Progetti di ricerca ingegneria delle strutture
Modelling, Analysis and DEsign of MOrphing SHElls. MADEMOSHE
Partecipating units:
University of Catania
University of Naples Federico II
University of Calabria
P.I. prof. Massimo CUOMO (UNICT)
Abstract of the project:
The research aims to develop a computational procedure for analysing and designing multistable compliant shells. Shape morphing systems, employed in several fields of engineering, are commonly realized with assemblage of rods and cables, that guarantee large flexibility in changing the configuration, but limited mechanical resistance. The use of shell for morphing system has several advantages: shells are efficient in sustaining external loads, and it is possible to take advantage of buckling for changing the configuration (snapping). However the design of morphing shells requires accurate non-linear analyses of the large deformations undergone by the system, including the prediction of buckling modes and bifurcation points, and a careful stress analysis for guaranteeing the serviceability of the design.
The project will develop along three directives. The first concerns the geometrical analysis of the shape changes undergone by the shell system. In order to allow morphing between several stable equilibrium configurations the shells must be endowed with a suitable state of prestress, that has to be induced during the forming process. Starting from an initial flat form, three mechanisms will be analysed for reaching the initial curved shape. Joining flat elements with cuts produce curved surfaces; these can be also obtained controlling the local metric of the sheet, introducing a pattern of locally bistable elements (dimples, anisotropic composite layers); a metamaterial sheet is so obtained, whose shape can be programmed by selectively activating the active inclusions. Linear or bending actuators, realized embedding in the shell rods that can undergo stretching or change of curvature, can produce the desired morphing. The phenomenon will be studied with direct and inverse analyses, that is, robust path following algorithms for predicting the changes of the configuration (direct method), and form-finding algorithms (inverse analysis) will be used. In this stage the actual material properties do not directly intervene in the analysis, but only the ratio between membrane and bending stiffness.
The second directive concerns the accurate analysis of the system for predicting all possible branching points, the deformation and the stress state, necessary for serviceability analysis. Dynamic analyses of the transition between the phase will also be performed. The third directive concerns the design of the morphing system. The algorithms developed in the previous WPs will be employed for optimizing the design by means of parametric models capable to assist the designer in selecting the proper forming and functioning technique, the activation pattern, and the proper material and geometry. Also the design of the actuating system will be object of the optimization analysis.
Finally, a proof of concept will be carried out with respect to a small scale sample, that will enable to validate the geometrical design tools developed in the project.
Accordo Tecnico di Attuazione dell'Accordo ex art 15 legge 7 agosto 1990 n. 241 tra il Consiglio Superiore dei Lavori Pubblici ed il Consorzio ReLUIS
L’Accordo Tecnico prevede la partecipazione di numerose Università italiane e ha come principale scopo l’applicazione e il miglioramento delle recenti Linee guida per la classificazione e gestione del rischio, la valutazione della sicurezza ed il monitoraggio dei ponti esistenti. L’unità di ricerca di Catania è attiva nel WP 2 (Applicazioni delle Linee Guida a tratte sperimentali) nell’applicazione delle Linee Guida su ponti dell’Autostrada A18 (Messina-Catania) e dell’Autostrada A19 (Catania-Palermo) e nella valutazione e modifica delle schede di ispezione visiva primaria previste al livello 1 delle Linee Guida. Inoltre, l’unità di ricerca contribuisce al WP 4 (Sperimentazione su componenti strutturali e/o speciali) nella proposta di modelli numerici e procedure di valutazione della capacità resistente di elementi in c.a. con armature longitudinali e trasversali corrose. L’Ente finanziatore è il Consiglio Superiore dei Lavori Pubblici per il tramite del Consorzio RELUIS. L’importo destinato all’unità di ricerca di Catania è di 100000,00 €. Coordinatore nazionale: Prof. E. Cosenza. Responsabile scientifico dell’unità di ricerca di Catania: Prof. P.P.Rossi. Altri componenti dell’unita di ricerca di Catania: Prof. E.M. Marino, Prof.ssa M. Bosco, Prof. N. Spinella, Ing. F. Barbagallo, Ing. A. Floridia e Ing. Dario Panarelli. Periodo di sviluppo: maggio 2021-dicembre 2024. https://www.reluis.it/csllpp-sperimentazione-delle-linee-guida-per-la-cl...