Search results for "LFW"
showing 10 items of 15 documents
Nitrogen broadening of SF6 transitions in the nu3 band
2001
Abstract Nitrogen induced pressure-broadened halfwidths of a number of ν3 transitions of SF6 are calculated using the complex Robert–Bonamy (CRB) formalism. The calculations are made at 200, 250, 296 and 350 K and the temperature dependence of the halfwidths are determined. The intermolecular potential is taken as a sum of the leading electrostatic and Lennard-Jones [6] , [7] , [8] , [9] , [10] , [11] , [12] atom–atom components. The dynamics of the collision process are correct to second order in time. The calculated halfwidths are used to simulate the ν3 spectrum, which is compared to a simulation made using the HITRAN96 halfwidths and measurements made at the Universite Pierre et Marie C…
On the fem simulation of FSW and LFW operations
2010
Effect of process parameters in Linear Friction Welding Processes of Steels
2011
An Illustration to Ælfric’s De temporibus anni in Ælfwine’s Prayerbook
2020
L'articolo esamina un diagramma contenuto nel manoscritto London, British Library, Cotton Titus D.xxvii+xxvi, generalmente noto come 'Ælfwine’s Prayerbook'. Il diagramma, che si trova al fol. 21 v , è stato in genere interpretato come una rota incompleta, o delle maree o dei venti (dal momento che contiene solo 4 dei canonici 12 venti della tradizione scientifica medievale). Una analisi comparativa e dettagliata delle caratteristiche del diagramma, tuttavia, mostra come l'ipotesi della rota delle maree sia da rigettare in favore della teoria di una rota ventorum. Inoltre, l'analisi dei testi contenuti nel manoscritto rivela una stretta connessione tra il diagramma e il De temporibus anni di…
Experimental and Numerical Analysis of Microstructure Evolution during Linear Friction Welding of Ti6Al4V
2015
Abstract Linear Friction Welding (LFW) is a solid state welding process used to joint bulk components. In the paper, an experimental and numerical study on LFW of Ti6Al4V titanium alloy is presented. A laboratory designed LFW machine has been used to weld the specimens with different contact pressure and oscillation frequency. The joint microstructure has been experimentally observed with SEM and EDS. A dedicated numerical model, able to predict temperature, strain and strain rate distribution as well as the phase volume fraction evolution, has been utilized to predict the final microstructure in the welded parts. It was found that complete transformation of the alpha phase into beta phase …
Trasmissioni per sistemi di propulsione ibrida e Linear Friction Welding
2017
Trasmissioni per sistemi di propulsione ibrida. In tale ambito presentano interessanti caratteristiche e prestazioni, le trasmissioni a variazione continua del rapporto di tipo Power Split (PS-CVTs). La progettazione di tali trasmissioni può essere molto insidiosa a causa della notevole numero di opzioni possibili e della complessità costruttiva. Una vasta letteratura, sia sperimentale che teorica, si è occupata dell'analisi, dell'ottimizzazione e del controllo, di specifiche soluzioni costruttive. Tuttavia la selezione del layout è fondamentale e qualunque scelta aprioristica, a volte dettata solo dalla pratica, potrebbe portare a soluzioni sub-ottimali, nonostante il tempo e le risorse im…
Fundamental investigation on the mechanical behavior of weld seams
The solid state welding processes allow joints free from defects with reduced residual stresses and low distortion. However, such processes are generally characterized by a complex mechanical junction because of the particular material flow. Therefore, the design and optimization of the processes in which the solid bonding phenomenon occurs are difficult and requires a large number of tests. The purpose of this research is the description on the mechanical behavior of welded seams obtained through the friction stir welding (FSW) and linear friction welding (LFW) processes by analyzing the same phenomenon that occurs in both metallurgical processes, named the solid bonding phenomenon. The ai…
Numerical modelling of the linear friction welding process
2010
Linear friction welding (LFW) is a solid-state joining process applied to non-axisymmetric components. LFW involves joining of materials through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. In the present work the authors present a numerical model of the linear friction welding process of AISI 1045 parts. The numerical model allowed to highlight the process mechanics and the physical conditions which must be r…
Numerical simulation of linear fiction welding (LFW) processes
2011
Solid state welding processes are becoming increasingly important due to a large number of advantages related to joining ''unweldable'' materials and in particular light weight alloys. Linear friction welding (LFW) has been used successfully to bond non-axisymmetric components of a range of materials including titanium alloys, steels, aluminum alloys, nickel, copper, and also dissimilar material combinations. The technique is useful in the research of quality of the joints and in reducing costs of components and parts of the aeronautic and automotive industries.LFW involves parts to be welded through the relative reciprocating motion of two components under an axial force. In such process t…
Una más de la familia. Au pairs atrapadas entre el capital humano y la economía moral
2018
In contemporary societies we are witnessing an expansion of the messages of human capital. These messages have as their central dimension idea of the self-entrepreneur, which implies a deepening in the logic of activation, while blurring the wage relations. In this scenario, young people with university degrees are becoming a favourite target in the offensive of human capital. The penetration of these human capital messages can be seen in the discourses of young university students who have been forced to leave the country during the crisis. In the present text we approach the discourses of young women who came out as au pairs. The characteristics of this figure place it in a space halfway …