Mechanical behaviour of 3D printed Lightweight Nano-composites

2021 ◽  
Vol 06 ◽  
Author(s):  
Mrityunjay Doddamani

Background: The nanoclay (NC) and glass micro balloons (GMB) based reinforced polymer composites are explored extensively through traditional processing methods. NC shows substantial enhancement in mechanical properties. Polymer composites developed by reinforcing GMB fillers provide a substantial reduction in weight, which is essential in the marine, aerospace, and automotive field. In this study, an attempt is made by developing polymer nano composites by reinforcing NC and GMB particles. Objective: The paper deals with 3 dimensional printing (3DP) of lightweight nanocomposite foam (NF) developed by mixing nanoclay (NC) and glass micro balloons (GMB) in high-density polyethylene (HDPE). The NF blend is prepared by keeping NC at 5 weight %. Subsequently, GMBs are added by volume (20 - 60 %) to NC/HDPE blend to realize lightweight NFs. Methods: The lightweight feedstock filaments are developed by extruding the blends using a single screw extruder. The extruded NF filaments are used as an input in a 3D printer to print NFs. The density of extruded filaments and prints are measured. The printed NFs are subjected to tensile and flexural testing. Conclusion: With an increase in GMB loading the density of both filaments and prints decreases. Compared to neat HDPE, printed NFs show ~30 % weight reducing potential. The tensile, flexural modulus and strength increases with GMB loading. NFs exhibited superior mechanical performance as compared to HDPE and NC/HDPE. Further, the property map reveals that the 3D printed NFs show superior tensile, flexural modulus, and strength in comparison with injection and compression-molded foams.

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Francis Dantas ◽  
Kevin Couling ◽  
Gregory J. Gibbons

Abstract The aim of this study was to identify the effect of material type (matrix and reinforcement) and process parameters, on the mechanical properties of 3D Printed long-fibre reinforced polymer composites manufactured using a commercial 3D Printer (Mark Two). The effect of matrix material (Onyx or polyamide), reinforcement type (Carbon, Kevlar®, and HSHT glass), volume of reinforcement, and reinforcement lay-up orientation on both Ultimate Tensile Strength (UTS) and Flexural Modulus were investigated. For Onyx, carbon fibre reinforcement offered the largest increase in both UTS and Flexural Modulus over unreinforced material (1228 ± 19% and 1114 ± 6% respectively). Kevlar® and HSHT also provided improvements but these were less significant. Similarly, for Nylon, the UTS and Flexural Modulus were increased by 1431 ± 56% and 1924 ± 5% by the addition of carbon fibre reinforcement. Statistical analysis indicated that changing the number of layers of reinforcement had the largest impact on both UTS and Flexural Strength, and all parameters were statistically significant.


Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1220 ◽  
Author(s):  
Sofiane Guessasma ◽  
Sofiane Belhabib ◽  
Hedi Nouri

Polyethylene terephthalate glycol (PETG) is a thermoplastic formed by polyethylene terephthalate (PET) and ethylene glycol and known for his high impact resistance and ductility. The printability of PETG for fused deposition modelling (FDM) is studied by monitoring the filament temperature using an infra-red camera. The microstructural arrangement of 3D printed PETG is analysed by means of X-ray micro-tomography and tensile performance is investigated in a wide range of printing temperatures from 210 °C to 255 °C. A finite element model is implemented based on 3D microstructure of the printed material to reveal the deformation mechanisms and the role of the microstructural defects on the mechanical performance. The results show that PETG can be printed within a limited range of printing temperatures. The results suggest a significant loss of the mechanical performance due to the FDM processing and particularly a substantial reduction of the elongation at break is observed. The loss of this property is explained by the inhomogeneous deformation of the PETG filament. X-ray micro-tomography results reveal a limited amount of process-induced porosity, which only extends through the sample thickness. The FE predictions point out the combination of local shearing and inhomogeneous stretching that are correlated to the filament arrangement within the plane of construction.


Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1369 ◽  
Author(s):  
Yueke Ming ◽  
Yugang Duan ◽  
Ben Wang ◽  
Hong Xiao ◽  
Xiaohui Zhang

Recently, 3D printing of fiber-reinforced composites has gained significant research attention. However, commercial utilization is limited by the low fiber content and poor fiber–resin interface. Herein, a novel 3D printing process to fabricate continuous fiber-reinforced thermosetting polymer composites (CFRTPCs) is proposed. In brief, the proposed process is based on the viscosity–temperature characteristics of the thermosetting epoxy resin (E-20). First, the desired 3D printing filament was prepared by impregnating a 3K carbon fiber with a thermosetting matrix at 130 °C. The adhesion and support required during printing were then provided by melting the resin into a viscous state in the heating head and rapidly cooling after pulling out from the printing nozzle. Finally, a powder compression post-curing method was used to accomplish the cross-linking reaction and shape preservation. Furthermore, the 3D-printed CFRTPCs exhibited a tensile strength and tensile modulus of 1476.11 MPa and 100.28 GPa, respectively, a flexural strength and flexural modulus of 858.05 MPa and 71.95 GPa, respectively, and an interlaminar shear strength of 48.75 MPa. Owing to its high performance and low concentration of defects, the proposed printing technique shows promise in further utilization and industrialization of 3D printing for different applications.


2020 ◽  
Author(s):  
Francis Dantas ◽  
Greg Gibbons

Abstract Additive Manufacturing (AM), also known as 3D Printing, has been around for more than 2 decades and has recently gained importance for use in direct manufacturing. The quantified physical properties of materials are required by design engineers to inform and validate their designs, and this is no less true for AM that it is for traditional manufacturing methods. Recent innovation in AM has seen the emergence of long-fibre composite AM technologies, such as the Mark Two (Markforged Inc, USA) system, enabling the manufacture of thermoplastic polymer composites with long-fibre reinforcement. To date though, the mechanical response of the materials with respect to build parameter variation is little understood. In this project, selected mechanical properties (ultimate tensile strength – UTS and flexural modulus) of samples processed using the Mark Two printer were studied. The effect of the reinforcement type (Carbon, Kevlar®, and HSHT glass), amount of reinforcement, reinforcement lay-up orientation, and the base matrix material (Onyx and polyamide) on these properties were assessed using accepted standard test methods. For Onyx, the UTS and Flexural Modulus was improved by a maximum of 244 ± 10 MPa (1228 ± 19%) and 14.2 ± 0.3 GPa (1114 ± 6%) (Carbon), by 143 ± 1 MPa (721 ± 18%) and 7.1 ± 0.3 GPa (560 ± 6%) (Kevlar®) and 209 ± 4 MPa (1049 ± 19%) and 6.0 ± 0.1 GPa (469 ± 6%) (HSHT glass). For Nylon the UTS and Flexural Modulus was improved by 235 ± 4 MPa (1431 ± 56%) and 14.1 ± 0.2 GPa (1924 ± 5%) (Carbon), 143 ± 3 MPa (867 ± 56%) and 6.79 ± 0.08 GPa (927 ± 5%) (Kevlar®) and 204 ± 2 MPa (1250 ± 55%) and 5.73 ± 0.09 GPa (782 ± 5%) (HSHT glass). A regression and ANOVA analysis for UTS indicated that the number of layers of reinforcement had the largest impact on UTS (F = 11,483 P < 0.005), with the second most important parameter being the type of reinforcement (F = 855 P < 0.005). The parameter effects for all four parameters were significant (P ≤ 0.05). For the Flexural Modulus, the number of layers of reinforcement was again the most significant parameter (F = 2733 P < 0.005), with the second most important parameter again being the type of reinforcement (F = 1339 P < 0.005). Again, the parameter effects for all four parameters were significant (P ≤ 0.05), although the influence of base material had much less significant effect on determining the Flexural Modulus than it did in controlling UTS.


