Browse Topic: Fabrication
This specification covers a corrosion and heat-resistant steel in the form of bars, forgings, and forging stock. These products have been used typically for parts requiring oxidation resistance and high strength up to 800 °F (427 °C) and where such parts may require welding during fabrication, but usage is not limited to such applications.
This specification covers bonded honeycomb core made of aluminum alloy and supplied in the form of blocks, slices, or other configurations as ordered.
This specification covers an aluminum alloy in the form of extruded bars, rods, wire, profiles, and tubing.
Blade–wake interaction (BWI) is a significant source of broadband noise and is often dominant in rotors with high blade counts. Accurately capturing the resulting unsteady blade loading is computationally expensive and, therefore, drives the cost of BWI noise calculation. To address this challenge, a low-fidelity BWI noise prediction tool was developed using aerodynamic data from the blade element momentum theory (BEMT) and the lattice Boltzmann method (LBM) for a series of rotor configurations with medium to high solidity. Starting from a six-bladed baseline rotor, 13 additional configurations were generated by varying blade twist, taper, root collective, solidity, and blade count. The relationship between vortex miss distance and blade loading unsteadiness was quantified to construct a semi-empirical BWI noise model. The model predicted BWI noise with a root mean square error of 3.9 dBA and a mean absolute percentage error of 1%. It was subsequently integrated into a BEMT framework
In the proposed article, the authors will focus on two manufacturing method FUSED FILAMENT FABRICATION (FFF) and FUSED DEPOSITION MODELING (FDM) showing examples of application in aviation production and the resulting benefits.
Over 4 decades of research works on the nutating, now pericyclic, mechanical transmission have studied its capability to achieve high power density, low noise, and amplified single-stage reduction ratios of up to 100:1. These analytical efforts have culminated into the fabrication of a 50 HP and 32:1 reduction ratio pericyclic transmission prototype. This work introduces the prototype with highlights of the assembly and alignment procedures validated by static testing evaluation. Then, discussion of the dynamic test stand integration, instrumentation, and lubrication components lay out the framework of the high-speed testing plan. Power transmission data validated the pericyclic reduction ratio model. Accelerometer data demonstrated the transmission's capability to operate at low vibration, with peak amplitudes of 1.2 and 2.5 inches per second on the pericyclic gear train and output shaft respectively. Acoustic emission data captured the first 5 harmonics of the shaft speed as well as
The Autoclave processing is commonly used in manufacturing high-performance fibre-reinforced thermoset composite components in the aerospace industry. Variations in the cure cycle, sometimes even apparently minor deviations from the prescribed cure cycle, can harm the laminate properties. Given the costly and time-consuming autoclave manufacturing process, there is a strong need to cure the maximum number of parts in the shortest possible time without compromising quality. In order to achieve high-rate automated manufacturing with the optimized autoclave process, it is important to construct a digital twin modelling approach to mirror the physical composite curing process in the virtual domain based on the integration of high-fidelity multi-physics models. The resulting digital twin includes a thermal CFD model, a thermo-chemo-mechanical module, and an efficient and accurate block coupling between these two modules. The customized Abaqus driven by local and spatial variation of the
ABSTRACT
ABSTRACT
Bismaleimide (BMI) resins are commonly used in advanced carbon composites for their high service temperature and excellent mechanical properties. In this study, two different BMI resins were compared: 1) formula RS-8HT, a high-cure temperature resin requiring pressurized consolidation, and 2) formula BMI-2, a lower cure temperature resin compatible with vacuum bag only fabrication. The objective was to identify a suitable high-temperature resin system for hybrid aerospace gear application, however, these materials are applicable to a variety of hot-zone parts. Laminates were fabricated from each resin type and characterized by their fiber volume fraction, compression strength vs. temperature, and glass transition temperature (Tg). Optical microscopy was performed to verify laminate quality. It was found that the carbon/RS-8HT laminates were prone to thermally-induced cracking, especially during post-cure. Carbon/BMI-2 laminates were found to attain a high degree of cure and high Tg
Additive Manufacturing (AM) and/or 3-D printing has been used for decades for fabrication of prototyping parts to validate design, geometries and kinematics. The ability to rapidly "grow" one-off and low-volume parts for evaluation and iterative design development is a perfect use of AM processes. As AM materials and machines advance, the repeatability, reproducibility and quality are maturing. Today, AM parts are moving into limited production applications with opportunity for future design features, competitive pricing, lower weight through design optimization, and potential for "on-demand" deliveries. The vast majority of AM parts remain limited to development and prototype phases of a program. As production ramps up, production part fabrications transition to more traditional processes. The higher quantities and schedule demand of production as well as conformity with certified materials and processes still favor traditional manufacturing methods. However, as production ends and
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