquid metal corrosion, irradiation embrittlement, and compatibility with the coolant. However, simultaneous presence of mechanical strain and LBE environment can induce liquid metal embrittlement (LME) in these materials. In this study, a Specimen from candidate ferritic-martensitic steel T91 was Tested by Constant Extension Rate Tensile (CERT) test exposed to PbBi environment with oxygen concentration 6 × 10-6 wt % at 300 °C up to rupture. Post-test examination using scanning electron microscopy (SEM) showed a deep crack indicating features of LME in the plastic strained region of the Tested Specimen. Further investigations focused on characterization of the fracture path and microstructure determination using focused ion beam (FIB) and energy dispersive X-ray spectrometry/electron backscatter diffraction (EDX/EBSD). This observation revealed that the dominant LME failure mode of the observed crack is translath or transgranular and the crack stopped at the high-angle grain boundary. The role of oxides in the crack initiation is discussed.
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Microstructural Investigation of LME Crack Initiated in Ferritic/Martensitic Steel T91 Loaded in Liquid Lead-Bismuth Eutectic at 300 °C
MDPI AG, 2018Co-Authors: Patricie Halodová, Jan Lorinčík, Anna HojnáAbstract:Liquid lead-bismuth eutectic (LBE) is one of the candidate materials for advanced nuclear systems. The structural materials used in contact with LBE are selected according to the resistance to liquid metal corrosion, irradiation embrittlement, and compatibility with the coolant. However, simultaneous presence of mechanical strain and LBE environment can induce liquid metal embrittlement (LME) in these materials. In this study, a Specimen from candidate ferritic-martensitic steel T91 was Tested by Constant Extension Rate Tensile (CERT) test exposed to PbBi environment with oxygen concentration 6 × 10−6 wt % at 300 °C up to rupture. Post-test examination using scanning electron microscopy (SEM) showed a deep crack indicating features of LME in the plastic strained region of the Tested Specimen. Further investigations focused on characterization of the fracture path and microstructure determination using focused ion beam (FIB) and energy dispersive X-ray spectrometry/electron backscatter diffraction (EDX/EBSD). This observation revealed that the dominant LME failure mode of the observed crack is translath or transgranular and the crack stopped at the high-angle grain boundary. The role of oxides in the crack initiation is discussed
Crescenzo Petrone - One of the best experts on this subject based on the ideXlab platform.
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shake table tests on standard and innovative temporary partition walls
Earthquake Engineering & Structural Dynamics, 2017Co-Authors: Crescenzo Petrone, Gennaro Magliulo, Gaetano ManfrediAbstract:Summary Shake table tests are performed on temporary internal partitions for office buildings. Four different Specimens are Tested. A steel frame is designed to exhibit relative displacements which typically occur at a given story of ordinary buildings. Four different partition walls are Tested simultaneously for each Specimen typology. This allows investigating the influence of an innovative device on the seismic performance of the Tested components. The innovative device avoids the unhooking of the panels from the supporting studs. Several shake table tests are performed subjecting the Specimens to interstory drift ratios up to 1.57%. Both the hysteretic curves and the natural frequency trend highlight that the partitions do not contribute to the lateral stiffness of the test setup. The damping ratio increases after the partition walls are installed within the test frame, causing a beneficial effect in the dynamic response. Minor damage state occurs for interstory drift ratio (IDR) in the range 0.41–0.65% in standard Specimens, whereas moderate and major damage states are attained for IDR in the range 0.51–0.95%. Significant increase of collapse IDR is recorded with the introduction of the innovative device, up to IDR larger than 1.45%. It can be therefore concluded that a simple innovative device is defined, which significantly improves the seismic performance of the Tested Specimen. Copyright © 2017 John Wiley & Sons, Ltd.
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out of plane seismic performance of plasterboard partition walls via quasi static tests
Bulletin of the New Zealand National Society for Earthquake Engineering, 2016Co-Authors: Crescenzo Petrone, Gennaro Magliulo, Pauline Lopez, Gaetano ManfrediAbstract:Internal partitions, as many nonstructural components, should be subjected to a careful and rational seismic design, as for structural elements. A quasi-static test campaign aimed at the evaluation of the out-of-plane seismic performance of Siniat plasterboard internal partitions with steel studs is conducted according to FEMA 461 testing protocol. Four tall, i.e. 5 m high, Specimens are selected from the range of internal partition developed in Europe by Siniat, a leading supplier of plasterboard components in Europe. Under the specified testing protocol, a significant nonlinear pinched behavior of the Tested Specimen is observed. The pinched behavior is caused by the damage in the screwed connections, whose cyclic behavior is strongly degrading. Both stiffness and strength of the Specimens are significantly influenced by the board typology and the amount of screwed connections. Finally, it is concluded that Eurocodes significantly underestimate the resisting bending moment of the Tested Specimens.
