| 1. |
- Karlsson, Lennart, et al.
(författare)
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Mechanics of materials and structures: a simulation-driven design approach
- 2011
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Ingår i: Journal of Mechanics of Materials and Structures. - Berkeley, USA : Mathematical Sciences Publishers. - 1559-3959 .- 2157-5428. ; 6:1-4, s. 277-301
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Tidskriftsartikel (refereegranskat)abstract
- Engineering product development has developed considerably over the past decade. In order for industry to keep up with continuously changing requirements, it is necessary to develop new and innovative simulation methods. However, few tools and methods for simulation-driven design have been applied in industrial settings and proven to actually drive the development and selection of the ideal solution. Such tools, based on fundamental equations, are the focus of this paper. In this paper the work is based on two cases of mechanics of materials and structures: welding and rotor dynamical simulations. These two examples of simulation-driven design indicate that a larger design space can be explored and that more possible solutions can be evaluated. Therefore, the approach improves the probability of innovations and finding optimal solutions. A calibrated block dumping approach can be used to increase the efficiency of welding simulations when many simulations are required.
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| 2. |
- Pahkamaa, Andreas, et al.
(författare)
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A method to improve efficiency in welding simulations for simulaton driven design
- 2010
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Ingår i: Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - 2010. - New York : American Society of Mechanical Engineers. ; , s. 1-10
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Konferensbidrag (refereegranskat)abstract
- Welding is one of the most commonly used methods of joining metal pieces. In product development it is often desirable to predict residual stresses and distortions to verify that e.g., alignment tolerances, strength demands, fatigue requirements, stress corrosion cracking, etc. are fulfilled. The objective of this paper is to derive a strategy to improve the efficiency of welding simulations aiming at a (future) simulation-driven design methodology. In this paper, a weld bead deposition technique called block dumping has been applied to improve the efficiency. The proposed strategy is divided into seven steps, where the first four steps are verified by two welding simulation cases (a benchmark problem for a single weld bead-on-plate specimen and a T-welded structure). This study shows that by use of the block dumping technique, the computation time can be reduced by as much as 93% compared to moving heat source, still with acceptable accuracy of the model.
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| 3. |
- Pavasson, Jonas, et al.
(författare)
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Challenges and opportunities within simulation-driven functional product development and operation : Special Session: Product Development for Through-Life Engineering Services
- 2014
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271 .- 2212-8271. ; 22, s. 169-174
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Tidskriftsartikel (refereegranskat)abstract
- The product development process at industrial companies has traditionally focused on hardware-oriented solutions. Business strategies strive towards more service-oriented solutions e.g., functional product business models. In this paper two case studies are developed and the objective is to highlight important challenges and opportunities by implementing a simulation-driven strategy in functional product development and operation. It can be concluded that challenges and opportunities within simulation-driven functional product development and operation are related to both quality and management of the simulations. With the proposed strategies for validation and coupling of the simulations, some of the challenges within functional product development can be overcome.
