scholarly journals Effect of Extrusion Parameters on Short Fiber Alignment in Fused Filament Fabrication

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2443
Author(s):  
Patrick Consul ◽  
Kai-Uwe Beuerlein ◽  
Genc Luzha ◽  
Klaus Drechsler
Keyword(s):  
Process Design ◽  
Short Fiber ◽  
Strong Impact ◽  
Fiber Reinforced ◽  
Fused Filament Fabrication ◽  
Fiber Alignment ◽  
Inhomogeneous Strain ◽  
Reinforced Composite ◽  
3D Printed ◽  
Fiber Misalignment

Additive manufacturing by material extrusion such as the widespread fused filament fabrication is able to improve 3D printed part performance by using short fiber reinforced composite materials. Fiber alignment is critical for the exploitation of their reinforcing effect. This work investigates the influence extrusion parameters have on the fiber alignment by conducting set of experiments on the process parameters determining whether the flow under the nozzle is convergent or divergent. A strong impact of flow conditions during extrusion line shaping on the fiber alignment is observed and two extremes are tested which show a large difference in strength, stiffness and strain at break in tensile testing along the extrusion lines. From highest to lowest fiber alignment, strength is reduced by 41% and stiffness by 54%. Fiber misalignment also leads to inhomogeneous strain fields in the layers when tested perpendicular to the extrusion lines. It is demonstrated that material flow after the nozzle has a high impact on the material properties of short fiber reinforced 3D printed parts and needs to be considered in process design.

Anisotropic Effective Moduli of Cracked Short-Fiber Reinforced Composites

1999 ◽  
Vol 66 (3) ◽  
pp. 709-713 ◽  
Author(s):  
R. S. Feltman ◽  
M. H. Santare
Keyword(s):  
Short Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Effective Moduli ◽  
Fiber Reinforced ◽  
Fiber Fracture ◽  
Composite Systems ◽  
Reinforced Composite ◽  
Anisotropic Elastic ◽  
Energy Dissipated

A model is presented to analyze the effect of fiber fracture on the anisotropic elastic properties of short-fiber reinforced composite materials. The effective moduli of the material are modeled using a self-consistent scheme which includes the calculated energy dissipated through the opening of a crack in an arbitrarily oriented elliptical inclusion. The model is an extension of previous works which have modeled isotropic properties of short-fiber reinforced composites with fiber breakage and anisotropic properties of monolithic materials with microcracks. Two-dimensional planar composite systems are considered. The model allows for the calculation of moduli under varying degrees of fiber alignment and damage orientation. In the results, both aligned fiber systems and randomly oriented fiber systems with damage-induced anisotropy are examined.

Root Canal Retreatment and Intracoronal Bleaching on the Maxillary First Premolar

2020 ◽  
Vol 48 ◽  
pp. 10-14
Author(s):  
Cynthia Carissa ◽  
Tunjung Nugraheni ◽  
Yulita Kristanti
Keyword(s):  
Root Canal ◽  
Good Condition ◽  
Glass Ionomer Cement ◽  
Short Fiber ◽  
Root Canal Treatment ◽  
Glass Ionomer ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Root Canal Retreatment

Introduction. Inadequate root canal preparation and obturation are potential causes of endodontic failure. Failed root canal treatment with intrinsic discoloration requires root canal re-treatment and intracoronal bleaching. Due to the extensive loss of hard tissues on occlusal area, the restoration requires intracanal retention with short fiber-reinforced composite. Case report. A 17-year-old male patient came to the Clinic of Conservative Dentistry Dental Hospital Prof. Soedomo. He reported pain and discomfort on maxillary first premolar while chewing after root canal procedure had been performed few months before. He felt unconvinience with the discoloration happened on those tooth. Patient had endodontic treatment one year ago and the tooth was restored with glass ionomer cement. Objective examination showed glass ionomer restoration was still in good condition, the tooth was sensitive to percussion but not to palpation, and showed no mobility. Periapical radiograph showed incomplete obturation with radioluscent around periapical region. Retreatment followed by intracoronal bleaching was performed under rubber dam isolation. Tooth was restored with short fiber reinforced composite and composite resin. After 3 month, patient was recalled for examine the previous sign and symptomps. Periapical radiograph showed diameter of periapical lesion was smaller and tooth functioned normally. Conclusion. Root canal retreatment and intracoronal bleaching are suitable options for teeth with failed root canal treatment and intrinsic discoloration

Stiffness prediction of 3D printed fiber-reinforced thermoplastic composites

2019 ◽  
Vol 26 (3) ◽  
pp. 549-555
Author(s):  
Jin Young Choi ◽  
Mark Timothy Kortschot
Keyword(s):  
Mechanical Properties ◽  
Extrusion Direction ◽  
Analytical Models ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Flat Plates ◽  
Fused Filament Fabrication ◽  
Element Analysis ◽  
Content Type ◽  
3D Printed

Purpose The purpose of this study is to confirm that the stiffness of fused filament fabrication (FFF) three-dimensionally (3D) printed fiber-reinforced thermoplastic (FRP) materials can be predicted using classical laminate theory (CLT), and to subsequently use the model to demonstrate its potential to improve the mechanical properties of FFF 3D printed parts intended for load-bearing applications. Design/methodology/approach The porosity and the fiber orientation in specimens printed with carbon fiber reinforced filament were calculated from micro-computed tomography (µCT) images. The infill portion of the sample was modeled using CLT, while the perimeter contour portion was modeled with a rule of mixtures (ROM) approach. Findings The µCT scan images showed that a low porosity of 0.7 ± 0.1% was achieved, and the fibers were highly oriented in the filament extrusion direction. CLT and ROM were effective analytical models to predict the elastic modulus and Poisson’s ratio of FFF 3D printed FRP laminates. Research limitations/implications In this study, the CLT model was only used to predict the properties of flat plates. Once the in-plane properties are known, however, they can be used in a finite element analysis to predict the behavior of plate and shell structures. Practical implications By controlling the raster orientation, the mechanical properties of a FFF part can be optimized for the intended application. Originality/value Before this study, CLT had not been validated for FFF 3D printed FRPs. CLT can be used to help designers tailor the raster pattern of each layer for specific stiffness requirements.

scholarly journals Experimental Validation of an Additively Manufactured Stiffness-Optimized Short-Fiber Reinforced Composite Clevis Joint

2019 ◽  
Vol 59 (6) ◽  
pp. 859-869 ◽  
Author(s):  
Y. Saito ◽  
F. Fernandez ◽  
D.A. Tortorelli ◽  
W.S. Compel ◽  
J.P. Lewicki ◽  
...  
Keyword(s):  
Experimental Validation ◽  
Short Fiber ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite
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