Search results for "Mod"
showing 10 items of 39605 documents
A numerical model for Wire integrity prediction in Friction Stir Extrusion of magnesium alloys
2017
Abstract A numerical model for the prediction of the wire quality produced by the novel direct machining chip recycling technique known as Friction Stir Extrusion (FSE) is presented. Wire microstructure and wire integrity have been predicted by embedding in the code the equations enabling the calculation of the Zener-Hollomon parameter as well as the W parameter of the Pivnik-Plata solid bonding criterion. The proposed model, developed for the AZ31 magnesium alloy using the commercial simulation package DEFORM, is 3D Lagrangian, thermo-mechanically coupled with visco-plastic material behavior. The model was first validated against experimental temperature measurements and then used to predi…
A new approach to simulate coating thickness in cold spray
2020
Abstract In the process of cold spray on complex components, the coating thickness is an important indicator to monitor and control. Current methods such as destructive tests or direct mechanical measurements can only be performed after spraying. Besides, these methods lead to production shutdown and additional costs . This article presents a novel approach predicting coating thickness for components with complex curved surfaces, especially in the case of shadow effects. Firstly, a three-dimensional geometric model of the coating profile based on Gaussian distribution was developed. In addition, the relative deposition efficiency (RDE) resulting from the different robot kinematic parameters…
Innovative method to estimate state of charge of the hydride hydrogen tank: application of fuel cell electric vehicles
2021
International audience; Significant attention has been paid to metal hydrides (MH) as an environmentally friendly and safe way to store hydrogen. This technology has considerable potential for the application of embedded hydrogen storage in fuel cell electric vehicles, but its widespread application faces a major problem in terms of estimating the remaining hydrogen amount in the tank. In this work, a new method is proposed for estimating the state of charge (SoC) of the hydrogen hydride tank (HHT) by application of piezoelectric material. The idea is to cover the entire inner wall of the metal-hydride tank with a layer of piezoelectric material. During the process of hydrogen absorption, t…
Contactless generation of cavitation in high temperature liquid metals and its impact on particle dispersion in solidified iron and steel samples
2021
Abstract A recently developed method for the contactless magnetic generation of cavitation is demonstrated for high-melting-point metals. The approach is based on the floating-zone technique, which is truly contactless and crucible-free as it uses electromagnetic forces. Using this method, ultra-high-temperature ceramic particles, such as TiN, TiB2 and TiC, are admixed in liquid iron and 316L steel. The dispersion and particle refinement caused by cavitation treatment during melting and solidification are investigated. Magnetic fields up to 8 T that correspond to pressure oscillation amplitude of 0.83 MPa are used. The signal emitted by the collapsing bubbles is captured and visualized for …
Influence of residual stress, surface roughness and crystallographic texture induced by machining on the corrosion behaviour of copper in salt-fog at…
2012
International audience; The influence of quadratic stress, crystallographic texture, lubrication and surface roughness generated by superfinish turning on the corrosion behaviour of pure copper was quantified in salt-fog atmosphere. This was done using statistical analysis (Pearson's correlation matrix). Three compounds were found after corrosion tests: atacamite/paratacamite and a black layer (mixture of the lubricant and the salt atmosphere). Surface characteristics were classified according to their decreasing influence on the formation of atacamite/paratacamite as follows: surface roughness and quadratic stress. Lubrication and the crystallographic texture have the lowest influence on c…
Surface Characteristics of Machined Polystyrene with 3D Printed Thermoplastic Tool
2020
An effort is made in this work to appraise the surface characteristics of machined expandable polystyrene (EPS) with a novel 3D printed thermoplastic acrylonitrile-butadiene-styrene (ABS) tool. Linear grooves on EPS were made on a vertical milling machine that was modified to conduct experiments in the laboratory. The tests were designed as per the Taguchi L9 based factorial design of experimentation while varying process parameters such as depth of cut, spindle speed, and feed rate. The machining responses dimensional accuracy and surface roughness of the machined grooves were studied. Furthermore, the surface topography of the machined specimens was considered to investigate the mechanism…
Decorous combinatorial lower bounds for row layout problems
2020
Abstract In this paper we consider the Double-Row Facility Layout Problem (DRFLP). Given a set of departments and pairwise transport weights between them the DRFLP asks for a non-overlapping arrangement of the departments along both sides of a common path such that the weighted sum of the center-to-center distances between the departments is minimized. Despite its broad applicability in factory planning, only small instances can be solved to optimality in reasonable time. Apart from this even deriving good lower bounds using existing integer programming formulations and branch-and-cut methods is a challenging problem. We focus here on deriving combinatorial lower bounds which can be compute…
Mathematical models for a cutting problem in the glass manufacturing industry
2021
Abstract The glass cutting problem proposed for the ROADEF 2018 challenge is a two-dimensional, three-stage guillotine cutting process, with an additional cut to obtain pieces in some specific situations. However, it is not a standard problem because it includes specific constraints. The sheets produced in the glass manufacturing process have defects that make them different and have to be used in order. The pieces to be cut are grouped into subsets and the pieces from each subset must be cut in order. We approach the problem by developing and solving integer linear models. We start with the basic model, which includes the essential features of the problem, as a classical three-stage cuttin…
A strategic oscillation simheuristic for the Time Capacitated Arc Routing Problem with stochastic demands
2021
Abstract The Time Capacitated Arc Routing Problem (TCARP) extends the classical Capacitated Arc Routing Problem by considering time-based capacities instead of traditional loading capacities. In the TCARP, the costs associated with traversing and servicing arcs, as well as the vehicle’s capacity, are measured in time units. The increasing use of electric vehicles and unmanned aerial vehicles, which use batteries of limited duration, illustrates the importance of time-capacitated routing problems. In this paper, we consider the TCARP with stochastic demands, i.e.: the actual demands on each edge are random variables which specific values are only revealed once the vehicle traverses the arc. …
Modeling and control of uncertain nonlinear systems
2018
A survey of the methodologies associated with the modeling and control of uncertain nonlinear systems has been given due importance in this paper. The basic criteria that highlights the work is relied on the various patterns of techniques incorporated for the solutions of fuzzy equations that corresponds to fuzzy controllability subject. The solutions which are generated by these equations are considered to be the controllers. Currently, numerical techniques have come out as superior techniques in order to solve these types of problems. The implementation of neural networks technique is contributed in the complex way of dealing the appropriate coefficients and solutions of the fuzzy systems.