scholarly journals Fatigue Cracking of Additively Manufactured Materials—Process and Material Perspectives

2020 ◽  
Vol 10 (16) ◽  
pp. 5556
Author(s):  
Torsten Fischer ◽  
Bernd Kuhn ◽  
Detlef Rieck ◽  
Axel Schulz ◽  
Ralf Trieglaff ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Fatigue Strength ◽  
Process Control ◽  
High Performance ◽  
Chemical Engineering ◽  
Fatigue Cracking ◽  
Metal Powders ◽  
Wide Range ◽  
Manufacturing Techniques ◽  
The Impact

Strong efforts are made internationally to optimize the process control of laser additive manufacturing processes. For this purpose, advanced detectors and monitoring software are being developed to control the quality of production. However, commercial suppliers of metal powders and part manufacturers are essentially focused on well-established materials. This article demonstrates the potential of optimized process control. Furthermore, we outline the development of a new high temperature structural steel, tailored to best utilize the advantages of additive manufacturing techniques. In this context, the impact of production-induced porosity on fatigue strength of austenitic 316L is presented. Additionally, we discuss the first conceptual results of a novel ferritic steel, named HiperFer (High Performance Ferrite), which was designed for increased fatigue strength. This ferritic, Laves phase-strengthened, stainless steel could be used for a wide range of structural components in power and (petro)chemical engineering at maximum temperatures ranging from about 580 to 650 °C. This material benefits from in situ heat treatment and counteracts process-related defects by “reactive” crack obstruction mechanisms, hampering both crack initiation and crack propagation. In this way, increased fatigue resistance and safety can be achieved.

Automation of Process Control in Chemical Plant

2015 ◽  
Vol 2 (1) ◽  
pp. 6-12
Author(s):  
Agus Sugiarta ◽  
Houtman P. Siregar ◽  
Dedy Loebis
Keyword(s):  
Process Control ◽  
Pid Control ◽  
Control Algorithm ◽  
Chemical Engineering ◽  
Chemical Plant ◽  
Raw Material ◽  
Flow Rates ◽  
Material Supply ◽  
Wide Range ◽  
Inherent Problem

Automation of process control in chemical plant is an inspiring application field of mechatronicengineering. In order to understand the complexity of the automation and its application requireknowledges of chemical engineering, mechatronic and other numerous interconnected studies.The background of this paper is an inherent problem of overheating due to lack of level controlsystem. The objective of this research is to control the dynamic process of desired level more tightlywhich is able to stabilize raw material supply into the chemical plant system.The chemical plant is operated within a wide range of feed compositions and flow rates whichmake the process control become difficult. This research uses modelling for efficiency reason andanalyzes the model by PID control algorithm along with its simulations by using Matlab.

scholarly journals A Review on Additive Manufacturing of Micromixing Devices

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Marina Garcia-Cardosa ◽  
Francisco-Javier Granados-Ortiz ◽  
Joaquín Ortega-Casanova
Keyword(s):  
Life Cycle ◽  
Additive Manufacturing ◽  
High Performance ◽  
Future Prospects ◽  
High Quality ◽  
Printing Technology ◽  
Wide Range ◽  
The Moment ◽  
Manufacturing Technologies

In recent years, additive manufacturing has gained importance in a wide range of research applications such as medicine, biotechnology, engineering, etc. It has become one of the most innovative and high-performance manufacturing technologies of the moment. This review aims to show and discuss the characteristics of different existing additive manufacturing technologies for the construction of micromixers, which are devices used to mix two or more fluids at microscale. The present manuscript discusses all the choices to be made throughout the printing life cycle of a micromixer in order to achieve a high-quality microdevice. Resolution, precision, materials, and price, amongst other relevant characteristics, are discussed and reviewed in detail for each printing technology. Key information, suggestions, and future prospects are provided for manufacturing of micromixing machines based on the results from this review.

