| 1. |
- Müller, Jakob, 1987, et al.
(författare)
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Enhanced function-means modeling supporting design space exploration
- 2019
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Ingår i: Artificial intelligence for engineering design, analysis and manufacturing. - : Cambridge University Press. - 0890-0604 .- 1469-1760. ; 33:4, s. 502-516
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Tidskriftsartikel (refereegranskat)abstract
- One problem in incremental product development is that geometric models are limited in their ability to explore radical alternative design variants. In this publication, a function modeling approach is suggested to increase the amount and variety of explored alternatives, since function models (FM) provide greater model flexibility. An enhanced function-means (EF-M) model capable of representing the constraints of the design space as well as alternative designs is created through a reverse engineering process. This model is then used as a basis for the development of a new product variant. This work describes the EF-M model's capabilities for representing the design space and integrating novel solutions into the existing product structure and explains how these capabilities support the exploration of alternative design variants. First-order analyses are executed, and the EF-M model is used to capture and represent already existing design information for further analyses. Based on these findings, a design space exploration approach is developed. It positions the FM as a connection between legacy and novel designs and, through this, allows for the exploration of more diverse product concepts. This approach is based on three steps-decomposition, design, and embodiment-A nd builds on the capabilities of EF-M to model alternative solutions for different requirements. While the embodiment step of creating the novel product's geometry is still a topic for future research, the design space exploration concept can be used to enable wider, more methodological, and potentially automated design space exploration.
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| 2. |
- Isaksson, Ola, 1969, et al.
(författare)
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Trends, observations and drivers for change in systems engineering design
- 2017
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Ingår i: Proceedings of the International Conference on Engineering Design, ICED. - : The Design Society. ; 3, s. 201-210
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Konferensbidrag (refereegranskat)abstract
- Manufactures, developing products, need to adapt and improve their practices taking advantage of technology advancements and simultaneously develop products and solutions to fit a new world. This paper discusses how societal and technological trends drive the need for change and evolution in what is called Systems Engineering Design (SED), indicating a systems view on engineering design. Through an analysis and selected examples it is argued that SED capabilities need to better address the width and complexity of design problem, takes advantages of increased computational power and sensing technologies to master future challenges. An important factor for successful deployment and change in industrial context, is the need for interactive and visual AIDS and easily accessible support methods. This can pave the way also for advanced SED support.
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| 3. |
- Raja, Visakha, 1985, et al.
(författare)
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A simulation-assisted complexity metric for design optimization of integrated architecture aero-engine structures
- 2019
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Ingår i: Structural and Multidisciplinary Optimization. - : Springer Science and Business Media LLC. - 1615-1488 .- 1615-147X. ; 60:1, s. 287-300
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Tidskriftsartikel (refereegranskat)abstract
- Traditional metrics for assessing system complexity are based on aspects such as number of and interaction among components. For functionally integrated structures, the application of such metrics can be difficult and/or limited due to the inseparability of the structure into components or sub-systems; a single monolithic structure satisfies all required functions. At the same time, complexity metrics are necessary for effective application of design optimization and systems engineering principles. Aero-engine static structures are typical examples of functionally integrated architecture. In this paper, we present a complexity metric for integrated architecture structures that can be included as an objective or constraint in design optimization problem formulations. The proposed metric is based on two existing metrics, one providing a system wide scheme for complexity calculations and the second, giving complexity for individual components. In order to account for its integrated architecture, different regions of the structure are considered. Interactions are estimated as load paths through the structure, identified by means of physical simulations. Complexity evaluations are demonstrated using two detail-designed aero-engine structures with similar functions but belonging to different engine designs. Despite the similarities, the structures differ in complexity. This enables quantitative comparison among different designs of integrated architecture structures based on physical arrangements and main functions. Moreover, the metric can be used to identify regions with most influence on complexity which in turn enables design improvements on those regions. Automated computation of the metric can result in rapid comparison and selection among a number of structure designs, and thus be used in optimization studies. Finally, a correlation of the metric with the development time or cost can be useful for future integrated architecture structure design optimization.
