scholarly journals Rotational 3D printing of damage-tolerant composites with programmable mechanics

2018 ◽  
Vol 115 (6) ◽  
pp. 1198-1203 ◽  
Author(s):  
Jordan R. Raney ◽  
Brett G. Compton ◽  
Jochen Mueller ◽  
Thomas J. Ober ◽  
Kristina Shea ◽  
...  
Keyword(s):  
3D Printing ◽  
Mechanical Performance ◽  
Damage Tolerance ◽  
Short Fibers ◽  
Natural Systems ◽  
Performance Space ◽  
Natural Composites ◽  
And Performance ◽  
Damage Tolerant ◽  
Carbon Fiber Epoxy

Natural composites exhibit exceptional mechanical performance that often arises from complex fiber arrangements within continuous matrices. Inspired by these natural systems, we developed a rotational 3D printing method that enables spatially controlled orientation of short fibers in polymer matrices solely by varying the nozzle rotation speed relative to the printing speed. Using this method, we fabricated carbon fiber–epoxy composites composed of volume elements (voxels) with programmably defined fiber arrangements, including adjacent regions with orthogonally and helically oriented fibers that lead to nonuniform strain and failure as well as those with purely helical fiber orientations akin to natural composites that exhibit enhanced damage tolerance. Our approach broadens the design, microstructural complexity, and performance space for fiber-reinforced composites through site-specific optimization of their fiber orientation, strain, failure, and damage tolerance.

scholarly journals Preparation and Performance Evaluation of Duotone 3D-Printed Polyetheretherketone as Oral Prosthetic Materials: A Proof-of-Concept Study

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1949
Author(s):  
Ling Ding ◽  
Wei Lu ◽  
Jiaqi Zhang ◽  
Chuncheng Yang ◽  
Guofeng Wu
Keyword(s):  
Titanium Dioxide ◽  
Performance Evaluation ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Flexural Properties ◽  
Proof Of Concept ◽  
Tooth Color ◽  
Dental Application ◽  
3D Printed ◽  
And Performance

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.

scholarly journals Effects of 3D Printing-Line Directions for Stretchable Sensor Performances

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1791
Author(s):  
Chi Cuong Vu ◽  
Thanh Tai Nguyen ◽  
Sangun Kim ◽  
Jooyong Kim
Keyword(s):  
3D Printing ◽  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Optimal Solution ◽  
Human Motion ◽  
Repeated Measurements ◽  
Fused Filament Fabrication ◽  
And Performance ◽  
The Times ◽  
Stretchable Sensors

Health monitoring sensors that are attached to clothing are a new trend of the times, especially stretchable sensors for human motion measurements or biological markers. However, price, durability, and performance always are major problems to be addressed and three-dimensional (3D) printing combined with conductive flexible materials (thermoplastic polyurethane) can be an optimal solution. Herein, we evaluate the effects of 3D printing-line directions (45°, 90°, 180°) on the sensor performances. Using fused filament fabrication (FDM) technology, the sensors are created with different print styles for specific purposes. We also discuss some main issues of the stretch sensors from Carbon Nanotube/Thermoplastic Polyurethane (CNT/TPU) and FDM. Our sensor achieves outstanding stability (10,000 cycles) and reliability, which are verified through repeated measurements. Its capability is demonstrated in a real application when detecting finger motion by a sensor-integrated into gloves. This paper is expected to bring contribution to the development of flexible conductive materials—based on 3D printing.

New Rotor with Variable Clearance in the Short Fiber Rubber Composite Mixing

2013 ◽  
Vol 328 ◽  
pp. 387-392
Author(s):  
Cai Jun Liu ◽  
Chuan Sheng Wang
Keyword(s):  
Production Efficiency ◽  
Short Fiber ◽  
Short Fibers ◽  
Mixing Chamber ◽  
Small Clearance ◽  
Rubber Composite ◽  
Mixing Quality ◽  
And Performance

The mixing mechanism of short fiber/rubber composite was analyzed. The clearance between the rotor edge peak and mixing chamber influenced mixing, dispersion and length of the short fibers in compound. The new rotor was designed with variable clearance. The large clearance gap improve the mixing, and the small clearance gap helped to improve the dispersion of short fiber. The mixing quality and performance of short fiber/rubber composite were improved by using the new rotor, and the production efficiency increased.

