scholarly journals Composites Manufactured by Stereolithography

2021 ◽  
Author(s):  
Patrick Simpson ◽  
Michael Holthaus ◽  
Luke Gibbon ◽  
Chad Ulven

Stereolithography (SLA) is a widely utilized rapid additive manufacturing process for prototypes and proof-of-concept models with high resolution. In order to create structurally sound components using SLA, reinforcement needs to be incorporated in the UV-based resins typically used. However, the introduction of reinforcement into vat-based SLA printers has had limited success due to a host of processing challenges including the creation of a homogeneous resin mixture and UV-inhibiting constituents. The effectiveness of using a dual curing system, consisting of a photo and thermal initiator, for the additive manufacturing of carbon fiber short-fiber composites via vat photopolymerization, was investigated. The necessary processing parameters were developed that resulted in successful printing and curing of composites at a 5% fiber volume. Manufacturing with reinforcements that have different densities from the resin creates separation issues, either suspending to the top or settling to the bottom. Following the approaches discussed in this chapter, an even distribution of short fibers was achieved throughout SLA printed samples using a modified commercial printer. Separation was overcome by inducing a continuous flow of reinforced liquid resin in the printer vat during printing. This flow field adaptation allows commercial SLA printers the ability to produce composite parts with different densities of the constituents utilized.

2011 ◽  
Vol 474-476 ◽  
pp. 548-552
Author(s):  
Jun Tian

Constant stress tensile creep tests were conducted on AZ91D–20 vol.%, 25 vol.%, and 30 vol.% Al2O3-SiO2short fiber composites and on an unreinforced AZ91D matrix alloy. The creep resistance of the reinforced materials is shown to be considerably improved compared with the matrix alloy. With the increasing volume fraction of short fibers, the creep resistance of AZ91D composites is improved, and their creep threshold stresses are also increased accordingly. Because of the increasing volume fraction of short fibers, loads of bearing and transmission of short fibers will increase, and thus the creep resistance of AZ91D composites further improves, but the precipitation of β-Mg17Al12precipitate increases in the number, it is easy to soften coarse, so that threshold stress of AZ91D composite does not increase greatly.


2021 ◽  
Vol 5 (12) ◽  
pp. 325
Author(s):  
Olusanmi Adeniran ◽  
Weilong Cong ◽  
Eric Bediako ◽  
Victor Aladesanmi

The additive manufacturing (AM) of carbon fiber reinforced plastic (CFRP) composites continue to grow due to the attractive strength-to-weight and modulus-to-weight ratios afforded by the composites combined with the ease of processibility achievable through the AM technique. Short fiber design factors such as fiber content effects have been shown to play determinant roles in the mechanical performance of AM fabricated CFRP composites. However, this has only been investigated for tensile and flexural properties, with no investigations to date on compressive properties effects of fiber content. This study examined the axial and transverse compressive properties of AM fabricated CFRP composites by testing CF-ABS with fiber contents from 0%, 10%, 20%, and 30% for samples printed in the axial and transverse build orientations, and for axial tensile in comparison to the axial compression properties. The results were that increasing carbon fiber content for the short-fiber thermoplastic CFRP composites slightly reduced compressive strength and modulus. However, it increased ductility and toughness. The 20% carbon fiber content provided the overall content with the most decent compressive properties for the 0–30% content studied. The AM fabricated composite demonstrates a generally higher compressive property than tensile property because of the higher plastic deformation ability which characterizes compression loaded parts, which were observed from the different failure modes.


