1,721,068 research outputs found
Determinazione del filtro relativo alla pressione del vento modellata come un processo aleatorio non gaussiano
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Non-gaussian approach for stochastic analysis of offshore structures
No full textAn approach that is able to obtain the stochastic characteristics in terms of, stochastic momen.ts of a SDOF system excited by loads due to a fluid-structure mteraction is presented. In This approach the fluid horizontal velocity is considered as a filtered white noise, and the actual load expression is replaced by a Thirddegree polynomial of this velocity. The tools needed to p.romptly obtain the filters parameters and the equations governing the response moments are also presented; in particular, if the structure is sufficiently stiff, It is shown that these equations do not need any closure scheme III order to be solved. © ASCE
New investigations in the North-East quarter of Motya. The archaic cemetery and Building J
No full textIn June 2013 the University of Palermo excavations on Motya were resumed.
The main goal of the new project is to investigate the north-east quarter of
the Phoenician settlement and its urban development since the time of its
foundation. Two main areas of excavation were opened. In the early
cemetery sixteen cremation burials of the archaic period were uncovered.
The most striking discoveries, never attested before, were a tomb containing
Hellenistic offerings, and the occurrence of archaic infant cremations. The
second excavation was conducted east of Zone K in Building J, which is
characterized by its use of a fine ‘pier and rubble’ construction technique.
Two rooms have been partially cleared: one with a pillared doorway and a
plastered mud-brick bench, the other containing a stone vat in the centre. A
thick destruction layer, containing among other things bronze arrow-heads,
is clear evidence of the siege and fall of Motya in 397 BC
65. Tell Shiyukh Tahtani
No full textThis volume presents the long history of Syria through a jouney of the most important and recently-excavated archaeological sites. The sites cover over 1.8 million years and all regions in Syria; 110 academics have contributed information on 103 excavations for this volume. Based on these contributions the volume offers a detailed summary of the history of Syria, a history as important as any in terms of the development of human society. It is hoped that this knowledge will offer not only an increased understanding of the country but also act as a deterrent to the destruction of Syrian cultural heritage and facilitate the protection of Syrian sites
Identificazione dinamica di una struttura complessa in muratura attraverso rumore ambientale: problematiche e strategie
No full textThe effect of local random defects on the response of pantographic sheets
No full textIn the last decade, pantographic structures have attracted the attention of many scientists because of their exotic mechanical behaviors. Despite several studies conducted on this field, probabilistic remarks cannot be found in the literature. This paper aims to fill this gap by providing the first stochastic study on pantographic sheets. A new simplified procedure is proposed to investigate the effects of local axial, bending, and torsional defects on their mechanical responses. The suggested approach involves a generalization of an existing theoretical result and the use of Monte Carlo simulations to derive probability density functions, mean values, standard deviations, and coefficients of variation of the random kinematic unknowns. It, surely, can be applied to any mechanical system. The achieved results allow stating that pantographic structures are not particularly affected by local random defects thanks to their redundant and complex microstructures. Moreover, the interdependencies among their substructures, beams, and pivots, make it not easy to find the positions of defects that minimize, once fixed all the other things, the randomness of the mechanical responses. A minimization problem should be solved and a work on this topic is in progress
Simplified Formulation of Solution for Beams on Winkler Foundation allowing Discontinuities due to Loads and Constraints
No full textThe paper discusses material for a course in Structural Mechanics addressed to second-Year Civil Engineering students. The response of beams on a Winkler foundation characterized by discontinuities in both the displacements (deflections and/or slopes) and forces (internal forces and/or loads) is studied. In particular, a simplified formulation for the solution of the discontinuous differential equation governing this problem is given. In some cases, the formulation is able to give the exact solution in a closed form. This is made possible through the use of the generalized functions, such as the well-known Unit Step Function and the Dirac delta function. The cases of discontinuities due to both loads and constraints are treated. The method of presentation of this material is by lecture. The time required to cover the arguments is 2 to 3 hours with 1 to 2 hours of revision. The lecture must be given after the classical beam theory has been covered. The new formulation presented in this paper will demonstrate that some particular aspects of mathematician analysis many he used to advantage to simplify an important problem in structural mechanics
Probability-Based Approach for Inverse Stochastic Structural Problems
No full textThe topic of this paper is related to the inverse stochastic mechanic problems, in which it is necessary to estimate the unknown mechanical and geometrical random quantities of the structures once the external loads and displacement responses are probabilistically known. In particular, in this work, a probability-based approach for inverse stochastic problems, working directly in terms of probability density functions (PDFs), is presented. This approach has been possible thanks to the application of the probability transformation method (PTM), which has been recently introduced for the solution of many stochastic analysis problems
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