Not All Transformational Leadership Behaviors Are Equal: The Impact of Followers’ Identification With Leader and Modernity on Taking Charge

2016 ◽  
Vol 24 (3) ◽  
pp. 318-334 ◽  
Author(s):  
Jie Li ◽  
Stacie Furst-Holloway ◽  
Larry Gales ◽  
Suzanne S. Masterson ◽  
Brian D. Blume
Keyword(s):  
Transformational Leadership ◽  
Indirect Effects ◽  
High Performance ◽  
Relative Effect ◽  
Future Research ◽  
Intellectual Stimulation ◽  
Performance Expectations ◽  
Wide Range ◽  
Taking Charge ◽  
The Impact

This study investigates how each dimension of transformational leadership directly and indirectly influences followers’ change-oriented behaviors. Using a sample of 329 independent leader–follower dyads from a wide range of Chinese organizations, we examine followers’ identification with leader as an intervening variable between the four dimensions of transformational leadership (“core” transformational behaviors, high-performance expectations, individualized support, and intellectual stimulation) and followers’ taking charge behaviors. Results showed that intellectual stimulation had the highest relative effect size that was largely due to its direct effect on taking charge. Individualized support only exerted a significant indirect effect. Additionally, the negative direct and positive indirect effects of high-performance expectations rendered its total effect nonsignificant. Furthermore, the direct, indirect, and total effects of “core” transformational behaviors were nonsignificant. We also found that followers’ value of modernity moderated the effect of identification with leader on taking charge. The indirect effects of intellectual stimulation, individualized support, and high-performance expectations were significant when modernity was high but nonsignificant when it was low. Implications for theory, practice, and future research are discussed.

scholarly journals Bonding between high-performance polymer processed by Fused Filament Fabrication and PEEK/carbon fiber laminate

2021 ◽  
Author(s):  
Isciane Caprais ◽  
Pierre Joyot ◽  
Emmanuel Duc ◽  
Simon Deseur
Keyword(s):  
Additive Manufacturing ◽  
Composite Structures ◽  
Composite Laminate ◽  
High Performance ◽  
Processing Conditions ◽  
Fused Filament Fabrication ◽  
Fiber Placement ◽  
High Performance Polymer ◽  
Automated Fiber Placement ◽  
The Impact

Automated fiber placement processes could be combined with additive manufacturing to produce more functionally complex composite structures with more flexibility. The challenge is to add functions or reinforcements to PEEK/carbon composite parts manufactured by automated fiber placement process, with additive manufacturing by fused filament fabrication. This consists of extruding a molten polymer through a nozzle to create a 3D part. Bonding between polymer filaments is a thermally driven phenomenon and determines the integrity and the final mechanical strength of the printed part. 3d-printing high performance polymers is still very challenging because they involve high thermal gradients during the process. The purpose of this work is to find a process window where the bonding strength is maximized between the composite laminate and the first layer of printed polymer, and inside the printed function as well. Experimental measurements of the temperature profiles at the interface between a composite substrate and 3d-printed PEI under different processing conditions were carried out. The interface was observed using microscopic sections. The methodology for studying the impact of printing parameters on the cohesion and adhesion of printed parts with a composite laminate is described. This work provides insights about the influence of processing conditions on the bond formation between high-performance polymer surfaces. It highlights the importance of controlling the thermal history of the materials all along the process.

Effect Ultrasonic Nanocrystal Surface Modification (UNSM) Treatment on Fatigue Strength of Additive Manufactured UNS S31603

2020 ◽  
Author(s):  
Young Sik Pyun ◽  
Ruslan Karimbaev ◽  
Seimi Choi ◽  
Jun Suek Ro ◽  
Choong Ho Sanseong ◽  
...  
Keyword(s):  
Surface Modification ◽  
Additive Manufacturing ◽  
Fatigue Strength ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Complex Geometry ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Wide Range

Abstract Additive Manufacturing (AM) which is also known as metal 3D printing technique is one of the promising manufacturing processes due to the capability to process a complex geometry component. This is implemented in wide range of applications in various industries such as automotive, aerospace, power plants, etc. The aging nuclear power plant components and the obsolescence of those components has become a concern in this industry, and AM has come as an alternative solution for this matter. The Board on Pressure and Technology Codes and Standards (BPTCS) and Board on Nuclear Codes and Standards (BNCS) Special Committees started to study the application of Powder Bed Fusion (PBF) technique for pressure retaining equipment made from UNS S31603. Also, later Korean International Working Group (KIWG) was also started a Task Group on Additive Manufacturing for Valves which focusing on Powder Bed Fusion (PBF) and Direct Energy Disposition (DED) process for pressure-retaining valve manufacturing especially for nuclear power plant application with the same material. However, the poor mechanical properties and performance, especially fatigue strength of AM materials become a concern due to the defects and flaws as the results of layering and multiple interfaces and welding related discontinuities. In this study, the fatigue strength of PBF and DED manufactured and Ultrasonic Nanocrystal Surface Modification (UNSM) treated UNS S31603 austenitic stainless steel was investigated.