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| 4. |
- Pavasson, Jonas
(författare)
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Reliability prediction at early functional product development stages
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A trend among industrial companies is to change business strategies from hardware-oriented to more service-oriented solutions, e.g. functional product business models. Functional products are typically constituted by hardware together with a service support system. For functional product businesses, availability is one critical property upon which the customer and provider must agree. Hence, during functional product development and operation, it is important to enable simulations of functional product availability, which is a function of reliability and maintainability. To more rapidly converge on optimal solutions, simulation-driven design strategies have further been proposed by several researchers. In these strategies, the simulations are used to drive the development rather than simply verify suggested solutions. Measured data or estimated data are often used as input to reliability prediction methods such as fault tree analysis and failure mode and effect analysis. However, when designing new systems, reliability input data may not exist and, hence, prototypes are often manufactured and tested, which requires a significant amount of time.The objective of the work presented in this thesis is to develop a simulation-driven methodology for how to predict hardware reliability, as a part of functional product availability.This methodology shall be applied at early concept stages of the functional product development process, where limited component reliability information exists.The conducted research is based on theories regarding product development methodologies, reliability prediction methods and deterministic simulation methods (e.g. rigid body dynamics). The research presented in this thesis followed a 5-step procedure including as-is study, to-be scenario development (where a future functional business situation is described), method development, method verification (through case studies) and method validation.During the as-is study, existing reliability methods were evaluated according tosuitability in different development stages. Fault tree analysis and probabilistic variation mode and effect analysis were found to give accurate results (since objective input data are used). However, those methods would need further development in order to be used for reliability prediction at early concept stages. Traditional probabilistic variation mode and effect analysis did not result in reliability in terms of a probabilistic quantity. Therefore, the probabilistic variation mode and effect analysis method was further developed and verified through a case study which can be used for probabilistic measures.A method based on deterministic simulations to derive component reliabilityinformation has been further developed. This method takes different variations into account and through a series of simulations, input data for system reliability (such as fault tree analysis and probabilistic variation mode and effect analysis) can be derived.Hence, by combining deterministic and probabilistic simulations, hardware system reliability can be predicted, even when limited component reliability information exists. This hardware reliability prediction method is a critical part of a simulation-driven methodology to be used at early stages of functional product development
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| 5. |
- Pavasson, Jonas, et al.
(författare)
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Reliability Prediction Based on Variation Mode and Effect Analysis
- 2013
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Ingår i: Quality and Reliability Engineering International. - : Wiley. - 0748-8017 .- 1099-1638. ; 29:5, s. 699-708
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of predicting the reliability of hardware for both components and systems is important in engineering design. Today, there are several methods for predicting the reliability of hardware systems and for identifying the causes of failure and failure modes, for example, fault tree analysis and failure mode and effect analysis. Many failures are caused by variations resulting in a substantial effect on safety or functional requirements. To identify, to assess and to manage unwanted sources of variation, a method called probabilistic variation mode and effect analysis (VMEA) has been developed. With a prescribed reliability, VMEA can be used to derive safety factors in different applications. However, there are few reports on how to derive the reliability based on probabilistic VMEA, especially for transmission clutch shafts. Hence, the objective of this article was to show how to derive system reliability based on probabilistic VMEA. In particular, wheel loader automatic transmission clutch shaft reliability is investigated to show how different sources of variation affect reliability. In this article, a new method for predicting system reliability based on probabilistic VMEA is proposed. The method is further verified by a case study on a clutch shaft. It is shown that the reliability of the clutch shaft was close to 1.0 and that the most significant variation contribution was due to mean radius of the friction surface and friction of the disc.
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| 6. |
- Pavasson, Jonas
(författare)
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Simulation-Driven Development for Increased System Reliability
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The product development process at industrial companies has traditionally focused on hardware-oriented solutions. However, a current trend is to extend business offers to include more service-oriented solutions e.g., functional product business models. A functional product typically includes the four main constituent’s hardware, software, service support system and management of operation. Availability is one critical property for functional product businesses which the customer and provider must agree upon. Hence, performing simulations for functional product development and operation enables the possibility for functional product availability prediction andincreases the possibilities for business offerings. Functional product availability is a function of reliability and maintainability. Today, many companies measure the strength of the hardware product in terms of durability or life length. However,measuring strength in terms of reliability, which is based on a statistically significant basis, supports the functional product development process. Simulations have generally been used to verify existing solutions; therefore, simulation-driven design strategies have been proposed to more rapidly converge on optimal solutions i.e., simulations are used to drive the development rather than simply verify suggested solutions.Today, measured data or estimated