An Investigation to Study the Effect of Process Parameters on the Strength and Fatigue Behavior of 3D-Printed PLA-Graphene

3D printing, an additive manufacturing process, draws particular attention due to its ability to produce components directly from a 3D model; however, the mechanical properties of the produced pieces are limited. In this paper, we present, from the experimental aspect, the fatigue behavior and damage analysis of polylactic acid (PLA)-Graphene manufactured using 3D printing. The main purpose of this paper is to analyze the combined effect of process parameters, loading amplitude, and frequency on fatigue behavior of the 3D-printed PLA-Graphene specimens. Firstly, a specific case study (single printed filament) was analyzed and compared with spool material for understanding the nature of 3D printing of the material. Specific experiments of quasi-static tensile tests are performed. A strong variation of fatigue strength as a function of the loading amplitude, frequency, and process parameters is also presented. The obtained experimental results highlight that fatigue lifetime clearly depends on the process parameters as well as the loading amplitude and frequency. Moreover, when the frequency is 80 Hz, the coupling effect of thermal and mechanical fatigue causes self-heating, which decreases the fatigue lifetime. This paper comprises useful data regarding the mechanical behavior and fatigue lifetime of 3D-printed PLA-Graphene specimens. In fact, it evaluates the effect of process parameters based on the nature of this process, which is classified as a thermally-driven process

Effects of Power and Laser Speed on the Mechanical Properties of AlSi7Mg0.6 Manufactured by Laser Powder Bed Fusion

The AlSi7Mg0.6 alloy, with its good tolerance against strain, is used in laser powder bed fusion (LPBF) to produce parts with complex geometries for aerospace engineering. Production of parts with good mechanical strength requires, however, the optimization of laser parameters. This study thus evaluated the influence of scanning speed, laser power, and strategy on several mechanical properties (tensile/resilience/hardness) to identify an optimal processing region. Results have shown the profound influence of laser power and scanning speed on mechanical properties, with a limited influence from the laser strategy. Tensile strength values ranging from 122 to 394 MPa were obtained, while Young’s Modulus varied from 17 to 29 GPa, and the elongation at break ranged from 2.1 to 9.8%. Surface plots of each property against laser power and speed revealed a region of higher mechanical properties. This region is found when using 50 µm thick layers for energy densities between 25 and 35 J/mm3. Operating at higher values of energy density yielded sub-optimal properties, while a lower energy density resulted in poor performances. Results have shown that any optimization strategy must not only account for the volumic energy density value, but also for laser power itself when thick layers are used for fabrication. This was shown through parts exhibiting reduced mechanical performances that were produced within the optimal energy density range, but at low laser power. By combining mid-speed and power within the optimal region, parts with good microstructure and limited defects such as balling, keyhole pores, and hot cracking will be produced. Heat-treating AlSi7Mg0.6 parts to T6 temper negatively affected mechanical performances. Adapted tempering conditions are thus required if improvements are sought through tempering

Dual linearly polarised 3D printed Phoenix cell for wide band metal only reflectarrays

International audienceThis study shows the potential of additive manufacturing for the fabrication of 3D Phoenix phase-shifting cell. With traditional microstrip printing technology, the cell has many advantages. Here, the authors demonstrate that the 3D printed version of the cell exhibits very good intrinsic performances in the 17-21 GHz frequency band. A deep insight into the operation mode of the cell is drawn in order to have a better understanding of its behaviour. Different prototypes are fabricated and measured to validate experimentally the numerical results

Améliorée de la bande passante de réseau réflecteur entièrement métallique à base de cellules Phoenix 3D

International audienceCet article étudie des réseaux réflecteurs entièrement métalliques à base de cellules Phoenix 3D, pour une réalisation en fabrication additive. La possibilité de faire varier la géométrie de la cellule dans les trois dimensions offre un avantage pour accroître la bande passante. Ici, l'effet de la hauteur des cellules est mis à profit pour atteindre une bande passante (-1dB sur le gain) de 18% à 20GHz

Améliorée de la bande passante de réseau réflecteur entièrement métallique à base de cellules Phoenix 3D

International audienceCet article étudie des réseaux réflecteurs entièrement métalliques à base de cellules Phoenix 3D, pour une réalisation en fabrication additive. La possibilité de faire varier la géométrie de la cellule dans les trois dimensions offre un avantage pour accroître la bande passante. Ici, l'effet de la hauteur des cellules est mis à profit pour atteindre une bande passante (-1dB sur le gain) de 18% à 20GHz

