A model for Manufacturing Large Parts with WAAM Technology

Wire Arc Additive Manufacturing (WAAM) is a metallic additive manufacturing process based on the fusion of metallic wire using an electric arc as a heat source. The challenge associated with WAAM is heat management and understanding bead geometry. The printing process involves high temperatures, which results in the build-up of residual stresses can often cause deformations in a component. All of the process variables, such as torch speed (TS), wire feed speed (WFS), idle time, combine to produce the geometry of the deposit bead that results in the desired component shape. So, determining a method for choosing a good combined parameter process is very important to obtain a high-quality part. This article presents a study on how to use the WAAM process to produce a complexity part of aluminium alloys. The step of the determination process parameter is concentrated to develop in this study. An experimental design is determined to study the influence between the process parameters, for example, WFS, TS, high layer, length of bead. Different samples are made using the Yaskawa robot, using the classic CMT (Cold Metal Transfer) as a manufacturing method, using zigzag filling as a manufacturing strategy with the same WFS and same idle times and different TS, different bead lengths. A new manufacturing method using the zigzag filling strategy is proposed by adding an important step in determining the process parameters. The results indicate that the length of the bead has a significant impact on another parameter of the process.

Ti6Al4V Thin Walls Production using Laser Directed Energy Deposition (L-DED) Process

One of the main applications of Directed Energy Deposition (DED) is the production of thin-wall structures, where it has significant advantages over traditional milling and machining techniques, or even welded analogues. These kinds of structures are frequently employed in aerospace components, field where titanium alloys have a primary role to play. Amongst them, the most employed is the Ti6Al4V with an alpha + beta alloy containing 6% Aluminium (Al) and 4% Vanadium (V). It has an excellent combination of strength and toughness along with excellent corrosion resistance. For the study hereby, thin-wall structures were constructed employing a Laser Directed Energy Deposition machine (L-DED), working with powder material. Analyse identified some microstructural and mechanical characteristics, thorough metallographic study, wear test (micro-adhesive) and micro hardness test. Finding a grain refined structure with competitive mechanical properties compared to materials manufactured by traditional processes. Results positioning DED as an attractive manufacturing technology, with a huge potential to improve costs and material usage, besides almost no restriction on component shape.

Hierarchy-of-Visual-Words: a Learning-based Approach for Trademark Image Retrieval

In this paper, we present the Hierarchy-of-Visual-Words (HoVW), a novel trademark image retrieval (TIR) method that decomposes images into simpler geometric shapes and defines a descriptor for binary trademark image representation by encoding the hierarchical arrangement of component shapes. The proposed hierarchical organization of visual data stores each component shape as a visual word. It is capable of representing the geometry of individual elements and the topology of the trademark image, making the descriptor robust against linear as well as to some level of nonlinear transformation. Experiments show that HoVW outperforms previous TIR methods on the MPEG-7 CE-1 and MPEG-7 CE-2 image databases.

Numerical Simulation of Darcy–Forchheimer 3D Unsteady Nanofluid Flow Comprising Carbon Nanotubes with Cattaneo–Christov Heat Flux and Velocity and Thermal Slip Conditions

A mathematical model comprising Darcy Forchheimer effects on the 3D nanofluid flow with engine oil as a base fluid containing suspended carbon nanotubes (CNTs) is envisioned. The CNTs are of both types i.e., multi-wall carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs). The flow is initiated by an exponentially stretched surface. The impacts of Cattaneo–Christov heat flux along with velocity and thermal slip conditions are key factors in the novelty of the defined model. The boundary layer notion is designed to convert the compact form of equations into the component shape. Appropriate transformations lead to differential equations with high nonlinearity. The final non-dimensional system is solved numerically by a “MATLAB” function known as bvp4c. For both CNTs, different graphical sketches are drawn to present the influence of arising parameters versus related profiles. The outcomes show that higher slip parameter boosts the axial velocity, whereas fluid temperature lowers for a sturdier relaxation parameter.

Functional Performance Tailoring of Additively Manufactured Components via Topology Optimization

The freedom of design that is afforded by Additive Manufacturing (AM) processes opens exciting possibilities for the production of lightweight, high performance components and structures. Consequently, in recent years the development of software tools to enable engineering design methods that exploit the unique features of AM has become a subject of increased research interest. In this paper we explore the use of Topology Optimization (TO) algorithms to tailor component shape in order to achieve the intended functionality of additively manufactured components at the macro length scale. We present two case studies: the first concerns the hierarchical nesting of functions in a hand tool, while the second covers the development of a metamaterial component substructure for an Uninhabited Underwater Vehicle (UUV) hull. We offer conclusions regarding the usefulness of TO techniques for the design of AM components, and a summary of future work, which we feel is necessary to improve such methodologies.

Genes, Personality Traits, and the Sense of Civic Duty

Political scientists have long known that the sense of civic duty is one of the strongest predictors of individual voter turnout, yet scholars are only just starting to study and understand the origins of this orientation. Recent genopolitics research has indicated that the sense of civic duty is heritable, and recent research in political psychology has illustrated that individual personality traits, many of which have a heritable component, shape feelings of civic obligation. In this article, we link these two lines of inquiry to better understand how individual differences shape the sense of civic duty. More specifically, we explore the relationship between personality traits, measured using the Big Five model; genes; and the sense of civic duty. We show that genetic factors account for between 70% and 87% of the correlation between civic duty and four of the Big Five personality traits. Overall, the results presented here expand our understanding of the process through which prosocial orientations, such as civic duty, are formed.

Deformation Mechanism and Characteristics of Thin-Walled Component in Aluminum Alloy

During milling of thin-walled components, obtaining minimum distortion is essential in order to achieve production goals. In this study, a mechanical model based on deformation machanism is established, and is help to analyse relationship between residual stress and deformation in component. Researched on simulation and experiment, the stress-deformation characteristics of different component shape is obtained. The results indicate that the deformation of thin-walled component in milling primarily depends on the distribution of initial residual stress, which can generate bending moment and lead to distortion. And then milling stress on the surface is easy to make bending moment baesd on this distortion, and make the deformation of component intensify.