| 1. |
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| 2. |
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INNOTRACK: Concluding technical report
- 2010
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Editorial collection (peer-reviewed)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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| 3. |
- Högman, Ulf, 1961, et al.
(author)
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Requirements on New Technology and the Technology Implementation Process
- 2010
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In: 8th International NordDesign Conference, NordDesign 2010; Goteborg; Sweden; 25 August 2010 through 27 August 2010. ; 2, s. 289-300
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Conference paper (peer-reviewed)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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| 4. |
- Yang, Shun-Han, 1987, et al.
(author)
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Parametric study of the dynamic motions and mechanical characteristics of power cables for wave energy converters
- 2018
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In: Journal of Marine Science and Technology. - : Springer Science and Business Media LLC. - 0948-4280 .- 1437-8213. ; 23:1, s. 10-29
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Journal article (peer-reviewed)abstract
- A case study of a point-absorber wave energy converter (WEC) system is presented. The WEC system forms an array, with several WECs located around a central hub to which they are each connected by a short, free-hanging power cable. The objective of the study is to analyse the dynamic characteristics and estimate the fatigue life of the power cable which is not yet in use or available on the commercial market. Hence, a novel approach is adopted in the study considering that the power cable’s length is restricted by several factors (e.g., the clearances between the service vessel and seabed and the cable), and the cable is subject to motion and loading from the WEC and to environmental loads from waves and currents (i.e., dynamic cable). The power cable’s characteristics are assessed using a numerical model subjected to a parametric analysis, in which the environmental parameters and the cable’s design parameters are varied. The results of the numerical simulations are compared and discussed regarding the responses of the power cables, including dynamic motion, curvature, cross-sectional forces, and accumulated fatigue damage. The effects of environmental conditions on the long-term mechanical life spans of the power cables are also investigated. Important cable design parameters that result in a long power cable (fatigue) service life are identified, and the cable service life is predicted. This study contributes a methodology for the first-principle design of WEC cables that enables the prediction of cable fatigue life by considering environmental conditions and variations in cable design parameters.
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| 5. |
- Heshmati, Mohsen, 1987, et al.
(author)
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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
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In: Materials and Design. - : Elsevier BV. - 1873-4197 .- 0264-1275. ; 122, s. 433-447
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Journal article (peer-reviewed)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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| 6. |
- Evertsson, Magnus, 1967, et al.
(author)
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Control systems for improvement of cone crusher yield and operation
- 2014
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In: Proceedings of Comminution '14.
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Conference paper (other academic/artistic)abstract
- Gyratory and cone crushers are regaining interest and are becoming more frequently used in order to create more energy efficient comminution circuits. A typical example is found in coarse comminution circuits were HPGRs are used as a first milling stage. In this case the preparation of a suitable feed with a well-defined width of the particle size distribution and a controlled top size are of high importance. In turn, this emphasizes the importance of a stable and controlled operation of the preceding crushing stages. Control systems for cone and gyratory crushers were first introduced during the early 60ths. The common opinion is that if these systems are able to compensate for the wear of the crushing liners the production yield can be increased with 20-25%. Over the years these types of systems have been widely used but the theory behind the principles have not been thoroughly scientifically scrutinized and presented. Of special interest is the capability to protect the crushers from long term overloading commonly defined as fatigue.With developments in electronics and plant control the crusher control systems have become more refined over the years. Though, there are sometimes conflicting interests in the control strategies between process requirements and crusher protection. In the paper an overview of the challenges, opportunities and existing control systems for cone and gyratory crushers is presented. A requirement specification for a system that is possible to fully integrate into modern plant control systems is outlined.
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| 7. |
- Evertsson, Magnus, 1967, et al.
(author)
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Monitoring and validation of life time prediction of cone crusher with respect to loading and feeding conditions
- 2016
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In: Comminution 16. - 9781510826670 ; 904 (1 Vol)
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Conference paper (peer-reviewed)abstract
- The interest and need for compressive crushing in gyratory, cone and HPGR crushers are increasing since ores become more competent and more difficult to break. Compressive crushing is energy efficient as a consequence of the crushing principle and the imposed stress-state. The stress variations can be described by stress amplitudes and it is a known fact that many different materials, components and machines suffer from cyclic loading which shortens the service lifetime. This phenomena is explained by density variations of the particle beds in the equipment which in turn originates from particle segregation and feeding alignment. The phenomena is often called fatigue and the consequence is premature breakdowns and a relatively shorter lifetime than expected. In this paper, a previously developed theory for lifetime assessment of cone crushers will be used as a foundation for evaluation of full-scale operating cone crushers in minerals processing plants. Lifetime is calculated as a consequence of the load spectrum. The data shows that improper feeding conditions will substantially decrease the lifetime of the crusher equipment leading to excessive operating costs. An adequate control system should be able to recognise the hazardous lifetime decreasing overloads and to warn the operator. There are sometimes conflicting interests in the control strategies between production yield (process requirements) and crusher protection.
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| 8. |
- Linnéusson, Gary, et al.
(author)
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Towards strategic development of maintenance and its effects on production performance by using system dynamics in the automotive industry
- 2018
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In: International Journal of Production Economics. - : Elsevier. - 0925-5273 .- 1873-7579. ; 200, s. 151-169
-
Journal article (peer-reviewed)abstract
- Managing maintenance within an economical short-termism framework, without considering the consequential long-term cost effect, is very common in industry. This research presents a novel conceptual system dynamics model for the study of the dynamic behaviors of maintenance performance and costs, which aims to illuminate insights for the support of the long-term, strategic development of manufacturing maintenance. By novel, we claim the model promotes a system's view of maintenance costs that include its dynamic consequential costs as the combined result of several interacting maintenance levels throughout the constituent feedback structures. These range from the applied combination of maintenance methodologies to the resulting proactiveness in production, which is based on the rate of continuous improvements arising from the root cause analyses of breakdowns. The purpose of using system dynamics is to support the investigations of the causal relationships between strategic initiatives and performance results, and to enable analyses that take into consideration the time delays between different actions, in order to support the sound formulation of policies to develop maintenance and production performances. The model construction and validation process has been supported by two large maintenance organizations operating in the Swedish automotive industry. Experimental results show that intended changes can have both short and long-term consequences, and that obvious and hidden dynamic behavioral effects, which have not been reported in the literature previously, may be in the system. We believe the model can help to illuminate the holistic value of maintenance on the one hand and support its strategic development as well as the organizational transformation into proactiveness on the other.
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| 9. |
- Löfstrand, Magnus, et al.