Modeling and Design of a Solar Rotary Dryer Bench Test for Phosphate Sludge

As an eco-friendlier way to manage mining waste, the use of solar energy to dry phosphate sludge in a rotary dryer is envisioned. As a first step toward this end, a design study for a bench-scale rotary dryer for phosphate sludge is detailed, using a one-dimensional mathematical model developed for this task. Using the Engineering Equation Solver (EES) software, a steady-state transport phenomena model was developed that enables an estimation of the moisture and temperature profiles for both gas and product in the dryer. A sensitivity analysis evaluated the effects and influence of different geometric parameters and operating conditions on the product moisture profile. Parameters involved include the diameter of the dryer, the residence time of the product to dry, inlet air temperature, and inlet product humidity. This allowed for the selection of suitable design parameters for the operation of a phosphate sludge dryer with a 1.5 m length and an internal diameter of 11.5 cm. The inlet air temperature of the rotary dryer was set at 200°C to achieve a reduction of moisture content in the product from 30% to 7%. The model was validated through literature and experimental datasets, with an error averaging 0.22% and 1.52%, respectively

Bandwidth Enhancement of a Metal-Only Reflectarray Based on the Phoenix Cell

This paper presents a detailed analysis of the effect of the height of the 3D Phoenix Cell on the performance of Metal-Only Reflectarray Antennas. An improved design approach is proposed and a 18% bandwidth (for gain variations less than 1 dB) is obtained after the optimization

Effects of Power and Laser Speed on the Mechanical Properties of AlSi7Mg0.6 Manufactured by Laser Powder Bed Fusion

The AlSi7Mg0.6 alloy, with its good tolerance against strain, is used in laser powder bed fusion (LPBF) to produce parts with complex geometries for aerospace engineering. Production of parts with good mechanical strength requires, however, the optimization of laser parameters. This study thus evaluated the influence of scanning speed, laser power, and strategy on several mechanical properties (tensile/resilience/hardness) to identify an optimal processing region. Results have shown the profound influence of laser power and scanning speed on mechanical properties, with a limited influence from the laser strategy. Tensile strength values ranging from 122 to 394 MPa were obtained, while Young’s Modulus varied from 17 to 29 GPa, and the elongation at break ranged from 2.1 to 9.8%. Surface plots of each property against laser power and speed revealed a region of higher mechanical properties. This region is found when using 50 µm thick layers for energy densities between 25 and 35 J/mm3. Operating at higher values of energy density yielded sub-optimal properties, while a lower energy density resulted in poor performances. Results have shown that any optimization strategy must not only account for the volumic energy density value, but also for laser power itself when thick layers are used for fabrication. This was shown through parts exhibiting reduced mechanical performances that were produced within the optimal energy density range, but at low laser power. By combining mid-speed and power within the optimal region, parts with good microstructure and limited defects such as balling, keyhole pores, and hot cracking will be produced. Heat-treating AlSi7Mg0.6 parts to T6 temper negatively affected mechanical performances. Adapted tempering conditions are thus required if improvements are sought through tempering

A Metal-Only Reflectarray Made of 3D Phoenix Cells

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3D Metal-Only Phoenix Cell and its Application for Transmit-reflect-array

International audienceThis paper presents a 3D metal-only waveguide-based phoenix cell. The proposed cell uses open-ended waveguides, which allow a portion of the incident wave to pass through the phoenix cell. It thus has the ability to control both reflection and transmission phases. Its principle is analyzed in detail. Two metal-only transmit-reflect-array antennas are then designed. The proposed transmit-reflect-array antennas are able to produce both transmitted and reflected beams at 16 GHz in the target directions simultaneously. One of the transmit-reflect-array antennas is fabricated using selective laser melting 3D printing technology. The measured results show that a good agreement between the simulated and measured radiation patterns is achieved. The side lobe and cross polarization levels at 16-GHz are −15.3-dB and −23.1-dB respectively. The measured gain of transmitted and reflected beams at 16-GHz are 25.7-dBi and 24.1-dBi respectively. Both the simulation and measurement results fully demonstrate the capabilities of the proposed 3D metal-only phoenix cell