bluuebunny/crossref_metadata_2025_split huggingface dataset:
Woven Carbon Fiber Reinforced Laminate Matrix Composite Through Fused Deposition Modeling
Authors: Ranjan Rachit , Raote Piyush , Bajpai Vivek 
Published: January 2021

Abstract
A novel fused deposition modeling (FDM) based fabrication technique for Woven carbon fiber (WCF) reinforced PLA matrix laminated composite was proposed. The composite was fabricated by placing a layer of carbon fiber (CF) after every 5th layer of PLA matrix such that there was a total of 3 layers of CF in every tensile specimen fabricated. The parameter such as extrusion temperature, feed rate, and bed temperature was initially optimized by the Taguchi L9 optimization technique to get high-density low surface roughness specimens. Mechanical properties such as tensile strength and flexural strength of the specimen were measured in Hounsfield tensile testing machine. The composite has the yield and ultimate tensile strength of 43.378 MPa and 70.84 MPa which is 114.01% and 172.94% higher than the unreinforced specimen. The Flexural strength of the composite was found to be 117.88 MPa which is 17.91 % higher than the unreinforced 3D printed specimen. The proposed technique has offered a potential strategy to fabricate low-cost products with variable design for versatile applications such as aerospace and automobile industries.
Tip Induced Growth of Zinc Oxide Nanoflakes Through Electrochemical Discharge Deposition Process and Their Optical Characterization
Authors: Kumar Deepak , Bishwakarma Harish , Kumar Mohan , Singh Nirmal Kumar , Bajpai Vivek 
Published: January 2021

Abstract
ZnO nanoflakes with varying thickness (10–120 nm) and width (250–1600 nm) were synthesized on the tooltip (∅ ≤ 200 μm) by a novel route method called electrochemical spark deposition and growth method. The leaf-like nanostructures were found under varying pulsated DC voltage potentials (50–80V) at normal room temperature (25°C). Equimolar concentration (0.1M) of zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and methenamine ((CH2)6N4) HMTA) mixture was used as a growth (precursor) solution. The anodization time (deposition and growth time) was varying from 10 seconds to 25 seconds. Further, the consequence of pulse voltage on the growth morphology was examined critically. The structural evolution and elemental composition were investigated by field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX) respectively. The size distribution (thickness and width) of ZnO nanoflakes were estimated by image processing software (Image J). Ultimately, the ultraviolet visible infrared spectroscopy (UV-Vis) analysis was carried out to determine the excitation energy of the zinc oxide nanoflakes. The estimated bandgap energy (via. Tauc plot) of the nanoflakes was found approximately 2.63 eV.
3D Freeze Printing: Development of an Experimental Setup and Determination of 3D Printing Parameters
Authors: Tetik Halil , Lin Dong 
Published: January 2021

Abstract
3D freeze printing is a hybrid manufacturing method composed of freeze casting and inkjet-based printing. It is a facile method to fabricate lightweight, porous, and functional structures. Freeze casting is a well-known method for fabricating porous bodies and is capable of manipulating the micro-structure of the resulting product. Freeze casting simply involves solidification of a liquid suspension using low temperature and sublimation of the solvent using low temperature and pressure. After the sublimation of the solvent crystals, we obtain a porous structure where the pores are a replica of solvent crystal. Making use of the temperature gradient, as seen in unidirectional and bidirectional freeze casting, during the solidification with low temperature values, the solvent crystals grow along the temperature gradient. Furthermore, by manipulating the freezing kinetics during solidification, we can have a control on the average pore size distribution. For instance, when lower freezing temperatures result in finer pores with higher amount, higher freezing temperatures result in coarser pores with less amount. Also, the use of some additives inside the suspension leads to changes in the morphology of the solvent crystals as well as the resulting pores. However, the macro-structure of the fabricated body is highly dependent on the mold used during the process. In order to eliminate the dependency on the mold during the freeze casting process, our group recently combined this technique with inkjet-based 3D printing. With inkjet-based 3D printing, we fabricated uniform lines from single droplets, and complex 3D shapes from the lines. This provided us the ability of tailoring the macro structure of the final product without any dependency on a mold as seen in freeze casting. As a result of the 3D freeze printing process, we achieved fabricating lightweight, porous, and functional bodies with engineered micro and macro-structures. However, achieving fine droplets, and uniform lines by merging the droplets requires a good combination of fabrication parameters such as pressure adjustment inside the print head, print head speed, jetting frequency. Also, fabricating complex shapes from uniform lines requires well-adjusted parameters such as line thickness and layer height. In this study, we briefly explained the mechanics of the 3D freeze printing process. Following that we presented the development process of an open-source inkjet-based 3D printer. Finally, we explained the determination of inkjet dispensing and 3D printing parameters required for a high-quality 3D printing. During our experiments for the determination of fabrication parameters, we used a nanocellulose crystals-based ink due to its low cost and ease of preparation.
Evaluation of Microstructure and Mechanical Properties of Al-TaC Composites Developed by Muti-Step Stir Casting Process
Authors: Khalkho J. S. , Vidyasagar Ch. S. , Karunakar D. B. 
Published: January 2021

