scholarly journals Curvilinear Variable Stiffness 3D Printing For Improved Mechanical Performance

2021 ◽  
Author(s):  
Sadben Khan
Keyword(s):  
3D Printing ◽  
Mechanical Performance ◽  
Variable Stiffness ◽  
Fused Filament Fabrication ◽  
Work Cell ◽  
Material Deposition ◽  
Stiffness Design ◽  
Open Hole ◽  
Line Scanner ◽  
Novel Design

<div>Continuous Curvilinear Variable Stiffness (CCVS) is proposed as a novel design technique to generate Variable Stiffness design for improving the performance of composite panels featuring open-hole cut-outs. Compared to existing VS design techniques, CCVS steers the fibers around the cut-out without breaking at the holes using only a single design variable the geometry. The technique utilises a numerical method known as Source Panel method, which is typically utilised in the fluid dynamics world. Utilising this technique, the performance of an open hole ASTM D5766 coupon manufactured using Fused Filament Fabrication (FFF) was improved 16-38% depending on the ratio of the hole to the width of the specimen. The technique was further</div><div>improved on to allow for arbitrary geometries such as fuselage cut-outs. A fuselage cut-out case was examined, and it was shown that a CCVS design can improve the performance over a QuasiIsotropic design by 57%. To validate CCVS, it is necessary to first manufacture and validate the part. This was done by developing a robotic 3D printing work-cell capable of 5 axis of material deposition of both thermoplastic and pre-impregnated carbon fiber. Finally, an in-process inspection technique was developed using a laser line scanner in the work-cell for the purposes of quality control. </div>

scholarly journals Curvilinear Variable Stiffness 3D Printing For Improved Mechanical Performance

2021 ◽  
Author(s):  
Sadben Khan
Keyword(s):  
3D Printing ◽  
Mechanical Performance ◽  
Variable Stiffness ◽  
Fused Filament Fabrication ◽  
Work Cell ◽  
Material Deposition ◽  
Stiffness Design ◽  
Open Hole ◽  
Line Scanner ◽  
Novel Design

<div>Continuous Curvilinear Variable Stiffness (CCVS) is proposed as a novel design technique to generate Variable Stiffness design for improving the performance of composite panels featuring open-hole cut-outs. Compared to existing VS design techniques, CCVS steers the fibers around the cut-out without breaking at the holes using only a single design variable the geometry. The technique utilises a numerical method known as Source Panel method, which is typically utilised in the fluid dynamics world. Utilising this technique, the performance of an open hole ASTM D5766 coupon manufactured using Fused Filament Fabrication (FFF) was improved 16-38% depending on the ratio of the hole to the width of the specimen. The technique was further</div><div>improved on to allow for arbitrary geometries such as fuselage cut-outs. A fuselage cut-out case was examined, and it was shown that a CCVS design can improve the performance over a QuasiIsotropic design by 57%. To validate CCVS, it is necessary to first manufacture and validate the part. This was done by developing a robotic 3D printing work-cell capable of 5 axis of material deposition of both thermoplastic and pre-impregnated carbon fiber. Finally, an in-process inspection technique was developed using a laser line scanner in the work-cell for the purposes of quality control. </div>

scholarly journals 3D Printing of Fibre-Reinforced Thermoplastic Composites Using Fused Filament Fabrication—A Review

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2188
Author(s):  
Andrew N. Dickson ◽  
Hisham M. Abourayana ◽  
Denis P. Dowling
Keyword(s):  
3D Printing ◽  
Polymer Composites ◽  
Mechanical Performance ◽  
Polymer Processing ◽  
Thermoplastic Composites ◽  
Fused Filament Fabrication ◽  
Compression Moulding ◽  
Processing Technologies ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer

Three-dimensional (3D) printing has been successfully applied for the fabrication of polymer components ranging from prototypes to final products. An issue, however, is that the resulting 3D printed parts exhibit inferior mechanical performance to parts fabricated using conventional polymer processing technologies, such as compression moulding. The addition of fibres and other materials into the polymer matrix to form a composite can yield a significant enhancement in the structural strength of printed polymer parts. This review focuses on the enhanced mechanical performance obtained through the printing of fibre-reinforced polymer composites, using the fused filament fabrication (FFF) 3D printing technique. The uses of both short and continuous fibre-reinforced polymer composites are reviewed. Finally, examples of some applications of FFF printed polymer composites using robotic processes are highlighted.

