ANALISI TEORICO-SPERIMENTALE DI UNA GRID SHELL A MAGLIE VORONOI

RIASSUNTO ANALITICO La presente tesi si inserisce all’interno di un’attività di ricerca, intrapresa dal gruppo di lavoro GRIFF, riguardante un innovativo pattern di discretizzazione di superfici continue free form di tipo poligonale a maglie Voronoi. A partire dai risultati di tale lavoro di ricerca, l’obiettivo è quello di approfondirne alcuni aspetti tramite l’applicazione del remeshing allo studio di una superficie complessa. I risultati dell’analisi numerica sulla grid shell sono stati confrontati con le risposte sperimentali di un modello fisico in grande scala, realizzato presso il Laboratorio Ufficiale per le Esperienze sui Materiali da Costruzione. Un ulteriore passo è stato quello di costruire una rappresentazione analitica a partire dalla valutazione del comportamento sperimentale del prototipo, desunto da prove statiche e dinamiche. Le prime realizzate con l’apposizione di pesi a incrementi e conseguente valutazione degli spostamenti di punti sensibili; le seconde, di tipo classico con forzante impulsiva e modale operativa, finalizzate alla stima dei parametri del sistema. Laboriosa è risultata la valutazione dello stato in opera del prototipo e delle differenze con il modello analitico ‘perfetto’; tali aspetti hanno condizionato fortemente il regime comportamentale dell’oggetto esaminato. ABSTRACT This thesis is part of a reserch activity of working group GRIFF concerning an innovative tessellation for continous free-form surfaces creating a polygonal hex-dominant Voronoi meshes. The objective of work is to further investigate some aspects in the study of a complex surface through the application of GRIFF remeshing algorithm. The results of numerical analysis on the grid shell are compared with the experimental response of a large scale physical replica, carried out at the Laboratorio Ufficiale per le Esperienze sui Materiali da Costruzione. A further step is to build an analytical representation starting from the evaluation of the experimental behavior of the prototype, derived from static and dynamic tests. The first are made by affixing weights in increments in some structural nodes and, at the same time, measuring sensitive points deflections from undeformed configuration; the second are led both in the classical way with impulsive excitation and following operational analysis, are finalized to estimate modal parameters of the system. The evaluation of physical model condition and its variance between analytical perfect model have strongly affected the behavior of the examined object

Experimental static and dynamic tests on a large-scale free-form Voronoi grid shell mock-up in comparison with finite-element method results

Abstract Grid shells supporting transparent or opaque panels are largely used to cover long-spanned spaces because of their lightness, the easy setup, and economy. This paper presents the results of experimental static and dynamic investigations carried out on a large-scale free-form grid shell mock-up, whose geometry descended from an innovative Voronoi polygonal pattern. Accompanying finite-element method (FEM) simulations followed. To these purposes, a four-step procedure was adopted: (1) a perfect FEM model was analyzed; (2) using the modal shapes scaled by measuring the mock-up, a deformed unloaded geometry was built, which took into account the defects caused by the assembly phase; (3) experimental static tests were executed by affixing weights to the mock-up, and a simplified representative FEM model was calibrated, choosing the nodes stiffness and the material properties as parameters; and (4) modal identification was performed through operational modal analysis and impulsive tests, and then, a simplified FEM dynamical model was calibrated. Due to the high deformability of the mock-up, only a symmetric load case configuration was adopted

A new seismic isolation device based on tribological smooth rocking (TROCKSISD)

In the field of seismic risk mitigation of art objects, an innovative isolation device is here illus-trated. The device, called TROCKSISD (Tribological ROCKing Seismic ISolation Device), couples multiple components to dissipate energy and control smooth rocking: spherical con-tact surfaces with frictional layers, elastic springs ensuring re-centering and viscous elastic dampers. The conceptual idea is described and the equations of motions of the two degrees of freedom system presented, discussing the performance-based structural behaviour and the mechanical/geometric parameters involved. Moreover, dynamic analyses are performed to understand the role of the frictional layers with respect to the peripheral dampers in the miti-gation of motion under spectrum compatible seismic records. The results in terms of rocking spectra are presented and comparisons with the equivalent single degree of freedom system without the isolation device are made

