Search results for "cost"
showing 10 items of 5421 documents
NUMERICAL-EXPERIMENTAL METHOD FOR THE ANALYSIS OF RESIDUAL STRESSES IN COLD-EXPANDED HOLES
2012
Hole cold expansion is a technique widely used to improve the fatigue life of components with holes, e.g. bolted or riveted joints. As it has been demonstrated in literature by analytical, numerical and experimental analyses carried out by several authors, the compressive residual stresses introduced by the hole cold expansion have a beneficial influence on both the static and the fatigue strength of the treated component, because they reduce significantly the typical stress peaks around the hole due to stress concentration. In the literature, various analyses of the residual stresses introduced by the hole cold expansion have been performed by using several methods such as X-ray diffractio…
Measuring Inaccessible Residual Stresses Using Multiple Methods and Superposition
2010
The traditional contour method maps a single component of residual stress by cutting a body carefully in two and measuring the contour of the cut surface. The cut also exposes previously inaccessible regions of the body to residual stress measurement using a variety of other techniques, but the stresses have been changed by the relaxation after cutting. In this paper, it is shown that superposition of stresses measured post-cutting with results from the contour method analysis can determine the original (pre-cut) residual stresses. The general superposition theory using Bueckner’s principle is developed and limitations are discussed. The procedure is experimentally demonstrated by determini…
Innovative user defined density profile approach to fsw of aluminium foam
2007
Metallic foams are one of the most exciting materials in the world of mechanical industry due to their reduced mass and the good mechanical, thermal and acoustic characteristics. Consequently, their application, is increasing day by day even with the important drawbacks that reduce their suitability and diffusion such as high manufacturing cost and difficulty in processing. An innovative approach is outlined in this paper that enables the production of complex shapes taking advantage of deformation processing and friction stir welding (FSW). The aim is to create customized tailored manufactured parts. The cellular construction of foams makes this approach rather challenging as the cell wall…
Tanta/δέδωκεν: Quando la retorica assume forma e vigore di legge
2012
In riguardo alla genesi delle costituzioni Tanta e dedoken di Giustiniano (a. 533), prefatorie ai Digesta, l’autore si sofferma sulla retorica della traduzione indagandone le modalità e gli intendimenti, basandosi soprattutto sul 21 prescelto come campione significativo. Oltre alla conferma che dedoken costituisca il testo-fonte e Tanta il testo-versione, si avvalora il convincimento che Triboniano sia l’autore della versione/revisione, mentre dedoken dovrebbe rappresentare soprattutto un prodotto degli adiutores che stavano a disposizione del magister sacri palatii.
Speckle Interferometry Analysis of Full-bending Behavior of GFRP Pultruded Material
2016
Abstract The use of Glass Fiber Reinforced Polymer materials (GFRP) has increased in the last years even among civil structural engineering due to their high specific strength, lightweight and excellent corrosion resistance. With application of the pultrusion method, the manufacture of large-scale profiles with various cross-section forms became potentially possible with relatively low costs. Usually two different technological approaches are available to realize the element: in the first one a mat-roving-mat sequence is adopted, in the second one only roving is present. Continuous filament mat (CFM, fibers distributed randomly in all directions) is often used to build up laminate thickness…
Experimental application of digital image correlation for the tensile characterization of basalt FRCM composites
2021
Abstract Composites made with inorganic matrix, namely fabric reinforced cementitious mortar (FRCM) composites are becoming widespread as strengthening materials for existing masonry structures. These composites are made of a dry grid of fibres embedded in an inorganic matrix. FRCMs can be considered a valid alternative to traditional organic composites such as fibre reinforced polymers (FRPs) because of their better compatibility with the masonry support. This work presents an experimental study for the tensile characterization of a basalt fabric reinforced cementitious mortar (BFRCM) composite. Tensile tests were carried out on coupons reinforced with one, two or three layers of grid to i…
Experimental assessment of the shield-to-salt-fog properties of basalt and glass fiber reinforced composites in cork core sandwich panels applications
2018
Abstract In this paper, the effect of salt-fog exposition on the mechanical behavior of sandwich panels having cork agglomerate core was investigated. In particular, the aim of this research work is to assess the shield function of unidirectional basalt and E-glass reinforced polymer on the aging and failure mechanism of the core when such class of material are destined to operate in hostile environments (e.g., marine environment). To do this, the manufactured sandwich panels were exposed up to 60 days to salt-fog environment, according to ASTM B 117 standard. Unaged and aged specimens were analyzed through three point bending tests after aging time of 10, 25 and 60 days. Digital Image Corr…
Il Filtro Integrale Auto-Regressivo Continuo (I-ARC) per l’Analisi di Strutture Esposte al Vento
2010
In questo studio viene proposto un metodo per la rappresentazione di processi aleatori Gaussiani e stazionari, utile a modellare la turbolenza della velocità del vento, introducendo la versione integrale del modello auto-regressivo discreto già proposto in precedenza. La rappresentazione di un processo aleatorio di assegnata funzione di correlazione viene condotta integrando un’equazione integro-differenziale in cui viene coinvolto un nucleo, che rappresenta la memoria del processo, in presenza di un rumore bianco Gaussiano. La soluzione dell’equazione rappresenta un campione del processo aleatorio della turbolenza della velocità del vento. E’ stato mostrato che il modello I-ARC fornisce, n…
Damage and plasticity at the interfaces in composite materials and structures
2009
Abstract The structural behavior at the interface between two surfaces of ductile, brittle or quasi-brittle materials is studied by a new analytical elastoplastic damaging model. The model is developed in the framework of a thermodynamically consistent theory. The Helmholtz free energy is written to predict the materials’ hardening or softening. An isotropic damage is considered and the possible effects of dilatancy are taken into account including non-associative flow rules. The interface laws are presented both in a rate and a discrete incremental form. The analytical formulation is then implemented into a finite element code and two structural members are studied to validate the model. T…
The UN in the Lab
2013
We consider two alternatives to inaction for governments combating terrorism, which we term Deterrence and Prevention. Deterrence – investing in resources that reduce the impact of an attack – generates a negative externality to other governments, making their countries a more attractive objective for terrorists, while Prevention – investing in resources that reduce the ability of the terrorist organization to mount an attack – creates a positive externality by reducing the overall threat of terrorism for all. Due to the structure of this interaction, countries can benefit from coordination of policy choices, and international institutions (such as the UN) can be utilized to facilitate coor…