(author)
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A model for predicting and monitoring industrial system availability
- 2012
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In: International Journal of Product Development. - Bucks, United Kingdom : InderScience Publishers. - 1477-9056 .- 1741-8178. ; 16:2, s. 140-157
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Journal article (peer-reviewed)abstract
- This paper describes the integration of a sensor data stream monitoring system into a proposed functional product model capable of predicting functional availability. Such monitoring systems enable predictive maintenance to be carried out pre-emptive maintenance that is scheduled in response to imminent hardware failure and are in widespread use in industry. The industrial motivation for this research is that agreed upon system availability is a critical element of any business-to-business agreement regarding functional sales. Such a model is important when making strategic choices regarding FPs and can be used to develop a high availability product design through simulation driven development, as well as to provide operational decision support that reflects the current reality to enable optimal availability to be achieved in practice. The proposed model integrates hardware, support system and monitoring system models, and is able to incorporate actual operational data. It has been partly verified based on previous research.
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| 10. |
- Löfstrand, Magnus, 1974-, et al.
(author)
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A model for predicting and monitoring industrial system availability
- 2012
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In: International Journal of Product Development. - Bucks, United Kingdom : InderScience Publishers. - 1477-9056 .- 1741-8178. ; 16:2, s. 140-157
-
Journal article (other academic/artistic)abstract
- This paper describes the integration of a sensor data stream monitoring system into a proposed functional product model capable of predicting functional availability. Such monitoring systems enable predictive maintenance to be carried out pre-emptive maintenance that is scheduled in response to imminent hardware failure and are in widespread use in industry. The industrial motivation for this research is that agreed upon system availability is a critical element of any business-to-business agreement regarding functional sales. Such a model is important when making strategic choices regarding FPs and can be used to develop a high availability product design through simulation driven development, as well as to provide operational decision support that reflects the current reality to enable optimal availability to be achieved in practice. The proposed model integrates hardware, support system and monitoring system models, and is able to incorporate actual operational data. It has been partly verified based on previous research.
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| 11. |
- Reed, Sean, 1982-, et al.
(author)
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Quantified economic and environmental values through Functional Productization : A simulation approach
- 2018
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In: Environmental impact assessment review. - : Elsevier. - 0195-9255 .- 1873-6432. ; 70, s. 71-80
-
Journal article (peer-reviewed)abstract
- Industrial companies rely on hardware and services from external providers to deliver functions that are critical to their operations, increasingly demanding solutions that not only meet technical and availability requirements but are sustainable too. Traditionally, industrial companies choose and purchase hardware and maintenance support to fulfil their functional requirements. An alternative arrangement, known as Functional Product (FP), involves external providers supplying customers with the functionality they require through contracts that specify guaranteed functional availability whilst giving providers freedom to choose and retain ownership of the supplied hardware and services. This paper describes an innovative simulation modelling and optimization approach to quantitatively compare economic and environmental values resulting from transition from traditional to FP arrangements. The approach is demonstrated through the analysis of a scenario involving a hydraulic drive system provider and set of customers in Sweden, with the results exhibiting simultaneous improvement in economic and environmental values at each stage of the transition.
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| 12. |
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| 13. |
- Liwång, Hans, 1974, et al.
(author)
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Quantitative risk analysis – Ship security analysis for effective risk control options
- 2013
-
In: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 58:1, s. 98-112
-
Journal article (peer-reviewed)abstract
- This study reviews ship security assessment. The objectives are to explore the possibilities for quantifying and performing a more thorough ship security risk analysis than that described in the International Ship and Port Facility Security code and to evaluate to what extent this more detailed analysis increases ship security and facilitate the effective selection of risk control options.The study focuses on Somali-based maritime piracy, using piracy on the Indian Ocean as a case study. Data are collected using questionnaires and interviews with civilian and military security experts who possess firsthand experience of piracy off the coast of Somalia. The data are collected specifically for this study and describe and quantify the threat’s capability, intent and likelihood of exploiting a ship’s vulnerability. Based on the collected description of the threat, the study analyzes and describes: probability of detection by pirates, probability of successful approach, and probability of successful boarding.The performed work shows good agreement between calculated probabilities and frequencies in the cited incident reports. Also, the developed scenarios describe the most important influences on the analysed areas. The research therefore shows that the proposed risk-based approach, which uses structurally collected and documented information on the threat, can increase ship security by assisting in selecting risk control options. The approach also allows for a better understanding of the causal relationship between threat and risk than that provided in today’s security analysis by ship owners, for example. This understanding is crucial to choosing effective and robust risk control options.
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| 14. |
- Mao, Wengang, 1980, et al.
(author)
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A comparison of two wave models and their influence on fatigue damage in ship structures
- 2013
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In: Proceedings of The ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2013). - 9780791855324 ; 2A, s. 1-9
-
Conference paper (peer-reviewed)abstract
- In the maritime industry, fatigue failure is one of the most significant failure modes for ship structures. The fatigue damage in ship structures is mainly caused by the variation of wave loadings applied on ships, leading to variable structural stresses. Therefore, a reliable description of wave environments encountered during a ship’s service life is essential for accurate fatigue assessment of ship structures. Besides the wave scatter diagram provided by classification society rules, different statistical wave models have also been built up to model wave environments along arbitrary ship routes. The wave models could provide more specific wave environment for any chosen sailing routes of an individual ship. They may have the potential to be used for some practical applications, such as conceptual ship fatigue design, remaining fatigue life prediction when a ship plans to change its original trade region, and crack maintenance planning etc. Since the development of these models may be based on different sources, e.g. satellite measurements, hindcast data, buoys, etc., the reliability and consistence of wave generations from various wave models must be validated by the measured wave environments in order to be used for those practical applications. In this paper, waves generated from two different wave models, one based on hindcast data and one mainly on satellite data, are compared with measured wave environments encountered by a 2800 TEU container vessel on the North Atlantic route. These wave models are used in the calculation of the fatigue damage in the vessel. The results obtained using waves generated from the two wave models are compared with the fatigue damage calculated based on strain measurements in the ship. Recommendations for future development of the wave models and further investigation to make the applications more realistic for ship fatigue assessment are also presented.
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| 15. |
- Peng, Yong, et al.
(author)
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Development of head injury risk functions based on real-world accident reconstruction
- 2014
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In: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 19:2, s. 105-114
-
Journal article (peer-reviewed)abstract
- The objective of this study is to assess head injury risks of adult pedestrians using computer reconstructions of the accidents. For this purpose, accident reconstructions were developed based on the real-world pedestrian accidents. The impact conditions, which were obtained from the previous study [Y. Peng, C. Deck, J.K. Yang, D. Otte, and R. Willinger, A study of adult pedestrian head impact conditions and injury risks in passenger car collisions based on real world accident data, Traffic Inj. Prev., doi: 10.1080/15389588.2012.733841] including head impact velocity, head position and head orientation, were defined as initial loading conditions in a simulation of the head striking to a windscreen by using a finite element (FE) Hybrid III head model. Logistic regression models were developed to study brain injury risk with respect to injury related variables: the head linear acceleration, HIC value, skull fracture correlate (SFC), resultant angular acceleration and head impact power (HIP). The results from Hybrid III head impact simulations indicated that the predicted head linear acceleration, HIC value, resultant angular acceleration and HIP for 50% probability of AIS 2+ and AIS 3+head injury risk are 116g, 825, 11368 rad/s(2), 37 kW and 162g, 1442, 18775 rad/s(2), 68 kW, respectively, and the predicted values of 50% probability of skull fracture is 135g. The knowledge from this study could be a prerequisite for developing guidelines to improve pedestrian safety.