2020 ◽  
Author(s):  
Francis Dantas ◽  
Kevin Couling ◽  
Greg Gibbons

Abstract The aim of this study was to identify the effect of material type (matrix and reinforcement) and process parameters, on the mechanical properties of 3D Printed long-fibre reinforced polymer composites manufactured using a commercial 3D Printer (Mark Two). The effect of matrix material (Onyx or polyamide), reinforcement type (Carbon, Kevlar®, and HSHT glass), volume of reinforcement, and reinforcement lay-up orientation on both Ultimate Tensile Strength (UTS) and Flexural Modulus were investigated. For Onyx, carbon fibre reinforcement offered the largest increase in both UTS and Flexural Modulus over unreinforced material (1,228±19 % and 1,114±6 % respectively). Kevlar® and HSHT also provided improvements but these were less significant. Similarly, for Nylon, the UTS and Flexural Modulus were increased by 1,431±56 % and 1,924±5 % by the addition of carbon fibre reinforcement. Statistical analysis indicated that changing the number of layers of reinforcement had the largest impact on both UTS and Flexural Strength, and all parameters were statistically significant.


2021 ◽  
Author(s):  
AU Yap ◽  
HS Choo ◽  
HY Choo ◽  
NA Yahya

Clinical Relevance The strength of some bioactive materials can be compromised by cariogenic challenges. This may impact the clinical longevity of restorations, especially in stress-bearing areas. SUMMARY This study determined the mechanical performance of bioactive restoratives in cariogenic environments and compared the flexural properties of various bioactive materials. The materials evaluated included a conventional resin-based composite (Filtek Z350 [FZ]) and 3 bioactive restoratives, namely an alkasite (Cention N [CN]), a giomer (Beautifil-bulk Restorative [BB]), and an enhanced resin-modified glass ionomer (Activa Bioactive Restorative [AV]). Beam-shaped specimens (12 x 2 x 2 mm) were produced, randomly allocated to 4 groups (n=10), and conditioned in deionized solution, remineralizing solution, demineralizing solution (DE), or pH cycled for 14 days at 37°C. After conditioning/pH cycling, the specimens were subjected to 3-point flexural testing. Flexural data were subjected to statistical analysis using analysis of variance or Tukey’s test (α=0.05). Mean flexural modulus and strength ranged from 3.54 ± 0.33 to 7.44 ± 0.28 GPa, and 87.07 ± 8.99 to 123.54 ± 12.37 MPa, respectively. While the flexural modulus of the bioactive restoratives was not affected by cariogenic/acidic conditions, flexural strength usually decreased, with the exception of CN. The strength of BB was significantly reduced by DE and pH cycling, while that of AV was lowered by DE. For all conditioning mediums, AV had a significantly lower modulus than the other materials. Apart from conditioning in DE, where differences in flexural strength was insignificant, FZ and AV were generally significantly stronger than BB and CN. The effect of cariogenic environments on flexural strength was found to be material dependent, and aside from the alkasite material (CN), cariogenic conditions were observed to significantly decrease the strength of bioactive restoratives.


2021 ◽  
pp. 194589242110035
Author(s):  
Muhamed A. Masalha ◽  
Kyle K. VanKoevering ◽  
Omar S. Latif ◽  
Allison R. Powell ◽  
Ashley Zhang ◽  
...  

Background Acquiring proficiency for the repair of a cerebrospinal fluid (CSF) leak is challenging in great part due to its relative rarity, which offers a finite number of training opportunities. Objective The purpose of this study was to evaluates the use of a 3-dimensional (3D) printed, anatomically accurate model to simulate CSF leak closure. Methods Volunteer participants completed two simulation sessions. Questionnaires to assess their professional qualifications and a standardized 5-point Likert scale to estimate the level of confidence, were completed before and after each session. Participants were also queried on the overall educational utility of the simulation. Results Thirteen otolaryngologists and 11 neurosurgeons, met the inclusion criteria. A successful repair of the CSF leak was achieved by 20/24 (83.33%), and 24/24 (100%) during the first and second simulation sessions respectively (average time 04:04 ± 1.39 and 02:10 ± 01:11). Time-to-close-the-CSF-leak during the second session was significantly shorter than the first (p < 0.001). Confidence scores increased across the training sessions (3.3 ± 1.0, before the simulation, 3.7 ± 0.6 after the first simulation, and 4.2 ± 0.4 after the second simulation; p < 0.001). All participants reported an increase in confidence and believed that the model represented a valuable training tool. Conclusions Despite significant differences with varying clinical scenarios, 3D printed models for cerebrospinal leak repair offer a feasible simulation for the training of residents and novice surgeons outside the constrictions of a clinical environment.


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