Abstract
In the present study, four AA7075 composite samples reinforced with varying amounts of TaC in the range of 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, were developed using a multi-step stir casting to improve the mechanical properties. The mechanical properties of the developed samples such as microhardness, tensile strength, compression strength, and elongation were characterized using a computerized Vickers hardness testing machine for microhardness and a Universal Testing Machine for both tensile and compression respectively. The effect of Tantalum carbide on the microstructures of the composite samples was characterized using an optical microscope. The microstructures and the mechanical properties of the developed composites were correlated. The results show a gradual increase in the mechanical properties with an increase in TaC reinforcement, However, the elongation decreased gradually with the increase in TaC content. The highest mechanical properties were found in the composite reinforced with 0.4. wt% TaC with the highest microhardness of 121 Hv, Ultimate Tensile Strength of 369 MPa, Yield Strength of 338 MPa and compression strength of 784 MPa.
Influence of the Porous Volume in the Structure of Resin Bond Composite Abrasives by its Mechanical Performance
Authors: Chitan Matheus de Mendonça , Candioto Katia Cristiane Gandolpho 
Published: January 2021

Abstract
Abrasive tools consist of abrasive grains, binder and pores. Binders are the matrix of the material and may be of the metallic, vitrified or resin type. The wide use of polymeric materials (resinoid) is due to their low cost and excellent mechanical properties. The grain has the function of roughing the material, the binder, on the other hand, has the characteristics of ensuring grain adhesion and the pores in the structure are responsible for cooling the abrasive tool. In this work, we report the preparation and evaluation of the mechanical characteristics of resin bond composite abrasives with different structures based on the porous concentration. The composite abrasives were made with phenolic resin and alumina grains. Four different structures were studied from 10 to 30% of porous volume fraction with 50% of grain volume fraction. The concentration of porous and bond in the structure composition were employed to compare the mechanical performance of the prepared composite abrasive. To evaluate the mechanical properties of composites, Impact strength, Young’s Modulus by impulse excitation and flexural strength were realized. It was observed that as the porosity is higher, the impact resistance (absorbed energy) is lower, which confirms the lower resistance produced by the surface area contact (grain/binder) and a greater accumulation of tension in the binder material, the higher porosity value, higher the flexural strength value until 20% of porosity. Samples with higher volumes level of porosity presented lower Young’s Modulus but the presence of pores produced by volatiles by-products (mainly water) should act as stress concentrators, thus favoring lower mechanical properties at the resin-grain interface.
Toward Detecting Cyber-Physical Attacks in Additive Manufacturing Using Multi-View Visual Odometry
Authors: Kutzer Michael D. , Donnal John S. , Sinsley Gregory L. , McDowell Ryan S. 
Published: January 2021

