| 1. |
- Dabhilkar, Mandar, et al.
(författare)
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Supplier selection or collaboration? : Determining factors of performance improvement when outsourcing manufacturing
- 2009
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Ingår i: Journal of Purchasing and Supply Management. - : Elsevier BV. - 1478-4092 .- 1873-6505. ; 15:3, s. 143-153
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Tidskriftsartikel (refereegranskat)abstract
- An empirical study was designed to determine factors of performance improvement when outsourcing manufacturing. Findings from a survey of 136 manufacturing plants in Sweden show that most of them achieve their outsourcing motives, but not without trade-offs. Factors of performance improvements such as economies of scale or operations in low-cost countries can improve one performance dimension, such as product cost, yet negatively impact volume flexibility, speed or product innovation. The results show part characteristics and supplier operating capabilities are more important than supplier relationship strategies when outsourcing manufacturing, meaning that supplier selection trumps supplier collaboration in the make-or-buy decision.
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| 2. |
- Munjulury, Raghu Chaitanya, et al.
(författare)
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Knowledge-based future combat aircraft optimization
- 2016
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Ingår i: 30th Congress of the International Council of the AeronauticalSciences (ICAS 2016). - Bonn : International Council of Aeronautical Sciences (ICAS). - 9781510834552 ; , s. 273-280
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Konferensbidrag (refereegranskat)abstract
- Future combat aircraft inherently conceal all the components internally essentially for stealth reasons. The geometry is optimized for subsonic and supersonic flight area distribution and the components and payload to be fitted inside the aircraft. The basic requirements to accomplish are fuel consumption, mission profile, and military performance. Analytical methods comprise of a quick aerodynamic and structural optimization. The result obtained is then compared with multi-fidelity aero-structural analysis
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| 3. |
- Jahedi, Mohammad, 1984-, et al.
(författare)
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Quenching a rotary hollow cylinder by multiple configurations of water-impinging jets
- 2019
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Ingår i: International Journal of Heat and Mass Transfer. - : Elsevier. - 0017-9310 .- 1879-2189. ; 137, s. 124-137
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Tidskriftsartikel (refereegranskat)abstract
- Experiments have been conducted to analyze quenching of a hot rotary hollow cylinder by one and two rows of water-impinging jets. Sub-cooled water jets (ΔTsub = 45–85 K) with flow rate 8006 to 36,738 impinged on hollow cylinder with rotation speed 10 to 70 rpm at various initial wall superheat temperatures from 250 to 600ºC. Jet-to-jet and jet-to-surface spacing varied between 4 to 10d and 1.5 to 7d respectively and angular position of impinging jets were tested from 0 to 135º. Effectiveness of the defined parameters on stagnation point’s local average heat flux was found lower in the film and nucleate boiling compare to transition boiling regime where rotation speed had the highest impact. Characteristic of maximum heat flux (MHF) at stagnation point and upwash flow point were analyzed based on surface heat flux, time and temperature corresponding to MHF. Same maximum heat flux levels were captured in the both points which reveals importance of the flow behavior at the upwash flow point. The effectiveness of the parameters to improve average heat transfer was studied based on cooling area of each water impingingjet in the multiple configurations. Higher average heat transfer was obtained by increasing flow rate and subcooling temperature and lower initial wall superheat temperature corresponding to onset of transition boiling regime.
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| 4. |
- Ryberg, Ann-Britt, 1974-
(författare)
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Metamodel-Based Multidisciplinary Design Optimization of Automotive Structures
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multidisciplinary design optimization (MDO) can be used in computer aided engineering (CAE) to efficiently improve and balance performance of automotive structures. However, large-scale MDO is not yet generally integrated within automotive product development due to several challenges, of which excessive computing times is the most important one. In this thesis, a metamodel-based MDO process that fits normal company organizations and CAE-based development processes is presented. The introduction of global metamodels offers means to increase computational efficiency and distribute work without implementing complicated multi-level MDO methods.The presented MDO process is proven to be efficient for thickness optimization studies with the objective to minimize mass. It can also be used for spot weld optimization if the models are prepared correctly. A comparison of different methods reveals that topology optimization, which requires less model preparation and computational effort, is an alternative if load cases involving simulations of linear systems are judged to be of major importance.A technical challenge when performing metamodel-based design optimization is lack of accuracy for metamodels representing complex responses including discontinuities, which are common in for example crashworthiness applications. The decision boundary from a support vector machine (SVM) can be used to identify the border between different types of deformation behaviour. In this thesis, this information is used to improve the accuracy of feedforward neural network metamodels. Three different approaches are tested; to split the design space and fit separate metamodels for the different regions, to add estimated guiding samples to the fitting set along the boundary before a global metamodel is fitted, and to use a special SVM-based sequential sampling method. Substantial improvements in accuracy are observed, and it is found that implementing SVM-based sequential sampling and estimated guiding samples can result in successful optimization studies for cases where more conventional methods fail.
