| 1. |
- Madrid, Julia, 1988, et al.
(författare)
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Development of a conceptual framework to assess producibility for fabricated aerospace components
- 2016
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 41, s. 681-686
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Konferensbidrag (refereegranskat)abstract
- The aerospace industry is undergoing an intense competitive pressure due to new market demands and regulations. In the next 20 years thenumber of aircraft in service is expected to double. At the same time, there is a rapid development of new technologies to fulfil tougherrequirements, typically with regards to lower emissions and fuel consumption, where lightweight is a key issue. Along with this, some aircraftenginemanufactures have adopted a fabrication approach to build their large structural components. Within fabrication, smaller parts arewelded together into the final shape. This manufacturing approach has significantly broadened the number of possible variants of a definedproduct and production concept. In addition, fabrication has brought to the forefront important problems such as geometrical variation and weldquality. Tailoring the product design to fulfil customer requirements and moreover, tailoring the fabrication process to suit the product design,becomes really complex. Therefore, a systematic approach is required to assess the producibility of the different design solutions in order tosecure the final product quality throughout the fabrication process. In this paper, a conceptual framework, by means of a model, is presented.This model serves to identify, in a structural way, the parameters and features that are contributors to variation in the process quality output.Furthermore, the model helps to describe the parameters within the manufacturing process that build up the quality into the product, andultimately, what are the product characteristics that deliver the final quality to the custome
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| 2. |
- Vallhagen, Johan, 1965, et al.
(författare)
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An approach for producibility and DFM-methodology in aerospace engine component development
- 2013
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 11, s. 151-156
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Konferensbidrag (refereegranskat)abstract
- The competitiveness in the aerospace industry is steadilly increasing, at the same time there is a rapid development of new technology for next generations of jet engines. To achieve one of the most important goals, reducing weight, fabrication of structural components is one possible approach, common to many aerospace manufacturers. However, the engineering work becomes more difficult and requires new knowledge. Production becomes significantly more complicated as the need of different manufacturing processes increases, as well as the complexity of other production related activities. In the paper, definitions of producibility and manufacturability are discussed, together with related metrics for measurement of the impact of the product design on a production system. The result is a recommended set of methodologies and tools to manage and evaluate the manufacturing interests and targets, and how they must be reached and balanced within the product development process, in order to improve producibility. The work has also identified gaps and opportunities for improvements, and suggested an approach for next step in order to increase producibility in manufacturing of aerospace engine components
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| 3. |
- Wärmefjord, Kristina, 1976, et al.
(författare)
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Joining in Nonrigid Variation Simulation
- 2016
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Ingår i: Computer-aided Technologies - Applications in Engineering and Medicine. - 9789535127888
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Geometrical variation is closely related to fulfillment of both functional and esthetical requirements on the final product. To investigate the fulfillment of those requirements, Monte Carlo (MC)-based variation simulations can be executed in order to predict the levels of geometrical variation on subassembly and/or product level. If the variation simulations are accurate enough, physical tests and try-outs can be replaced, which reduce cost and lead-time. To ensure high accuracy, the joining process is important to include in the variation simulation. In this chapter, an overview of nonrigid variation simulation is given and aspects such as the type and number of joining points, the joining sequence and joining forces are discussed.
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| 4. |
- Wärmefjord, Kristina, 1976, et al.
(författare)
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Form Division for Welded Aero Components in Platform-Based Development
- 2015
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Ingår i: Journal of Aerospace Engineering. - 1943-5525 .- 0893-1321. ; 28:5
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Tidskriftsartikel (refereegranskat)abstract
- In aerospace engine industry, large casted components are, because of sustainability considerations, being replaced by smaller parts that are welded together. This reduces weight because some parts can be made of lighter material. It also opens up for use of platforms. The division of a large component into smaller parts is called form division. The form division affects the geometrical robustness in the weld splitlines between the parts and thereby the weldability. By optimizing the robustness in weld splitlines, conditions for welding can be improved. A greedy algorithm for weld splitline division is described and exemplified on aerospace case studies.
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| 5. |
- Madrid, Julia, 1988, et al.
