| 1. |
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| 2. |
- Okda, Sherif, et al.
(författare)
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Testing of the Aerodynamic Characteristics of an Inflatable Airfoil Section
- 2020
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Ingår i: Journal of Aerospace Engineering. - 1943-5525 .- 0893-1321. ; 33:5
-
Tidskriftsartikel (refereegranskat)abstract
- Inflatable structures are characterized by being light and easy to manufacture and deploy. Hence, they find many applications in aerospace and aeronautical engineering. In this paper, an inflatable segment with a The National Advisory Committee for Aeronautics (NACA) 0021 airfoil cross-section is designed, fabricated, and tested. The geometrical accuracy of the manufactured inflatable segment is measured using laser scanning. Measurements show that the average normalized error of the chord length and thickness are 2.97% and 0.554%, respectively. The aerodynamic behavior of the inflatable segment is then tested in a wind tunnel at different wind speeds and angles of attack. Lift forces are measured using a six-component balance, while the drag forces are calculated from the wake measurements. The lift and drag coefficients of the inflatable section are compared to those of a standard NACA 0021 airfoil. Finally, flow visualization is examined at different angles of attack using two methods: smoke and tufts. Both methods show that flow separation starts at 15° and full stall occurs at 25°. Results indicate that inflatables can find more applications in the design and construction of aerodynamic structures, such as wings.
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| 3. |
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INNOTRACK: Concluding technical report
- 2010
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- The track structure, rails, switches and crossings account for more than 50% of maintenance and renewal costs for the rail industry. To improve the competitiveness of rail transportation, the cost-efficiency of these areas needs to be addressed.This the background to INNOTRACK, an integrated research project funded by the European Commission’s 6th research framework pro- gramme. Running from September 2006 to December 2009, INN- OTRACK has developed a multitude of innovative solutions in the areas of track substructure, rails & welds, and switches & crossings. The solutions have been assessed from technical, logistics and life cycle cost point of views.This Concluding Technical Report of INNOTRACK includes an overview of the project. It further details implementable results, and clusters them into ”highlight” areas. In addition, the book acts as a ”key” to the vast amount of information from INNOTRACK: All sections refer to project reports where more information can be found.
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| 4. |
- Stylidis, Kostas, 1978, et al.
(författare)
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Perceived quality framework in product generation engineering: an automotive industry example
- 2019
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Ingår i: Design Science. - : Cambridge University Press (CUP). - 2053-4701 .- 2053-4701. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Perceived quality refers to customers’ cognitive and emotional responses to a particular design, often also associated with craftsmanship and customer satisfaction. Previous research defined a taxonomy of perceived quality and provided understanding about how engineering design decisions impact customer satisfaction. Furthermore, development of new products is frequently based on carrying over attributes of existing products, either from the same producer or from competitors. Previous research offered a new product development methodology combining variations of subsystems to carry over from existing products. This brief presents how these two lines of research combined to design the central console of the Porsche Panamera automobile and discusses the opportunities and challenges posed in the practical implementation of this research.
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| 5. |
- Stylidis, Kostas, 1978, et al.
(författare)
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Perceived quality of products: a framework and attributes ranking method
- 2020
-
Ingår i: Journal of Engineering Design. - : Informa UK Limited. - 1466-1837 .- 0954-4828. ; 31:1, s. 37-67
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Tidskriftsartikel (refereegranskat)abstract
- Perceived quality is one of the most critical aspects of product development that defines the successful design. This paper presents a new approach to perceived quality assessment by examining its elements, decomposed into a structure with the bottom-up sensory approach from the level of basic (‘ground’) attributes, covering almost every aspect of quality perception from the engineering viewpoint. The paper proposes a novel method for perceived quality attributes relative importance ranking, resulting in the balanced perceived quality of the final product within the given conditions. The proposed method helps to reach the equilibrium of the product’s quality equation from the perspective of design effort, time, and costs estimations. The authors introduce the Perceived Quality Framework (PQF), which is the taxonomy system for perceived quality attributes and the core of the attributes importance ranking (PQAIR) method. The research outcomes are based on findings of the qualitative exploratory study, including European and North American premium and luxury automotive manufacturers. An empirical structural validity test was performed to assess the usability and rigour of the proposed method. The results indicate that perceived quality evaluation can be significantly improved during all stages of product development.