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| 5. |
- Shetty, Sandeep
(författare)
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Optimization of Vehicle Structures under Uncertainties
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Advancements in simulation tools and computer power have made it possible to incorporate simulation-based structural optimization in the automotive product development process. However, deterministic optimization without considering uncertainties such as variations in material properties, geometry or loading conditions might result in unreliable optimum designs. In this thesis, the capability of some established approaches to perform design optimization under uncertainties is assessed, and new improved methods are developed. In particular, vehicle structural problems which involve computationally expensive Finite Element (FE) simulations, are addressed.The first paper focuses on the evaluation of robustness, given some variation in input parameters, the capabilities of three well-known metamodels are evaluated. In the second paper, a comparative study of deterministic, reliability-based and robust design optimization approaches is performed. It is found that the overall accuracy of the single-stage (global) metamodels, which are used in the above study, is acceptable for deterministic optimization. However, the accuracy of performance variation prediction (local sensitivity) must be improved. In the third paper, a decoupled reliability-based design optimization (RBDO) approach is presented. In this approach, metamodels are employed for the deterministic optimization only while the uncertainty analysis is performed using FE simulations in order to ensure its accuracy.In the fifth paper, two new sequential sampling strategies are introduced that aim to improve the accuracy of the metamodels efficiently in critical regions. The capabilities of the methods presented are illustrated using analytical examples and a vehicle structural application.It is important to accurately represent physical variations in material properties since these might exert a major influence on the results. In previous work these variations have been treated in a simplified manner and the consequences of these simplifications have been poorly understood. In the fourth paper, the accuracy of several simple methods in representing the real material variation has been studied. It is shown that a scaling of the nominal stress-strain curve based on the Rm scatter is the best choice of the evaluated choices, when limited material data is available.In this thesis work, new pragmatic methods for non-deterministic optimization of large scale vehicle structural problems have been developed. The RBDO methods developed are shown to be flexible, more efficient and reasonably accurate, which enables their implementation in the current automotive product development process.
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| 6. |
- Grahn, Sten, et al.
(författare)
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Potential Advantages Using Large Anthropomorphic Robots in Human-robot Collaborative, Hand Guided Assembly
- 2016
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Ingår i: Procedia CIRP. - : Elsevier. - 2212-8271. ; 44, s. 281-286, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- Collaborative robot installations often mean man-machine workspace sharing. This mode of operation can lead to reductions of tact time and work space requirements. We have analyzed potential further benefits of man-machine collaboration, where operators and powerful robots share workspace, cooperating when lifting and handling large objects. We found that this mode of operation has the potential to generate economic advantages by reducing the need for manual operators and lifting tools and by offering new opportunities for component logistics.
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| 7. |
- Sundin, Erik, 1974-
(författare)
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Life-cycle Perspectives of Product/Service-Systems : In Design Theory
- 2009. - 1
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Ingår i: Introduction to Product/Service-System Design. - London : Springer. - 9781848829084 ; , s. 31-49
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Bokkapitel (refereegranskat)abstract
- Manufacturers are moving more and more towards the business approach of Product/Service Systems in order to achieve greater revenue. Product/Service Systems have many benefits such as achieving closer customer connection and generating increased profit from manufactured products. However, in order to achieve a Product/Service System which is adapted for this business approach, the products and services used need to consider a life-cycle perspective.The business approach of Product/Service Systems allows for the provider to control the flows of physical products, both the forward flow to the user and the reverse flow of products back to the provider. This new logic of material/product flows allows for adaptations along the product life-cycle. For example, maintenance and end-of-life strategies such as remanufacturing can become more beneficial due to the new circumstances that product/service systems provide the manufacturer.The aim of this chapter is to elucidate how manufacturers can develop their product/service systems with a life-cycle perspective. It shows the many aspects that should be considered throughout the life-cycle of both physical products and services. In addition, several considerations and theories are presented for the different stages of the Product/Service System life-cycle. Finally, this chapter presents theory on product/service design with a life-cycle perspective, which serves as a base for the practical design considerations presented in chapter (ID21) of this book.