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| 4. |
- Raja, Visakha, 1985, et al.
(författare)
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An optimization-based approach for supporting early product architecture decisions
- 2017
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Ingår i: 21st International Conference on Engineering Design, ICED 2017, Vancouver, Canada, 21-25 August 2017. - 2220-4342. ; 4:DS87-4, s. 377-384
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Konferensbidrag (refereegranskat)abstract
- An important aspect in designing the product architecture of turbo fan engine structural components is the load path and flow path of the components. We present an approach for deciding the preliminary load carrying configuration or LCC (arrangement of structural elements to carry loads) for a generic, static engine structure during early design phases. The LCC, which is a part of the load path aspect, withstands multiple load cases during engine operation. Each such load case for the LCC can be represented as an interface stiffness optimization problem. Our approach for deciding the preliminary LCC involves individual consideration of a number of problems (load cases), down-selecting a small number of interesting problems, and running a coordinated optimization for the down-selected problems using the non-hierarchical coordination. The optimization yields a compromise solution that can be considered as a starting point for detail design of the integrated product. This approach may allow better design resources allocation, as the obtained solution satisfies a number of load cases on the structure.
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| 5. |
- Raja, Visakha, 1985, et al.
(författare)
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Describing and evaluating functionally integrated and manufacturing restricted product architectures
- 2018
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Ingår i: Research in Engineering Design - Theory, Applications, and Concurrent Engineering. - : Springer Science and Business Media LLC. - 1435-6066 .- 0934-9839. ; 29:3, s. 367-391
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Tidskriftsartikel (refereegranskat)abstract
- Within manufacturing companies, the architectural description of how a product is built is typically well defined while the architecture of the product from a functional view describing how the functional requirements are met in the product is often less articulated. For products composed of many components (modular products) such descriptions are clear, whereas few representation schemes are available that treat highly functionally integrated components, where all the functions are satisfied by one integral, homogenous physical structure. In this paper, an approach to describe the architecture for integrated components in the aerospace industry is described. Different regions of the component, termed as sections, are assumed to satisfy the functions required of the structure which are often manufactured by joining (welding) different segments. By assigning sectional and functional information to different manufactured segments of the structure, graphs are created that link the functional requirements and sections. Two different methods, one based on set compositions and other on creating an enhanced function-means (EF-M) tree are used to link the functions to the sections of the component, resulting in different graphs for different types of manufacturing splits for the same component. Comparison of the methods is then carried out using properties of the graphs produced. The method that utilises set compositions performs well for entire component descriptions while the method that uses an EF-M tree to create a graph describes sections (regions) of the component well so that functional relationships can be better described (integration of already existing design knowledge). The product descriptions created can help designers to identify how alternative manufacturing splits impact the functionally defined product architecture which in turn enables both improved manufacturing and improved design decisions.
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| 6. |
- Raja, Visakha, 1985, et al.
(författare)
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Exploring Influence of Static Engine Component Design Variables on System Level Performance
- 2015
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Ingår i: 22nd International Symposium on Air Breathing Engines, ISABE2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- To reach even better operating efficiency and reduced fuel burn, aero engine manufacturers adopt various innovative design methods. Many of the design methods rely on more integrated component and engine design. This makes it necessary for component suppliers such as GKN to be involved more tightly in the design process with the engine integrator. It also necessitates the need for the component developer to predict the effects that its components produce at the engine level so that the designs can be better prepared for future engine architectures. In this paper, an integrated design method is used to make preliminary exploration of the effect of aero-engine static structure design variations on engine performance. Studies were performed on a turbine rear structure (TRS) which is a part of the low pressure (LPT) turbine module. Pressure losses from an aerodynamically well designed TRS (with good LPT outflow match) and a poor LPT outflow matched TRS were coupled to an engine performance model to simulate the effect on engine SFC. The effect on engine SFC due to poor LPT outflow matched TRS coupling is more pronounced than that for aerodynamically well designed TRS. Also pressure drops for an aerodynamically well designed TRS are themselves dependant on structural design variations such as changes in geometrical variables. In this case, the influence of component design variation on SFC is substantial and the relevance of an integrated engine-component design is apparent. Judging from the preliminary findings it can be concluded that additional studies with more variables coupled can reveal further dependencies between engine and the component which are previously un-explored. This seeks to motivate the development of methods to create a multi-level, multi-physics optimization platform for hot engine structures which is the future aim of the project as a part of which this study was conducted.