(författare)
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A Virtual Design of Experiments Method to Evaluate the Effect of Design and Welding Parameters on Weld Quality in Aerospace Applications
- 2019
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Ingår i: Aerospace. - : MDPI AG. - 2226-4310. ; 6:6, s. 74-
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Tidskriftsartikel (refereegranskat)abstract
- During multidisciplinary design of welded aircraft components, designs are principally optimized upon component performance, employing well-established modelling and simulation techniques. On the contrary, because of the complexity of modelling welding process phenomena,much of the welding experimentation relies on physical testing, which means welding producibility aspects are considered after the design has already been established. In addition, welding optimization research mainly focuses on welding process parameters, overlooking the potential impact of product design. As a consequence, redesign loops and welding rework increases product cost. To solve these problems, in this article, a novel method that combines the benefits of design of experiments (DOE) techniques with welding simulation is presented. The aim of the virtual design of experiments method is to model and optimize the effect of design and welding parameters interactions early in the design process. The method is explained through a case study, in which weld bead penetration and distortion are quality responses to optimize. First, a small number of physical welds are conducted to develop and tune the welding simulation. From this activity, a new combined heat source model is presented. Thereafter, the DOE technique optimal design is employed to design an experimental matrix that enables the conjointly incorporation of design and welding parameters. Welding simulations are then run and a response function is obtained. With virtual experiments, a large number of design and welding parameter combinations can be tested in a short time. In conclusion, the creation of a meta-model allows for performing welding producibility optimization and robustness analyses during early design phases of aircraft components
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| 6. |
- Madrid, Julia, 1988, et al.
(författare)
-
A virtual design of experiments method to evaluate the effect of design andwelding parameters on weld quality in aerospace applications
- 2019
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Ingår i: Aerospace. - 2226-4310. ; 6:6
-
Tidskriftsartikel (refereegranskat)abstract
- During multidisciplinary design of welded aircraft components, designs are principally optimized upon component performance, employing well-established modelling and simulation techniques. On the contrary, because of the complexity of modelling welding process phenomena, much of the welding experimentation relies on physical testing, which means welding producibility aspects are considered after the design has already been established. In addition, welding optimization research mainly focuses on welding process parameters, overlooking the potential impact of product design. As a consequence, redesign loops and welding rework increases product cost. To solve these problems, in this article, a novel method that combines the benefits of design of experiments (DOE) techniques with welding simulation is presented. The aim of the virtual design of experiments method is to model and optimize the effect of design and welding parameters interactions early in the design process. The method is explained through a case study, in which weld bead penetration and distortion are quality responses to optimize. First, a small number of physical welds are conducted to develop and tune the welding simulation. From this activity, a new combined heat source model is presented. Thereafter, the DOE technique optimal design is employed to design an experimental matrix that enables the conjointly incorporation of design and welding parameters. Welding simulations are then run and a response function is obtained. With virtual experiments, a large number of design and welding parameter combinations can be tested in a short time. In conclusion, the creation of a meta-model allows for performing welding producibility optimization and robustness analyses during early design phases of aircraft components.
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| 7. |
- Forslund, Anders, 1982, et al.
(författare)
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Minimizing Weld Variation Effects Using Permutation Genetic Algorithms and Virtual Locator Trimming
- 2018
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Ingår i: Proceedings of the ASME 2017 International Mechanical Engineering Congress and Exposition.
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Konferensbidrag (refereegranskat)abstract
- The mass production paradigm strives for uniformity, and for assembly operations to be identical for each individual product. To accommodate geometric variation between individual parts in such a process, tolerances are introduced into the design. However, for certain assembly operations this method can yield suboptimal quality. For instance, in welded assemblies, geometric variation in ingoing parts can significantly impair quality. When parts misalign in interfaces, excessive clamping force must be applied, resulting in additional residual stresses in the welded assemblies. This problem may not always be cost-effective to address simply by tightening tolerances. Therefore, under new paradigm of mass customization, the manufacturing approach can be adapted on an individual level. Since parts in welded assemblies are not easily disassembled and reused, interchangeability is not a relevant concern. This recognition means that each welded assembly can be adapted individually for the specific idiosyncrasies of ingoing parts. This paper focuses on two specific mass customization techniques; permutation genetic algorithms to assemble nominally identical parts, and virtual locator trimming. Based on these techniques, a six-step method is proposed, aimed at minimizing thing effects of geometric variation. The six steps are nominal reference point optimization, permutation GA configuration optimization, virtual locator trimming, clamping, welding simulation, and fatigue life evaluation. A case study is presented which focuses on one specific product; the turbine rear structure of a commercial turbofan engine. Using this simulation approach, the effects of using permutation genetic algorithms and virtual locator trimming to reduce variation are evaluated. The results show that both methods significantly reduce seam variation. However, virtual locator trimming is far more effective in the test case presented, since it virtually eliminates seam variation. This can be attributed to the orthogonality in fixturing. Seam variation is linked to weldability, which in turn has significant impact on estimated fatigue life. These results underscore the potential of virtual trimming and genetic algorithms in manufacturing, as a means both to reduce cost and increase functional quality.
