Preliminary design trades for the liquid hydrogen storage system of a short-range aircraft are presented. Two promising insulation methods, namely rigid foam and multilayer insulation, are identified as main design drivers. In addition, the maximal pressure and the shape of the hydrogen storage tank influence the aircraft performance and the insulation efficiency. In this study, the hydrogen storage tanks are integrated in wing pods. The main effects driven by the design parameters are addressed using conceptual and preliminary methods: models are carried out for the storage mass, additional drag, propeller efficiency loss and the dynamical thermodynamic behavior of the liquid hydrogen storage. These effects are coupled making an integrated design method necessary. For the sizing of the liquid hydrogen storage, a multidisciplinary workflow is set up including the aircraft sensitivities on the design mission block fuel. The trade-off study reveals the opposing trend between insulation efficiency and aircraft performance. For the insulation architecture based on rigid foam, the penalties implied by the storage tank on aircraft level and the penalties due to vented hydrogen can be balanced and result in minimal block fuel for the design mission. The application of multilayer insulation avoids venting during the design mission, but has an increased penalty on the aircraft performance compared to rigid foam insulation. Besides the criterion of minimal block fuel, the dormancy time is compared, indicating the thermal efficiency. Applying multilayer insulation, the dormancy time can be increased significantly calling for a discussion of operational requirements for hydrogen-powered aircraft.

View Video Presentation: https://doi.org/10.2514/6.2021-3200.vid Urban Air Mobility (UAM) is increasingly becoming popular for Passenger or Cargo movement in dense smart cities. Several researches so far are focused on individual vehicle architectures such as multirotor or tiltrotor etc., but not much effort in a System of systems point of view where a homogenous fleet of vehicle with different passenger capacity, speed, and propulsive energy concepts are assessed in a framework for a successful UAM operations in a given city. An effort is made in this paper wherein, vehicle architecture is derived from the Concept of Operations (CONOPS) of scenarios such as urban and suburban operations and as well as propulsion subsystem for sustainable UAM. This paper approaches UAM aircraft design driven by System of Systems (SoS) approach and an agent-based simulation supports the vehicle architecture evaluation and fleet definition. The outcome of this study are: multiple aircraft design with subsystem architectures, ideal fleet size for the respective operational scenarios, autonomy and battery technology effectiveness on UAM throughput (to efficiently provide UAM on-demand service maximum passengers within 15 min wait time), and importantly, sustainability metrics such as total fleet energy required. Several System of Systems, system and subsystem level sensitivity research questions are addressed to understand the interlevel coupling.

Aircraft manufacturers provide their customers with a number of options for aircraft customization, including a wide variety of pre-qualified optional equipment from which they can select different components according to their requirements. The numerous options cover a variety of engines, navigation systems, and interior cabin designs. This flexibility gives the possibility to the airlines to differentiate their brands. Moreover, a unique cabin interior design leaves an enduring impression on their customers and constitutes their expectations for the upcoming flight. On the other hand, many choices result in many different specifications, long delivery periods, complicated installation procedures such as stopping the running assembly of the cabin, disassembling already installed cabin components, and assembling new cabin models. Therefore, aircraft customization increases the cost and the lead time of the aircraft manufacturing processes and thus decreases the production rates. It is in the best interest of aircraft manufacturers and airlines to automate and optimize the customization processes to make them more time and cost efficient. This paper presents a method for establishing reconfigurable and optimized scheduling for aircraft cabin assembly. The data necessary for calculating the optimal schedule are retrieved from cabin system architecture that is built with semantic web language. The focus is on building a system architecture ontology model for automated scheduling of assembly processes of an aircraft cabin, which opens up the possibility for cabin customization at every assembly step. Moreover, the cabin ontology can be used as a foundation for co-design where each expert of their branch can further upgrade the model. With the algorithm presented in this paper, the ontology can be upgraded with new data, which will automatically correlate with the existing data in the cabin ontology. The knowledge-based ontology model provides a view of the whole chain from design to realization and feedback links to all included parties. Moreover, it gives the possibility for agile changes in the assembly sequence in response to the updated demands of the clients.

The aviation industry is currently facing major challenges due to environmental and socio-economic trends toward sustainable and digitalized aviation. Revolutionary, more powerful and efficient technologies must be rapidly integrated into aircraft, while aircraft manufacturers must demonstrate the required safety. To support the implementation of new concepts, the DLR Institute of System Architectures in Aeronautics is researching methods for end-to-end digitalization from the preliminary design phase to assembly and production. In this context, Model-Based Systems Engineering (MBSE) and Multidisciplinary Design Optimization are important approaches for the development of complex systems. This paper presents a method for the end-to-end use of digital models for multidisciplinary optimization of system architectures. The Systems Modeling Language (SysML) is used to represent the system architecture. The focus is on the cabin and cabin systems, since they are highly coupled to other aircraft systems and have dynamic, customer-specific configuration requirements. The system architecture in SysML is instantiated and configured by the interface to the aircraft fuselage and cabin design parameter sets in the Common Parametric Configuration Schema. The subsequent coupling of the generated system architecture model with the cabin system design model developed in Matlab allows a multidisciplinary optimization of the system properties. A sensitivity analysis is performed using the Passenger Service Unit as an example. The effects of different cabin configurations on the system architecture are investigated and interdisciplinary synergies are identified and analyzed. The results of this analysis are discussed in this paper.

Model-based systems engineering (MBSE) is a fundamental approach for the end-to-end use of digital models in the development of complex systems. The aviation industry in particular, where system complexity is constantly increasing, needs new concepts and methods to overcome ecological and socio-economic challenges. Therefore, domain-specific models are needed for the design and evaluation of systems to support the various system investigations, such as requirements management, installation space optimization, or failure analyses. An end-to-end coupling and linking of these mostly heterogeneous systems offer many advantages (e.g. shorter development times) over working with isolated digital sub-models, natural language documents, and purely physical prototypes. In addition, digitalization allows global and interdisciplinary collaboration of multiple teams of experts on the same virtual product. Since this approach is particularly promising for the configuration of aircraft cabins, a virtual development platform is developed at the German Aerospace Center (DLR) for the conceptual design of the aircraft cabin and its systems. As a result, virtual prototypes of cabin configurations are quickly generated to allow new concepts to be visualized and investigated at an early design stage. Extending the conceptual cabin system design process with a functional system architecture and executable system architecture models promotes information traceability, early failure detection, and requirements verification. The methodology used for this purpose is presented in this paper. The systems modeling language (SysML) is used to build a model for the functional depiction of cabin systems and to link it to existing models of the conceptual cabin design process. The modeling is performed exemplarily for the passenger service functions. Subsequently, the results are automatically transferred to the virtual development platform to experience the generated cabin concept.