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| 7. |
- Raja, Visakha, 1985, et al.
(författare)
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Generic Functional Decomposition of an Integrated Jet Engine Mechanical Sub System Using a Configurable Component Approach
- 2015
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Ingår i: 22nd ISPE Inc. International Conference on Concurrent Engineering, CE 2015, TU Delft, Netherlands, 20-23 July 2015. - 9781614995449 ; 2, s. 337-346
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Konferensbidrag (refereegranskat)abstract
- A procedure is proposed to functionally decompose an already existing integrated mechanical jet engine subsystem. An integrated sub system is a system where the same design object satisfies multiple functions: which is typically the case in aircraft engine sub systems and components. A generic decomposition method will allow implementation and use in automated design systems and will function as a means to build experiences into platforms. Using the procedure, an enhanced function-means tree (E F-M tree) consisting of functional requirements, means to satisfy the requirements and constraints was created for the integrated jet engine component. The E F-M tree is then used to generate a hierarchy of configurable components (CCs). A configurable component (CC) is a stand-alone conceptual object that contains the functional requirement, means to satisfy the requirement (or design solution) and constraints at a certain level of the E F-M tree. A specific CC hierarchy configuration results in the description of the product concerned. The usage of the CC hierarchy as design documentation as well as a template to derive other designs from is demonstrated. Finally limitations of describing product functional requirements using CC method and recommendations for further development of the method are discussed.
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| 8. |
- Raja, Visakha, 1985, et al.
(författare)
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Modelling-integrated product architectures: an aero engine component example
- 2019
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Ingår i: Smart Innovation, Systems and Technologies. - Singapore : Springer Singapore. - 2190-3026 .- 2190-3018. ; 134, s. 847-858
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Konferensbidrag (refereegranskat)abstract
- A method to model functionally integrated product architectures is demonstrated on a static aero engine component. The scheme is based on concepts in set theory, graph theory and the creation of an enhanced function-means (EF-M) tree. Separate options for segmenting the component for manufacture affect these descriptions. Using the generated descriptions, implications for the chosen segmenting options are discussed with respect to overall functional satisfaction as well as functional realization at sections in the component. In addition to describing the architecture of integrated components, the description scheme might be utilized for studying product-feature integration opportunities facilitated by manufacturing techniques such as AM.
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| 9. |
- Raja, Visakha, 1985
(författare)
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On Integrated Product Architectures: Representation, modelling and evaluation
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Continued growth in the commercial aerospace industry makes aircraft manufacturers look for low maintenance, fuel efficient airplanes and aircraft engines are an important factor in the maintenance and fuel costs. The drive for operating cost reduction leads to innovative engine architectures that can place very different requirements on supplier provided components. The suppliers will then need to understand and predict consequences on their components and sub systems following the new system architectures proposed. Insights they get about the consequences of engine architecture changes help them to be prepared for future developments.This research presents two aspects of the behaviour of aero engine static components from a supplier: (1) the behaviour of the component as a whole in the system and (2) the internal organisation of the component so that the behaviour required of it is achieved by the system. System in this context refers to the aero engine. The component is integrated in that multiple functions are satisfied by one single structure. Studies in the first aspect provide a measure of the sensitivity of the whole engine to component designs. The studies also present an initial framework to perform such system-component interaction investigations. Studies in the second aspect provide a way to organise functions and means for an integrated architecture product so that the internal organisation is better understood and can be subjected to evaluations. Preliminary results show that the influence of the supplier component on system level operations cannot be neglected. The framework to evaluate system level effects of supplier component design needs further refinement with better fidelity models at all levels considered. With respect to the internal organisation of components, a method now exists to isolate, organise, represent and analyse design information of integrated components, taking into consideration different manufacturing options. Continued studies will focus on functional and physical domain decomposition of the component reliably and objectively so that alternative product architectures for the component can be evaluated and appropriate design and manufacturing decisions can be made.
