1,720,970 research outputs found
Numerical assessment of the impact behavior of honeycomb sandwich structures
No full textComposite sandwich structures are widely used in the high-performance applications where weight reduction is one of the most attractive design parameters. However, structural sandwich components have low resistance to out-of-plane impact due to the thin outer composite skins and the highly deformable cores. The present paper deals with a finite element study on the impact response of sandwich panels, obtained combining phenolic resin-based glass fiber reinforced plastics as skins and phenolic resin-impregnated aramid paper honeycomb structure (Nomex) as core. The numerical analysis has been performed using the LSDYNA software enabling to account for the main sandwich failure modes occurring during impact. The honeycomb core structure and composite skins have been modeled by means of solid and shell elements respectively. The properties of the finite element model have been calibrated on a series of experimental outcomes in order to achieve numerical parameters for both composite facesheet and orthotropic honeycomb material models. The major concerns are related to damage mechanisms, influence of strain-rate effects and energy absorbing capability. The model is validated using the results from experimental impact tests performed on different initial impact conditions. Good agreement was obtained between numerical and experimental results in terms of impact damage and force-displacement trend
Performance and damage assessment of 16th century St. Maria del Popolo church in Naples (Italy)
No full textExperimental characterization of strain rate effects and impact behaviour of phenolic sandwich structures
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Second World War damages of the architectural heritage: St. Maria del Popolo agli Incurabili church in Naples
No full textThe research concerns the case-study of the church of Santa Maria del Popolo into the historical Incurabili Hospital in Naples, seriously damaged during a bombing raid in 1943. The construction of a reinforced concrete trussed roof and floor above the main nave has caused serious structural problems and the church shows evident signs of deterioration today. The present situation offers the occasion to deep, in an interdisciplinary way and through historical sources, the delicate issue of the recent past strengthening operations realized with reinforced concrete that, associated with highly territorial seismicity, alarm about the condition of many historical buildings. In order to have a clear knowledge of the structural behavior of the church, assessing the actual in situ condition, a numerical FE analysis has been performed with the scope of evaluating the state of stress in the structural elements of the walls and of the roof, pointing out the structural deficiencies. The numerical damage assessment has been validated by means of comparisons with crack patterns. Providing a reliable model, it has been possible to fully simulate the behavior of historical structures when subjected to different and severe types of load, e.g. seismic loads.
The atructural assessment, together with the results of archival researches, brings the authors to reflect about the significance of post-war restorations and, consequently, of the church's main vulnerabilities
Thermoplastic composite structure for mass transit vehicle: design, computational engineering and experimental validation
No full textIn the present paper, a thermoplastic composite component of a mass transit vehicle, is designed using a complex mix of computational analyses and experimental testing. Among the currently available composite materials, Eglass fiber/polyetherimide (PEI) thermoplastic composite material is mainly considered for its inherently fire-retardant properties and in life cycle perspective. The thermoplastic composite panel is designed in order to satisfy AnsaldoBreda structural loading and performance requirements. The final configuration of the thermoplastic panel exhibits excellent weight saving of more 50% compared to the conventional aluminum panel
Structural behaviour of masonry panels strengthened with an innovative hemp fibre composite grid
No full textSustainability goals are essential driving principles for the development of innovative materials in the construction industry. Natural fibres represent an attractive alternative as reinforcing material due to both good mechanical properties and sustainability prerequisites. The present work investigates the shear behaviour of masonry panels strengthened with a mortar-based system reinforced with an innovative hemp fibre composite grid. The objective of the study is to assess the feasibility of using the proposed strengthening system for external retrofit of existing masonry walls and to compare its performances with typical retrofitting solutions. © 2015 Elsevier Ltd. All rights reserved
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