| 1. |
- Eek, Magnus
(författare)
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On Credibility Assessment in Aircraft System Simulation
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aeronautical industry is becoming increasingly reliant on Modeling and Simulation (M&S) for use throughout all system development phases, for system verification, and end-user training. To justify and to utilize the full potential of today’s model-based approach, the development of efficient and industrially applicable methods for credibility assessment of M&S efforts is a key challenge.This work addresses methods facilitating credibility assessment of simulation models and simulator applications used in aircraft system development. For models of individual aircraft subsystems, an uncertainty aggregation method is proposed that facilitates early model validation through approximate uncertainty quantification. The central idea is to integrate information obtained during component level validation directly into the component equations, and to utilize this information in model level uncertainty quantification.In addition to methods intended for models of individual subsystems, this work also proposes a method and an associated tool for credibility assessment of large-scale simulator applications. As a complement to traditional document-centric approaches, static and dynamic credibility information is here presented to end-users directly during simulation. This implies a support for detecting test plan deficiencies, or that a simulator configuration is not a suitable platform for the execution of a particular test. The credibility assessment tool has been implemented and evaluated in two large-scale system simulators for the Saab Gripen fighter aircraft. The work presented herein also includes an industrially applicable workflow for development, validation, and export of simulation models.
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| 2. |
- Safavi, Edris, et al.
(författare)
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Implementation of collaborative multidisciplinary design optimization for conceptual design of a complex engineering product
- 2016
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Ingår i: Concurrent Engineering - Research and Applications. - : Sage Publications. - 1063-293X .- 1531-2003. ; 24:3, s. 251-265
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the performance of the collaborative multidisciplinary design optimization framework and how it facilitates the knowledge integration process. The framework is used to design and optimize an innovative concept of a tidal water power plant. The case study helps to highlight the challenges that may occur during implementation. The result is presented as a modified framework with less implementation difficulties. The improved framework shows significant reduction in design time and improvement in collaborative design optimization for a design team. The geometry of the product is optimized to minimize weight and maximize the power generated by the turbine with respect to some mechanical constraints.
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| 3. |
- Munjulury, Raghu Chaitanya, et al.
(författare)
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A comprehensive computational multidisciplinary design optimization approach for a tidal power plant turbine
- 2017
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Ingår i: Advances in Mechanical Engineering. - London : Sage Publications. - 1687-8132 .- 1687-8140. ; 9:3, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Multidisciplinary design optimization has become a powerful technique to facilitate continuous improvement of complex and multidisciplinary products. Parametric modeling is an essential part with tremendous impact on the flexibility and robustness of multidisciplinary design optimization. This article investigates the effect of relational and non-relational parameterization techniques on the robustness and flexibility of the conceptual design of a multidisciplinary product. Bench marking between relational and non-relational parameterization and their effect on flexibility and robustness indicate that the relational parameterization is an efficient method in the multidisciplinary design optimization process. The inherent properties of the method contribute to an efficient parametric modeling with improved communication between different disciplines. This enhances the performance of the multidisciplinary design optimization process and allows a more flexible and robust design. The considered disciplines are computer-aided design, computational fluid dynamics, finite element analysis, and dynamic simulation. A high-fidelity geometry created in a computer-aided design environment is computer-aided design centric approach and later used in computational fluid dynamics, finite element analysis for a better understanding of the product as it leads to precise outcomes. The proposed approach is implemented for the conceptual design of a novel product, a tidal power plant developed by Minesto AB using a multidisciplinary design optimization process.
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| 4. |
- Andersson, Henric, et al.
(författare)
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Experience from Model and Software Reuse in Aircraft Simulator Product Line Engineering
- 2013
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Ingår i: Information and Software Technology. - : Elsevier BV. - 0950-5849 .- 1873-6025. ; 55:3, s. 595-606
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Tidskriftsartikel (refereegranskat)abstract
- Context: "Reuse" and "Model Based Development" are two prominent trends for improving industrial development efficiency. Product lines are used to reduce the time to create product variants by reusing components. The model based approach provides the opportunity to enhance knowledge capture for a system in the early stages in order to be reused throughout its lifecycle. This paper describes how these two trends are combined to support development and support of a simulator product line for the SAAB 39 Gripen fighter aircraft.Objective: The work aims at improving the support (in terms of efficiency and quality) when creating simulation model configurations. The objective is to increase the level of reuse when combining and customizing models for usage in a range of development and training simulators.Method: The research has been conducted with an interactive approach using prototyping and demonstrations, and the evaluation is based on an iterative and a retrospective method.Results: A product line of simulator models for the SAAB 39 Gripen aircraft has been analyzed and defined in a Product Variant Master. A configurator system has been implemented for creation, integration, and customization of stringent simulator model configurations. The system is currently under incorporation in the standard development process at SAAB Aeronautics.Conclusion: The explicit and visual description of products and their variability through a configurator system enables better insights and a common understanding so that collaboration on possible product configurations improves and the potential of software reuse increases. The combination of application fields imposes constraints on how traditional tools and methods may be utilized. Solutions for Design Automation and Knowledge Based Engineering are available, but their application has limitations for Software Product Line engineering and the reuse of simulation models.