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| 6. |
- Stylidis, Konstantinos, 1978, et al.
(författare)
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Towards Overcoming the Boundaries between Manufacturing and Perceived Quality: An Example of Automotive Industry
- 2017
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 63, s. 733-738
-
Konferensbidrag (refereegranskat)abstract
- Automotive manufacturing enterprises face many challenges today. Remaining as one of the biggest among them is delivering value to the customers through product quality. Moreover, good manufacturing or technical quality does not always result in high perceived quality from a customer perspective. At the same time, perceived quality is a property that has to be incorporated into the product during the whole product lifecycle, from design to production. Throughout the production stage, every manufacturing operation contributes to the building of final product's perceived quality. Thus, there is a need to control manufacturing operations related to this matter. This paper addresses the connection of the perceived quality framework, which defines dimensions of the perceived quality, to a manufacturing model that represents the manufacturing variation and propagation during different assembly operations. The aim of the study is to overcome boundaries between manufacturing and perceived quality. An industrial example, within the automotive premium sector, has been used to draw this connection illustrating the case of welded assemblies.
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| 7. |
- Brahma, Arindam, 1987, et al.
(författare)
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A study on the mechanisms of change propagation in mechanical design
- 2021
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Ingår i: Journal of Mechanical Design - Transactions of the ASME. - : ASME International. - 1050-0472. ; 143:12
-
Tidskriftsartikel (refereegranskat)abstract
- Design changes and change propagation have been recognized as ubiquitous in the engineering design process. But why are some design changes propagated while others are absorbed? This paper reports on a study to investigate the specific properties of a mechanical design that influence whether a change is either propagated or absorbed. Student participants in the study were asked to complete a well-defined mechanical design task and then to introduce several design changes. Analysis of the recorded design processes reveals new insight into the mechanisms of change propagation in terms of properties of the design. The insights suggest avenues for future research to make designs more tolerant to potential future change and to develop improved methods to predict change propagation.
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| 8. |
- Högman, Ulf, 1961, et al.
(författare)
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Requirements on New Technology and the Technology Implementation Process
- 2010
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Ingår i: 8th International NordDesign Conference, NordDesign 2010; Goteborg; Sweden; 25 August 2010 through 27 August 2010. ; 2, s. 289-300
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Konferensbidrag (refereegranskat)abstract
- In literature, many authors have pointed to the importance of technology and technology development for company competitiveness. In this study we aim to study the technology in more detail and attempt to develop an understanding on the requirements and needs on “technology” from the perspective of product development. The research question which we aim to answer in this study is:“What are the requirements on maturity of technology when this technology is about to enter into the product development process?“A qualitative research strategy, based on three study cases involving 17 interviewees, has been chosen. All three cases come from one single company, Volvo Aero Corporation (VAC) in Sweden, in the context of the aero engine industry. The study contributes with a broad mapping of requirements and how they relate to different categories of technologies, showing big differences both regarding content and timing. It is concluded that attention should be payed both to how the organization builds new capabilities and to the capabilities of the technology itself. A surprisingly complicated picture on the requirements relating to the implementation of new technologies has emerged in the study. This contributes to the understanding regarding the difficulties of developing new technology and integrating it into an application.