DANNI DA PARLATORIA OLEAE COLV. SULLE OLIVE DA TAVOLA IN PUGLIA

L'autore riporta i risultati di una indagine riguardante i danni causati in Puglia da Parlatoria oleae Colv. (Horn. Coccidae-Diaspini) sui frutti di olivo, segnatamente su quelli da tavola da consumare allo stato verde. Il danno consiste, essenzialmente, in un deprezzamento commerciale del prodotto. The author reports the results of an investigation carried aut in Apulia concerning the damage caused to olive fruit, especially to those consumed directly as green product, by Parlatoria oleae Colv. (Horn. Coccidae-Diaspini). The damage affects essentially the commerciai value o the product

CONTRIBUTO ALLA CONOSCENZA DELLA BIOLOGIA DELLA TIGNOLA DELL'OLIVO, PRAYS OLEAE (BERNARD) LESNE (LEPIDOPTERA, HYPONOMEUTIDAE)

The author reports some data collected on four Olive cv. («S. Agostino», « Oliva di Spagna " Coratina » and Ogliarola ) concerning the biology of the carpophaga generation of the Olive moth (Prays oleae [Bernard] Lesne) (Lepidoptera-Hyponomeutidae) in Apulia. Of particular interest is the capability of some larvae of this generation to feed exclusively on mesocarp (pulp). This observation leads the author to the conclusion that larvae of this generation might complete their life cycle feeding on a single part of the fruit (mesocarp) besides, as is commonly known, being able to feed on ali parts of the fruit (mesocarp, endocarp, ecc.). In the area where these observations have been carried out, the phenomenon seems to be more intense on the cv. Coratina on which, in case of severe attacks, 6% of the fruit, with peaks of 20%, harbored larvae which had fed exclusively on mesocarp.  L'Autore dopo aver riassunto alcuni dati biologici sulla generazione carpofaga della Tignola dell'olivo (Prays oleae Bernard  Lesne, Lepidoptera-Hyponomeutidae su quattro cv. di olivo coltivate in Puglia ( S. Agostino, Oliva di Spagna, Coratina e Ogliarola ) descrive il comportamento di alcune larve della stessa generazione che si nutrono a totale carico del mesocarpo (polpa) arrivando alla conclusione che le larve stesse possono completare il loro accrescimento nutrendosi di una sola parte (mesocarpo) o di tutte le parti della drupa (mesocarpo, endocarpo, ecc.). Il fenomeno interessa soprattutto, nella zona studiata, la cv. Coratina sulla quale le larve vissute a carico del mesocarpo rappresentano, in annate di forte intestazione da Tignola, il 6% delle olive colpite, con punte del 20%.

Measuring Outcomes of Occupational Therapy Facilitated in Natural Settings with Young Children

To date, there is limited evidence to support the effectiveness of Occupational Therapy (OT) services delivered outside in nature. This study explored the benefits of OT intervention in Natural Settings (NS) for children by examining development in the areas of self-regulation, social skills, sensory processing, confidence, and motor skills. A quantitative, quasi-experimental pre-test/post-test design was used in this study. Researchers partnered with a local outpatient OT clinic that offers an 8-week outdoor program. Seven children and their parents were recruited and participated in the study. A modified version of the COPM and two BOT-2 subtests, along with a novel log climb measure were used to track changes among participants. Group results are presented, as well as two case vignettes that capture individual progress of two participants. Results showed that performance and satisfaction ratings, as well as scores from the balance and catching subtests from the BOT-2 generally improved from pre-test to post-test after the eight weeks. Additionally, the speed, efficiency, and quality of movement data gathered from the novel log climb generally improved by the end of the 8-week period. Overall, though there are several limitations to the study, the data showed improvement in key areas across parent reports and motor skill measures

Measuring Outcomes of Occupational Therapy Facilitated in Natural Settings with Young Children