scholarly journals Environmental and Economic Analysis of FDM, SLS and MJF Additive Manufacturing Technologies

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4161 ◽  
Author(s):  
Vincenzo Tagliaferri ◽  
Federica Trovalusci ◽  
Stefano Guarino ◽  
Simone Venettacci
Keyword(s):  
Additive Manufacturing ◽  
High Performance ◽  
Large Scale ◽  
Fused Deposition Modeling ◽  
Production Capacity ◽  
Optimal Choice ◽  
Scale Production ◽  
Fused Deposition ◽  
Manufacturing Technologies ◽  
The Impact

In this study, the authors present a comparative analysis of different additive manufacturing (AM) technologies for high-performance components. Four 3D printers, currently available on the Italian national manufacturing market and belonging to three different AM technologies, were considered. The analysis focused on technical aspects to highlight the characteristics and performance limits of each technology, economic aspects to allow for an assessment of the costs associated with the different processes, and environmental aspects to focus on the impact of the production cycles associated with these technologies on the ecosystem, resources and human health. This study highlighted the current limits of additive manufacturing technologies in terms of production capacity in the case of large-scale production of plastic components, especially large ones. At the same time, this study highlights how the geometry of the object to be developed greatly influences the optimal choice between the various AM technologies, in both technological and economic terms. Fused deposition modeling (FDM) is the technology that exhibits the greatest limitations hindering mass production due to production times and costs, but also due to the associated environmental impact.

scholarly journals Electro-textile wearable antennas in wireless body area networks: materials, antenna design, manufacturing techniques, and human body consideration—a review

2020 ◽  
pp. 004051752093223 ◽  
Author(s):  
Bahaa Almohammed ◽  
Alyani Ismail ◽  
Aduwati Sali
Keyword(s):  
Human Body ◽  
High Performance ◽  
Material Selection ◽  
Wireless Body Area Network ◽  
Area Network ◽  
Body Area ◽  
Wearable Antennas ◽  
Wide Range ◽  
Manufacturing Techniques ◽  
The Internet Of Things

The latest progress in the emerging wireless technology has resulted in the development of wearable antennas made of various fabrics. This unique antenna is an integral part of the wireless body area network (WBAN). A wide range of applications are made by the wearable antennas in the fields of the Internet of Things, sport, defense, public safety, telemedicine, navigation, and tracking. The focus point of the current review is the recent progress of electro-textiles research with special attention on the materials properties, criteria, and manufacturing techniques. Existing as well as upcoming materials specifically and potentially used for electro-textile fabrication are discussed. Various manufacturing techniques are discussed to match the importance of material selection. The current work highlights the performance when the antennas tagging are applied in WBAN objects and illustrates how the human body affects the performance of the wearable antenna and vice versa. The findings of this review by introducing the best materials, techniques, and designs could be used in future to provide high-performance materials for body-centric applications.

scholarly journals Present Status in Polymeric Mouthguards. A Future Area for Additive Manufacturing?

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1490 ◽  
Author(s):  
Ana M. Sousa ◽  
Ana C. Pinho ◽  
Ana Messias ◽  
Ana P. Piedade
Keyword(s):  
Additive Manufacturing ◽  
Impact Energy ◽  
Present Status ◽  
Material Characterization ◽  
Control Parameters ◽  
Contact Sports ◽  
Different Types ◽  
Manufacturing Techniques ◽  
The Impact ◽  
The Ideal

