Search results for " Indentation"
showing 7 items of 7 documents
Experimental and numerical analysis of aluminum-aluminum bolted joints subject to an indentation process
2015
Abstract The increasing interest of the industry (especially automotive, aviation and marine) in the fastener joints (riveted, bolted, etc.) between metallic materials, has re-opened the study on the possibility to improve the performance of the drilled structure using plastic deformation processes. Indentation process, performed before the drilling operation, creates circumferential compression stresses around the hole which increase significantly the mechanical performance of the drilled structures. In this paper, static and the fatigue performances of aluminum–aluminum (AW 6082-T6) single-lap bolted joints are studied. In particular, the study compares the mechanical strength of only dri…
Investigation on the behaviour of fully thermoplastic composite sandwich beams under concentrated loads
2009
The recent development of new low cost manufacturing processes adopting thermoplastic matrices in the production of structural long fibre reinforced laminates is fostering an increasing interest towards this class of materials. The automotive sector in particular is attracted by the high energy absorbing, damage tolerance performances and manufacturing and recycling potentials of structural thermoplastic composites. In this study a number of fully thermoplastic sandwich beams have been manufactured in order to investigate flexural and shear rigidity performances as well as the indentation behavior under static concentrated loads.
ANALISI DEL COMPORTAMENTO AD INDENTAZIONE IN TRAVI SANDWICH IN COMPOSITO CON ANIMA IN SCHIUMA POLIMERICA
2010
Nel presente lavoro si propone una estensione dei modelli basati sulla teoria delle travi vincolate su una fondazione cedevole di tipo Winkler per lo studio del comportamento ad indentazione di travi sandwich in schiuma polimerica sollecitate da carichi concentrati. L’approccio proposto è in grado di considerare schiume polimeriche aventi comportamento a compressione di tipo non lineare. Sono derivate soluzioni analitiche in forma chiusa della curva di indentazione per anime in schiuma polimerica il cui comportamento a compressione è approssimabile con un andamento bi-lineare. In tal modo è possibile considerare comportamenti di softening o hardening della schiuma nel tratto post-elastico. …
Effect of Cold Working and Ring Indentation on Fatigue Life of Aluminum Alloy Specimens
2013
The article deals with the fatigue life of plates with hole made of aluminum alloy. Specifically, the combined effect of cold working expansion and ring indentation on improved fatigue life performance was investigated. Multiple fatigue tests were performed to determine the cycles to failure and the corresponding W¨ ohler diagram. Experimental results were compared with those of nontreated specimens. The conclusion was that cold working expansion and indentation create a delay on crack formation and fatigue failure.
Indentation of rigidly supported sandwich beams with foam cores exhibiting non-linear compressive behaviour.
2011
A generalized analytical approach to investigate the indentation of sandwich beams under concentrated loads is presented, based on the Winkler foundation theory. A segment-wise model is implemented to the case of fully backed sandwich beams with polymeric foam cores exhibiting generic non-linear compressive behaviours. Closed-form analytical solutions of the indentation curve are obtained for simplified foam compression behaviours: elastic-perfectly-plastic, bilinear and bilinear-perfectly-plastic. Analytical predictions are compared with experimental data from sandwiches employing foam cores with peculiar non-linear behaviours. The proposed models are found to give a better match of the e…
Investigation on the indentation behavior of sandwich beams using crushable and hyperelastic foam cores
2010
In this work the indentation behaviour of sandwich beams is studied adopting the classical approach representing the core material as a Winkler-type foundation. It is shown how most of the proposed theories can be derived from a general fourth order linear differential equation expressing the equilibrium of the indented beam skin. Different assumptions on the supporting boundary constraints and materials constitutive behaviour, lead to simplifications of the general equation and to the prediction of different indentation features. An extension of the Segment-Wise approach recently proposed in the literature is in particular presented with potential to better simulate foam cores with markedl…
Cutting performance and indentation behaviour of diamond films on Co-cemented tungsten carbide
2000
Abstract Diamond films were grown by Hot Filament Chemical Vapour Deposition (HFCVD) on differently pretreated ISO-grade K10 cemented carbide (WC-5.8 wt.%Co) cutting inserts. Etching with diluted HNO3 and surface roughening by Murakami's reagent were used as substrate pretreatments. The adhesion of the films was evaluated by indentation tests. In order to obtain a reliable estimation of the adhesion by the slope of the crack radius–indentation load curves, a careful SEM measurement of the crack lengths was performed. Bare and diamond-coated cutting inserts were used for turning tests of Al2O3-reinforced aluminum alloy. The adhesion levels obtained from the indentation curves correlated well…