Review of the mechanical performance of variable stiffness design fiber-reinforced composites

2018 ◽  
Vol 25 (3) ◽  
pp. 425-437 ◽  
Author(s):  
Zhibo Xin ◽  
Yugang Duan ◽  
Wu Xu ◽  
Tianyu Zhang ◽  
Ben Wang
Keyword(s):  
Mechanical Performance ◽  
Variable Stiffness ◽  
Structure Design ◽  
Fiber Reinforced Composites ◽  
Basic Knowledge ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Reinforced Composite ◽  
Stiffness Design ◽  
Research Situation

Abstract Variable stiffness design (VSD) has been paid more attention for its capability of further exploiting the potential of fiber-reinforced composite in composite structure design. VSD under different mechanical property indexes is reviewed in this paper. The review mostly focuses on strength, buckling, frequency, and other more common mechanical indices. Subsequently, the usage of VSD method for several years is briefly summarized. Some successful tests about variable stiffness composite parts are introduced and the experiment results are also addressed. The article summarizes the research situation from both perspectives based on a number of papers about the VSD of composite materials in recent years and provides theoretical reference and basic knowledge to new researchers.

Curvilinear variable stiffness 3D printing technology for improved open-hole tensile strength

2018 ◽  
Vol 24 ◽  
pp. 378-385 ◽  
Author(s):  
Sadben Khan ◽  
Kazem Fayazbakhsh ◽  
Zouheir Fawaz ◽  
Mahdi Arian Nik
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Variable Stiffness ◽  
Printing Technology ◽  
3D Printing Technology ◽  
Open Hole

scholarly journals On the Mechanical Response of Silicon Dioxide Nanofiller Concentration on Fused Filament Fabrication 3D Printed Isotactic Polypropylene Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2029
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Emmanouil Velidakis ◽  
Lazaros Tzounis ◽  
Nikolaos Mountakis ◽  
...  
Keyword(s):  
3D Printing ◽  
Silicon Dioxide ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Microstructural Analysis ◽  
Melt Flow Index ◽  
International Standards ◽  
Flow Index ◽  
Fused Filament Fabrication ◽  
Melt Mixing

Utilization of advanced engineering thermoplastic materials in fused filament fabrication (FFF) 3D printing process is critical in expanding additive manufacturing (AM) applications. Polypropylene (PP) is a widely used thermoplastic material, while silicon dioxide (SiO2) nanoparticles (NPs), which can be found in many living organisms, are commonly employed as fillers in polymers to improve their mechanical properties and processability. In this work, PP/SiO2 nanocomposite filaments at various concentrations were developed following a melt mixing extrusion process, and used for FFF 3D printing of specimens’ characterization according to international standards. Tensile, flexural, impact, microhardness, and dynamic mechanical analysis (DMA) tests were conducted to determine the effect of the nanofiller loading on the mechanical and viscoelastic properties of the polymer matrix. Scanning electron microscopy (SEM), Raman spectroscopy and atomic force microscopy (AFM) were performed for microstructural analysis, and finally melt flow index (MFI) tests were conducted to assess the melt rheological properties. An improvement in the mechanical performance was observed for silica loading up to 2.0 wt.%, while 4.0 wt.% was a potential threshold revealing processability challenges. Overall, PP/SiO2 nanocomposites could be ideal candidates for advanced 3D printing engineering applications towards structural plastic components with enhanced mechanical performance.

scholarly journals Mechanical Performance of Fused Filament Fabricated and 3D-Printed Polycarbonate Polymer and Polycarbonate/Cellulose Nanofiber Nanocomposites

Fibers ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 74
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Emmanouil Velidakis ◽  
Mariza Spiridaki ◽  
John D. Kechagias
Keyword(s):  
3D Printing ◽  
Mechanical Performance ◽  
Matrix Material ◽  
Mechanical Analysis ◽  
Cellulose Nanofiber ◽  
Fused Filament Fabrication ◽  
Melt Mixing ◽  
The Matrix ◽  
3D Printed ◽  
Printing Parameters

