Search results for " scienza delle costruzioni"
showing 10 items of 496 documents
Il metodo degli spostamenti nella formulazione simmetrica degli elementi di contorno
2000
Il metodo degli elementi di contorno nella sua versione simmetrica (SGBEM) sta assumendo un ruolo sempre più incisivo per la soluzione di vari problemi di ingegneria. Recentemente ci si è occupati di impiegare tale metodo a corpi bidimensionali piani costituiti da materiale aventi differenti proprietà fisiche attraverso una suddivisione in sottodomini denominati macroelementi.
Internal spring distribution for quasi brittle fracture via Symmetric Boundary Element Method
2009
Abstract In this paper the symmetric boundary element formulation is applied to the fracture mechanics problems for quasi brittle materials . The basic aim of the present work is the development and implementation of two discrete cohesive zone models using Symmetric Galerkin multi-zone Boundary Elements Method . The non-linearity at the process zone of the crack will be simulated through a discrete distribution of nodal springs whose generalized (or weighted) stiffnesses are obtainable by the cohesive forces and relative displacements modelling. This goal is reached coherently with the constitutive relation σ − Δ u that describes the interaction between mechanical and kinematical quantities…
A SGBEM approach for static shakedown analysis as CQO problem
2011
In this paper the shakedown static approach was rephrased by using the Symmetric Galerkin Boundary Element Method (SGBEM) for multidomain type problems. The present formulation utilizes the self-equilibrium stress equation, connecting the stresses at the Gauss points of each substructure (bem-e) to plastic strains, through a stiffness matrix (self-stress matrix), involving all the bem-elements of the discretized system. The optimization problem was solved by Conic Quadratic Optimization (CQO) and implemented using the Karnak.sGbem code coupled with MatLab. In order to prove the efficency of the proposed strategy, some numerical tests, in which the shakedown multiplier was checked by SGBEM e…
Tecniche di trasformazione di integrali di dominio in integrali di contorno nell'ambito del SBEM
2008
A modal approach for the evaluation of the response sensitivity of structural systems subjected to non-stationary random processes
2005
A method for the evaluation of the response sensitivity of both classically and non-classically damped discrete linear structural systems under stochastic actions is presented. The proposed approach requires the following items: (a) a suitable modal expansion of the response; (b) the derivation in analytical form of the equations governing the evolution of the derivatives of the response (the so-called sensitivity equations) with respect to the parameters that define the structural model; (c) an extensive use of the Kronecker algebra for determining the analytical expressions of the sensitivity of the structural response statistics to non-stationary random input processes. Moreover, a step-…
On the modern use of the bòvedas tabicadas
2009
The paper concerns the study of the so-called “bòvedas tabicadas” (i.e. thin vaults constituted by layers of “rasillas” suitably superimposed) based on the results obtained by specific experimental investigations effected on the material of which they are constituted as well as on a vault that is still working. In particular, aim of the present research is the implementation of a first analysis of the structure in its present configuration (often unusable), with the purpose to evaluate the real structure serviceability related to the prescribed intensity of the acting loads, and moreover the execution of a new second analysis of the same structure but suitably reinforced by placing further …
EFFECT OF SURFACE FINISH ON THE TENSILE BEHAVIOR OF DACRON© 360 WOVEN
2011
Nel presente lavoro vengono presentate alcune indagini sperimentali mirate alla caratterizzazione dell’effetto del trattamento superficiale sul comportamento costitutivo di un tessuto in Dacron© 360. Tale tessuto, largamente utilizzato nella realizzazione di vele, è ottenuto dalla tessitura di fili di polietilene tereftalato (PET) e presenta alcune peculiarità dovute al processo manifatturiero. Le prove di trazione realizzate evidenziano le caratteristiche di ortotropia del materiale e l’effetto del trattamento superficiale che si manifesta principalmente in un comportamento più rigido nella direzione dell’ordito ed in quella inclinata e in un aumento della resistenza ultima in tutte le dir…
Adhesive inter-laminar and cohesive inner-layer damage mechanisms for composite materials
2009
DUTTILITÀ STRUTTURALE DI OPERE IN CALCESTRUZZO ARMATO
2012
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.