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| 9. |
- Bayani, Mohsen, 1981
(författare)
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Squeak and Rattle Prediction for Robust Product Development in the automotive industry
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Squeak and rattle are nonstationary, irregular, and impulsive sounds that are audible inside the car cabin. For decades, customer complaints about squeak and rattle have been, and still are, among the top quality issues in the automotive industry. These annoying sounds are perceived as quality defect indications and burden warranty costs to the car manufacturers. Today, the quality improvements regarding the persistent type of sounds in the car, as well as the increasing popularity of electric engines, as green and quiet propulsion solutions, stress the necessity for attenuating annoying sounds like squeak and rattle more than in the past. The economical and robust solutions to this problem are to be sought in the pre-design-freeze phases of the product development and by employing design-concept-related practices. To achieve this goal, prediction and evaluation tools and methods are required to deal with the squeak and rattle quality issues upfront in the product development process. The available tools and methods for the prediction of squeak and rattle sounds in the pre-design-freeze phases of a car development process are not yet sufficiently mature. The complexity of the squeak and rattle events, the existing knowledge gap about the mechanisms behind the squeak and rattle sounds, the lack of accurate simulation and post-processing methods, as well as the computational cost of complex simulations are some of the significant hurdles in this immaturity. This research addresses this problem by identifying a framework for the prediction of squeak and rattle sounds based on a cause-and-effect diagram. The main domains and the elements and the sub-contributors to the problem in each domain within this framework are determined through literature studies, field explorations and descriptive studies conducted on the subject. Further, improvement suggestions for the squeak and rattle evaluation and prediction methods are proposed through prescriptive studies. The applications of some of the proposed methods in the automotive industry are demonstrated and examined in industrial problems. The outcome of this study enhances the understanding of some of the parameters engaged in the squeak and rattle generation. Simulation methods are proposed to actively involve the contributing factors studied in this work for squeak and rattle risk evaluation. To enhance the efficiency and accuracy of the risk evaluation process, methods were investigated and proposed for the system excitation efficiency, modelling accuracy and efficiency and quantification of the response in the time and frequency domains. The demonstrated simulation methods besides the improved understanding of the mechanisms behind the phenomenon can facilitate a more accurate and robust prediction of squeak and rattle risk during the pre-design-freeze stages of the car development.
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| 10. |
- Heshmati, Mohsen, 1987, et al.
(författare)
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Dependency of cohesive laws of a structural adhesive in Mode-I and Mode-II loading on moisture, freeze-thaw cycling, and their synergy
- 2017
-
Ingår i: Materials and Design. - : Elsevier BV. - 1873-4197 .- 0264-1275. ; 122, s. 433-447
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, adhesive bonding has found its way to construction applications such as bridges. Given the harsh conditions that such structures are usually exposed to, it is necessary to account for environmental factors, particularly moisture and temperature, in the design phase. Cohesive zone modelling has attracted much attention in the last decade as a promising method to design adhesive joints. Despite this interest, the effects of moisture and thermal cycles on cohesive laws have not been investigated to the knowledge of the authors. In this paper, we present a method to directly measure the environmental-dependent cohesive laws of a structural adhesive loaded in pure Mode-I and Mode-II. Special consideration is given to overcome issues such as the time-consuming nature of moisture ingression and specimen dimensions, which could be problematic due to the size-limitations of conditioning equipment. The accuracy of this method was verified through simulation of the experiments using the finite element analysis. The effects of exposure to 95% relative humidity, immersion in saltwater and distilled water, and freeze-thaw cycles in the presence or absence of moisture were investigated. The results indicate the damaging effects of combined saltwater and freeze-thaw cycles which were clearly reflected on the shape of the cohesive laws.
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| 11. |
- Clasén, Kristoffer, 1992, et al.
(författare)
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Investigation of Homogeneous Lean SI Combustion in High Load Operating Conditions
- 2020
-
Ingår i: SAE International Journal of Advances & Current Practices in Mobility. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 2641-9645 .- 2641-9637. ; 2:4, s. 2051-2066
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Tidskriftsartikel (refereegranskat)abstract
- Homogeneous lean combustion (HLC) can be utilized to substantially improve spark ignited (SI) internal combustion engine efficiency. Higher efficiency is vital to enable clean, efficient and affordable propulsion for the next generation light duty vehicles. More research is needed to ensure robustness, fuel efficiency/NOx trade-off and utilization of HLC. Utilization can be improved by expanding the HLC operating window to higher engine torque domains which increases impact on real driving. The authors have earlier assessed boosted HLC operation in a downsized two-litre engine, but it was found that HLC operation could not be achieved above 15 bar NMEP due to instability and knocking combustion. The observation led to the conclusion that there exists a lean load limit. Therefore, further experiments have been conducted in a single cylinder research DISI engine to increase understanding of high load lean operation. HLC is known to suppress end-gas autoignition (knock) by decreasing reactivity and temperatures, but during the experiments knock was observed to be prominent and increasing in severity when engine load was increased despite operating ultra-lean close to lambda 2. Knock is normally mitigated by spark retardation which decreases peak cylinder pressure. However, to maintain stable combustion at lambda = 2 the combustion phasing had to be kept close to TC which resulted in high peak cylinder pressures. Therefore, the combustion event had to be balanced in a window where early combustion promoted knock and late resulted in instability and partial burns. A tumble flap was introduced to increase in-cylinder tumble which reduced knock and improved combustion stability. It could be observed that for most load-points assessed; increased tumble could suppress knock and increase the air-dilution limit which proved beneficial in decreasing the NOx emissions. The highest engine load that could be achieved with highly diluted combustion was 16 bar NMEP.