Athletes from contact sports are more prone to orofacial injuries because of the exposure to possible shocks and collisions derived from physical proximity. The use of protector polymeric mouthguards proved to be useful in the prevention of the described injuries. There are different types of mouthguards with varying ranges of protection and prices, but they are all made from polymers and share the same propose: to absorb and dissipate the impact energy resulting from the shocks. As they are used inside the mouth, they should not impair breathing and speaking nor compromise the comfort of the athlete. However, the ideal mouthguard is yet to be created. The choice of the most appropriate polymeric material and the standard required properties have not yet been reported. Regardless of the numerous studies in this field, normalized control parameters for both material characterization and mouthguard fabrication are absent. This paper aims to present a review of the current types of available mouthguards and their properties/characteristics. Moreover, a detailed description of the most common polymers for the fabrication of mouthguards, together with the manufacturing techniques, are discussed.

Investigation of the Influence of Consequential Design Parameters on the Mechanical Performance of Biodegradable Bone Scaffolds, Fabricated Using Pneumatic Micro-Extrusion Additive Manufacturing Process

2020 ◽  
Author(s):  
Daguan Zhao ◽  
Mohan Yu ◽  
Logan Lawrence ◽  
Pier Paolo Claudio ◽  
James B. Day ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Additive Manufacturing ◽  
High Resolution ◽  
Functional Properties ◽  
Manufacturing Process ◽  
Design Parameters ◽  
Bone Scaffolds ◽  
Material Deposition ◽  
Wide Range ◽  
The Impact

Abstract Pneumatic micro-extrusion (PME) is a high-resolution direct-write additive manufacturing process, which has emerged as the process of choice for tissue engineering and biofabrication of a broad spectrum of organs and tissues (e.g., bone, aortic valve, blood vessels, human ear, and nose). Despite the advantages and host of biomedical applications engendered by the PME process — including, for example, (i) accommodation of a wide range of material viscosity (enabled via thermopneumatic material deposition), (ii) large build volume and standoff distance for tissue engineering, (iii) in situ UV curing, and (iv) high-resolution multimaterial deposition — there are intrinsically complex design, material, and process factors as well as interactions, which influence the functional properties of PME-fabricated tissues and organs. Consequently, investigation of the impact and interaction of each factor aligned with establishment of a physics-based, optimal material deposition regime is inevitably a burgeoning need. In this study, using the Taguchi design, the influence of four significant factors, i.e., layer height, infill density, infill pattern, and print speed, is investigated on the compression properties as well as the dimensional accuracy of polycaprolactone (PCL) bone scaffolds, fabricated using the PME process. Furthermore, a 3D, transient two-phase flow CFD model is forwarded with the aim to observe the flow of material within the deposition head as well as the micro-capillary (nozzle). The results of this study pave the way for further investigation of the bio-functional properties of bone scaffolds, e.g., biodegradation, cell proliferation and growth rate.

Topological Design of Strain Sensing Nanocomposites

2021 ◽  
Author(s):  
Long Wang ◽  
Wei-Hung Chiang ◽  
Kenneth J. Loh
Keyword(s):  
High Performance ◽  
Human Performance ◽  
Structural Integrity ◽  
Material Model ◽  
Material System ◽  
Strain Sensing ◽  
Topological Design ◽  
Bulk Film ◽  
Wide Range ◽  
Manufacturing Techniques

Abstract High-performance piezoresistive nanocomposites have attracted extensive attention because of their significant potential as next-generation sensing devices for a broad range of applications, such as monitoring structural integrity and human performance. While various piezoresistive nanocomposites have been successfully developed using different material compositions and manufacturing techniques, current development procedures typically involve empirical trial and error that can be laborious, inefficient, and, most importantly, unpredictable. Therefore, this paper aims to propose and validate a topological design-based methodology to strategically manipulate the piezoresistive effect of nanocomposites to achieve a wide range of optimized strain sensitivities without changing the material system. In particular, this work designed patterned nanocomposite thin films with stress-concentrating and stress-releasing topologies. The strain sensing properties of the different topology nanocomposites were characterized and compared via electromechanical experiments. Those results were compared to both linear and nonlinear piezoresistive material model numerical simulations. Both the experimental and computational results indicated that the stress-concentrating topologies could enhance strain sensitivity, whereas the stress-releasing topologies could significantly suppress bulk film piezoresistivity.

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