0000000000137940
AUTHOR
Marianna Zito
Analisi del comportamento flessionale del legno attraverso la interferometria Speckle
Nel lavoro vengono presentati i risultati di uno studio sperimentale effettuato sul comportamento flessionale di due differenti essenze di legno: l’abete rosso ed il ciliegio. L’analisi viene effettuata sottoponendo il provino al test di flessione a quattro punti ed utilizzando la interferometria speckle, una tecnica di misura non a contatto ed a campo intero, che consente di ottenere i campi di spostamento e di deformazione sulla superficie del provino. Al fine di mettere in evidenza le peculiarità del comportamento flessionale del legno i risultati ottenuti vengono confrontati con quelli di un provino di Plexiglas nelle stesse condizioni. Tale confronto conferma la complessità del comport…
Shakedown Boundary of Limited Ductility Structures Accounting for Buckling
A formulation devoted to the determination of the borderline between the elastic/plastic shakedown domains and the incremental/instantaneous collapse zones of the Bree diagram for elastic perfectly plastic structures is proposed. In particular, reference will be made to truss structures and the actions will be given as a combination of mechanical fixed loads and mechanical perfect cyclic loads. The borderline between the above cited domains is determined by solving a search problem consisting into a sequence of maximum fixed load multiplier problems for assigned values of the cyclic load multiplier. In order to take into account suitable limits related to the structure ductility features, s…
Shakedown design of trusses accounting for buckling
Shakedown design of trusses accounting for buckling.
Optimal design of circular plates according to different criteria
Optimal design of circular plates according to different criteria.
How preconditioning and pretensioning of grafts used in ACLigaments surgical reconstruction are influenced by their mechanical time-dependent characteristics: Can we optimize their initial loading state?
Abstract Purpose Consensus about a pre-implant preparation protocol adaptable to any graft used in Anterior Cruciate Ligament reconstruction is still lacking. In fact, there is not agreement on reliable metrics that consider both specific graft dimensional characteristics, such as its diameter, and the inherent properties of its constitutive material, i.e. ligaments or tendons. Aim of the present study was to investigate and propose the applied engineering stress as a possible metrics. Methods Preconditioning and pretensioning protocol involved groups of grafts with different section (10 or 32 mm2) and materials (i.e. human patellar and hamstring tendons, and synthetic grafts). A 140 N load…
Il principio di gerarchia delle resistenze capacity design
The devastating effects generated by earthquakes occurred in different parts of the world have attract at a major interest in Earthquake Engineering. This branch of Structural Engineering studies the response and capacity of structural systems subjected to seismic actions, and develops design and prediction methods aimed at achieving adequate safety standards in presence of seismic events. A strategy used for the seismic prediction of RC structures, based on the capacity design of structural elements is the "hierarchy of strengths" (HS) principle. The paper shows how a proper use of the HS capacity design method can be included within the seismic design of RC structures achieving high level…
DUTTILITÀ STRUTTURALE DI OPERE IN CALCESTRUZZO ARMATO
Based on the new national territory seismic classification and on the current antiseismic regulations, the study and implementation of seismic-resistant structures, with sufficient capacity to plastic deformation to dissipate the seismic energy incoming, is crucial nowaday. This paper therefore addresses the study of ductility property of structures which can be obtained through appropriate deformation capacity of materials, sections and structural elements.
Some considerations in support of solid propulsion for space debris disposal.
Some considerations on the use of solid rocket motors for space debris disposal are presented. From the synthesis of a de-orbit sample mission and a tradeoff study on costs and benefits, a solid propellant unit for end-of-life missions and debris in-space disposal missions is evaluated. The enhanced operation flexibility, the propellant development and an advanced ignition concept granting multiple and independent firing capability of a new solid propulsion concept are discussed.
Elastic/plastic shakedown load boundary determination accounting for limited ductility structures
The problem related to the determination of the borderline between elastic/plastic shakedown and incremental/instantaneous collapse domains in the Bree diagramfor elastic perfectly plastic structures subkected to a combination of fixed and perfect cyclic load is studied. The relevant boundary is determined taking into account suitable limits related to the structures ductility features. In particular, basing on a special bounding theorem, it is possible to introduce appropriate boundary constraints on chosen measure of the plastic strains occurring at the end of the transient phase of the structural response
CRITICAL ANALYSIS OF SHORELINE LOCALIZATION METHODS BY MEANS OF AERIAL OR SATELLITE IMAGERY ON MEDITERRANEAN SANDY BEACHES
Shoreline localization is fundamental for designing and planning shore protection works as well as for managing and monitoring various anthropic activities along the coast. The sea-land boundary, however, changes continually with time because of waves and tides, which makes the shoreline detection complex and dubious and the boundary line finally assumed can only be conventional. In the last few decades the use of several geomorphologic indicators has been proposed, such as the berm above sea level, the groundwater exit point, historic high tide levels, etc., but the aim has not been achieved yet. Among the methods used, analysis of aerial and satellite imagery is common, in particular when…