Employing U-shaped 3D printed polymer to improve flexural properties of cementitious tailings backfills

2022 ◽  
Vol 320 ◽  
pp. 126296
Author(s):  
Shiwen Qin ◽  
Shuai Cao ◽  
Erol Yilmaz
Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1949
Author(s):  
Ling Ding ◽  
Wei Lu ◽  
Jiaqi Zhang ◽  
Chuncheng Yang ◽  
Guofeng Wu

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.


2021 ◽  
pp. 002199832110022
Author(s):  
Ahmed Alhelal ◽  
Zaheeruddin Mohammed ◽  
Shaik Jeelani ◽  
Vijaya K Rangari

Semi-crystalline carbon biochar is derived from spent coffee grounds (SCG) by a controlled pyrolysis process at high temperature/pressure conditions. Obtained biochar is characterized using XRD, SEM, and TEM techniques. Biochar particles are in the micrometer range with nanostructured morphologies. The SCG biochar thus produced is used as reinforcement in epoxy resin to 3 D print samples using the direct-write (DW) method with 1 and 3 wt. % loadings. Rheology results show that the addition of biochar makes resin viscous, enabling it to be stable soon after print; however, it could also lead to clogging of resin in printer head. The printed samples are characterized for chemical, thermal and mechanical properties using FTIR, TGA, DMA and flexure tests. Storage modulus improved with 1 wt. % biochar addition up to 27.5% and flexural modulus and strength increased up to 55.55% and 43.30% respectively. However, with higher loading of 3 wt. % both viscoelastic and flexural properties of 3D printed samples drastically reduced thus undermining the feasibility of 3D printing biochar reinforced epoxies at higher loadings.


2021 ◽  
Vol 296 ◽  
pp. 123639
Author(s):  
Miao Liu ◽  
Yimiao Huang ◽  
Fang Wang ◽  
Junbo Sun ◽  
Guowei Ma

Author(s):  
Silas Z. Gebrehiwot ◽  
L. Espinosa Leal ◽  
J. N. Eickhoff ◽  
L. Rechenberg

AbstractWe used finite element analyses (FEA) on Abaqus to study flexural properties of additive manufactured beams using polylactic acid (PLA) polymer. Experimental stress–strain data from flexural testing are used to define elastic–plastic properties of the material in the computation software. The flexural experiments are used to validate the FEA approach suggested. The method provides good results of deflection and stress with errors well below 10% in most of the cases. Therefore, by using the proposed approach, costs related to repeated experimental works can be avoided. In addition, the flexural rigidities of the additive manufactured beams are studied. Five different beam stiffener designs (diamond, honeycomb, square, triangular and wiggle) are studied based on beam bending theory. The force–deflection data from the flexural tests are used to determine the area moments of inertia of the beams. The honeycomb stiffener showed the highest force–deflection behaviour that led to the highest calculated area moment of inertia. However, with the lowest force–deflection behaviour, the square stiffener had the lowest calculated area moment of inertia.


2021 ◽  
Vol 112 (1) ◽  
pp. 13-22
Author(s):  
A. El Magri ◽  
S. Vaudreuil

Purpose: This work aims to study the relationship between various processing parameters to fabricate PLA-graphene based 3D parts with high mechanical properties. The selected parameters in this study are known for their critical impact on the final properties of printed parts. Design/methodology/approach: Three key printing parameters are simultaneously studied in a systematic manner using central composite design (CCD). The selected printing parameters are printing temperature, printing speed, and layer thickness. Findings: Through a variance analysis, all tested printing parameters significantly impact the final properties of printed PLA-graphene’s parts. A response surface methodology (RSM) was also applied to analyse the results and to optimize the tensile and the flexural properties. According to this latter methodology, the optimum factor levels are found at 200°C printing temperature, 34.65 mm s-1 printing speed and 0.2 mm layer thickness. Research limitations/implications: Results indicate that layer thickness and printing speed are the dominant contributors to tensile and flexural properties. Originality/value: As one of the few polymers loaded with nanoparticles available, polylactic acid (PLA) reinforced graphene was selected in this study as a base material for FFF 3D printing process. A response surface methodology was applied to analyse the results and to maximize the tensile and flexural properties of 3D printed PLA-graphene composite.


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