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| 12. |
- Pradas Gómez, Alejandro, 1986, et al.
(författare)
-
Design automation strategies for aerospace components during conceptual design phases
- 2023
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper explores the different design automation strategies used for the design of aerospace components. A literature review of the applicable strategies, together with the strategies used in the DEFAINE project are presented and compared. An opportunity to explore the combination of two strategies is presented (Enhanced Function-Mean and Knowledge Based Engineering), which has the potential to increase the discovery of novel design solutions while being able to assess their structural performance. The preliminary results of the combined strategy are presented, using a DEFAINE use case of a Turbine Rear Structure jet engine component.
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| 13. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Squeak and rattle prevention by geometric variation management using a two-stage evolutionary optimisation approach
- 2020
-
Ingår i: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). ; 2B-2020
-
Konferensbidrag (refereegranskat)abstract
- Squeak and rattle are annoying sounds that often are regarded as the indicators for defects and quality issues by the automotive customers. Among the major causes for the generation of squeak and rattle sounds, geometric variation or tolerance stack-up is a key contributor. In the assembly process, the dimensional variation in critical interfaces for generating squeak and rattle events can be magnified due to tolerance stackup. One provision to manage the tolerance stack-up in these critical interfaces is to optimise the location of connectors between parts in an assembly. Hence, the focus of this work is to prevent squeak and rattle by introducing a geometric variation management approach to be used in the design phase in the automotive industry. The objective is to identify connection configurations that result in minimum variation and deviation in selected measure points from the critical interfaces for squeak and rattle. In this study, a two-stage evolutionary optimisation scheme, based on the genetic algorithm employing the elitism pool, is introduced to fine-tune the connectors’ configuration in an assembly. The objective function was defined as the variation and the deviation in the normal direction and the squeak plane. In the first stage, the location of one-dimensional connectors was found by minimising the objective function in the rattle direction. In the second stage, the best combination of some of the connectors from the first stage was found to define planar fasteners to optimise the objective function both in the rattle direction and the squeak plane. It was shown that by using the proposed two-stage optimisation scheme, the variation and deviation results in critical interfaces for squeak and rattle improved compared to the baseline results.
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| 14. |
- Bergman, Martin, 1985
(författare)
-
Affective Surface Engineering for Product Design
- 2016
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Design research, sensation and perception, hard metrology, emotional functions, semantics, surface roughness, product interaction, core values, total appearance… the list of scientific phrases never ends. Yet, what do they mean and how shall we use it when we are communicating with the industry and our end users? Is it possible to link the product experience to process parameters, put a number onto it? When you can measure spoken needs or even better, implied needs, of a product, and relate that data to the production, it is possible do create advanced products with high interaction stimuli. By joining engineering sciences (hard metrology) with design science (soft metrology) correlations between customer’s product experience (emotional functions) and surface properties (technical functions) can be established.The research briefly handles an optimization process where the framework from Kansei Engineering (KE) is used to evaluate the semantics issues primarily regarding materials and functional surfaces of products. The basic idea is that; the stakeholder’s experience shall be observed already at the phase of ideation in the product development process, which then facilitates the project (in regard to the total appearance) later on when a concept reaches the production stage. The results presented in this thesis are carried out through a number of case studies together with the industry. The main result and aim of the research is a developed robust approach that links emotional functions with technical functions, which in the next step facilitates the improvement of the total appearance of a product. Nevertheless, it should be recognized that research is not yet complete. It is an iterative process, which confirms that the loop of the method needs to be complete. The developed method is a toolbox with the fundamental tools and workshops to facilitate the correlation process mentioned above, however the packaging of the final step in the method is not yet complete. The future research outlook will focus on the “independent industry implementation” where the method is used by the industry by guidelines only, thus without researchers support.