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| 10. |
- Raja, Visakha, 1985
(författare)
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On the Design of Functionally Integrated Aero-engine Structures: Modeling and Evaluation Methods for Architecture and Complexity
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The drive for airplanes with radically reduced fuel consumption and emissions motivates engine manufacturers to explore innovative engine designs. The novelty of such engines results in changed operating conditions, such as newly introduced constraints, increased loads or rearranged interfaces. To be competitive, component developers and manufacturers must understand and predict the consequences of such changes on their sub-systems. Presently, such assessments are based on detailed geometrical models (CAD or finite element) and consume significant amounts of time. The preparation of such models is resource intensive unless parametrization is employed. Even with parametrization, alternative geometrical layouts for designs are difficult to achieve. In contrast to geometrical model-based estimations, a component architecture representation and evaluation scheme can quickly identify the functional implications for a system-level change and likely consequences on the component. The schemes can, in turn, point to the type and location of needed evaluations with detailed geometry. This will benefit the development of new engine designs and facilitate improvements upon existing designs. The availability of architecture representation schemes for functionally integrated (all functions being satisfied by one monolithic structure) aero-engine structural components is limited. The research in this thesis focuses on supporting the design of aero-engine structural components by representing their architecture as well as by developing means for the quantitative evaluation and comparison of different component designs. The research has been conducted in collaboration with GKN Aerospace Sweden AB, and the components are aero-engine structures developed and manufactured at GKN. Architectural information is generated and described based on concepts from set theory, graph theory and enhanced function–means trees. In addition, the complexities of the components are evaluated using a new complexity metric. Specifically, the developed modeling and evaluation methods facilitate the following activities: · identification and representation of function–means information for the component · representation and evaluation of component architecture · product complexity evaluation · early selection of load path architecture · impact assessment for the component’s functioning in the system By means of the methods developed in this thesis, the design rationale for a component is made explicit, and the storing, communicating and retrieving of information about the component in the future is enabled. Through their application to real-life engine structures, the usability of the methods in identifying early load carrying configurations and selecting a manufacturing segmenting option is demonstrated. Together, the methods provide development engineers the ability to compare alternative architectures. Further research could focus on exploring the system (engine) effects of changes in component architecture and improvements to the complexity metric by incorporating manufacturing information.
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| 11. |
- Zhao, Xin, 1986, et al.
(författare)
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Conceptual Mean-line Design of a Low Pressure Turbine for a Geared Turbofan with Rear Structure Interaction
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- One of the most important features of a geared turbofan (GTF) is a reduced number of low pressure turbine (LPT) stages resulting from a faster spinning spool. Compared to a direct drive turbofan (DDTF), in which the LPT normally constitutes a considerable part of the engine total weight, from 10% to more than 25%, dependent on the engine bypass ratio (BPR), fewer stages can cut the weight into half or even less for the LPT. With this benefit, the weight of the LPT alone is no longer a dominating factor for the selection of its configuration. To obtain an optimal LPT configuration for a GTF requires a new balance between weight and performance involving both the LPT and the downstream component, the turbine rear structure (TRS). A conceptual design of the LPT for a mid- to long-range GTF is presented here to clarify this new balance. By comparing a range of designs based on different number of stages and turbine hade angles, the selection of the LPT design for the GTF is described. More importantly, interactions between the LPT design and the TRS design are considered. Results indicate that a joint design is necessary as the TRS plays an important role in designing the LPT of a GTF. It is shown that if the LPT design is done in isolation from the TRS design, a 3-stage LPT performs better than a 4-stage design from a fuel burn perspective. However, when the TRS design is considered, the advantage of the 3-stage LPT design is offset by the associated TRS weight and loss increase, compared to the 4-stage LPT design.
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