Search results for "Welding"
showing 10 items of 317 documents
Analisi numerico-sperimentale per la determinazione delle tensioni residue in un giunto saldato
2013
La durata di un componente dipende dall’interazione tra le caratteristiche meccaniche del materiale con cui è costruito e gli sforzi a cui esso è sottoposto. Per la determinazione dello stato tensionale agente, oltre agli sforzi dovuti ai carichi imposti durante l’esercizio, è necessario conoscere accuratamente gli stati tensionali residui derivanti dal processo di produzione. Generalmente, le tensioni residue sono indesiderate poiché possono essere di entità elevata e tale da ridurre la resistenza complessiva del componente meccanico. Un aspetto particolarmente insidioso delle tensioni residue è che la loro presenza viene generalmente riconosciuta solo dopo il verificarsi di un malfunziona…
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…
Study Regarding Process of the Electrical Discharge Machining with Magnetic Activation of the Welded Joints of some Materials High Alloy Steel
2021
The scientific paper presents an extensive research on modeling and optimizing the technological parameters of the process for processing by processing electric discharges with massive electrode with and without magnetic activation. Scientific research is based on real data collected from the process of electrical discharges performed on various samples extracted from areas of welded joints of metal components made of high alloy steel. The processing of experimental data was performed both classically and actively, especially the method of the central factorial experiment composed of orthogonal and rotary. The process parameters that were initially modeled and subsequently optimized were ba…
Joining by plastic deformation
2013
Abstract As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating opportunities to design new products through joining dissimilar materials. This paper aims to provide an overview of the state of the art in such joining processes, including cold welding, friction stir welding, self-pierce riveting, mechanical clinching and joining by forming. The paper includes description of the mechanism of joint formation, and analysis of joint performance and applicability.
The Continuous Extrusion Process CONFORM: a full 3D Thermal and Mechanical Analysis
2000
The principle of the Conform extrusion process is based on the action of a rotating wheel that drags and push the feed material by means of the frictional force existing between them. The Conform process has several advantages over the traditional extrusion processes. The preheating phase may be neglected, so that furnaces for heating are not necessary; furthermore, the product is continuous and welding phase of the billets is not required. The influence of three operative parameters, die geometry, velocity and die cooling rate, has been analysed in this paper by means of an “outranking approach” able to give precious indications for the assessment of the process.
Studio delle prestazioni di giunzioni incollate ibride (Strength evaluation of structural hybrid bonded joints)
2013
The idea of “hybrid joints” arises from the need of joining together materials, producing a tough, stiff and lightweight joint. The core concept is: use two different joining techniques, with the aim to increase the strength and gather the advantages of each technique, reducing the drawbacks. In this work hybrid joints consist in joints produced with two different kinds of joining techniques: one of them being adhesive bonding and the other being one among Resistance Spot Welding, Pop Riveting, Clinching, Self Piercing Riveting. The performance of hybrid joints are compared with those of traditional joints for the single lap joint geometry, for different geometric (plates thickness, pitch o…
Influence of correlations between stresses on calculated fatigue life of machine elements
1996
The correlation between components of the random stress tensor and its influence on the calculated fatigue life of machine elements were analysed. Three covariance matrices of components of biaxial stress state were considered. They were determined from measurements of strains in an element of a vibrating screen for aggregate, in the back wall of a bus, and in a welded element of excavator fittings. Calculations were made according to four criteria of multiaxial random fatigue. Cycles were counted with the rainflow method, and damage was cumulated with the Palmgren-Miner hypothesis. It was found that convariances of random stress state components strongly influence the calculated fatigue li…
A Neural Network Based Approach for the Design of FSW Processes
2009
Friction Stir Welding (FSW) is an energy efficient and environmentally "friendly" welding process. The parts are welded together in a solid-state joining process at a temperature below the melting point of the workpiece material under a combination of extruding and forging. This technology has been successfully used to join materials that are difficult-to-weld or ‘unweldable’ by fusion welding methods. In the paper a neural network was set up and trained in order to predict the final grain size in the transverse section of a FSW butt joint of aluminum alloys. What is more, due to the relationship between the extension of the “material zones” and the joint resistance, the AI tool was able to…
A Laboratory Scale Equipment to Relieve Force and Pressure in Cold Extrusion of Lead Hollow Components
2008
Nowadays, many researchers are involved in studies aimed to the explanation of some peculiar aspects regarding manufacturing processes. In this paper, an experimental campaign was carried out in order to reproduce tube extrusion starting from a cylindrical billet. In particular, the development of a proper equipment is presented: the aim was to measure both the total load, by using the testing machine load cell, and the local pressure value on the porthole. The latter task was carried out performing a proper system based on the use of a small load-cell. The tube was extruded with a good surface quality and the external area does not show any welding line evidence. Pure Lead was used for the…
Review of push-out and shear response of hybrid steel-trussed concrete beams
2018
The hybrid steel trussed concrete beams examined in the present study are comprised of two principal components, i.e., a steel joist with inclined rebars, realized in industry, which is welded to a smooth steel plate and then embedded within the concrete cast in situ. The paper presents first the state of the art on laboratory tests and analytical modeling of the steel-to-concrete stress transfer mechanism investigated by push-out tests. Next, the most relevant scientific contributions currently available in the technical literature regarding experimental investigation on actual shear behavior are summarized and discussed. Lastly codes and analytical models are reviewed.