In this study, nanocomposites were fabricated with polycarbonate (PC) as the matrix material. Cellulose Nanofiber (CNF) at low filler loadings (0.5 wt.% and 1.0 wt.%) was used as the filler. Samples were produced using melt mixing extrusion with the Fused Filament Fabrication (FFF) process. The optimum 3D-printing parameters were experimentally determined and the required specimens for each tested material were manufactured using FFF 3D printing. Tests conducted for mechanical performance were tensile, flexural, impact, and Dynamic Mechanical Analysis (DMA) tests, while images of the side and the fracture area of the specimens were acquired using Scanning Electron Microscopy (SEM), aiming to determine the morphology of the specimens and the fracture mechanism. It was concluded that the filler’s ratio addition of 0.5 wt.% created the optimum performance when compared to pure PC and PC CNF 1.0 wt.% nanocomposite material.

scholarly journals Generation of Wholly Thermoplastic Composites and Their Processing in Additive Manufacturing

2021 ◽  
Author(s):  
Tianran Chen
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
High Performance ◽  
Liquid Crystalline ◽  
Mechanical Performance ◽  
Crystalline Polymer ◽  
Extrusion Process ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Fused Filament Fabrication

3D printing has attracted great interest over the past three decades due to its high precision, less waste generation and design freedom [1-3]. One of the major challenges 3D printing is the poor mechanical performance of pure polymer parts. Researchers used traditional carbon and glass fiber reinforced composites to overcome this issue [4-7]. The traditional fibers can improve the mechanical properties of printed parts. However, the manufacturing techniques and printing process restrict the overall performance of the printed parts. Thermotropic liquid crystalline polymer (TLCP) is another reinforcement which offers lighter weight, lower viscosity, excellent mechanical performance and great recyclability [8-15]. TLCPs are capable of forming extended conformations when subjected to extensional or shear deformation.[16, 17] The formation of highly orientated molecular structure enables the generation of high mechanical properties. In this study, polyamide was reinforced with TLCP by the dual-extrusion technique to generate high performance composite filaments [18]. Rheological tests were used to optimize the processing conditions of the dual-extrusion process, which could minimize the degradation of matrix polymer. High performance and lightweight fiber-reinforced composite parts were fabricated by utilizing the fused filament fabrication (FFF) technique. The composite filaments were printed at the temperature below the melting point of TLCP to avoid the relaxation of TLCP. The mechanical performances of printed parts are greater than 3D printed parts which are reinforced by conventional fibers.

scholarly journals Generation of Wholly Thermoplastic Composites and Their Processing in Additive Manufacturing

2021 ◽  
Author(s):  
Tianran Chen ◽  
Donald Baid
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
High Performance ◽  
Liquid Crystalline ◽  
Mechanical Performance ◽  
Crystalline Polymer ◽  
Extrusion Process ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Fused Filament Fabrication

3D printing has attracted great interest over the past three decades due to its high precision, less waste generation and design freedom[1-3]. One of the major challenges 3D printing is the poor mechanical performance of pure polymer parts. Researchers used traditional carbon and glass fiber reinforced composites to overcome this issue [4-7]. The traditional fibers can improve the mechanical properties of printed parts. However, the manufacturing techniques and printing process restrict the overall performance of the printed parts. Thermotropic liquid crystalline polymer (TLCP) is another reinforcement which offers lighter weight, lower viscosity, excellent mechanical performance and great recyclability [8-15]. TLCPs are capable of forming extended conformations when subjected to extensional or shear deformation.[16, 17] The formation of highly orientated molecular structure enables the generation of high mechanical properties . In this study, polyamide was reinforced with TLCP by the dual-extrusion technique to generate high performance composite filaments [18]. Rheological tests were used to optimize the processing conditions of the dual-extrusion process, which could minimize the degradation of matrix polymer. High performance and lightweight fiber-reinforced composite parts were fabricated by utilizing the fused filament fabrication (FFF) technique. The composite filaments were printed at the temperature below the melting point of TLCP to avoid the relaxation of TLCP. The mechanical performances of printed parts are greater than 3D printed parts which are reinforced by conventional fibers.

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