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| 5. |
- Drego, Adelia Darlene, 1987-
(författare)
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On Early Product Development in the Context of Aircraft Thermal Management Design
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Military aircraft face several contemporary challenges. From a thermal management perspective, they include the more extensive use of electrically driven technologies and more power-hungry tactical systems. These systems demand more cooling power from the aircraft thermal management system. Thermal management systems of modern aircraft face another challenge with shrinking heat sink capability. This is because of platform design aspects. Increasing use of composite materials for airframe skin over traditional metals impedes the dissipation of waste heat through skin. Infrared and radar cross-section signatures are minimised to improve aircraft stealth by minimising the cross-sectional areas of ram air intakes. This reduces the amount of waste heat that can be dumped over-board through ram air. And there are only two options for heat sinks, air (ram or engine fan) and fuel. All these contemporary challenges create a strong need to carry out thermal management design effectively at the aircraft concept stage.A framework is presented in this thesis that demonstrates how effective thermal management design at the concept stage can be conducted at an aircraft developer like Saab. The framework was created with data collection through workshops, document studies, interviews, and group discussions conducted at Saab. Therefore, the framework is based on industrial reality. It can be tested for application at the aircraft concept stage of Saab projects. Further, the methods created in this thesis can be used in a broader context that transcend their primary application in thermal management design. They can also complement other methods presented in literature on aircraft thermal management. Thus, this thesis makes industrial and scientific contributions to aircraft thermal management design.
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| 6. |
- Eek, Magnus, et al.
(författare)
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A Framework for Early and Approximate Uncertainty Quantification of Large System Simulation Models
- 2015
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Ingår i: Proceedings of the 56th Conference on Simulation and Modelling (SIMS 56), October, 7-9, 2015, Linköping University, Sweden. - Linköping : Linköping University Electronic Press. - 9789176859001 ; , s. 91-104
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Konferensbidrag (refereegranskat)abstract
- Uncertainty Quantification (UQ) is vital to ensure credibility in simulation results and to justify model-based design decisions – especially in early development phases when system level measurement data for traditional model validation purposes are scarce. Central UQ challenges in industrial applications are computational cost and availability of information and resources for uncertainty characterization. In an attempt to meet these challenges, this paper proposes a framework for early and approximate UQ intended for large simulation models of dynamical systems. A Modelica simulation model of an aircraft environmental control system including a liquid cooling circuit is used to evaluate the industrial applicability of the proposed framework.
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| 7. |
- Eek, Magnus, 1980-, et al.
(författare)
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Definition and Implementation of a Method for Uncertainty Aggregation in Component-Based System Simulation Models
- 2017
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Ingår i: Journal of Verification, Validation and Uncertainty Quantification. - New York : ASME Press. - 2377-2158 .- 2377-2166. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Component-based system simulation models are used throughout all development phases for design and verification of both physical systems and control software, not least in the aeronautical industry. However, the application of structured methods for uncertainty quantification (UQ) of system simulation models is rarely seen. To enable dimensionality reduction of a UQ problem and to thereby make UQ more feasible for industry-grade system simulation models, this paper describes a pragmatic method for uncertainty aggregation. The central idea of the proposed aggregation method is to integrate information obtained during common practice component-level validation directly into the components, and to utilize this information in model-level UQ. A generic component output uncertainty description has been defined and implemented in a Modelica library for modeling and simulation (M&S) of aircraft vehicle systems. An example is provided on how to characterize and quantify a component’s aggregated output uncertainty based on the component-level bench test measurement data. Furthermore, the industrial applicability of the uncertainty aggregation method is demonstrated in an approximate UQ of an aircraft liquid cooling system simulation model. For cases when the concept of thorough UQ resulting in probability boxes is not feasible, the demonstrated approximate UQ using aggregated uncertainties is considered to be a pragmatic alternative fairly in reach for the common M&S practitioner within the area of system simulation
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| 8. |
- Knöös Franzén, Ludvig, 1990-, et al.