To date, there is limited evidence to support the effectiveness of Occupational Therapy (OT) services delivered outside in nature. This study explored the benefits of OT intervention in Natural Settings (NS) for children by examining development in the areas of self-regulation, social skills, sensory processing, confidence, and motor skills. A quantitative, quasi-experimental pre-test/post-test design was used in this study. Researchers partnered with a local outpatient OT clinic that offers an 8-week outdoor program. Seven children and their parents were recruited and participated in the study. A modified version of the COPM and two BOT-2 subtests, along with a novel log climb measure were used to track changes among participants. Results showed that performance and satisfaction ratings as well as scores from the balance and catching subtests from the BOT-2 generally improved from pre-test to post-test after the eight weeks. Additionally, the speed, efficiency and quality of movement data gathered from the novel log climb generally improved by the end of the 8-week period. Overall, though there are several limitations to the study, the data showed improvement in key areas across parent reports and motor skill measures.https://scholar.dominican.edu/occupational-therapy-student-research-posters/1003/thumbnail.jp

Automated generation of flat tileable patterns and 3D reduced model simulation

The computational fabrication community is developing an increasing interest in the use of patterned surfaces, which can be designed to show ornamental and unconventional aesthetics or to perform as a proper structural material with a wide range of features. Geometrically designing and controlling the deformation capabilities of these patterns in response to external stimuli is a complex task due to the large number of variables involved. This paper introduces a method for generating sets of tileable and exchangeable flat patterns as well as a model-reduction strategy that enables their mechanical simulation at interactive rates. This method is included in a design pipeline that aims to turn any general flat surface into a pattern tessellation, which is able to deform under a given loading scenario. To validate our approach, we apply it to different contexts, including real-scale 3D printed specimens, for which we compare our results with the ones provided by a ground-truth solver

Conception And Parametric Design Workflow For A Timber Large-Spanned Reversible Grid Shell To Shelter The Archaeological Site Of The Roman Shipwrecks In Pisa

Reciprocal structures or nexorade are composed by the assembling of groups of three or more beams mutually connected by mono-lateral T joints in a way that any relative movement is suppressed. This kind of structures can be easily built in relatively unprepared sites, dismantled, transported and re-used even by not specialized handcraft. For these reasons, reciprocal structures have been widely used in the past for military purposes, and nowadays they seem to satisfy very well the different requirements of a quick and temporary shelter of a large archaeological area when they are shaped as grid shells. This paper proposes the design of a reversible, reciprocal framed grid shell to shelter the archaeological site of the Roman Shipwrecks in Pisa. The structure must protect excavations and archaeologists from the weather and provide an easy access to visitors. Additionally, it must allow for easy disassembling and moving to another site. The design choices aim at optimizing both structural efficiency and esthetical qualities. A parametric workflow for both the form finding and the digital fabrication processes has been developed, and a prototype of accommodative steel T-joint for timber reciprocal beams has been realized. Finally, a model using CNC-cutting tested the structural feasibility of such a design approach

Distribuzione e parassiti di Aleurothrixus floccosus Mask. e Dialeurodes citri Ashm. (Hom. Aleyrodidae) su agrumi in Puglia

DISTRIBUTION AND PARASITES OF A/eurothrixus jloccosus MASK. AND Dia/eurodes citn· ASHM. (HOM.-ALEYRODIDAE) ON citrus SPP. IN APULIA (SOUTHERN ITALY) O n Citrus spp. in Apulia (soutern Italy) two species of Aleyrodidae (A/eurothrixus floccosus Mask . and Dia/eurodes citn· Ashm.) prove to be noxious; the territorial distribution and parasites have been investigated on citrus trees (orange, mandarin, algerian tangerine, lemon). A. floccosus, detected in 1985 , affected the entire province of Lecce and part of the province of Brindisi (about 4.000 Km2) in autumn of 1986. Ca/es noaki How., one of its parasites, introduced imo a citrus orchard (by a farmer) in 1985, was found 8 km away in the autumn of 1986. D. citn·proved to be more or less abundant in ali citrus orchards as was its parasite, Encarsia /ahorensis How., vhich destroyed up to 33% of its victims. Viene segnalata la presenza e verificata la distribuzione di A. floccosus Mask. e D. citri Ashm. nelle aree agrumicole pugliesi. Di essi viene riportata anche l'entità della parassitizzazione realizza- ta rispettivamente da C. noaki How. ed E. /ahorensis How. L'areale del D. citri comprende tutta la Puglia, mentre l'areale dell'A. floccosus è limitato alla provincia di Lecce e parte di quella di Brindisi, ma è in rapidissima espansione