scholarly journals SPIF process of axisymmetric parts made of AA1060-H14 aluminum alloy tested on  2 axis-NC lathe machine

2020 ◽  
Author(s):  
Ben Said Lotfi ◽  
Abir Bouhamed ◽  
Mondher Wali ◽  
Lioua Kolsi ◽  
Fakhreddine Dammak
Keyword(s):  
Aluminum Alloy ◽  
Surface Quality ◽  
Incremental Forming ◽  
Numerical Study ◽  
Industrial Applications ◽  
Milling Machine ◽  
Nc Milling ◽  
Lathe Machine ◽  
High Degree

Abstract This paper deals with an experimental and numerical study focused on the SPIF process of a dome part manufactured by means of a 2-axis NC lathe machine. The main objective is to enhance the understanding of a set of parameters in connection with ISF operations applied to this type of machine unusually used in incremental forming processes, despite the high degree of development of NC lathe machines. Nowadays 4 and 5 axis lathe centers are widely used in industrial applications. This makes NC lathe machines useful in SPIF process especially in the case of axisymmetric parts. The present results, covering thinning, appearance of cracks, surface quality and FLD diagram; prove the efficiency of NC turning machines to perform SPIF application of parts commonly manufactured by a 3-axis NC milling machine.

scholarly journals Numerical Analysis of Air Vortex Interaction with Porous Screen

Fluids ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 70
Author(s):  
Xudong An ◽  
Lin Jiang ◽  
Fatemeh Hassanipour
Keyword(s):  
Physical Properties ◽  
Vortex Ring ◽  
Numerical Study ◽  
Flow Behavior ◽  
Industrial Applications ◽  
Moving Mesh ◽  
Vortex Flows ◽  
Vortex Interaction ◽  
Piston Cylinder ◽  
Porous Screen

In many industrial applications, a permeable mesh (porous screen) is used to control the unsteady (most commonly vortex) flows. Vortex flows are known to display intriguing behavior while propagating through porous screens. This numerical study aims to investigate the effects of physical properties such as porosity, Reynolds number, inlet flow dimension, and distance to the screen on the flow behavior. The simulation model includes a piston-cylinder vortex ring generator and a permeable mesh constructed by evenly arranged rods. Two methods of user-defined function and moving mesh have been applied to model the vortex ring generation. The results show the formation, evolution, and characteristics of the vortical rings under various conditions. The results for vorticity contours and the kinetic energy dissipation indicate that the physical properties alter the flow behavior in various ways while propagating through the porous screens. The numerical model, cross-validated with the experimental results, provides a better understanding of the fluid–solid interactions of vortex flows and porous screens.

scholarly journals Influence of High-Productivity Process Parameters on the Surface Quality and Residual Stress State of AISI 316L Components Produced by Directed Energy Deposition

2021 ◽  
Author(s):  
Gabriele Piscopo ◽  
Alessandro Salmi ◽  
Eleonora Atzeni
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Quality ◽  
Process Parameters ◽  
Energy Deposition ◽  
Industrial Applications ◽  
High Productivity ◽  
Directed Energy Deposition ◽  
Productivity Process ◽  
Directed Energy

AbstractThe production of large components is one of the most powerful applications of laser powder-directed energy deposition (LP-DED) processes. High productivity could be achieved, when focusing on industrial applications, by selecting the proper process parameters. However, it is of crucial importance to understand the strategies that are necessary to increase productivity while maintaining the overall part quality and minimizing the need for post-processing. In this paper, an analysis of the dimensional deviations, surface roughness and subsurface residual stresses of samples produced by LP-DED is described as a function of the applied energy input. The aim of this work is to analyze the effects of high-productivity process parameters on the surface quality and the mechanical characteristics of the samples. The obtained results show that the analyzed process parameters affect the dimensional deviations and the residual stresses, but have a very little influence on surface roughness, which is instead dominated by the presence of unmelted particles.

An experimental and numerical study of the resonant flow between a hull and a wall

2021 ◽  
Vol 930 ◽  
Author(s):  
I.A. Milne ◽  
O. Kimmoun ◽  
J.M.R. Graham ◽  
B. Molin
Keyword(s):  
Vortex Shedding ◽  
Particle Image ◽  
Numerical Study ◽  
Numerical Models ◽  
Vertical Wall ◽  
Liquefied Natural Gas ◽  
Narrow Gap ◽  
Image Velocimetry ◽  
High Degree ◽  
Wave Induced

The wave-induced resonant flow in a narrow gap between a stationary hull and a vertical wall is studied experimentally and numerically. Vortex shedding from the sharp bilge edge of the hull gives rise to a quadratically damped free surface response in the gap, where the damping coefficient is approximately independent of wave steepness and frequency. Particle image velocimetry and direct numerical simulations were used to characterise the shedding dynamics and explore the influence of discretisation in the measurements and computations. Secondary separation was identified as a particular feature which occurred at the hull bilge in these gap flows. This can result in the generation of a system with multiple vortical regions and asymmetries between the inflow and outflow. The shedding dynamics was found to exhibit a high degree of invariance to the amplitude in the gap and the spanwise position of the barge. The new measurements and the evaluation of numerical models of varying fidelity can assist in informing offshore operations such as the side by side offloading from floating liquefied natural gas facilities.

3D-to-2D Mapping of Cutter Paths in NC Programming of Complex Engineering Parts

1993 ◽  
Author(s):  
Chao-Hwa Chang
Keyword(s):  
Three Dimensional ◽  
Machining Process ◽  
Milling Machine ◽  
Systematic Method ◽  
Nc Programming ◽  
Cutter Path ◽  
Nc Milling ◽  
Complex Engineering ◽  
High Level ◽  
Mapping Concept

Abstract The concept of mapping a three dimensional (3D) contouring cutter path with major motion in a plane parallel to the Z axis onto the X-Y plane or one perpendicular to the Z axis is introduced. A systematic method is developed that can be used to program, in APT or other high-level languages, complex contouring cutter motion based on the concept introduced. As a result, NC programming of contouring motion for many complex engineering parts on a 3-axis numerically controlled (NC) milling machine, which is often considered difficult, can be greatly simplified. Part examples are discussed; and the APT programs defining the cutter path based on the 3D-to-2D mapping concept, are also analyzed in detail. The concept and method introduced proved to be a powerful tool for programming the NC machining process for many parts, particularly dies and molds.

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