Search results for "SIMULATION"
showing 10 items of 5095 documents
The role of coatings in controlling the cutting process when turning with coated indexable inserts
1998
Abstract This paper is concerned with the variations in the specific cutting pressure and the tool–chip interface temperature that occur when machining a medium carbon steel and an austenitic stainless steel with TiC-, TiC/TiN- and TiC/Al2O3/TiN- coated inserts. Extensive experimental studies involving the cutting force and the interface temperature were performed. A standard thermocouple embedded in the workpiece was used to determine the cutting temperature. Two new parameters were introduced in order to compare both the mechanical and thermal loadings of the tool–chip contact for coated flat-faced and grooved inserts. Some optimal coating structures for high speed machining of these stee…
Friction and wear properties of titanium and oxidised titanium in dry sliding against hardened C45 steel
2004
Abstract The aim of the paper is to present the results of conformal pin-on-disc tribological tests concerning the hard oxidised zone created in superficial layer of a titanium specimen sliding against the hardened to a hardness of 690 HV carbon C45 steel counterspecimen. Tribological testing was carried out at room temperature and at unlubricated conditions. After tests the structures and chemical compositions of the wear debris and worn surfaces were a subject of SEM and X-ray investigations. In comparison with the baseline the technical quality titanium/C45 steel couple, the wear and lifetime performance of the oxidised titanium/steel C45couple was markedly superior. Dominant wear debris…
Frontiers in molecular simulation of solvated ions, molecules and interfaces.
2020
This themed collection is a collection of articles on frontiers in molecular simulation of solvated ions, molecules and interfaces.
Laser-induced damage in cold-sprayed composite coatings
2011
International audience; Ag-Ni composite coatings were achieved using the cold spray process. In this work, two blends were sprayed to lead to coatings with different mechanical properties, which corresponded to either a fine or a coarse microstructure. These coatings were studied using SEM and X-ray microtomography (XMT) to determine the best coating quality through characterization of particle-to-particle bonding. The fine microstructure showed better properties than the coarse microstructure. To avoid time-consuming characterization techniques such as SEM and XMT, an innovative laser characterization test was developed. The principle of this test is based on the thermal shock-induced by a…
A local chemical potential approach within the variable charge method formalism
2008
A new and computationally efficient implementation of the variable charge method of Streitz and Mintmire (1994 Phys. Rev. B 50 11996) is presented. In particular a local chemical potential approach that optimizes the charge on only those atoms expected to be ionic is developed. By doing so, the charge fluctuation problem experienced in regions far from any oxygen is solved, leading to a linear minimization problem of the electrostatic energy. In the dilute oxygen limit, such an approach can lead to at least an order of magnitude saving in computation.
Turbulence structures over irregular rough surfaces
2010
Turbulent flow in a channel with irregular two-dimensional rough surfaces is analysed through wall-resolving large eddy simulation (LES). Both walls of the channel are roughened through the superimposition of sinusoidal functions having random amplitude and four different wavelengths. The downward shift of the velocity profile in the log region due to the roughness, known as roughness function, is well captured in the simulations. The spanwise and wall-normal turbulence intensities are found to increase with the roughness height, while the streamwise component decreases. The analysis of the Reynolds stress anisotropy tensor highlights a tendency towards isotropisation, confirmed by the vort…
Numerical simulations of the mechanical characteristics of glass fibre reinforced C-profiles
2006
A mechanical characterisation analysis on pultruded glass fibre reinforced C-shaped profiles, developed as modular construction elements to assemble fastening systems, such as doors, window frames and shutters is presented. The key idea is to perform the analysis, and all the related identification procedures of the material parameters, via a coupled approach, based on a limited number of standard laboratory tests and on the numerical finite element simulations of the same tests. The proposed approach allows one to identify all those material parameters which are difficult to detect, by means of simple laboratory experiments on specimens that are extracted from commercial products. It also …
Viscous fingering in magnetic fluids: numerical simulation of radial Hele–Shaw flow
1999
Abstract In this paper, the viscous fingering phenomena of the magnetic liquids in the case when the magnetic field is applied normally to the Hele–Shaw cell is investigated by the numerical simulation technique. It is shown that the magnetic field causes additional destabilization of the free interface arising at the air injection in the magnetic liquid. Here the peculiarities of the interface dynamics – inward motion of the tips of the fjords, the gyration radius dependence on the perimeter found by the numerical simulations are in good accordance with the experiments.
Numerical modelling of the electrochemical behaviour of 316L stainless steel based upon static and dynamic experimental microcapillary-based techniqu…
2008
Microcapillary-based techniques allow the selection and interrogation of single metallurgical sites and are therefore becoming increasingly popular to investigate the electrochemical behaviour of metallic phases and non-metallic heterogeneities in alloys. This study has been carried out to assess the differences between current measurements made using a 'closed' microcapillary system (the electrochemical microcell technique) with current measurements derived from a flowing 'open' microcapillary droplet cell (the scanning droplet cell). The experimental results were compared with calculations derived from a model system adopting a finite element approach. The corrosion system consists of fou…
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…