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shake table tests for the seismic assessment of hollow brick internal partitions
Engineering Structures, 2014Co-Authors: Crescenzo Petrone, Gennaro Magliulo, Gaetano ManfrediAbstract:The collapse of hollow brick internal partitions is one of the most widely reported nonstructural damage after an earthquake, especially in the European area. Full-scale experimental tests on standard hollow brick partitions are described in the paper. In particular, bidirectional shaking table tests are performed in order to investigate the seismic performance of hollow brick partitions, subjecting the partition simultaneously to interstorey relative displacements in their own plane and accelerations in the out of plane direction. A steel test frame is properly defined in order to simulate the seismic effects at a generic building storey. A set of five couples of accelerograms are selected matching the target response spectrum provided by the U.S. code for nonstructural components in order to investigate a wide range of seismic input. Three damage states are considered in this study and correlated to an engineering demand parameter, i.e. the interstorey drift ratio, through the use of a damage scheme. The Tested Specimen exhibits significant damage for 0.3% interstorey drift and extensive damage for drift close to 1%. The correlation between the dynamic characteristics of the test setup, in terms of damping ratio and natural frequency, and the recorded damage is shown.
Giovanni Magenes - One of the best experts on this subject based on the ideXlab platform.
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Shaking table test on a full scale URM cavity wall building
Bulletin of Earthquake Engineering, 2017Co-Authors: Francesco Graziotti, U. Tomassetti, S. Kallioras, Andrea Penna, Giovanni MagenesAbstract:A shaking table test on a two-storey full scale unreinforced masonry (URM) building was performed at the EUCENTRE laboratory within a comprehensive research programme on the seismic vulnerability of the existing Dutch URM structures. The building Specimen was meant to represent the end-unit of a terraced house, built with cavity walls and without any particular seismic design or detailing. Cavity walls are usually composed of an inner loadbearing leaf and an outer leaf having aesthetic and weather-protection functions. In the Tested Specimen, the loadbearing masonry was composed of calcium silicate bricks, sustaining two reinforced concrete floors. A pitched timber roof was supported by two gable walls. The veneer was made of clay bricks connected to the inner masonry by means of metallic ties, as seen in common construction practice. An incremental dynamic test was carried out up to the near-collapse limit state of the Specimen. The input motions were selected to be consistent with the characteristics of induced seismicity ground motions. The article describes the characteristics of the building and presents the results obtained during the material characterization and the shaking table tests, illustrating the response of the structure, the damage mechanism and its evolution during the experimental phases. All the processed data are freely available upon request (see http://www.eucentre.it/nam-project ).
M Kathirselvam - One of the best experts on this subject based on the ideXlab platform.
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evaluation of mechanical properties of banana and sisal fiber reinforced epoxy composites influence of glass fiber hybridization
Materials & Design, 2014Co-Authors: V P Arthanarieswaran, A Kumaravel, M KathirselvamAbstract:Abstract In this work, the effect of glass fiber hybridization with the randomly oriented natural fibers has been analyzed. The banana (B), sisal (S) fibers were chopped and woven E-glass (G) synthetic fibers were reinforced with epoxy matrix. Nine different kinds of laminates were prepared in the following stacking sequence of B, S, BS, G/B/G, G/S/G, G/BS/G, G/B/G/B/G, G/S/G/S/G and G/BS/G/BS/G. Mechanical properties like tensile strength, flexural strength and impact strength were evaluated and compared. Interfacial analysis was also carried out with the help of Scanning Electron Microscope (SEM) to study the micro structural behavior of the Tested Specimen. It was observed that the addition of two and three layer of glass fiber can improve the tensile strength by a factor of 2.34 and 4.13 respectively. The flexural properties were enhanced on banana–sisal fiber with two layers of glass fibers rather than three layers and the laminate with sisal and three glass ply offers better impact strength.
