Search results for "DEFORMATIONS"
showing 10 items of 24 documents
Infinitesimal deformations of double covers of smooth algebraic varieties
2003
The goal of this paper is to give a method to compute the space of infinitesimal deformations of a double cover of a smooth algebraic variety. The space of all infinitesimal deformations has a representation as a direct sum of two subspaces. One is isomorphic to the space of simultaneous deformations of the branch locus and the base of the double covering. The second summand is the subspace of deformations of the double covering which induce trivial deformations of the branch divisor. The main result of the paper is a description of the effect of imposing singularities in the branch locus. As a special case we study deformations of Calabi--Yau threefolds which are non--singular models of do…
GEOMATIC TECHNIQUES FOR THE COLONNADE STRUCTURAL ANALYSIS OF THE HISTORICAL “ CHIARAMONTE STERI” BUILDING
2019
The monitoring of building structures has an increasingly important role in the engineering field, above all because they are concerned with the impact that such structures have in the area where they were built. Often, when walking through the old town centres, we realize just how obsolete and dangerous some buildings (even historic-cultural ones) are. The interest of some local governments in this problem has led, in the last few years, to the study and the trying out of measuring and monitoring methods which, quickly and at low cost, allow to define the extent of the deformation and the degrade in an accurate and reliable way. The Courtyard of “Palazzo Steri - Chiaramonte” is composed of…
Deformative Properties of Monotropic Plastic Foams with a Pronounced Strut-Like Strukture
1996
Disertācija angļu valodā, kopsavilkums arī latviešu un vācu valodā.
Simplified technique for constitutive analysis of SFRC
2014
Steel fibre reinforced concrete (SFRC) has become widespread material in areas such as underground shotcrete structures and industrial floors. However, due to the absence of material models of SFRC reliable for numerical analysis, application fields of this material are still limited. Due to interaction of concrete with fibres, a cracked section is able to carry a significant portion of tensile stresses, called the residual stresses. In present practices, residual stresses used for strength, deflection and crack width analysis are quantified by means of standard tests. However, interpretation of these test results is based on approximation using empirically deduced relationships, adequacy o…
Limits of Sobolev homeomorphisms
2017
Let X; Y subset of R-2 be topologically equivalent bounded Lipschitz domains. We prove that weak and strong limits of homeomorphisms h: X (onto)-> Y in the Sobolev space W-1,W-p (X, R-2), p >= 2; are the same. As an application, we establish the existence of 2D-traction free minimal deformations for fairly general energy integrals. Peer reviewed
Comparison between topographic and photogrammetric techniques for deformation monitoring of the dome of the Massimo Theatre in Palermo
2012
This paper shows the first results of a study aimed at monitoring the deformations of the dome of the Massimo Theatre in Palermo caused by thermal dilatations, with the use of topographic and photogrammetric integrated techniques. Particularly, two robotic total stations and high precision digital photogrammetric systems were employed. In order to correlate the displacements of the rollers on which the steel structure of the dome rest with the thermal gradients, different thermal images were acquired by a thermal imaging camera. The main goal of the work was to compare the two techniques with reference to very small (submillimeter) deformation measurements. The obtained results show that th…
Monitoraggio delle deformazioni della cupola del Teatro Massimo di Palermo con l’impiego di tecniche topografiche e fotogrammetriche integrate.
2012
L’articolo riporta i primi risultati di uno studio finalizzato al monitoraggio delle deformazioni della cupola del Teatro Massimo di Palermo provocate dalle dilatazioni termiche, con l’impiego di tecniche topografiche e fotogrammetriche integrate. In particolare, sono state utilizzate due stazioni totali robotizzate e sistemi di fotogrammetria digitale di elevata precisione. Per correlare gli spostamenti dei carrelli sui quali poggia la struttura in acciaio della cupola con i gradienti termici, sono state acquisite immagini termiche diversificate. L’obiettivo principale del lavoro consisteva nel confronto delle due tecniche di rilievo in relazione a misure di deformazione di entità molto ri…
Reliable measures of plastic deformations for elastic plastic structures in shakedown conditions
2020
A new formulation for evaluating reliable measures of the plastic deformations occurring in the transient phase of a structure in shakedown conditions is proposed. The structure is thought as constituted by elastic perfectly plastic material and subjected to a combination of fixed and cyclic loads. The proposed formulation consists in the search for the optimal plastic strain field that minimize a suitable objective function defining a strain energy measure related to the plastic strains at the shakedown limit. The typical self-stress field can be obtained as the elastic structural response to an assigned plastic strain field respecting appropriate ductility limits for the material. Without…
Isotropic p-harmonic systems in 2D Jacobian estimates and univalent solutions
2016
The core result of this paper is an inequality (rather tricky) for the Jacobian determinant of solutions of nonlinear elliptic systems in the plane. The model case is the isotropic (rotationally invariant) p-harmonic system ...
Serviceability of segmental concrete arch-frame bridges built by cantilevering
2013
The evaluation of the safety degree in service life for a segmental prestressed concrete bridge built by the cantilever method presents different aspects related to strength, deformability, durability and to effects of time-dependent phenomena as creep and shrinkage. The case-study of a prestressed concrete frame bridge with inclined piers is presented, built by cantilevering, with precast segments. By considering the fundamental items of design and construction stages, the implications due to the arch effect in this static scheme are investigated, with respect to an equivalent bridge with a final scheme of continuous girder on vertical piers. The birth of a significant value of axial force…