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| 16. |
- Ringsberg, Jonas, 1971, et al.
(author)
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Analysis of impact loads on a self-elevating unit during jacking operation
- 2017
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In: Journal of Offshore Mechanics and Arctic Engineering. - : ASME International. - 0892-7219 .- 1528-896X. ; 139:3, s. 1-9
-
Journal article (peer-reviewed)abstract
- A method is presented that enables the analysis of weather window assessments for the installation and retrieval phases of a self-elevating unit (SEU). The method takes site-specific parameters, defined as soil type and water depth, into account in addition to vessel-specific and environmental parameters. The inclusion of site-specific parameters is the novel contribution compared to assessment methodologies used today. A simulation model is presented that incorporates a coupled non-linear time-domain analysis of vessel motion and soil-structure interaction. Soil deformation behaviour during impact is described by resistance curves based on a bearing capacity theory. A structural evaluation criterion against which impact forces are compared is used for weather window assessments. The simulation model is applied on a case study utilizing different soil types to study impact forces and the capacity of the structure for withstanding such impacts and eventually performing a weather window assessment. The results show that the jacking operation can be divided into two phases when it comes to loads on the spudcan: a phase dominated by vertical forces followed by a phase dominated by horizontal forces. It is found that including soil deformation behaviour is of paramount importance to the magnitude of the resulting impact forces and that class-recommended practice does indeed produce rather large force estimates. Thus, assessments where site-specific parameters are incorporated could definitely increase the operable weather window for SEUs, and, consequently, increase the economic competitiveness of, for example, the offshore wind industry.
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| 17. |
- Schreuder, Martin, 1970, et al.
(author)
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A method for assessment of the survival time of a ship damaged by collision
- 2011
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In: Transactions - Society of Naval Architects and Marine Engineers. - 0081-1661. ; 55:2, s. 86-99
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Journal article (peer-reviewed)abstract
- Following an interdisciplinary calculation procedure, the chain of events of ship collision, flooding, and loss of stability within given time have been investigated. The method established in the current work concerns the interaction between structural and damage stability computations and has been used to study the influence of various parameters, e.g., significant wave height and size of damage opening on a RoPax-ferry damaged in a collision with a ship of similar size.
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| 18. |
- Bergsjö, Dag Henrik, 1980
(author)
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The PLM user perspective: identification of user needs and their organisational impacts
- 2015
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In: International Journal of Product Lifecycle Management. - 1743-5129 .- 1743-5110. ; 8:2, s. 172-187
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Journal article (peer-reviewed)abstract
- This paper concerns the user perspective when implementing and improving PLM in anorganisation. The main issues investigated are how to efficiently identify, collect andprioritise the engineers' need towards PLM. This paper presents results from one qualitativeand one quantitative case study performed at one independent automotive OEM, in Sweden.The case studies show that there are means to collect user-requirements efficiently thatrepresent both the management and the engineering needs of the organisation
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| 19. |
- Elg, Mattias, 1968-, et al.
(author)
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The Future of Work for Quality Management – Challenges in the Digitalized Era
- 2018
-
Conference paper (other academic/artistic)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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| 20. |
- Falck, Ann-Christine, 1949, et al.
(author)
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A calculation model for ergonomics cost-benefit analyses in early product development stages
- 2012
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In: Advances in ergonomics in manufacturing. - : CRC Press. - 9781439870402 ; , s. 399-408
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Book chapter (other academic/artistic)abstract
- Increasing international competition between companies has put high focus on cost-cutting actions at all levels in companies and organizations. In product development there are many design requirements to meet and often tough project budgets to keep. Requirements that are considered not profitable will often be neglected, which often affects assembly ergonomics. The objective of this study is to demonstrate the relationship between ergonomics, assembly related quality errors and associated costs and develop a cost-beneficial assessment model. The results showed that ergonomics high risk issues had 5-8 times as many quality errors as low risk issues and the earlier risk issues were found the less were the action costs. A model for cost-benefit analyses was developed based on the obtained quality data.
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| 21. |
- Gopalakrishnan, Maheshwaran, 1987, et al.
(author)
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Machine criticality assessment for productivity improvement: Smart maintenance decision support
- 2019
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In: International Journal of Productivity and Performance Management. - : EMERALD GROUP PUBLISHING LTD. - 1741-0401 .- 1758-6658. ; 68:5, s. 858-878
-
Journal article (peer-reviewed)abstract
- Purpose The purpose of this paper is to increase productivity through smart maintenance planning by including productivity as one of the objectives of the maintenance organization. Therefore, the goals of the paper are to investigate existing machine criticality assessment and identify components of the criticality assessment tool to increase productivity. Design/methodology/approach An embedded multiple case study research design was adopted in this paper. Six different cases were chosen from six different production sites operated by three multi-national manufacturing companies. Data collection was carried out in the form of interviews, focus groups and archival records. More than one source of data was collected in each of the cases. The cases included different production layouts such as machining, assembly and foundry, which ensured data variety. Findings The main finding of the paper is a deeper understanding of how manufacturing companies assess machine criticality and plan maintenance activities. The empirical findings showed that there is a lack of trust regarding existing criticality assessment tools. As a result, necessary changes within the maintenance organizations in order to increase productivity were identified. These are technological advancements, i.e. a dynamic and data-driven approach and organizational changes, i.e. approaching with a systems perspective when performing maintenance prioritization. Originality/value Machine criticality assessment studies are rare, especially empirical research. The originality of this paper lies in the empirical research conducted on smart maintenance planning for productivity improvement. In addition, identifying the components for machine criticality assessment is equally important for research and industries to efficient planning of maintenance activities.
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| 22. |
- Hellman, Pasi, et al.
(author)
-
Development of Quality Management Systems : How Have Disruptive Technological Innovations in Quality Management Affected Organizations?
- 2013
-
In: Quality Innovation Prosperity. - : Quality Innovation Prosperity. - 1335-1745 .- 1338-984X. ; 17:1, s. 104-119
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Journal article (peer-reviewed)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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| 23. |
- Hermans, Johanna, et al.
