Search results for "Fin"
showing 10 items of 15836 documents
Weld quality prediction in linear friction welding of AA6082-T6 through an integrated numerical tool
2016
Abstract A numerical and an experimental campaign were carried out with varying oscillation frequency and interface pressure. The local values of the main field variables at the contact interface between the specimens were predicted by a Lagrangian, implicit, thermo-mechanical FEM model and used as input of a dedicated Neural Network (NN). The NN, integrated in the FEM environment, was designed in order to calculate both a Boolean output, indicating the occurrence of welding, and a continuous output, indicating the quality of the obtained solid state weld. The analysis of the obtained results allowed three different levels of bonding quality, i.e., no weld, sound weld and excess of heat, to…
Springback of thick sheet AHSS subject to bending under tension
2012
Lien vers la version éditeur : http://www.sciencedirect.com/science/article/pii/S0020740312000677 The springback behavior of four advanced high-strength sheet steels (Dual-Phase, TRIP, ferrite-bainite) with thicknesses ranging from 1.2 to 4 mm was investigated by means of the bending-under-tension (BUT) test. The applicability of several guidelines from the literature was investigated experimentally and numerically. The monotonic decrease of springback as back force increased was confirmed for this category of sheet steels, and a general trend for the non-linear influence of the tool radius was observed. The influence of numerical factors on the predicted values of springback was investigat…
Assessment of material models through simple machining tests
2008
The accuracy of the results obtained from FEM simulation of machining operations depends on the accuracy of input data. Among these, the flow stress data of the workpiece are extremely important together with the friction along the tool-chip interface. In this study, an identification procedure for the determination of material parameters that are used for the FEM simulation of machining processes is proposed. The procedure is based on the coupling of a numerical identification procedure and Arbitrarian Lagrangian Eulerian (ALE) Finite Element simulations of turning operations. An experimental campaign was developed in order to calibrate the model and to validate the procedure. The basic id…
Modelling and Simulation of Machining Processes and Operations
2008
This chapter provides the state-of-the-art knowledge engineering and modelling techniques applied in manufacturing/machining and overviews future trends observed at a global scale. Modelling methods for machining processes and operations are classified. The chapter also highlights the multiple tasks of modelling and simulation in modern machining/manufacturing systems. The most popular techniques of numerical simulation including finite difference method and finite element method (FEM) related to mechanical and thermal problems arising in machining processes are described. Practical examples of FE models of various metal cutting operations and their importance in modern manufacturing are pr…
Data-based modeling and estimation of vehicle crash processes in frontal fixed-barrier crashes
2017
Abstract As a complex process, vehicle crash is challenging to be described and estimated mathematically. Although different mathematical models are developed, it is still difficult to balance the complexity of models and the performance of estimation. The aim of this work is to propose a novel scheme to model and estimate the processes of vehicle-barrier frontal crashes. In this work, a piecewise model structure is predefined to represent the accelerations of vehicle in frontal crashes. Each segment in the model is corresponding to the energy absorbing component in the crashworthiness structure. With the help of Ensemble Empirical Mode Decomposition (EEMD), a robust scheme is proposed for …
Advanced Machining Processes
2017
This chapter provides comprehensive knowledge regarding both well-established achievements in manufacturing and new trends in improving machining processes, taking into account physical, design and technological aspects. The background of machining advancements is outlined, including all components of the machining system and typical machining operations such as turning, milling and drilling and different construction materials. In particular, this short survey covers such machining techniques as high-speed machining/cutting (HSM/HSC), hard part machining, dry and near-dry machining (MQL), high-performance machining (HPM), multitasking/complete machining, and assisted and hybrid machining. …
Finite-time stability and stabilisation for a class of nonlinear systems with time-varying delay
2014
This paper is concerned with the problems of finite-time stability FTS and finite-time stabilisation for a class of nonlinear systems with time-varying delay, which can be represented by Takagi–Sugeno fuzzy system. Some new delay-dependent FTS conditions are provided and applied to the design problem of finite-time fuzzy controllers. First, based on an integral inequality and a fuzzy Lyapunov–Krasovskii functional, a delay-dependent FTS criterion is proposed for open-loop fuzzy system by introducing some free fuzzy weighting matrices, which are less conservative than other existing ones. Then, the parallel distributed compensation controller is designed to ensure FTS of the time-delay fuzzy…
Process mechanics in Friction Stir Extrusion of magnesium alloys chips through experiments and numerical simulation
2017
Abstract Friction Stir Extrusion (FSE) is a novel process designed to directly recycle machining chips. An experimental campaign was carried out on AZ31 milling chips using variations in extrusion ratio, force and tool rotation rate. The process mechanics were studied and correlated to the material flow, which was elucidated through use of a copper marker. A 3D, Lagrangian, thermo-mechanically coupled dedicated numerical model was set up and validated through temperature measurements. The combination of experimental and numerical results permitted to reconstruct the complex 3D material flow induced by tool rotation and plunge into the extrusion billet chamber.
Surface and mechanical characterization of stationary shoulder friction stir welded lap joints: experimental and numerical approach
2020
Friction Stir Welding (FSW) is one of the most used solid-state welding processes in the aeronautical, aerospace, ground transportation and naval fields. Stationary Shoulder Friction Stir Welding (SSFSW) is a recently introduced variant of the process allowing lower heat input into the joints, with beneficial effects in terms of joint mechanical properties, microstructure and top surface finish. In the paper, lap joints produced by SSFSW and made out of AA6082-T6 aluminum alloy sheets have been analyzed with the aim to investigate the effect of the stationary shoulder on the lap joints surface, metallurgical, and mechanical properties. The lap joints produced by SSFSW have been compared to …
Impact of accounting process characteristics on accounting outsourcing - Comparison of users and non-users of cloud-based accounting information syst…
2019
Article In Press The article of record as published may be found at https://doi.org/10.1016/j.accinf.2019.06.002 Prior literature informs us that a company's decision to outsource a business process depends on process characteristics such as how frequently the process is performed or how specific the assets required by the process are. In this article, we compare the effects of accounting process characteristics on outsourcing decisions across users of traditional and cloud-based accounting information systems (AIS). By focusing on outsourcing of accounting processes among small and medium sized enterprises, we investigate the effect of five business process characteristics (frequency, huma…