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| 15. |
- Berlin, Cecilia, 1981, et al.
(författare)
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Using the ACD3-ladder to manage multi-phase requirements on end-user products
- 2017
-
Ingår i: Proceedings of the International Conference on Engineering Design, ICED. - 2220-4334 .- 2220-4342. - 9781904670872 ; 4:DS87-4, s. 425-434
-
Konferensbidrag (refereegranskat)abstract
- During the development of any end-user product, a multitude of design decisions need to be made. But if design activities and decisions happen at the wrong time, or not at all, unintentional and sometimes negative design outcomes can be the result. Determining all requirements early in the product development is traditionally recommended, but may force design decisions to be made prematurely onthe basis of incomplete preconditions. Requirements at different degrees of resolution are useful and purposeful at different stages of the development process. To address these requirements management challenges, this paper proposes an approach for incrementally developing requirements in parallel with design, based upon a previously developed framework called ACD³, which draws on a combination of theoretically compatible ideas and concepts from Design Engineering, Human Factors/Ergonomics,Usability and Systems Theory. This approach helps designers identify and handle the possible interdependencies of design variables. The paper also theoretically motivates and demonstrates with an example how the different resolution levels of requirements relate within the framework.
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| 16. |
- Brahma, Arindam, 1987, et al.
(författare)
-
A new model for capturing design information with an aim to aid change propagation assessment and subsequent redesign
- 2018
-
Ingår i: DS 92: Proceedings of the DESIGN 2018 15th International Design Conference. - : Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Croatia; The Design Society, Glasgow, UK. - 1847-9073.
-
Konferensbidrag (refereegranskat)abstract
- A new model is developed to investigate the causes of change propagation and guide the redesign process. The model offers a micro-level perspective on the mechanisms through which changes propagate or are absorbed. Extending the Information Structure Framework (ISF) reported by Ahmad et al. (2013), the model uses a multi-domain approach combined with a reformulated detail design process layer. It is illustrated through a desk-based case study of routine mechanical design. Advantages and limitations are discussed along with possibilities for further work.
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| 17. |
- Brahma, Arindam, 1987, et al.
(författare)
-
Concepts of change propagation analysis in engineering design
- 2023
-
Ingår i: Research in Engineering Design - Theory, Applications, and Concurrent Engineering. - : Springer Science and Business Media LLC. - 1435-6066 .- 0934-9839. ; 34:1, s. 117-151
-
Tidskriftsartikel (refereegranskat)abstract
- Interest in change propagation analysis for engineering design has increased rapidly since the topic gained prominence in the late 1990s. Although there are now many approaches and models, there is a smaller number of underlying key concepts. This article contributes a literature review and organising framework that summarises and relates these key concepts. Approaches that have been taken to address each key concept are collected and discussed. A visual analysis of the literature is presented to uncover some trends and gaps. The article thereby provides a thematic analysis of state-of-the-art in design change propagation analysis, and highlights opportunities for further work.
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| 18. |
- Dabhilkar, Mandar, et al.
(författare)
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Supplier selection or collaboration? : Determining factors of performance improvement when outsourcing manufacturing
- 2009
-
Ingår i: Journal of Purchasing and Supply Management. - : Elsevier BV. - 1478-4092 .- 1873-6505. ; 15:3, s. 143-153
-
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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| 19. |
- Finnsgård, Christian, 1974
(författare)
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Assembly processes and materials supply systems design
- 2009
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lean production has over the last decades emerged as the most important paradigm for production, with the assembly processes in focus, including the objective to minimize non-value-adding work. Thus, much attention has been on the work of the assembly operator. However, little focus has been devoted to how the new requirements from lean production have been transformed into materials supply systems supporting the assembly processes. Hence, the purpose of this thesis is to contribute to increased knowledge about the relation between assembly processes and materials supply systems design.A framework is introduced in this thesis, describing how requirements from the assembly processes are transformed by the materials supply system into the actual materials flow. In the results of this thesis, a model structuring requirements in materials supply and assembly processes is proposed, tested, and subsequently different requirements were identified. Materials exposure is introduced as the transition from the materials supply system to the assembly system. Results show that that the materials exposure has a large impact on assembly workstations performance in terms of space needed, non-value-adding work and ergonomics. Further, an experiment showed that the materials exposure factors with the largest impact on picking time were packaging, angle of packaging and height above floor.Major contributions in this thesis are the identification and structuring of requirements in assembly processes and materials supply systems, and explaining how the materials exposure affects the assembly processes. How this knowledge can be applied in the design of new, or redesign of existing, production systems and materials supply processes in particular, is a managerial contribution.