(author)
-
Quality management in the new product development : A PPAP approach
- 2013
-
In: Quality Innovation Prosperity. - : Quality Innovation Prosperity. - 1335-1745 .- 1338-984X. ; 17:2, s. 37-51
-
Journal article (peer-reviewed)abstract
- The purpose of this paper is to test Production Part Approval Process (PPAP) as a tool to build quality into the new product and processes and ensure that it meets the customer expectations. Research method is qualitative method using so called case-study to study the suitability of PPAP as a tool for quality management by building quality right into the new product and process. The case studies have been made with three different kinds of companies. PPAP is suitable tool for quality management in NPD processes when taking into account many requirements about personnel, processes, documentation etc. The paper has some limitations such as limited sample size. The results are encouraging managers to use PPAP as a tool for managing their company’s product development processes, quality work and supply chain partnerships. The manner in which the stakeholders could use to facilitate a sense of partnerships or co-workers aiming the same goals rather than have a traditional customer-seller relationship was valued in this study.
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| 24. |
- Hjort af Ornäs, Viktor, 1976, et al.
(author)
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The spread of product development methodology: Exploring drivers and barriers in Swedish Industry
- 2014
-
In: 10th Biannual NordDesign Conference, NordDesign 2014, Espoo, Finland, 27-29 August. - 9781904670582 ; , s. 540-549
-
Conference paper (peer-reviewed)abstract
- The outcome of Design, Innovation and Product development research is often manifested asrecommendations in the form of methods, but these do not always find their way intoindustrial application. This paper elaborates on drivers and barriers for the spread of productdevelopment methodology based on 41 interviews with managers, designers, developers andknowledge brokers. Results indicate a range of motives for adopting methods including e.g.coordination of different actors, generation of documentation, methods serving as tools forvarious design tasks etc. However; the value of tools must be seen in relation to localconditions and practices. The spread of methods occurs between and within organisations andmay be actively supported while ideally “good tools spread themselves”. Participants call formethods to be scalable or malleable, guiding, informing and enabling without constraining orenforcing too rigid procedures.
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| 25. |
- Hoffenson, Steven, 1985, et al.
(author)
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Tolerance Optimization of a Mobile Phone Considering Consumer Demand for Quality and Sustainability in China, Sweden, and the United States
- 2013
-
In: International Conference on Engineering Design. - : Design Research Society. ; 7 DS75-07, s. 467-476, s. 467-476
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Journal article (peer-reviewed)abstract
- Dimensional tolerances are chosen during the product development process to balance quality requirements against manufacturing costs. Designers typically judge how much variance should be allowed while still maintaining the perception of a high quality product or brand, but this is rarely based on an understanding of how consumers perceive that variance. Additionally, ecological sustainability priorities are often chosen without knowing how they will be received by consumers. This paper presents a survey-based technique for understanding how tolerance and pricing decisions influence a product developing firm’s profits, accounting for consumer perceptions of quality and environmental friendliness. A case study of a mobile phone design is explored, including variance propagation modeling, the design and administration of an online choice-based conjoint (CBC) survey, construction of consumer demand models, and profit maximization for the markets in three different countries. The results show a slight preference for high quality products compared with stronger preferences for other product attributes like low price, and the differences among the three markets are highlighted.
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| 26. |
- Jagtap, Santosh, et al.
(author)
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How design process for the Base of the Pyramid differs from that for the Top of the Pyramid
- 2014
-
In: Design Studies. - : Elsevier BV. - 0142-694X .- 1872-6909. ; 35:5, s. 527-558
-
Journal article (peer-reviewed)abstract
- The base (BOP) and the top (TOP) of the world income pyramid represent the poor people and the people from developed countries, respectively. The design of products for the BOP is an important ingredient of the poverty reduction approach that combines business development with poverty alleviation. However, the current understanding of the design for the BOP is limited. This study, using a protocol analysis, compared design processes for the BOP and TOP markets. The results indicate the difference between the design processes for these markets in terms of the design strategy employed by the designers (i.e. problem driven, solution driven strategy), their requirements handling behaviour, and their information behaviour.
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| 27. |
- Madrid, Julia, 1988, et al.
(author)
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Enabling reuse of inspection data to support robust design: a case in the aerospace industry
- 2016
-
In: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 43, s. 41-46
-
Conference paper (peer-reviewed)abstract
- The use and reuse of information and knowledge from manufacturing are crucial to secure the quality of the product throughout the product realization process. Robust design, variation simulation, virtual verification and root causes analysis are activities that require inspection data to ensure a robust process. In many industries, the level of inspection data reused is rather low. In this study, general barriers for reusing data concerning manufacturing processes have been identified in scientific literature and compared with specific barriers identified in a case study performed at an aerospace engine manufacturer. As an output of this comparison, barriers to the reuse of inspection data have been classified in three types: informational, technical, and organizational. In addition, the informational barriers are decomposed in four questions: Why, What, When and, How to measure. A support to answer those questions and overcome the informational barriers is proposed.
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| 28. |
- Michaelis, Marcel, 1982, et al.
(author)
-
Integrating Product and Manufacturing System Platforms - Exploring a Configurable System Approach
- 2010
-
In: Proceedings of the 11th International Design Conference DESIGN 2010. - 9789537738075 ; , s. 1605 - 1614
-
Conference paper (peer-reviewed)abstract
- While platform strategies are not the silver bullet to the development of products and manufacturing systems, they might at least yield some benefits. This paper explores a specific platform approach looking at products and manufacturing units as configurable systems. It reports an explorative empirical study identifying issues in integrated development. These issues are matched with the capability of the chosen approach to help solving them. Expressing information on appropriate levels of abstraction and illustrating interconnections of the systems are concluded to be two of the benefits.
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| 29. |
- Michaelis, Marcel, 1982, et al.
(author)
-
Plattform-Based Development
- 2011
-
In: Entering the Tiger's Cave - Perspectives on Japanese and Swedisch Product Development. Dag Bergsjö (Ed.). ; , s. 31-35
-
Book chapter (other academic/artistic)abstract
- One of the main drivers for platform-based development and production is the possibility to combine customization with economies of scale. The reuse of common resources in multiple, customized design variants is one way of achieving this. However, the economic benefits may be easily lost. A relatively small design differentiation, for example, may lead to a relatively large number of parts having to be modified. More fruitful approaches that can support carry-over without major drawbacks include, for example, adopting a carefully planned development process or to reusing more abstract design knowledge.
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| 30. |
- Si, Shubin, et al.