data are often used as input to reliabilityprediction methods e.g., fault tree analysis or Bayesian network. When designing new hardware systems, concepts need to be evaluated by means of reliability, but such data may not exist and prototypes often need to be manufactured, which is expensive and time-consuming. A combination of deterministic and probabilistic simulations can be used to derive needed input data for reliability prediction methods i.e., concepts can be evaluated by means of reliability in early stages of the functional product development process, even before a physical prototype is manufactured. The objective of the work presented in this thesis is to develop a simulation-drivenreliability prediction methodology for product development processes.This methodology shall be applied in early phases of existing product development processes, especially to generate, evaluate and select concepts in terms of reliability, to be used as a decision basis for systems solutions. Further, this methodology takes important variations into account and includes a combination of deterministic and probabilistic simulations.The conducted research is based on theories regarding the functional productdevelopment process, product development methodologies (e.g., stage-gated process), reliability prediction methods (e.g., fault tree analysis), deterministic simulation methods (e.g. rigid body dynamics) and reliability engineering (e.g., probability and reliability theory, distribution functions and Monte Carlo method). The research presented in this thesis followed a 5-step procedure including as-is study, to-be scenario development (simulation-driven methodology and a future functional business situation are described), methodology development, methodology verification (through case studies) and methodology validation (through system testing).Existing reliability methods were evaluated according to suitability in differentdevelopment phases during the as-is study. Fault tree analysis and probabilistic variation mode and effect analysis were found to give accurate results due to use of objective input data. It can be concluded that deterministic simulations (such as rigid body dynamics or welding sequences) can be used to derive input data to be used for probabilistic reliability prediction methods. Probabilistic variation mode and effect analysis can be used to derive a safety factor when designing systems, based on components variation contribution. Hence, a method has been developed based on probabilistic variation mode and effect analysis to derive system reliability. The method uses a distribution function (Normal distribution) and the variation contribution from included components. A method based on deterministic simulations to derive component reliability information has further been developed. This method takes different variations intoaccount and through a series of simulations, input data for system reliability (such as fault tree analysis and Bayesian network) can be derived.A simulation-driven hardware system reliability prediction methodology wasdeveloped, including both deterministic and probabilistic simulation models and methods. The methodology is used to predict hardware system reliability in early phases of the functional product development process and to partly exclude hardware system testing. The methodology takes into account component variations when a limited amount of information exists. The simulation-driven methodology will further be implemented in the company product development process. A case scenario was developed for the simulation-driven mobility function methodology. The methodology manages an increased amount of multidisciplinary interactions to combine deterministic and probabilistic simulation, both in parallel and coupled, within and between the four main constituents. The simulation-driven methodology is primarily focused on mobility functions but is more general and canpartly be used in the simulation-driven methodology for hardware system reliability prediction.
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| 7. |
- Pavasson, Jonas, et al.
(författare)
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Simulation-driven mobility function development
- 2013
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271 .- 2212-8271. ; 11, s. 157-162
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Tidskriftsartikel (refereegranskat)abstract
- A trend among industrial companies is to change business strategies from hardware-oriented to more service-oriented solutions, e.g. functional product business models. In this paper, a mobility function scenario is developed and the objective is to derive a simulation-driven methodology for development of sustainable mobility functions. It can be concluded that mobility function solutions may create incitements for sustainability. When developing mobility functions, a lot of new requirements, brought about by increased product complexity, need to be managed by the simulation methodology. However, the proposed simulation strategy can be used to drive mobility function development.
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| 8. |
- Pavasson, Jonas, et al.
(författare)
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System reliability estimation with input data from deterministic simulations
- 2012
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Ingår i: Proceedings of the ASME 2012 International Mechanical Engineering Congress & Exposition IMECE2012. - New York : American Society of Mechanical Engineers. - 9780791845271 ; , s. 257-264
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Konferensbidrag (refereegranskat)abstract
- The possibility of estimating reliability of hardware, both for components and systems, is important in engineering design, since many failures result in substantial impact on safety or functional requirements. Existing reliability estimation methods require measured or estimated input data which can be difficult to retrieve. The objective of this paper is therefore to derive a simulation-driven method, including variation management, for combining deterministic simulations with Fault Tree Analysis, to estimate system reliability when measured data is not available. The research work started with a literature survey followed by description of a typical as-is situation and definition of a to-be scenario. Then, a simulation-driven method was derived and verified by a case study. In particular, the system used for the case study was modeled and simulated as a transient dynamical system to derive information about loads on components. It was found that deterministic simulations can be used to produce relevant input data for fault tree analysis. The derived simulation-driven system reliability estimation method includes variation management and can be used for evaluation of concepts in the early stages of product development when limited measurement data is available
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| 9. |
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