Additive manufacturing is a recent trend in production processes owing to its many benefits. It can be defined as the process of producing parts through the deposition of material in a layer-by-lay...

https://journals.sagepub.com/doi/pdf/10.1177/1687814018822880

Additive manufacturing: Challenges, trends, and applications:

Additive manufacturing in unmanned aerial vehicles (UAVs): Challenges and potential

A gradient-refractive-index radar absorbing structure(GRINRAS) for stealth aircraft is proposed in this paper. It is a layered shell composed of a gradient-refractive-index (GRIN) refractor, an absorber and a reflector. The GRIN refractor consists of the isotropic non-resonant woodpile metamaterials, which was designed according to the permittivity distribution equation of the electromagnetic(EM) black hole to bend and match the waves from the air to the radar absorbing structure. The absorber dissipates the EM waves and transforms them into the heat energy. The reflector reflects the EM waves to the absorber and prevents them from entering the inner space of the structure. A ring and a board GRINRAS were designed, and then fabricated by the three-dimensional (3D) printing process of stereolithography (SL). Simulation and experimental results show that the GRINRASes can control the wave propagation and their absorption capacity is better than −10 dB in the broadband of 12–18 GHz. The GRIN refractor and the absorber have almost equal contributions to the absorption capability. This is the first radar absorbing composite structure composed of the gradient 3D metamaterials. It demonstrates the feasibility of using the metamaterials and 3D printing technology in the innovative radar absorbing structure (RAS) of the stealth aircraft.

Design and characterization of radar absorbing structure based on gradient-refractive-index metamaterials

The proficiency to three-dimensional (3D) interweaves engineering complex structures enables component engineering with heterogeneous geometries, attributing mechanically robust lightweight cellular structures. 3D printing proffers versatile contingencies toward the single-step engineering of near-net heterogeneous 3D structure for engineering application. For enhancing the current spectrum of 3D printing technologies and rising concern toward environmental issues, 3D printing of bioactive polylactic acid is extensively exploited owing to its biodegradability and renewable aspects. Synchronously, curiosity for 3D printed composites through fiber infusion has led to the configuration of high-performance composites with augmented mechanical, physical, and chemical attributes, paving its way for wide-array engineering applications.

Review on Three-Dimensionally Emulated Fiber-Embedded Lactic Acid Polymer Composites: Opportunities in Engineering Sector

Received: 3 September 2020 Accepted: 17 December 2020 In the era of Digital Manufacturing and supporting state-of-the-art, i.e. Additive manufacturing (AM) technology is getting more popular known as 3D printing, AM has created its own space in the fastest growing industry. 3D printing has evolved in previous years, and now, it is being used in several social life domains. The main application of this process has found in prototyping, aerospace industry, biomedical and dental implants. Additive manufacturing prints a part in a layer by layer or line by line pattern. It opposes the basic concept of traditional manufacturing. Advances in composite and multi-material manufacturing provide new opportunities for the convenient manufacture of lightweight parts and modern products, such as flapping wings, satellite brackets, and lightweight components for the aviation industry. It is a particular technology that varies from conventional and subtractive development in terms of lightweight, enhanced features, lower fuel consumption, and optimized machine performance, so on. This paper addressed the progress of AM in the aerospace field and addressed the issues of AM linked to a specific aerospace component.

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A Review of Additive Manufacturing in Aerospace Application

This paper reports on a feasibility study to explore the impact of advanced manufacturing on the production and
maintenance of a 3D printed, unmanned aerial vehicle (UAV) in theatre. Specifically, this report focuses on fused
deposition modeling (FDM), the selective deposition of a molten thermoplastic. FDM is already a forward deployed
technology, primarily used for printing custom tools and replacement parts. The authors ask if it is feasible to expand the
printers’ capacity to produce aerial platforms; the reduction in logistics and labor could significantly decrease costs per
unit and enable far more platform customization and specialized deployment scenarios than are available in existing
aircraft.
The University of Virginia and The MITRE Corporation designed and built a prototype, 3D printed UAV for use as an
aerial sensor platform. This report
• Discusses the printed aerial platform, summarizes the design process, and compares printing methods
• Describes the benefits and limitations to selecting FDM printers as the technology both for deployment as well
as UAV design
• Concludes with the current state and future expectations for FDM printing technologies relevant to UAV
production.
Our findings suggest that although 3D printing is not yet entirely field-ready, many of its advantages can already be
realized.

Jonathan Rotner

Papers

Using advanced manufacturing to produce unmanned aerial vehicles: a feasibility study

Small Unmanned Aircraft: Characterizing the Threat