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ItemCFD Analysis of Buzz Saw Noise Employing Time-Domain Non-Linear Impedance Boundary Conditions(AIAA, 2024)Buzz saw noise emerges in turbofan engines featuring supersonic blade tip speeds and perturbed blade loadings. Such conditions occur at high-power climbing operations and result in considerable noise emissions. This paper employs Computational Fluid Dynamics (CFD) simulation to illustrate the non-linear interaction between the buzz saw noise generating mechanism and acoustic liners in a generic UHBR engine. Blade loading perturbations are modeled by applying blade twist deviations. Additionally, a newly developed time-domain non-linear impedance model is introduced as a boundary condition to incorporate the effects of acoustic liners. The study investigates the impact of both applied twist deviations and liners on the resulting buzz saw noise spectrum. The results demonstrate the capability of CFD simulation to accurately model buzz saw noise. Future research should focus on validating these results, improving the dynamics of the liner model, exploring the benefits of non-uniform liner design, and investigating aeroelastic interactions with liners.
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ItemDevelopment of a production approach to build a titanium flaperon rib by directed energy deposition(Springer, 2023)Laser powder-directed energy deposition (LP-DED) is gaining interest in the production of complex large parts at a high production rate compared to conventional machining. Typically, these products are milled out of solid blocks. The aim of this work is to show the whole production chain to manufacture a titanium flaperon rib starting from the process optimisation to production and post-processing of the part itself. First, the process parameters for thin and bulky structures were optimised in LP-DED. Then different characteristic design features of the rib were defined and the manufacturing strategies were optimised. Lastly, all optimised strategies were applied for the production of the full-scale flaperon ribs. In this work, several design guidelines and optimum process conditions were obtained for Ti6Al4V processed by LP-DED. On one hand, the process parameters for thin walls and solid features were obtained. In addition, intersections and overhang structures were studied to achieve stable and high-quality connections. On the other hand, different strategies for reducing the deformations were studied and minimum deformations were obtained for large slender build plates. All developed strategies were implemented to successfully produce a large-sized flaperon rib in Ti6Al4V by powder LP-DED.
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ItemTopology optimization for the design of a 3D-printed rotating shaft balance(Springer, 2023)Rotating shaft balances (RSBs) are devices that are used to measure rotor blade forces and moments of wind tunnel models during wind tunnel tests. The design of an RSB can be challenging, because it has to comply with many and sometimes contradicting requirements such as high stiffness and high strain gauge bridge outputs. The manufacturing of a conventional RSB consists of different subsequent steps, which can be time consuming, expensive and associated with many risks. Therefore, in this work, the authors investigate if a RSB can be designed by topology optimization and manufactured by 3D printing. A topology optimization method was developed with as design objective the minimization of strain energy with constraints for the volume of the RSB’s midsection, defined stresses at strain gauge locations used for the measurement of axial force and torque and an overhang constraint for additive manufacturing. The optimal preliminary design found by topology optimization was translated into a final printable design with the highest bridge sensitivity for axial force and torque, sufficient output for in-plane forces and moments and an acceptable safety factor on strength for combined loads. After adding extra supports required for printing, the RSB was successfully printed in metal by the laser powder bed fusion process, resulting in a product without external defects. The same topology optimization and manufacturing method can potentially be used for other balance types, leading to a reduction in total lead time and manufacturing costs while increasing the design freedom.
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ItemAugmented Intelligence for Instructional Systems in Simulation-Based Training(Springer, 2024)Augmented Intelligence is a design pattern for a human-centered collaboration model of people and artificial intelligence (AI), where machines assist humans in tasks such as data analysis, information retrieval, decision-making, and task execution. In this study, the concept of Augmented Intelligence is applied within the context of an instructional system for simulation-based training. Here, the collaboration between human and machine is focused on the role of the instructor, which is to guide the learning process of one or more trainees toward some learning objective. We identify different levels of machine support to assist an instructor in this role during an adaptive training cycle. Additionally, two design aspects are discussed that contribute to increased levels of intelligence, namely the challenge of domain alignment to empower automation capabilities, and the benefits of simulation-based task environments to deliver AI-enabled approaches. Examples are discussed in the context of military training.
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ItemA Literature Review and Proposal Towards the Futher Integration of Haptics in Aviation(Springer, 2024)Flight simulator training is essential for aircraft pilots to learn and maintain the ability to fly specific aircraft for both commercial and defence purposes. With recent advances in extended reality, the implementation thereof has made its way into proposed simulated flight training protocols. In conjunction to the advent of extended reality, research into the use of haptics or the sense of touch within VEs has accelerated. A few challenges persist within simulation training including training effectiveness, level of immersiveness, and the manageable exposure duration per training run. Extended reality experiences face similar challenges. The field of haptics might provide solutions for these challenges. Thus, this paper reviews the state-of-the-art of haptics, current challenges, and possible future applications within aviation simulation and training. It is found that research with respect to the integration of haptics in aviation training and simulation is not yet mature. A lot of potential exists for research into the improvement of training effectiveness, performance and immersiveness within extended reality based simulation for flight training and maintenance engineering purposes via haptics. Based thereupon future work is suggested to look into 1) decreasing simulator sickness by simulating and synchronizing expected real life perturbations within flight simulation via haptic wearables 2) simulating a sense of physical flight within a static simulator set-up by leveraging self-motion 3) enabling physical interaction of aircraft parts digital twins for improving extended reality based maintenance engineering performance by utilizing haptic wearables.