2019 ◽  
Vol 809 ◽  
pp. 509-514
Author(s):  
Olaf Reichert ◽  
Larisa Ausheyks ◽  
Stephan Baz ◽  
Joerg Hehl ◽  
Götz T. Gresser

Increasing waste streams of carbon fibers (CF) and carbon fiber reinforced plastics (CFRP) lead to increasing need for recycling and to growing amounts of recycled carbon fibers. A main issue in current research for carbon fiber recycling is the reuse of regained fibers. Carbon staple fibers such as recycled fibers hold big potential for mechanical properties of lightweight parts, if used properly. Applying recycled CF (rCF) as milled reinforcement fibers or as nonwoven in carbon fiber reinforced plastic leads to a poor yield of mechanical proper due to low fiber orientation, limitations in fiber volume content or due to short fiber length. The rC staple fiber tape presents a more efficient approach. Recycled carbon fibers are blended with 50 wt. % thermoplastic nylon 6 fibers and processed through a roller card to a sliver, which is a linear fibrous intermediate. The sliver is continuously drawn, formed, heated and consolidated to the thermoplastic rC staple fiber tape. The tape is similar to common carbon fiber tapes or to continuous tows but has different positive properties, such as high fiber orientation, homogeneous blend of fiber and matrix and suitability for deep drawing.


2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Paryanto Dwi Setyawan ◽  
Nasmi Herlina Sari ◽  
Dewa Gede Pertama Putra

Composite manufacturing is done by hand lay-up method with a fiber volume fraction 10%, 20%, 30%, and 40% with unidirectional and random short fiber orientation of pineapple leaves. Specimen testing is performed with a standard tensile strength test ASTM D3039. As a results is known that the tensile strength of composites increased with increasing fiber volume fraction for unidirectional fiber orientation, but rather to the random orientation of short fibers. Meanwhile, the composite tensile strain increases withincreasingfibervolume fractionfor both theorientation of thefibersof pineappleleaves.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1597 ◽  
Author(s):  
Suhyun Lee ◽  
Kwangduk Ko ◽  
Jiho Youk ◽  
Daeyoung Lim ◽  
Wonyoung Jeong

In this study, carbon nanotubes (CNTs) were introduced into carbon fiber (CF) wet-laid composites as functional nano-fillers to fabricate multi-functional composites with improved mechanical, electrical, and thermal properties. It was considered that the wet-laid process was most suitable in order to introduce filler into brittle and rigid carbon fiber substrates, and we established the conditions of the process that could impart dispersibility and bonding between the fibers. We introduced polyamide 6 (PA6) short fiber, which is the same polymeric material as the stacking film, into carbon fiber and CNT mixture to enhance the binding interactions between carbon fiber and CNTs. Various types of CNT-reinforced carbon fiber wet-laid composites with PA6 short fibers were prepared, and the morphology, mechanical and electrical properties of the composites were estimated. As CNT was added to the carbon fiber nonwoven, the electrical conductivity increased by 500% but the tensile strength decreased slightly. By introducing short fibers of the same material as the matrix between CNT–CF wet-laid nonwovens, it was possible to find optimum conditions to increase the electrical conductivity while maintaining mechanical properties.


1982 ◽  
Vol 49 (3) ◽  
pp. 536-540 ◽  
Author(s):  
Y. Takao ◽  
T. W. Chou ◽  
M. Taya

This paper examines the effective longitudinal Young’s modulus of composites containing misoriented short fibers. The analysis is based on the Eshelby’s equivalent inclusion method and the average induced strain approach of Taya, Mura, and Chou. The present approach is unique in that it takes into account the interactions among fibers at different orientations. Numerical results are presented to demonstrate the effects of fiber elastic property, aspect ratio, volume fraction, and orientation distribution function on composite Young’s modulus. Fiber orientation distribution has a more significant effect on composite longitudinal Young’s modulus than fiber volume friction, within the range examined.