(author)
-
Benchmarking and developing the operational competitiveness of Chinese state-owned manufacturing enterprises in a global context
- 2010
-
In: International Journal of Innovation and Learning. - : InderScience Publishers. - 1471-8197 .- 1741-8089. ; 7:2, s. 202-222
-
Journal article (peer-reviewed)abstract
- The purpose of this paper is to study the operational competitiveness of Chinese State-Owned Manufacturing Enterprises (CSOMEs) by analysing the case CSOME and comparing it with other global manufacturing companies in a Global Manufacturing Strategies (GMSS) database for developing innovation and learning. Analytical models are used to analyse the operational competitiveness of the case CSOME and its subsidiaries based on the weights of the multicriteria manufacturing strategies. The operational competitiveness development of its subsidiaries are applied to predict the future operational competitiveness of the case CSOME in a global context. The results show that quality is the most important competitive priority of the case CSOME and the case CSOME have some advantages when competing in a prospector group. The ranking and stability of the operational competitiveness of the case CSOME imply that: (1) the top CSOMEs have a strong operational competitiveness in the global context; however, they have some gaps compared to the top manufacturing enterprises in the world and (2) it will take a long time for the top CSOMEs to improve their operational competitiveness because of a huge organisational structure. Copyright © 2010 Inderscience Enterprises Ltd.
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| 31. |
- Wagersten, Ola S, 1976, et al.
(author)
-
Robust Design and Quality Assurance
- 2011
-
In: Entering the Tiger's Cave - Perspectives on Japanese and Swedisch Product Development. Dag Bergsjö (Ed.). ; , s. 37-44
-
Book chapter (other academic/artistic)abstract
- Robust design aims at reducing the effects of variation on a design, without eliminating the variation itself. It is a method of improving product quality with little or no additional manufacturing costs.Robust design methodology was pioneered by Japanese statistician Genichi Taguchi in the 1960s. His work is believed to have had a large influence on Japanese engineering tradition, and he is credited with playing a part in the Japanese industrial boom of the 1970s and 1980s. Today, robust design methodology is employed in companies all over the world, and extensive research has been conducted on the subject.
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| 32. |
- Nygårds, Thomas, 1980, et al.
(author)
-
Multibody modeling and vibration dynamics analysis of washing machines
- 2012
-
In: Multibody System Dynamics. - : Springer Science and Business Media LLC. - 1573-272X .- 1384-5640. ; 27:2, s. 197-238
-
Journal article (peer-reviewed)abstract
- In this paper a computational model of a horizontal axis washing machine is presented. The model has been built using a theoretical-experimental methodology consistingof integration of multibody system (MBS) formalism, detailed modeling of machine functional components and experimental data-based validation. The complete model of awashing machine is implemented in the commercial MBS environment Adams/View from MSC.Software. An undesirable impact of washing machine operation on the surroundingsis vibration and noise. The impact comes from system dynamics and poorly distributed load inside the drum, creating an imbalance. To get insight into vibration dynamics extensive simulations have been performed for washing machines in service as well as for machinesin the developing stage by using the created computational model. This paper presents several results of numerical studies of the vibration dynamics of washing machines including the study of sensitivity of system dynamics with respect to suspension structural parameters, and the results of investigation of the potential of the automatic counterbalancing technology for vibration output reduction. In particular, simulations of the considered two-plane balancing device has shown an existing significant potential in eliminating unbalanced loadat supercritical spinning speed, resulting in a substantial vibration reduction in washing machines.
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| 33. |
- Kumar, Mayank, 1991-, et al.
(author)
-
Influence of cutting fluid on reliability of threaded fastener joints
- 2019
-
In: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191. ; :December
-
Journal article (peer-reviewed)abstract
- This study reports on the effect of cutting fluids on friction behavior of the threaded fasteners. Underhead and thread friction are measured during tightening process of the hex-head threaded fasteners coated with different zinc-based coatings: electroplated zinc, zinc flake, and electroplated zinc nickel, commonly used in the automotive industry. The tests and data analysis are conducted considering ISO 16047 as a baseline. Test conditions are set close to the actual production conditions found in the motor vehicle industry. Water-based and ester-based cutting fluids are selected to unveil their impact on the reliability of the threaded fastener joints. It is shown that a change in the underhead interface conditions from dry to lubricated drastically reduces friction for the electroplated zinc and zinc nickel coatings.
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| 34. |
- Bergsjö, Dag Henrik, 1980
(author)
-
Flexible PLM architecture as an enabler for multidisciplinary engineering
- 2014
-
In: International Journal of Product Lifecycle Management. - 1743-5129 .- 1743-5110. ; 7:4, s. 249-265
-
Journal article (peer-reviewed)abstract
- This paper presents three case studies conducted at three independent automotive OEMs in Sweden: their purpose was to investigate the need for multidisciplinary integration in the product development process as well as the resulting engineering requirements on the PLM architecture. It is concluded on the basis of the three cases analysed that a flexible PLM architecture has the potential to fulfil the engineering need for flexibility and specialised tool support while maintaining well–documented data integration across companies. It also has the best potential to offer support over time, as local systems can be upgraded and replaced independently.
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| 35. |
- Forslund, Anders, 1982
(author)
-
Uncertainty and Robustness in Aerospace Structures
- 2016
-
Doctoral thesis (other academic/artistic)abstract
- Engineering is not an exact science. In fact, all engineering activity contain some degree of assumption, simplification, idealization, and abstraction. When engineered creations meet reality, every manufactured product behaves differently. This variation can be detrimental to product quality and functionality. In an aerospace context, this variation may even result in serious threats to the safety and reliability of aircraft. However, it is not the variation in and of itself that is harmful, but the effects it imposes on functionality—an important distinction to make. Reducing sources of variation is often associated with tightening tolerances and increasing cost. Instead, it is preferable to eliminate the effects of this variation by making designs more robust. This idea is at the core of robust design methodology. Aerospace is an industry characterized by the complexity of its products and the multidisciplinary nature of its product development. In such contexts, there are significant barriers against implementing uncertainty-based design practices. The research presented in this thesis aims at identifying the role of robust design in general, and geometry assurance in particular, in the early phases of aerospace component design. Further, this thesis proposes a methodology by which geometry assurance practices may be implemented in this setting. The methodology consists of a modelling approach linked to a multidisciplinary simulation environment. In a series of case studies, the methodology is tested in an industrial setting. The capability of the methodology is demonstrated through several applications, in which the effects of geometric variation on the aerodynamic, thermal, and structural performance of a load-bearing turbofan component are analysed. Investigated effects include part variation, fixture variation, part configuration and welding. The proposed methodology overcomes many of the current barriers, making it more feasible to assess geometric variation in the early design phases. Despite some limitations, the methodology contributes to an academic understanding of how to evaluate geometric variation in multidisciplinary simulations and provides a tool for industry. Geometric variation is only one source of uncertainty amongst many others. By evaluating geometric variation against the framework of uncertainty quantification, this thesis addresses the relative importance of geometry assurance against other product development activities.
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| 36. |
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| 37. |
- Karlsson, Nadine, 1988, et al.