Abstract
This paper presents a method using multi-view visual odometry as an independent tool to reconstruct deposition trajectories in additive manufacturing processes. A physical testbed is presented including camera and encoder retrofits to a Lulzbot TAZ 6. The system, including added sensors, is interfaced using the Wattsworth decentralized IoT framework for data acquisition, preliminary processing, and storage. The proposed visual odometry method is presented, and preliminary testbed results show reliable encoder feedback and camera calibration for use as ground truth in future validation.
Influence of Loading Frequency on Thermal and Micro-Mechanical Damage During Fatigue of Flax Fiber Reinforced Composites
Authors: Islam Md. Zahirul , Ulven Chad A. 
Published: January 2021

Abstract
Like synthetic fiber reinforced composites, natural fiber reinforced composites possess a good potential to be used in high performance applications due to their good balance of mechanical and damping properties. Composite materials used in sporting goods equipment and automotive applications are subjected to repeating, regular loads. Therefore a clear understanding about the reliability of composite materials under fatigue/cyclic loading is important for their design in high performance applications. Currently, the fatigue performance of natural fiber reinforced composites are not well understood or characterized. The fatigue damage of flax fiber reinforced polymer matrix composites can be divided into two components: thermal damage due to self-heating in the sample and micro-mechanical damage due to damage creation (i.e. crack initiation, crack propagation, delamination, etc.). In this study, fatigue tests were conducted at four different loading frequencies and the two energy components defined were separated experimentally. The fatigue life of flax fiber reinforced composites was found to decrease with increasing loading frequency. Thermal damage due to the high self-heating temperature of the sample was found to be the main responsible form of energy which decreases fatigue life with increasing loading frequency. Micro-mechanical damage due to cyclic loading was not found to change significantly with increasing loading frequency.
Uniaxial High-Speed Micro-Scale 3D Surface Topographical Measurements Using Fringe Projection
Authors: Zheng Yi , Li Beiwen 
Published: January 2021

Abstract
In-situ inspection has drawn many attentions in manufacturing due to the importance of quality assurance. With the rapid growth of additive manufacturing technology, the importance of in-line/in-situ inspections has been raised to a higher level due to many uncertainties that could occur during an additive printing process. Given this, having accurate and robust in-situ monitoring can assist corrective actions for a closed-loop control of a manufacturing process. Contact 3D profilometers such as stylus profilometers or coordinate measuring machines can achieve very high accuracies. However, due to the requirement for physical contact, such methods have limited measurement speeds and may cause damage to the tested surface. Thus, contact methods are not quite suitable for real-time in-situ metrology. Non-contact methods include both passive and active methods. Passive methods (e.g., focus variation or stereo vision) hinges on image-based depth analysis, yet the accuracies of passive methods may be impacted by light conditions of the environment and the texture quality of the surface. Active 3D scanning methods such as laser scanning or structured light are suitable for instant quality inspection due to their ability to conduct a quick non-contact 3D scan of the entire surface of a workpiece. Specifically, the fringe projection technique, as a variation of the structured light technique, has demonstrated significant potential for real-time in-situ monitoring and inspection given its merits of conducting simultaneous high-speed (from 30 Hz real-time to kilohertz high speeds) and high accuracy (tens of μm) measurements. However, high-speed 3D scanning methods like fringe projection technique are typically based on triangulation principle, meaning that the depth information is retrieved by analyzing the triangulation relationship between the light emitter (i.e., projector), the image receiver (i.e., camera) and the tested sample surface. Such measurement scheme cannot reconstruct 3D surfaces where large geometrical variations are present, such as a deep-hole or a stair geometry. This is because large geometrical variations will block the auxiliary light used in the triangulation based methods, which will resultantly cause a shadowed area to occur. In this paper, we propose a uniaxial fringe projection technique to address such limitation. We measured a stair model using both conventional triangulation based fringe projection technique and the proposed method for comparison. Our experiment demonstrates that the proposed uniaxial fringe projection technique can perform high-speed 3D scanning without shadows appearing in the scene. Quantitative testing shows that an accuracy of 35 μm can be obtained by measuring a step-height object using the proposed uniaxial fringe projection system.
Optimisation of Process Parameters for Electromagnetic Forming of AA6101 Tubes
Authors: Selvam Rajiv , Karibeeran Shanmuga Sundaram 
Published: January 2021

