Search results for "Lamination."

Bending effect on the risk for delamination at the reinforcement/matrix interface of 3D woven fabric composite using a shell-like RVE

2012

This paper presents a computational homogenisation-based technique for flexural effects in textile reinforced composite planar shells. An homogenisation procedure is used for the in-plane and the out-of-plane behaviour of three-dimensional woven composite shells, taking the in-plane periodicity of the material into account while relaxing any periodicity tying in the thickness direction. Several types of damage (matrix or reinforcement cracking, delamination, …) can appear in a composite material. In this paper, material non-linear computations are used to assess the importance of bending on the risk for delamination at the reinforcement/matrix interface. The normal and tangential stresses a…

Markers of the last interglacial sea level high stand along the coast of Italy: Tectonic implications.

2006

A compilation of the Marine Isotope Substage (MIS) 5.5 high stand (similar to 125Ka) sites spanning the coastline of Italy allows a picture of the vertical displacement pattern affecting the Central Mediterranean coasts since the Late Pleistocene to be drawn. For each of the 246 listed sites, the accurate elevation of the high stand is defined through well-known markers. Coupled with a refilled age assessment locally Supported by new radiometric dating, these markers provide robust constraints oil deformation. Significant alongshore differences in site elevation between + 175 and - 125 m a.s.l. resulted from the interplay of regional and local tectonic processes, including faulting and volc…

Cyclic Delamination Analysis: Experimental and Cohesive-Frictional interface Finite Element Modelling

2011

ELEMENTO D’INTERFACCIA PER LA SIMULAZIONE DI PROCESSI DI DANNEGGIAMENTO IN MODO MISTO I/II NEI MATERIALI COMPOSITI E NELLE GIUNZIONI ADESIVE

2018

E’ stato sviluppato un elemento coesivo in grado di connettere e simulare la crescita delle cricche tra sottodomini di elementi finiti modellati in modo indipendente con mesh incompatibili. L'approccio si basa su funzioni di penalità e presenta numerosi vantaggi rispetto alle tecniche FEM convenzionali nelle simulazioni di delaminazione. Il più importante è la possibilità di rilasciare una porzione dell'interfaccia più piccola della lunghezza degli elementi finiti locali. Pertanto la delaminazione non avanza solamente rilasciando i nodi del modello FEM, una limitazione comune a molti metodi trovati in letteratura. È stato anche sviluppato un nuovo approccio per modellare la crescita delle c…

A penalty-based interface technology

2009

Modern computers have enabled engineers to perform large scale analyses of complex structures like entire aircrafts, automobiles, and ships. One issue that arises often is the need to perform a unified analysis of a structural assembly using sub-structural models created independently. These sub-structural models are frequently designed by different engineers, thus they are likely to be incompatible at their interfaces. Finite element interface technology has been developed to facilitate the joining of independently modeled substructures. Here an effective and robust interface element is presented. This method has been developed using penalty constraints and allows computationally efficient…

The effect of the through-the-thickness compressive stress on mode II interlaminar fracture toughness

2017

The effect of through-the-thickness compressive stress on the mode II interlaminar fracture toughness is investigated experimentally and replicated numerically. The modified Transverse Crack Tensile specimen recently proposed by the authors is used, together with an experimental device designed to apply a constant transverse compressive stress on the surface of the specimen. Experiments are conducted using IM7/8552 specimens for different compressive stresses, ranging from 0 to 100 MPa, covering all the practical applications commonly encountered in the aeronautical industry (e.g., tightened filled holes or bolted joints). It is shown that the mode II interlaminar fracture toughness increas…

Mode I fracture toughness behaviour of epoxy resincarbon fiber composites cured by ionising radiation

2012

In this work Mode I fracture toughness behavior of Electron Beam cured unidirectional CFRP laminates is investigated by means of standardized Double Cantilever Beam (DCB) tests. A matrix system, comprising a DGEBA epoxy monomer and a typical initiator of cationic polymerization, was used and panel samples assembled by hand lay-up. Curing was achieved by 20 to 40 minutes irradiation on a pulsed 10 MeV Electron Beam accelerator. One batch of resin was also mixed with 10 phr of a PES thermoplastic monomer in order to enhance the matrix toughness. The influence of fibre-matrix adhesion, matrix toughening and matrix crosslinking density on the mode I delamination behavior have been investigated …

Experimental evaluation of through-the-thickness stress distribution in transverse crack tension test samples

2015

Transverse Crack Tension (TCT) samples represent an alternative to End Notched Flexure configurations for the characterization of pure mode II fracture toughness of Fibre Reinforced Polymer composites. TCT is supposed to reproduce a pure Mode II failure mechanism while avoiding the frictional energy dissipation between the flanks of a starter crack. The TCT geometry is that of a unidirectional tensile sample where a number of embedded plies, centered on the middle plane, are cut in the transverse fibres direction. The tensile loading should then activate four symmetric fronts of mode II delamination from the transverse cut tips. The present work describes the implementation of two full fiel…

L’altro e le sue immagini. Note sul soliloquio

2016

The paper examines the soliloquy activity by means of some conceptual artifacts borrowed from three research programs: 1) the Enunciative Narratology of René Rivara; 2) the Theory of Predicative and Enunciative Operations of Antoine Culioli; 3) the Dialogical Syntax of John Du Bois. It is composed by three parts. In the first one, we discuss some definitions of soliloquy. The second part is devoted to the analysis of some aspects of such activity with particular reference to some language operations: a) laminations of voice; b) construction of the (interior) co-enunciator. Finally, in the last part we examine some questions that remain open in the debate on soliloquy activity.

Solvent-Induced Delamination of a Multifunctional Two Dimensional Coordination Polymer

2012

A coordination polymer is fully exfoliated by solvent-assisted interaction only. The soft-delamination process results from the structure of the starting material, which shows a layered structure with weak layer-to-layer interactions and cavities with the ability to locate several solvents in an unselective way. These results represent a significant step forward towards the production of structurally designed one-molecule thick 2D materials with tailored physico-chemical properties.