000004993 001__ 4993
000004993 005__ 20141120140002.0
000004993 04107 $$aeng
000004993 046__ $$k2008-06-25
000004993 100__ $$aCafarella, F.
000004993 24500 $$aA MODEL FOR THE CORRELATION STRUCTURE OF THE RANDOM OUT-OF-FLATNESS IMPERFECTION OF THE PLATES

000004993 24630 $$n4.$$pProceedings of the 4th International ASRANet Colloquium
000004993 260__ $$bASRANet Ltd., 2008
000004993 506__ $$arestricted
000004993 520__ $$2eng$$aStructural reliability assessment requires accurate, realistic specifications of the stochastic properties of both the geometrical and mechanical uncertainties inherent in the system. For thin-walled structures, the most important factor determining the response variability is random deviation from the ideal shape: appropriate models of the configuration defects are therefore sought. For the plates of bridge and ship’s plating even today only very little information is available on the initial bowing in statistical terms, while theoretical approaches to the imperfection modelling appear quite arbitrary.
 The paper presents an analytical derivation of a second-moment stochastic model of the out-of-flatness imperfection of rectangular thin plates, closely fitting with the causal intervention of the manufacturing steps: (i) cutting from an indefinite, initially bent, sheet; (ii) best fitting at a specific member position; (iii) continuous welding to the boundary elements, with concomitant uneven heating and cooling. Via a mechanical-mathematical statement of the relations between the construction stages and the mid-surface warping, we reconstruct the analytical expression for the overall imperfection profile, which appears as the linear superposition of many contributions, that depend on a small number influencing factors. We use this representation to determine the first and second-order statistics of the non-homogeneous random field of the lack-of-flatness. In particular, we obtain the explicit format of the autocorrelation function, in terms of the stochastic properties of the “mother” sheet curvature tensor and of fastening and welding parameters.
 The achieved result is a deeper insight into the main features of the plate’s geometrical imperfection and a sort of correlation template, useful for evaluating other a priori assumed theoretical models. 

000004993 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000004993 653__ $$a

000004993 7112_ $$a4th International ASRANet Colloquium$$cAthens (GR)$$d2008-06-25 / 2008-06-27$$gASRANet4
000004993 720__ $$aCafarella, F.$$iBraconi, A.
000004993 8560_ $$ffischerc@itam.cas.cz
000004993 8564_ $$s388982$$uhttps://invenio.itam.cas.cz/record/4993/files/031_Cafarella,_F.pdf$$yOriginal version of the author's contribution as presented on CD, paper No. 31.
000004993 962__ $$r4967
000004993 980__ $$aPAPER