The current challenges facing the aerospace domain require unconventional solutions, which could be sought in new configurations of future aircraft and spacecraft. The choice of optimal concepts requires the consideration of a significant amount of competing engineering solutions and takes place under conditions of uncertainty. Such a problem can be addressed by enhancing existing methods for analysis and synthesis solutions, such as the Advanced Morphological Approach (AMA). It uses morphological analysis to provide a more exhaustive overview of possible problem solutions, relies on expert evaluations of alternative technological options and applies clustering to the solution space. Although an intuitive method for structured concept generation, the AMA exposes the need for more robust problem structuring, improved objectivity of options evaluation and accounting for uncertainties. The current article suggests ways to overcome these challenges and their possible integration in the process. In particular, the integration of fuzzy sets is proposed to model uncertainties during the evaluation of technological options by the experts. The Fuzzy Analytical Hierarchy Process is adapted for integration into the AMA and for the conceptual design of aerospace vehicles.
Disruptive technologies and novel aircraft generations represent a potential approach to address the ambitious emission reduction goals in aviation. However, the introduction of innovative concepts is a time-consuming process, which might not necessarily yield an optimal design for a given flight mission and within the defined time frame. In order to address the need for a structured and more exhaustive search for novel concept generations, the Advanced Morphological Approach (AMA) and its further enhancement was introduced earlier. It implies the decomposition of design problems into functional attributes and appropriate technological alternatives. Subsequently, these are evaluated and combined into solutions, which are then projected onto a solution space. The current paper focuses on the technology evaluation step by deriving and integrating structured expert judgment elicitation (SEJE) techniques into conceptual aircraft design with the AMA. For this purpose, the first aim of the work is to justify the developed method by giving an overview and discussing the most prominent SEJE methods and their applications in aerospace. Then, the derived SEJE concept is described and applied in the form of an expert workshop on the use case of wing morphing architecture. As a result, a solution space of wing morphing architecture configurations is generated and analyzed. The workshop conduction and the expert feedback serve as valuable findings for both the further AMA enhancement and similar research.
This work shows a study of the effect of the non-uniformity of photocathode response on 8 the energy resolution of plastic scintillators optimized for pulse-shape discrimination. 9The studies were performed with Hamamatsu R7600U-200 and R9779 photomultiplier tubes. The pulse-height and pulse-shape spectra were obtained for a small piece of radon-222 loaded plastic scintillator positioned at different places on the photocathode. We show that alpha spectra can be approximated well with a normal distribution if the nonuniformity of the photon response of the photocathode is minimized. In the cases when the non-uniformity cannot be minimized, we propose an analytical function which describes well the shape of the alpha peaks in a broad set of conditions. A possible effect of the non-uniformity of the photocathode response on the primary activity measurements by liquid scintillation counting is highlighted.
The development of innovative aircraft configurations can be an important contribution to achieve the emission reduction goals set for the aviation industry. However, current common aircraft conceptual design processes only allow the consideration of a limited number of initial configurations thus leaving possibly more efficient solutions out of scope. A significantly wider range of aircraft configurations can be taken into account by applying the Morphological Analysis. After a brief presentation of its historical background and actual applications in other domains, this article focuses on the use of this method and its benefits in aerospace. The summary and comparison of several applications in the field of aircraft design show that these still require a higher level of formalisation and robustness. For this purpose, the main steps required to integrate morphological analysis into the aircraft conceptual design phase based on the Advanced Morphological Approach are identified. These are the definition of the morphological matrix along with the evaluation criteria, the obtaining of option evaluations, filtering the impossible solutions and exploration of the solution space.
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