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| 20. |
- Finnsgård, Christian, 1974, et al.
(författare)
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Impact of materials exposure on assembly workstation performance
- 2011
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 49:24, s. 7253-7274
-
Tidskriftsartikel (refereegranskat)abstract
- This paper examines how the choice of materials exposure impacts workstation performance, in terms of non-value-adding work, space requirements and ergonomics. In a typical Swedish automotive setting, components are exposed in wooden pallets with frames beside the assembly line and supplied by forklift truck. In a case study, three workstations on an assembly line were studied and redesigned following the principles of lean production, using smaller plastic containers for the materials exposure. After the redesign, the space required for materials was reduced by 67%, non-value-adding work decreased by 20%, and walking distance was reduced by 52%. Furthermore, the ergonomics for the assembly operator improved greatly, with a 92% reduction of potentially harmful picking activities, thereby almost eliminating potentially harmful body movements. The theoretical contribution of this paper is firstly the development of an analysis model describing the impact of material exposure on workstation performance and secondly development of the existing categorization of work operations to include different materials handling activities. The most important managerial implication is an increased understanding of the relationship between space, ergonomics, non-value-adding work and materials exposure. These findings have direct implications on workstation design in industry.
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| 21. |
- Finnsgård, Christian, 1974
(författare)
-
Materials exposure: The interface between materials supply and assembly
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis concerns the supply of components to assembly in production sys- tems, and introduces materials exposure as the interface between materials sup- ply systems and assembly systems. The purpose of the thesis is to explain how materials exposure influences the performance of materials supply systems and assembly systems. The supply of components is crucial for assembly, for in serving the requirements from assembly. Still, the materials supply system has to remain efficient. In this way, materials exposure impacts the performance of a production system as a whole.The thesis is a based on five studies, all of which depart from theoretical frame- works developed from literature and empirically applied within the Swedish automotive industry. Four case studies and one experiment were conducted to answer three research questions, and the results are published in five papers.The results of the thesis provide several theoretical and practical contributions. Both the position of the exposure and the size of the packaging for a component impact the performance of the assembly workstation performance in terms of space required, non-value-adding work, and ergonomics. Materials exposure impacts manual picking time at assembly lines, for which packaging is the most influential factor, followed by angle of exposure and height of the exposed com- ponent. Materials exposure further impacts the configuration of the in-plant ma- terials supply system by requiring additional activities in the in-plant materials supply system, which impacts its performance. Concerning the impact of choice of packaging used in materials exposure, a model to evaluate the impact a pack- aging has on the performance of the materials supply system was developed. The Materials Flow Mapping methodology is another contribution that describes the activities in materials supply systems, as well as categorises the activities in material flows into materials handling, transportation, storage, and administra- tive activities.This thesis explains how the materials exposure influences the performance of materials supply systems and assembly systems. It shows how materials expo- sure impacts the assembly system performance and the in-plant materials supply system performance, and finally, how the packaging for materials exposure im- pacts the performance of the materials supply systems and assembly systems. The thesis can further be used as a guide for how materials should be exposed and in the selection of packaging for materials exposure. The most beneficial managerial use would be in the design and operation of assembly systems, mate- rials supply systems, and in particular, materials exposure.
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| 22. |
- Finnsgård, Christian, 1974, et al.