(författare)
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A System of Systems Approach for Search and Rescue Missions
- 2020
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Konferensbidrag (refereegranskat)abstract
- System-of-Systems Engineering (SoSE) has become a constantly growing field within product development for complex systems. Systems are becoming more and more connected with other systems and the operational environment in general. This takes the development process to new levels of complexity where high degrees of uncertainties are expected due to ever occurring changes in the operational environment, and other external factors such as politics, economy, and technology. This creates a need of being able to understand the influence of changes early in the development process and to facilitate the systems? perseverance. The focus of the development shifts from fulfilling specific requirements, to being able to meet needs and deliver capabilities over time. Additionally, modeling and simulation for complex systems and System-of-Systems (SoS) becomes a valued alternative to the economically prohibited and almost impossible prototype testing. In consideration of this problem, the presented work introduces a method for both modeling and simulation of a SoS. The method uses ontology with description logic reasoning to derive and narrow down a SoS design space which is further analyzed using Agent Based Simulation (ABS). A Search and Rescue (SAR) scenario is used as a case study to test the method. Measures of Effectiveness (MoE), based on the time it takes to find a rescue subject and the cost of doing so, are used to evaluate the SoS performances. The presented method is envisioned to be used early in the development of complex systems and SoS to increase the overall understanding of them.
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| 9. |
- Papageorgiou, Athanasios, 1984-, et al.
(författare)
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A Data Management and Visualization Tool for Integrating Optimization Results in Product Development
- 2018
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Ingår i: DS 91: Proceedings of NordDesign 2018, Linköping, Sweden, 14th - 17th August 2018. - 9789176851852
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a data management and visualization tool that was developed in parallel with a Multidisciplinary Design Optimization (MDO) framework in order to enable a more effective use of the obtained results within the Product Development Process (PDP). To this date, the main problem is that the majority of MDO case studies conclude by suggesting a small number of optimal configurations, which do not really hold any meaningful value for the decision makers since they represent only a narrow area of the design space. In this light, the proposed tool aims to provide designers with new possibilities in respect to post-processing of large data sets, and subsequently, to allow the non-technical teams to be engaged and benefit from the use of MDO in the company practices. As an example, an Unmanned Aerial Vehicle (UAV) configurator developed by using the Graphical User Interface (GUI) of MATLAB is herein presented, and it is shown that a tool for handling the results can be the logical next step towards integrating MDO in the manufacturing industry. Overall, this work aims to demonstrate the benefits of the present visualization and management tool as a complementary addition to an existing optimization framework, and also to determine if this approach can be the right strategy towards improving the MDO method for an eventual use in the PDP of complex pro-ducts like UAVs.
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| 10. |
- Papageorgiou, Athanasios, et al.
(författare)
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Development of a Multidisciplinary Design Optimization Framework Applied on UAV Design by Considering Models for Mission, Surveillance, and Stealth Performance
- 2017
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Ingår i: 18th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference. - Reston, Virginia : American Institute of Aeronautics and Astronautics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a Multidisciplinary Design Optimization (MDO) framework that is intended to be employed in the early design stages of Unmanned Aerial Vehicles (UAVs) when the primary focus is on the tradeoffs between the mission, stealth, and surveillance performance requirements. The proposed MDO framework takes into account the aircraft’s geometry, the aerodynamics, the trim, the stability, and the simulation of the mission, but it also includes two additional models for computing the Radar Cross Section (RCS) and the sensor performance. A multi-level solution architecture is implemented in order to tackle the increased complexity of the problem, and it is shown that this type of decomposition can be a more efficient optimization approach compared to the traditional single-level formulation. The operation of the framework is evaluated through single objective optimizations by using the weighted sum method, while it is also investigated whether or not metamodels can be a viable alternative to the computationally expensive RCS and sensor analysis models. Overall, the results show that the mission, stealth, and surveillance performance are conflicting objectives, and therefore, their concurrent consideration in an optimization framework can help increase the available knowledge early on in the design of UAV applications.
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