Anindya Bhar

Plates are simple two-dimensional structural elements and main load bearing component in many applications. But frequently as needed, they are appended and strengthened with beam like stiffener components that are combined referred as stiffened plates. The stiffeners, by considerably increasing the bending stiffness of the plates, enable them to sustain high transverse loads with least material addition. Hence, accurate structural analysis of such stiffened plates, prior to their effective design, is of practical requirement to use them in the best possible way. The finite element method (FEM) being possibly the most versatile and robust amongst such numerical methods, is at the forefront of these researches, including the present one. Amongst the different modified versions of the FEM developed so far by the research community, the relatively recently developed Isogeometric FE analysis (IGA) method is being considered as one of the most promising. The IGA has the potential to integrate the computer aided design (CAD) and the FE analysis into a single platform / software by way of using common basis functions, besides increasing the analysis accuracy and efficiency.

Le piastre/pannelli sono i principali componenti portanti in molte applicazioni strutturali. Tali strutture vengono spesso aggiunte con travi/collinette/piastre/rigidi per ottenere una maggiore resistenza e ottimizzazione del peso e sono denominate piastre/gusci irrigiditi. Quindi l'analisi di tali strutture irrigidite di importanza pratica. A causa dell'indisponibilit di un modello analitico robusto per l'analisi di tali strutture, l'uso di un metodo numerico basato su computer come il metodo agli elementi finiti (FE) sembra essere l'unica opzione fattibile. Il presente libro tratteggia una panoramica sullo stato dell'arte esistente per l'analisi FE di tali lastre irrigidite. Inoltre, viene sviluppato un modello ad elementi finiti a piastre irrigidite pi efficiente, robusto e semplice e ne viene dimostrata l'accuratezza e l'efficienza per l'analisi dei compositi laminati e delle piastre irrigidite funzionalmente graduate di forma diversa e con diverse configurazioni di irrigidimento.

As placas/pain is s o os principais componentes de suporte de carga em muitas aplica es estruturais. Tais estruturas s o frequentemente anexadas com vigas/fresas/stiquetas para alcan ar uma maior resist ncia e optimiza o do peso e referidas como placas/pain is r gidos. Portanto, a an lise de tais estruturas r gidas de import ncia pr tica. Devido indisponibilidade de modelo anal tico robusto para an lise de tais estruturas, a utiliza o de m todo num rico baseado em computador, como o m todo dos Elementos Finitos (FE), parece ser a nica op o vi vel. O presente livro esbo a uma vis o geral sobre o estado da arte existente para a an lise de FE de tais placas enrijecidas. Al m disso, desenvolvido um modelo mais eficiente, robusto e simples de elementos finitos de placas r gidas e a sua precis o e efici ncia demonstrada para a an lise de placas r gidas laminadas compostas e funcionalmente graduadas de diferentes formas e configura o vari vel de endurecedor.

Platten/Paneele sind die wichtigsten tragenden Komponenten in vielen strukturellen Anwendungen. Solche Strukturen werden h ufig mit Tr gern/Rippen/Versteifungen versehen, um eine verbesserte Festigkeit und Gewichtsoptimierung zu erreichen, und werden als versteifte Platten/Schalen bezeichnet. Daher ist die Analyse solcher versteiften Strukturen von praktischer Bedeutung. Da kein robustes analytisches Modell f r die Analyse solcher Strukturen zur Verf gung steht, scheint der Einsatz computergest tzter numerischer Methoden wie der Finite-Elemente-Methode (FE) die einzig gangbare Option zu sein. Das vorliegende Buch skizziert einen berblick ber den bestehenden Stand der Technik f r die FE-Analyse solcher versteiften Platten. Dar ber hinaus wird ein effizienteres, robusteres und einfacheres Finite-Elemente-Modell f r versteiften Platten entwickelt und dessen Genauigkeit und Effizienz f r die Analyse von laminierten, zusammengesetzten und funktional abgestuften versteiften Platten unterschiedlicher Form und unterschiedlicher Versteifungskonfiguration demonstriert.

Les plaques/panneaux sont les principaux l ments porteurs dans de nombreuses applications structurelles. Ces structures sont souvent compl t es par des poutrelles, des nervures et des raidisseurs afin d'am liorer la r sistance et d'optimiser le poids, et sont appel es plaques et coques renforc es. L'analyse de ces structures raidies est donc d'une importance pratique. En raison de l'absence d'un mod le analytique robuste pour l'analyse de ces structures, l'utilisation d'une m thode num rique informatis e comme la m thode des l ments finis (EF) semble tre la seule option possible. Le pr sent ouvrage donne un aper u de l' tat actuel des connaissances en mati re d'analyse par l ments finis de ces plaques renforc es. En outre, un mod le d' l ments finis de plaques raidies plus efficace, robuste et simple est d velopp et sa pr cision et son efficacit sont d montr es pour l'analyse de plaques raidies composites lamin es et fonctionnellement gradu es de formes diff rentes et de configurations de raidisseurs variables.

Plyty/panele są gl wnymi elementami nośnymi w wielu zastosowaniach konstrukcyjnych. Takie konstrukcje są często lączone z belkami/żebrami/usztywnieniami w celu uzyskania większej wytrzymalości i optymalizacji wagi i określane są jako usztywnione plyty/panele. Tak więc analiza takich usztywnionych konstrukcji ma praktyczne znaczenie. Ze względu na niedostępnośc solidnego modelu analitycznego do analizy takich konstrukcji, zastosowanie komputerowej metody numerycznej, takiej jak metoda element w skończonych (MES), wydaje się byc jedyną wykonalną opcją. Niniejszy szkic książkowy zawiera przegląd aktualnego stanu techniki w zakresie analizy MES takich plyt usztywnionych. Ponadto, opracowano bardziej wydajny, wytrzymaly i prosty model element w skończonych z blach usztywnionych, kt rego dokladnośc i wydajnośc wykazano w przypadku analizy kompozyt w laminowanych i funkcjonalnie klasyfikowanych blach usztywnionych o r żnych ksztaltach i r żnej konfiguracji usztywnień.

Plate/panels are the main load bearing components in many structural applications. Such structures are frequently appended with beams/ribs/stiffeners to achieve enhanced strength and weight optimization and referred as stiffened plates/shells. So the analysis of such stiffened structures is of practical importance. Because of unavailability of robust analytical model for analysis of such structures, use of computer-based numerical method like the Finite Element (FE) method seems to be the only feasible option. The present book sketches an overview on the existing state of art for FE analysis of such stiffened plates. Further, a more efficient, robust and simple stiffened plate finite element model is developed and its accuracy and efficiency is demonstrated for analysis of laminated composite and functionally graded stiffened plates of different shape and varying stiffener configuration. A simple and efficient semi refined higher-order sheat deformation theory (SRHSDT7) and a novel least square of error (LSE) method of accurate transverse stress recovery technique for laminated composites are presented. The book may serve as a benchmark on FE analysis of stiffened plates in future.