(author)
-
QUANTIFYING THE EFFECTS OF PRODUCTION MAINTENANCE DECISIONS USING DISCRETE EVENT SIMULATION
- 2014
-
In: Swedish Production Symposium, 2014, Gothenburg.
-
Conference paper (peer-reviewed)abstract
- Use of simulation to analyze and plan maintenance activities is still limited compared to planning production activities. The paper discusses a simulation based approach to quantify the effects of maintenance decision making by identifying the related performance indicators. The aim of the paper is to quantify the production maintenance related decisions, in terms of Key Performance Indicators (KPIs) determined trough interwievs and simulation. The approach is exemplified in a manufacturing case-study. The results show that use of simulation tool has the potential to be a strategic decision support tool for production maintenance in the production system.
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| 38. |
- Berbyuk, Viktor, 1953
(author)
-
Vibration Dynamics and Control
- 2010
-
Book (other academic/artistic)abstract
- Over the last decades there has been much work concerned with the vibration control of different dynamical systems. The objective in writing this textbook was to help students wishing to get deeper knowledge on structural dynamics and vibration control, while providing an overview of the potential of smart materials based sensor and actuator technologies for active vibration control. The textbook is aimed at first towards graduate and postgraduate students following Master and PhD programmes related to structural dynamics, mechatronics, control engineering, automotive engineering noise and vibrations. The only prerequisite for reading this book is some background in structural dynamics and in automatic control. The contents of the textbook consist of five parts: Vibration dynamics (Part 1), Passive and semi-active vibration control (Part 2), Active and hybrid vibration control (Part 3), Applications (Part 4), and Supplementary mathematics, List of Matlab codes and Answers and hints for the exercises (Part 5).The Part 1 of the textbook is called “Vibration dynamics”. It consists of Chapter 2 and Chapter 3. In Chapter 2 we present three approaches, which are usually used for developing of mathematical models of vibration dynamics of mechanical systems. These approaches are: free-body diagram approach, energy method and Lagrange formalism. Chapter 3 is devoted to elements of vibration dynamics analysis. The focus is set primarily on simple and widely recognizable vibrating mechanical systems. Attention is paid to analysis of vibration dynamics under harmonic excitations, transmissibility and vibration isolation. Some specific properties and phenomena that occur in nonlinear vibrating systems (like parametric resonance) are discussed.Vibration dynamics of a mechanical system can be affected by changing the initial state, or/and by changing the system’s structural/design parameters, or/and by varying the external force/torque excitations acting on the system. This type of problems is considered in the Part 2 of the textbook which is called “Passive and semi-active vibration control”. The Part 2 consists of Chapters 4 - 7. In Chapter 4 we consider so-called passive vibration control (PVC) problems. To this class belong the control problems dealing with determination of the initial state of the system or/and its structural (design) parameters which together with given external force/torque excitations guarantee prescribed (desirable) properties of vibration dynamics of the considered system. Dynamics of undamped as well as damped vibrating systems with tuned mass dampers are studied and analyzed. In many cases mechanical systems are inherently stable to begin with, and external control is applied to improve the performance. But, unfortunately, the introducing the active control, let say for vibration control by using feedback control, can often make the system unstable. Thus analysis of stability of the vibrating system after a control strategy is designed and applied to the system is an important step in engineering practice. In Chapter 5 the elements of the theory of stability which can be used for designing of active vibration control strategies which make the closed loop vibrating system stable, are presented.It is desirable to design active vibration control which uses real-time measurement data as a response of a system in question. In this case the control is mathematically represented as a function of parameters of the system response, e.g. as a function of positions and/or velocities. Such a control is called feedback control. Chapter 6 presents several details of physical and mathematical representations of feedback control. Some important properties of a system to be controlled such as controllability and observability are defined and discussed.In Chapter 7 we consider semi-active vibration control problems. The semi-active vibration control method is defined here as an approach which gives possibility to change damping or/and stiffness properties of functional components of a system, e.g., damping or/and stiffness coefficients of shock absorbers, and in this way to control vibration dynamics of the system in question. Some well-know semi-active control strategies based on skyhook approach are presented. A brief overview of magnetorheological (MR) fluids technology including modelling of MR dampers is presented and their applications for semi-active control are discussed. The Part 3 of the textbook is called “Hybrid and active vibration control”. It consists of Chapters 8 - 9. Chapter 8 presents several approaches and methods for designing of optimal control laws and algorithms for vibration attenuation and vibration suppression. Focus is put on LQR optimization technique, the calculus of variations approaches, the methods which are used first integrals of a vibrating system to be controlled, and the method for optimal vibration control based on Pontryagin maximum principle.The term hybrid control generally refers to a combined passive and active control system. Since a portion of the control objective is accomplished by the passive system, less active control effort, implying less power, is required. A side benefit of hybrid and semi-active control systems is that, in the case of a power failure, the passive components of the control still offer some degree of control, unlike a fully active control system.Chapter 9 presents the elements of theory of hybrid control techniques. A mathematical statement of the optimal control problem which is suitable for modelling of controlled motion and optimization of semi-passively actuated mechanical systems is proposed. A methodology and numerical algorithms for solving the control and optimization problems for semi-passively actuated mechanical systems are described. Special emphasis is put on the study of controlled mechanical systems having different degrees and types of actuation (underactuated and overactuated systems, external powered drives, unpowered spring-damper like drives, etc.). The solutions of energy-optimal control problems are presented for different kinds of semi-passively actuated multibody systems (closed-loop chain semi-passively actuated robot, multibody system modelled the human locomotor apparatus with above-knee prosthesis). The methodology and numerical algorithms described and implemented for particular control problems are also suitable for design of energy efficient active vibration control algorithm for nonlinear vibration mechanical systems. The Part 4 of the textbook is called “Applications”. Here a brief overview is given of the research on vibration dynamics and control performed at the Mechanical systems group of the division of Dynamics, department of Applied Mechanics, Chalmers University of Technology. The focus is on current doctoral projects which are related to vibration dynamics and control problems having applications in high speed train industry, automotive engineering, home appliances design and smart material based power harvesting from vibrations.During the last decades interest in research and development of smart actuators, sensors and power generators that use giant magnetostrictive materials has been continually growing. Both academia and industry are actively looking for broad utilization of this technology for different applications (active vibration and noise control, structural health monitoring, self-powered electronic equipments and systems, MEMS, robotics, biomedical engineering, etc.). Recent developments in miniaturized sensors, digital processors, self-powered electronics and wireless communication systems have many desirable applications. The realization of these applications however, is limited by the lack of a similarly sized power sources. Powering the above mentioned systems can be a significant engineering problem, as traditional solutions such as batteries are not always appropriate. The one issue that still needs to be resolved is a method to generate sufficient energy to power the electronics. The Chapter 10 deals with application of smart materials, namely giant magnetostrictive materials, for power harvesting from vibration. Mathematical modelling and design of magnetostrictive electric generators (MEG) are considered. A mathematical model, physical prototype of MEG and test rig have been developed for simulation and experimental study of conversion of mechanical energy of vibration into electrical energy using Terfenol-D as an active material. Simulation and experimental results have confirmed functionality of the designed MEG. The textbook ends with the Part 5 which comprises Supplementary mathematics, List of Matlab codes, and Answers and hints for the exercises.List of references consists of only those books and scientific papers which were used during preparation of the textbook or which were recommended for additional information on a studied topic.