Abstract
Electromagnetic forming is an inevitable and tedious task even in modern engineering practices. Aluminum alloys are widely used in industrial structures and components, where light-weight and good corrosion resistance is required. This paper explains the Response Surface Methodology (RSM)-based design of experiment (DoE) for the optimization of electromagnetic forming of AA6101 tubes. The forming experiments were conducted based on the full factorial DoE, by varying the energy level, air gap and number of turns as the forming parameters, against the responses of force, deformation and time. The combined effects of the energy level, air gap and number of turns on the performance measures of force, deformation and time were investigated by the analysis of variance. The optimization results were plotted using the RSM, and the optimal forming parameters were obtained. The validation experiments were conducted using the optimum forming considerations and the results were compared.
Fundamentals in Metal Plasticity: From the Initial Contact to Non-Stationary, Dynamic Chip
Authors: Lortz Wolfgang , Pavel Radu 
Published: January 2021

Abstract
The process mechanics phenomena play an important role in all metal cutting processes. Conditions are changing progressively not only to high velocities and deformation, but also to the interfacial friction between two different materials — tool and workpiece, and inside the same material, as a result of material flow with high temperatures. It will be shown, that during the ploughing effect in the interface between tool and chips there are two different kinds of friction, external and internal friction. All the existent models ignore this reality. Therefore, an alternative must be found to model the real phenomena during metal plastic flow in a more appropriate manner. In this study, we will consider the cutting process in fundamental terms based only on mathematics and physics. In connection with this fundamental development a question arises, “Which parameters are the best for characterizing the cutting process and can the equations be proven after processing, because nearly each parameter will disappear, such as stress, strain, friction or temperatures etc.”? It might be that only the plastic material deformation in connection with the external and internal friction can be identified and visualized after the cutting process for comparing the developed theoretical result with the experimental result of the chip formation region. That leads to the fact that, as long as agreement between theoretical and experimental result can be demonstrated, there is evidence that stress and strain, as well as friction and temperatures are correctly estimated. Therefore, this paper is focused on the plastic deformation ds in the plastic region during the cutting process. This plastic deformation will be expressed for the non-stationary, dynamic cutting process with non-uniform feed (toolworkpiece contact evolving from rubbing to material separation) and chip flow. This process behavior is relevant for the milling operation of metals as well as for carbon composites with glass fibers. For carbon composites with glass fibers, additional environmental and human safety aspects will arise, as described in this paper.
Dual Extrusion FDM Printer for Flexible and Rigid Polymers
Authors: McGrady Garrett , Walsh Kevin 
Published: January 2021

Abstract
Commercially available fused deposition modeling (FDM) printers have yet to bridge the gap between printing soft, flexible materials and printing hard, rigid materials. This work presents a custom printer solution, based on open-source hardware and software, which allows a user to print both flexible and rigid polymer materials. The materials printed include NinjaFlex, SemiFlex, acrylonitrile-butadiene-styrene (ABS), Nylon, and Polycarbonate.
In order to print rigid materials, a custom, high-temperature heated bed was designed to act as a print stage. Additionally, high temperature extruders were included in the design to accommodate the printing requirements of both flexible and rigid filaments. Across 25 equally spaced points on the print plate, the maximum temperature difference between any two points on the heated bed was found to be ∼9°C for a target temperature of 170°C. With a uniform temperature profile across the plate, functional prints were achieved in each material.
The print quality varied, dependent on material; however, the standard deviation of layer thicknesses and size measurements of the parts were comparable to those produced on a Zortrax M200 printer. After calibration and further process development, the custom printer will be integrated into the NEXUS system — a multiscale additive manufacturing instrument with integrated 3D printing and robotic assembly (NSF Award #1828355).
Characterization of High-Density WC-Co Bulk Structures Fabricated by Selective Laser Melting
Authors: Carroll Avery , Carey Rachel , Hurst Michael , Liu Michael , Kuttolamadom Mathew 
Published: January 2021