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| 8. |
- Sundin, Erik, 1974-
(författare)
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Life-cycle Perspectives of Product/Service-Systems: Practical Design Experiences
- 2009. - 1
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Ingår i: Introduction to Product/Service-System Design. - London : Springer. - 9781848829084 ; , s. 50-70
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Bokkapitel (refereegranskat)abstract
- Many manufacturers are moving more and more towards the business approach of product/service-systems in order to achieve more revenues. The business approach of product/service-systems puts new requirements on products in comparison to traditional selling. In order to achieve a product/service-system adapted for this business approach, the products and services used need to consider a life-cycle perspective. Having a life-cycle perspective on products and services in the business strategy of product/service-systems is becoming increasingly important as the strategy emerges and more and more companies see the benefits of controlling a larger share of the product value chain. The objective of this chapter is to elucidate how manufacturers have worked with, or could adapt their products for, product/service-systems. Supporting this are results from several case studies, performed at companies that manufacture household appliances, soil compactors and forklift trucks. A key factor when developing products for product/service-systems is to design the product from a life-cycle perspective, considering all the product’s life-cycle phases, e.g. manufacturing, use, maintenance and end-of-life treatment. Several design improvements, all of which are fairly inexpensive and easy to implement, are described. Many of these improvements deal with the accessibility of parts and components during maintenance and remanufacturing operations, and several of the design improvements could reduce the need and cost for maintenance, repair and remanufacturing.
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| 9. |
- Elg, Mattias, 1968-, et al.
(författare)
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The Future of Work for Quality Management – Challenges in the Digitalized Era
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose Digitalization provides both challenges and opportunities for Quality Management (QM). The purpose of this paper is to identify challenges induced by digitalization on current QM practices, in order to uncover the potential of how QM may support digitalization in organizations. This issue is addressed through an analytical framework that stresses two dimensions: first exploration and exploitation of digitalized QM processes and second value creation, which is performed by the customer or in interaction facilitated by the provider. Design/methodology/approach This paper is based on a cross-case study design with interview data collected from 33 quality management professionals in four large Swedish organizations. Findings Six different challenges and corresponding roles are proposed for QM: The gardener involved in the design of the many different currently utilized technologies; the bridge-builder - a role that connects implemented digitalized solutions that enable the movement from human-to-human to a human-to-digital interface; the assistant a contributor to better value in the customer sphere for already implemented digitalized solutions; the architect including planning, designs, and reviews together with many different stakeholders; the connector focusing on the continuous management of value-in-use and open up for opportunities for continuous interaction and value-adding; and explorer drawing attention towards the challenges of the existing power structures. Originality/value This paper contributes with empirical evidence on challenges induced by digitalization, an area often discussed but not as often studied empirically. Further, the study identifies challenges of digitalization affecting both exploitative and explorative practices throughout an organisations value-creation process.
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| 10. |
- Hellman, Pasi, et al.
(författare)
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Development of Quality Management Systems : How Have Disruptive Technological Innovations in Quality Management Affected Organizations?
- 2013
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Ingår i: Quality Innovation Prosperity. - : Quality Innovation Prosperity. - 1335-1745 .- 1338-984X. ; 17:1, s. 104-119
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Tidskriftsartikel (refereegranskat)abstract
- This research investigates the history of quality and development of quality management systems. History of quality is investigated from Hammurabi’s law all the way to today’s reigning quality initiatives including ISO, Six Sigma and Lean manufacturing. In the last chapters the current state of quality management is being examined. The foresight method is also opened up and examined. The Innovator’s dilemma concept, originally presented by Clayton Christensen, is used to analyse how quality management systems have been evolved in the last 100 years. Special emphasis is placed on the US manufacturing in the 1970s and 1980s. Based on the literature, the concept of Innovator’s dilemma and the fall of US manufacturing are merged. The result is a prime example that the Innovator’s Dilemma is a universal phenomenon. The industry leader is trying to maintain its position and do everything right but still it is destined to fail. The causes and effects are being discussed in later chapters.
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