2004 ◽  
Vol 261-263 ◽  
pp. 1073-1078 ◽  
Author(s):  
Yasuo Ochi ◽  
Kiyotaka Masaki ◽  
Takashi Matsumura ◽  
M. Wadasako

The rotating bending fatigue tests in high cycle region were carried out on alumina short fiber reinforced aluminum alloy composites (MMCs) at room and elevated temperatures of 200, 350, 400 and 450°C. The four kind of MMCs with 0%, 10%, 18% and 25% volume fraction were prepared in order to investigate the effects of alumina short fiber volume fraction on the fatigue property such as the fatigue strength, the crack initiation and propagation behaviors. As results, it was found that the fatigue strength at 107 cycles decreased with increase in the test temperature, but increased with an increase in alumina short fiber volume fraction at room and elevated temperatures. The crack initiation sites were large size alumina short fibers; some kind of cluster of short fibers and large size alumina particles (i.e. shots). And the crack growth paths were related to the distribution of the short fibers.


TAPPI Journal ◽  
2015 ◽  
Vol 14 (6) ◽  
pp. 353-359 ◽  
Author(s):  
PETER W. HART ◽  
RICARDO B. SANTOS

Eucalyptus plantations have been used as a source of short fiber for papermaking for more than 40 years. The development in genetic improvement and clonal programs has produced improved density plantations that have resulted in fast growing, increased fiber volume eucalypts becoming the most widely used source of short fibers in the world. High productivity and short rotation times, along with the uniformity and improved wood quality of clonal plantations have attracted private industry investment in eucalypt plantations. Currently, only a handful of species or hybrids are used in plantation efforts. Many more species are being evaluated to either enhance fiber properties or expand the range of eucalypt plantations. Eucalyptus plantations are frequently planted on nonforested land and may be used, in part, as a means of conserving native forests while allowing the production of high quality fiber for economic uses. Finally, eucalypt plantations can provide significant carbon sinks, which may be used to help offset the carbon released from burning fossil fuels. The development and expansion of eucalypt plantations represents a substantial revolution in pulp and paper manufacturing.


2021 ◽  
Vol 13 (15) ◽  
pp. 2877
Author(s):  
Yu Tao ◽  
Siting Xiong ◽  
Susan J. Conway ◽  
Jan-Peter Muller ◽  
Anthony Guimpier ◽  
...  

The lack of adequate stereo coverage and where available, lengthy processing time, various artefacts, and unsatisfactory quality and complexity of automating the selection of the best set of processing parameters, have long been big barriers for large-area planetary 3D mapping. In this paper, we propose a deep learning-based solution, called MADNet (Multi-scale generative Adversarial u-net with Dense convolutional and up-projection blocks), that avoids or resolves all of the above issues. We demonstrate the wide applicability of this technique with the ExoMars Trace Gas Orbiter Colour and Stereo Surface Imaging System (CaSSIS) 4.6 m/pixel images on Mars. Only a single input image and a coarse global 3D reference are required, without knowing any camera models or imaging parameters, to produce high-quality and high-resolution full-strip Digital Terrain Models (DTMs) in a few seconds. In this paper, we discuss technical details of the MADNet system and provide detailed comparisons and assessments of the results. The resultant MADNet 8 m/pixel CaSSIS DTMs are qualitatively very similar to the 1 m/pixel HiRISE DTMs. The resultant MADNet CaSSIS DTMs display excellent agreement with nested Mars Reconnaissance Orbiter Context Camera (CTX), Mars Express’s High-Resolution Stereo Camera (HRSC), and Mars Orbiter Laser Altimeter (MOLA) DTMs at large-scale, and meanwhile, show fairly good correlation with the High-Resolution Imaging Science Experiment (HiRISE) DTMs for fine-scale details. In addition, we show how MADNet outperforms traditional photogrammetric methods, both on speed and quality, for other datasets like HRSC, CTX, and HiRISE, without any parameter tuning or re-training of the model. We demonstrate the results for Oxia Planum (the landing site of the European Space Agency’s Rosalind Franklin ExoMars rover 2023) and a couple of sites of high scientific interest.


2019 ◽  
Vol 3 (2) ◽  
pp. 35 ◽  
Author(s):  
Miguel Reis Silva ◽  
António M. Pereira ◽  
Nuno Alves ◽  
Gonçalo Mateus ◽  
Artur Mateus ◽  
...  

This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.


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