The Masks of Greek Tragedy as Point of Departure for Modern Performance

2001 ◽  
Vol 17 (3) ◽  
pp. 254-272 ◽  
Author(s):  
Chris Vervain ◽  
David Wiles
Keyword(s):  
Greek Tragedy ◽  
Research Programme ◽  
Cambridge University ◽  
Performance Space ◽  
And Performance ◽  
The University ◽  
Near Future ◽  
Point Of Departure ◽  
Valuable Point ◽  
New Comedy

In this article, David Wiles and Chris Vervain stake out the ground for a substantial programme of continuing research. Chris Vervain, coming from a background in visual and performance art, is in the first instance a maker of masks. She is also now writing a thesis on the masks of classical tragedy and their possibilities in modern performance, and, in association with the University of Glasgow, working on an AHRB research programme that involves testing the effect of Greek New Comedy masks in performance. David Wiles, Professor of Theatre at Royal Holloway, University of London, has published books on the masks of Greek New Comedy and on Greek performance space, and lectured on Greek masks. Most recently, his Greek Theatre Performance: an Introduction (Cambridge University Press, 2000) included an investigation of the classical mask and insights provided by the work of Lecoq. He is now planning a book on the classical Greek mask. Wiles and Vervain are both committed to the idea that the mask was the determining convention which gave Greek tragedy its identity in the ancient world, and is a valuable point of departure for modern practitioners engaging with the form. They anticipate that their research will in the near future incorporate a symposium and a further report on work-in-progress.

Recently-Developed Aluminium Solutions for Aerospace Applications

2006 ◽  
Vol 519-521 ◽  
pp. 1271-1278 ◽  
Author(s):  
Timothy Warner
Keyword(s):  
New Technologies ◽  
Damage Tolerance ◽  
Grain Structure ◽  
Space Applications ◽  
Metallic Structures ◽  
Performance Improvements ◽  
The Past ◽  
Aerospace Applications ◽  
Aerospace Alloys ◽  
Damage Tolerant

Two principal approaches are available to materials’ engineers to improve the overall cost-weight balance of metallic airframe structures: improving alloy performance and optimising materials’ utilisation. Although both approaches have been successful in the past, they are most effective when applied concomitantly. The Aluminium industry has a long record of improving aerospace alloys’ performance. Nevertheless, even in apparently well-explored alloy systems such as the 7xxx family, products with improved damage tolerance-strength balances have recently been developed, thanks to an improved understanding of the optimum Zn-Mg-Cu combinations for the required property balances but also to developments in casting capability. Novel dispersoids and dispersoid combinations have enabled further improvements of the performance of existing alloy families. For example, appropriate Sc and Zr additions have a significant impact on the grain structure of 2xxx alloys and thus on performance. Another high potential approach for alloy performance improvements is the optimisation of Al-Cu-Li-(Mg-Ag-Zn) alloys. These so-called “third generation Al-Li alloys” were principally developed for military and space applications; in order to meet the demands of future commercial airframes, more damage tolerant variants are being developed. AA2198 and AA2050 are used to illustrate the potential of these higher damage tolerance Al-Cu-Li alloys. However, materials performance improvements are only part of the potential developments of metallic solutions for airframes. Further gains of a similar magnitude in component weight and cost can be achieved by applying new technologies and new design solutions to metallic structures. The future of metallic airframes will depend on the concomitant application of both these approaches.

3D Printable Resources for Engaging STEM Students in Laboratory Learning Activities and Outreach Programs: Inexpensive and User-Friendly Instrument Kits for Educators

MRS Advances ◽  
2018 ◽  
Vol 3 (49) ◽  
pp. 2937-2942 ◽  
Author(s):  
Lon A. Porter
Keyword(s):  
3D Printing ◽  
Mathematics Learning ◽  
Digital Design ◽  
Outreach Programs ◽  
Stem Students ◽  
3D Printed ◽  
Design Software ◽  
And Performance ◽  
And Mathematics ◽  
User Friendly

ABSTRACTContinued advances in digital design software and 3D printing methods enable innovative approaches in the development of new educational tools for laboratory-based STEM (science, technology, engineering and mathematics) learning. The decreasing cost of 3D printing equipment and greater access provided by university fabrication centers afford unique opportunities for educators to transcend the limitations of conventional modes of student engagement with analytical instrumentation. This work shares successful efforts at Wabash College to integrate user-friendly and inexpensive 3D printed instruments kits into introductory STEM coursework. The laboratory kits and activities described provide new tools for engaging students in the exploration of instrument design and performance. These experiences provide effective ways to assist active-learners in discovering the technology and fundamental principles of analysis and deliberately confront the “black box” perception of instrumentation.

Performance Oriented Design of Semiregular Anisotropic Porous Structures

2018 ◽  
Author(s):  
Chao Xu ◽  
Lili Pan ◽  
Ming Li ◽  
Shuming Gao
Keyword(s):  
3D Printing ◽  
Porous Materials ◽  
Design Problem ◽  
Degrees Of Freedom ◽  
Design Space ◽  
Manufacturing Technology ◽  
Porous Structures ◽  
Precise Control ◽  
And Performance

Porous materials / structures have wide applications in industry, since the sizes, shapes and positions of their pores can be adjusted on various demands. However, the precise control and performance oriented design of porous structures are still urgent and challenging, especially when the manufacturing technology is well developed due to 3D printing. In this study, the control and design of anisotropic porous structures are studied with more degrees of freedom than isotropic structures, and can achieve more complex mechanical goals. The proposed approach introduces Super Formula to represent the structural cells, maps the design problem to an optimal problem using PGD, and solves the optimal problem using MMA to obtain the structure with desired performance. The proposed approach is also tested on the performance of the expansion of design space, the capture of the physical orientation and so on.

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