(författare)
-
Swedish shippers’ strategies for coping with slow-steaming in deep sea container shipping
- 2018
-
Ingår i: Journal of Shipping and Trade. - : Springer. - 2364-4575. ; 3:8
-
Tidskriftsartikel (refereegranskat)abstract
- When container shipping lines experience over-capacity and high fuel costs, they typically respond by decreasing sailing speeds and, consequently, increasing transport time. Most of the literature on this phenomenon, often referred to as slow-steaming, takes the perspective of the shipping lines addressing technical, operational and financial effects, or a society perspective focusing on lower emissions and energy use. Few studies investigate the effects on the demand side of the market for container liner shipping. Hence, the aim of this study is to elaborate on the logistics consequences of slow-steaming, particularly the strategies that Swedish shippers purchasing deep sea container transport services employ to mitigate the effects of slow-steaming. Workshops and semi-structured interviews revealed that shippers felt they had little or no impact on sailing schedules and were more or less subject to container shipping lines’ decisions. The effects of slow-steaming were obviously most severe for firms with complex supply chains, where intermediate products are sent back and forth between production stages on different continents. The shippers developed a set of strategies to cope with the low punctuality of containerised shipping, and these were categorised in the domains of transfer-the-problem, transport, sourcing and distribution, logistics and manufacturing, and product design. All firms applied changes in the transport domain, although the lack of service segmentation limited the effects of the strategy. Most measures were applied by two firms, whereas only one firm changed the product design.
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| 23. |
- Gong, Xuejian, et al.
(författare)
-
Simulation-Driven Manufacturing Planning for Product-Production Variety Coordination
- 2017
-
Ingår i: IEEE International Conference on Industrial Engineering and Engineering Management. - 2157-3611 .- 2157-362X. ; 2017-December, s. 2039-2043
-
Konferensbidrag (refereegranskat)abstract
- Ambitious manufacturers are challenged to satisfy a broad range of customers while ensuring that the emerging product variety can be produced. Current practice suggests that products and production systems are modeled separately until the late stages of development when the designs are fixed and modifications are costly. In this paper, both product and production varieties are modeled, assessed, and evaluated using discrete-event simulation during preliminary stages. An illustrative example from the aerospace industry is used to demonstrate the approach. The simulation software Simio is used to model a sequence of operations and a set of input data related to a variety of aerospace sub-systems and a variety of welding resources. Through the simulations, the average utilization rate, the average throughput time, and the average work in process are generated. These outputs are used to evaluate the sets of product-production alternatives during the early stages of platform development when the cost to adjust the design of the products, production resources and operations are trifling.
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| 24. |
- Hanson, Robin, 1981, et al.
(författare)
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Impact of unit load size on in-plant materials supply efficiency
- 2014
-
Ingår i: International Journal of Production Economics. - : Elsevier BV. - 0925-5273 .- 1873-7579. ; 147:PART A, s. 46-52
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Tidskriftsartikel (refereegranskat)abstract
- The unit loads, e.g.; plastic containers or EUR-pallets, used in an assembly plant can have a significant impact on time efficiency, and hence cost, of both the materials supply and the receiving assembly stations. Smaller unit loads can reduce the time the assemblers spend fetching parts. However, larger unit loads result in fewer moves for a given volume of materials, which implies efficient in-plant materials supply. The current paper explores how the time efficiency of in-plant materials supply is affected by the size of unit loads. Based on the case study, it is clear that the efficiency of the in-plant materials supply is not proportional to the size of the unit loads. There are fundamental differences between how large pallets, compared to smaller unit loads, are delivered, meaning that the increased delivery frequency required for smaller unit loads does not necessarily result in an increased man-hour consumption.
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| 25. |
- Hoffenson, Steven, 1985, et al.
(författare)
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A Multi-objective Tolerance Optimization Approach for Economic, Ecological, and Social Sustainability
- 2013
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Ingår i: 20th CIRP International Conference on Life Cycle Engineering (LCE). - Singapore : Springer Singapore. - 9789814451475 - 9789814451482
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Konferensbidrag (refereegranskat)abstract
- Sustainable design requires simultaneous consideration of the economic, ecological, and social consequences of design decisions. The selection of dimensional tolerances and materials are two such decisions that have impacts in all three of these areas. This article presents an optimization framework along with generalized models for considering sustainability and understanding how different aspects of sustainability may trade off with one another. A mobile phone design is used as a case study to demonstrate the strengths of the approach when varying manufacturing tolerance and material choice, and the results include three-dimensional Pareto frontiers illustrating the design tradeoffs.
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