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| 39. |
- Sandström, Johan, et al.
(author)
-
Reliability analysis with VMEA of a rack and pinion mechanism in a wave energy gravity accumulator
- 2018
-
Reports (other academic/artistic)abstract
- The method Variation and Mode Effect Analysis (VMEA) is successfully implemented for the AGMA based gear design of the rack pinion mechanism. The rack and pinion is a feature in Ocean Harvesting Technologies (OHT) gravity accumulator device. The purpose of it is to make the electrical power output to the grid more uniform. This is a novel technology where previous experience in designing is absent. The VMEA method is there for useful for incorporating all known uncertainties to estimate the uncertainty and reliability of the technology. This allows for adequate safety factors to be set so the desired reliability can be achieved.The uncertainty and reliability analysis is performed for different OHT designs and methods where the reliability is calculated. This calculation can be used as basis for further analysis when more design details are determined and modifications are made, thus allowing for more optimized and reliable design to be made.
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| 40. |
- Fentaye, Amare Desalegn, et al.
(author)
-
Gas path fault diagnostics using a hybrid intelligent methodfor industrial gas turbine engines
- 2018
-
In: Journal of the Brazilian Society of Mechanical Sciences and Engineering. - : Springer. - 1678-5878 .- 1806-3691. ; 40
-
Journal article (peer-reviewed)abstract
- There are many challenges against an accurate gas turbine fault diagnostics, such as the nonlinearity of the engine health,the measurement uncertainty, and the occurrence of simultaneous faults. The conventional methods have limitations ineffectively handling these challenges. In this paper, a hybrid intelligent technique is devised by integrating an autoassociativeneural network (AANN), nested machine learning (ML) classifiers, and a multilayer perceptron (MLP). The AANNmodule is used as a data preprocessor to reduce measurement noise and extract the important features for visualisation andfault diagnostics. The features are extracted from the bottleneck layer output values based on the concept of the nonlinearprincipal component analysis (NLPCA). The nested classifier modules are then used in such a manner that fault and no-faultconditions, component and sensor faults, and different component faults are distinguished hierarchically. As part of the classification,evaluation of the fault classification performance of five widely used ML techniques aiming to identify alternativeapproaches is undertaken. In the end, the MLP approximator is utilised to estimate the magnitude of the isolated componentfaults in terms of flow capacity and isentropic efficiency indices. The developed system was implemented to diagnose up tothree simultaneous faults in a two-shaft industrial gas turbine engine. Its robustness towards the measurement uncertaintywas also evaluated based on Gaussian noise corrupted data. The test results show the derivable benefits of integrating twoor more methods in engine diagnostics on the basis of offsetting the weakness of the one with the strength of another.
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| 41. |
- Fentaye, Amare Desalegn, et al.
(author)
-
Gas turbine gas path diagnostics: : A review
- 2016
-
In: MATEC Web of Conferences 74, 00005. - : EDP Sciences. - 2261-236X.
-
Conference paper (peer-reviewed)abstract
- In this competitive business world one way to increase profitability of a power production unit is to reduce the operation and maintenance expenses. This is possible if the gas turbine availability and reliability is improved using the appropriate maintenance action at the right time. In that case, fault diagnostics is very critical and effective and advanced methods are essential. Gas turbine diagnostics has been studied for the past six decades and several methods are introduced. This paper aims to review and summarise the published literature on gas path diagnostics, giving more emphasis to the recent developments, and identify advantages and limitations of the methods so that beginners in diagnostics can easily be introduced. Towards this end, this paper, identifies various diagnostic methods and point out their pros and cons. Finally, the paper concludes the review along with some recommended future works.
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| 42. |
- Fentaye, Amare Desalegn, et al.
(author)
-
Gas turbine gas-path fault identification usingnested artificial neural networks
- 2018
-
In: Aircraft Engineering. - : Emerald Group Publishing Limited. - 0002-2667. ; 90:6, s. 992-999
-
Journal article (peer-reviewed)abstract
- Purpose – The purpose of this paper is to present a quantitative fault diagnostic technique for a two-shaft gas turbine engine applications.Design/methodology/approach – Nested artificial neural networks (NANNs) were used to estimate the progressive deterioration of single andmultiple gas-path components in terms of mass flow rate and isentropic efficiency indices. The data required to train and test this method areattained from a thermodynamic model of the engine under steady-state conditions. To evaluate the tolerance of the method against measurementuncertainties, Gaussian noise values were considered.Findings – The test results revealed that this proposed method is capable of quantifying single, double and triple component faults with asufficiently high degree of accuracy. Moreover, the authors confirmed that NANNs have derivable advantages over the single structure-basedmethods available in the public domain, particularly over those designed to perform single and multiple faults together.Practical implications – This method can be used to assess engine’s health status to schedule its maintenance.Originality/value – For complicated gas turbine diagnostic problems, the conventional single artificial neural network (ANN) structure-based faultdiagnostic technique may not be enough to get robust and accurate results. The diagnostic task can rather be better done if it is divided and sharedwith multiple neural network structures. The authors thus used seven decentralized ANN structures to assess seven different component faultscenarios, which enhances the fault identification accuracy significantly.
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| 43. |
- Fentaye, Amare Desalegn, et al.
(author)
-
Performance-based fault diagnosis of agas turbine engine using an integratedsupport vector machine and artificialneural network method
- 2019
-
In: Proceedings of the Institution of mechanical engineers. Part A, journal of power and energy. - : Sage Publications. - 0957-6509 .- 2041-2967. ; 233:6, s. 786-802
-
Journal article (peer-reviewed)abstract
- An effective and reliable gas path diagnostic method that could be used to detect, isolate, and identify gas turbinedegradations is crucial in a gas turbine condition-based maintenance. In this paper, we proposed a new combinedtechnique of artificial neural network and support vector machine for a two-shaft industrial gas turbine engine gaspath diagnostics. To this end, an autoassociative neural network is used as a preprocessor to minimize noise and generatenecessary features, a nested support vector machine to classify gas path faults, and a multilayer perceptron to assess themagnitude of the faults. The necessary data to train and test the method are obtained from a performance model of thecase engine under steady-state operating conditions. The test results indicate that the proposed method can diagnoseboth single- and multiple-component faults successfully and shows a clear advantage over some other methods in termsof multiple fault diagnosis. Moreover, 5-8 sets of measurements have been used to assess the prediction accuracy, andonly a 2.3% difference was observed. This result indicates that the proposed method can be used for multiple faultdiagnosis of gas turbines with limited measurements.