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| 8. |
- Forslund, Anders, 1982, et al.
(författare)
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Robust lifecycle optimization of turbine components using simulation platforms
- 2012
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Ingår i: Proceedings of the 28th Congress of the International Council of the Aeronautical Sciences, ICAS 2012. - 9781622767540 ; 4, s. 2593-2604
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Konferensbidrag (refereegranskat)abstract
- n early phases of turbofan engine component design, simulation is favored since it reduces the need for expensive physical testing. However, deterministic simulations for model validation do not consider uncertainty at all. Uncertainties can be classified into three types: aleatory uncertainties, epistemic uncertainties, and error. In this paper, we investigate the potential of a multidisciplinary simulation platform to address these uncertainties and errors for a given test case. We place specific focus on the geometry assurance of a given turbofan component - the Turbine Rear Structure (TRS). Simulations are generally performed based on nominal geometries, materials and loads. However, when a product is mass-produced, each realization of the product design will deviate from the nominal geometry. By generating CAD models from scanned 3D-data of manufactured parts and running them through the simulation platform, the effect that geometric variation has on aerodynamic and structural performance can be investigated. Further, by moving the reference points in a virtual assembly process, we can, to some extent, suppress the effects that this variation has on aerodynamic and structural performance. From a technical point of view, the suggested approach means a significantly improved ability to numerically simulate and optimize robustness of component designs with functionality criteria from principally different disciplines. From an industrial application point of view, the suggested approach provides a tool for including part variation in the early design face, rather than being treated downstream in the development process.
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| 9. |
- Lööf, Johan, 1979, et al.
(författare)
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Optimizing Locator Position to Maximize Robustness in Critical Product Dimensions
- 2010
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Ingår i: ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE2009; San Diego, CA; United States; 30 August 2009 through 2 September 2009. - 9780791848999 ; 2:PARTS A AND B, s. 515-522
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Konferensbidrag (refereegranskat)abstract
- The way parts are located in relation to each other or in fixtures is critical for how geometrical variation will propagate and cause variation in critical product dimensions. Therefore, more emphasis should be put on this activity in early design phases in order to avoid assembly and production problems later on. In earlier literature, locator positions have been defined using optimization to reach a robust locating scheme. This implies that the total robustness of a part is optimized by placing the locators in an optimal way. Sometimes there are areas on parts that are more sensitive to variation than others. Therefore, this paper suggests an approach for optimizing the positions of locators in a locating scheme to maximize robustness in defined critical dimensions. A formulation of an optimization problem is presented, and an algorithm solving this in a heuristic approach is developed. Finally, this algorithm is applied on an industrial example.
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| 10. |
- Forslund, Anders, 1982, et al.
(författare)
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Robust design of aero engine structures: Transferring form error data when mapping out design spaces for new turbine components
- 2016
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 43, s. 47-51
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Konferensbidrag (refereegranskat)abstract
- In aerospace modeling and simulation, nominal geometries are norm. However, it has been shown that form error, or irregular deviations in geometry, aggravates thermal stresses, which in turn reduces product life. While form error can be measured on manufactured products using 3D laser scanners, a simulation infrastructure is needed to analyze its effects on aerodynamic, structural and thermal performance. Moreover, in early product development phases, before manufacturing has begun, form error data is not available. This paper describes a method for including form error data in mainstream simulation activities. The suggested method works by creating parametric CAD-models to accommodate form error. There are two main benefits of this method. Firstly, it enables proactive robustness simulations where substantial design changes can be tested and evaluated. Secondly, it enables the mapping of data from previous products onto new designs, which means that robustness analyses can be performed in earlier design phases. To demonstrate this capability, a case study shows how a robust optimization scheme using genetic algorithms can improve product robustness to form error. The results show that form error have effects of the same order of magnitude as key design parameter changes. This finding underlines the importance of performing form error analyses in exploratory early design phases.
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