Abstract
The objective of this research is to evaluate the feasibility of using a high energy laser-based additive manufacturing process to fabricate tungsten-carbide-cobalt (WC-Co) bulk structures that have properties comparable to those achieved by traditional fabrication methods. In particular, this work will investigate the properties and performance of these hard carbides densified by sintering alone, as compared to methods (such as hot isostatic pressing (HIP) and spark plasma sintering (SPS)) which impart simultaneous compaction and sintering. For this, a design of experiments was utilized to investigate the pertinent process parameter design space for the selective laser melting (SLM) process with a view to manufacture structurally-integral samples. Besides organizing qualitative observations, the effects of these process conditions were correlated with the resulting physical properties (viz., density, micro-scale composite hardness, and nano-scale hardness and Young’s modulus), as well as with microstructure and chemical compositions. Results showed certain samples with competitively-high densities, hardness and moduli, but with a large spread in properties, as is typical for such manufacturing processes; also, microstructural characteristics in line with desirable traits achievable via traditional methods was observed. Altogether, this work shows the promise of using SLM to fabricate bulk carbide structures.
Additive Manufacturing of Continuous Carbon Fiber Reinforced Thermoplastic Composites: An Investigation on Process-Impregnation-Property Relationship
Authors: Wang Gongshuo , Jia Zhenyuan , Wang Fuji , Dong Chuanhe , Wu Bo 
Published: January 2021

Abstract
Fused filament fabrication (FFF) is one of the most broadly used additive manufacturing technologies, which possesses the advantage of a reduction in fabrication time and cost for complex-structural parts. FFF-fabricated continuous carbon fiber reinforced thermoplastic (C-CFRTP) composites have seen their great potentials in the industry due to the extraordinary mechanical properties. However, the relationship among process parameters, impregnation percentage, and mechanical properties is still unknown, which has greatly hindered both the manufacturing and application of those advanced composite parts. For this reason, the influence of process parameters on the impregnation percentage and mechanical properties of C-CFRTP specimens has been investigated in this paper. The process-impregnation-properties relationship of FFF-fabricated C-CFRTP specimens has been revealed through theoretical analyses and experimental measurement. It could be concluded that the impregnation percentage served as the bridge connecting process parameters and mechanical properties, which would provide a great insight into the property improvement. The experimental results of microscopic measurement and mechanical tests indicated that the combination of low transverse movement speed, high nozzle temperature, and small layer thickness led to an improved impregnation percentage, which ultimately produced better mechanical properties. The findings in this work will guide the fabrication of C-CFRTP parts with excellent mechanical performance for practical engineering applications.
Toolpath Generation for Additive Manufacturing Considering Structural Performance
Authors: Sales Eder , Kwok Tsz Ho , Chen Yong 
Published: January 2021

Abstract
The use of additive manufacturing (AM) has increased considerably in recent years. This technology possibilities the creating of complex shapes in an easy, fast, and with low wast of material. This creative freedom allows components to be highly optimized. Currently, some algorithms allow final users to perform topology optimization in the computer-aided design (CAD) phase. However, the optimization results might not be respected or considered during the downstream AM planning processes like slicing hence the optimized structural design may be lost during the actual fabrication process. This work has a focus on topology optimization in the toolpath planning process by taking into account the characteristics in the AM processes. This work develops a line based topology optimization using the principal stress line (PSL) as the guidance in generating optimized toolpaths. The method is efficient, controllable, and able to consider the characteristics of the AM process. Experimental structural tests were performed on the proposed method, and the results obtained demonstrate that the strategy of applying PSL-based optimization in toolpath planning is a promising direction to complement the topologically optimized results from the CAD phase.