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| 44. |
- Fentaye, Amare Desalegn, et al.
(author)
-
Two-shaft stationary gas turbine engine gas path diagnostics using fuzzy logic
- 2017
-
In: Journal of Mechanical Science and Technology. - : Springer Science and Business Media LLC. - 1738-494X .- 1976-3824. ; 31:11, s. 5593-5602
-
Journal article (peer-reviewed)abstract
- Our objective was to develop a Fuzzy logic (FL) based industrial two-shaft gas turbine gas path diagnostic method based on gas pathmeasurement deviations. Unlike most of the available FL based diagnostic techniques, the proposed method focused on a quantitativeanalysis of both single and multiple component faults. The data required to demonstrate and verify the method was generated from asimulation program, tuned to represent a GE LM2500 engine running at an existing oil & gas plant, taking into account the two mostcommon engine degradation causes, fouling and erosion. Gaussian noise is superimposed into the data to account measurement uncertainty.Finally, the fault isolation and quantification effectiveness of the proposed method was tested for single, double and triple componentfault scenarios. The test results show that the implanted single, double and triple component fault case patterns are isolated with anaverage success rate of 96 %, 92 % and 89 % and quantified with an average accuracy of 83 %, 80 % and 78.5 %, respectively.
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| 45. |
- Ringsberg, Jonas, 1971
(author)
-
Models and strategies
- 2017
-
In: Wave & Tidal Energy Network Magazine. ; :11, s. 27-27
-
Journal article (other academic/artistic)abstract
- The Wave Energy Group on the Division of Marine Technology on the Department of Mechanics and Maritime Sciences, Chalmers University of Technology, develops simulation models for structural integrity analysis of mooring lines and umbilical cables used in wave energy converter (WEC) systems. The article gives an overview of ongoing research projects and an outlook.
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| 46. |
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| 47. |
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| 48. |
- Catic, Amer, 1982, et al.
(author)
-
Implementing a Wiki to Capture and Share Engineering Knowledge
- 2010
-
In: Proceedings of NordDesign 2010. - 9789163370649 ; 1, s. 171-184
-
Conference paper (peer-reviewed)abstract
- This paper describes the implementation of a wiki system based on the wiki engine MediaWiki for the purpose of engineering knowledge capture and sharing in an internal R&D unit that is part of a global group of companies in the commercial vehicle industry. Three different knowledge processes are studied; 1. Knowledge creation that is based on a socialization process that mainly creates tacit knowledge distributed across individuals; 2. Knowledge transfer that is based on reuse of tacit knowledge by physical transferral of knowledge holders; and 3. Knowledge application which entails a core team of individuals applying their collective knowledge base to solve a given problem. It is found that a wiki system’s features of collaborative and web based input make it possible to support all three of the processes by making the tacit knowledge base explicit. It is concluded however that the implementation of a wiki also needs: 1. A structure that reflects the business processes in the unit; 2. A clear definition of knowledge as a deliverable in the processes; 3. A model for how the time spent on contributing to the wiki is financed; and 4. A strategy for tackling corporate IT governance policies’ inability to manage interactive Web 2.0 technologies.
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| 49. |
- Catic, Amer, 1982
(author)
-
Knowledge-based Engineering in Product Development Processes - Process, IT and Knowledge Management perspectives
- 2011
-
Doctoral thesis (other academic/artistic)abstract
- Product development as a field of practice and research has significantly changed due to the general trends of globalization changing the enterprise landscapes in which products are realized. The access to partners and suppliers with high technological specialization has also led to an increased specialization of original equipment manufacturers (OEMs). Furthermore, the products are becoming increasingly complex with a high functional and technological content and many variants. Combined with shorter lifecycles which require reuse of technologies and solutions, this has resulted in an overall increased knowledge intensity which necessitates a more explicit approach towards knowledge and knowledge management in product development. In parallel, methods and IT tools for managing knowledge have been developed and are more accessible and usable today. One such approach is knowledge-based engineering (KBE), a term that was coined in the mid-1980s as a label for applications which automate the design of rule-driven geometries. In this thesis the term KBE embraces the capture and application of engineering knowledge to automate engineering tasks, regardless of domain of application, and the thesis aims at contributing to a wider utilization of KBE in product development (PD). The thesis focuses on two perspectives of KBE; as a process improvement IT method and as a knowledge management (KM) method. In the first perspective, the lack of explicit regard for the constraints of the product lifecycle management (PLM) architecture, which governs the interaction of processes and IT in PD, has been identified to negatively affect the utilization of KBE in PD processes. In the second perspective, KM theories and models can complement existing methods for identifying potential for KBE applications.Regarding the first perspective, it is concluded that explicit regard for the PLM architecture decreases the need to develop and maintain software code related to hard coded redundant data and functions in the KBE application. The concept of service oriented architecture (SOA) has been found to enable an the explicit regard for the PLM architecture.. Regarding the second perspective, it is concluded that potential for KBE applications is indicated by: 1.) application of certain types of knowledge in PD processes 2.) high maturity and formalization of the applied knowledge 3.) a codification strategy for KM and 4.) an agreement and transparency regarding how the knowledge is applied, captured and transferred. It is also concluded that the formulation of explicit KM strategies in PD should be guided by knowledge application and its relation to strategic objectives focusing on types of knowledge, their role in the PD process and the methods and tools for their application. These, in turn, affect the methods and tools deployed for knowledge capture in order for it to integrate with the processes of knowledge origin. Finally, roles and processes for knowledge transfer have to be transparent to assure the motivation of individuals to engage in the KM strategy.
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| 50. |
- Catic, Amer, 1982, et al.
(author)
-
Requirements Management When Introducing New Mechatronic Sub-systems - Managing the Knowledge Gaps
- 2010
-
In: Proceedings of 11th International Design Conference - DESIGN 2010, Dubrovnik, Croatia. - 9789537738037 ; , s. 661-672
-
Conference paper (peer-reviewed)abstract
- This paper describes an empirical study of a driveline development project, featuring a new mechatronic sub-system, aiming to investigate the effect of knowledge gaps regarding the new sub-system on the development process. Findings indicate that knowledge gaps regarding interfaces and suppliers of the new sub-system and a lack of appropriate processes, methods and IT-tools have negatively affected requirements management. A set of recommendations on likely knowledge gaps when introducing new mechatronic sub-systems and how to bridge them prior to development project initiation are presented.
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