Multibody Simulation Model of the Roller Test Rig

Multibody simulation model of the roller test rig is presented in this work. The roller test rig consists of a paper machine’s tube roll supported with a hard bearing type balancing machine. The simulation model includes non-idealities that are measured from the physical structure. These non-idealities are the shell thickness variation of the roll and roundness errors of the shafts of the roll. These kinds of non-idealities are harmful since they can cause subharmonic resonances of the rotor system. In this case, the natural vibration mode of the rotor is excited when the rotation speed is a fraction of the natural frequency of the system. With the simulation model, the half critical resonance is studied in detail and a sensitivity analysis is performed by simulating several analyses with slightly different input parameters. The model is verified by comparing the simulation results with those obtained by measuring the real structure. Comparison shows that good accuracy is achieved, since equivalent responses are achieved within the error limit of the input parameters.

Experimental and discrete element simulation studies of bell-less charging of blast furnace

This thesis presents an experimental study and numerical study, based on the discrete element method (DEM), of bell-less charging in the blast furnace. The numerical models are based on the microscopic interaction between the particles in the blast furnace charging process. The emphasis is put on model validation, investigating several phenomena in the charging process, and on finding factors that influence the results. The study considers and simulates size segregation in the hopper discharging process, particle flow and behavior on the chute, which is the key equipment in the charging system, using mono-size spherical particles, multi-size spheres and nonspherical particles. The behavior of the particles at the burden surface and pellet percolation into a coke layer is also studied. Small-scale experiments are used to validate the DEM models.

Liikkuvan kivimurskaimen syötinosan rakenneanalyysi osarakennetekniikan avulla

Työn tarkoituksena oli selvittää, miten osarakennetekniikkaa voidaan soveltaa siirrettävän kivimurskaimen syötinosan simuloinnissa. Tätä tutkittiin luomalla kahdella eri ohjelmistolla simulaatiomalli syötinosasta ja mallintamalla syötinosan runko joustavaksi kappaleeksi osarakennetekniikan avulla. Luotujen simulointimallien tarkkuutta selvitettiin vertaamalla niistä saatuja rungon jännityksiä tutkittavan rakenteen rungosta mitattuihin jännityksiin. Työn tarkoituksena oli myös tutkia, miten hyvin simulaatiomallit soveltuvat käytettäväksi syötinosan tuotekehityksessä. Tässä työssä käytettiin syötinosan simulaatiomallin luomiseen ANSYS-ohjelmistoa ja ADAMS-ohjelmistoa. Simulaatiomalleihin lisättiin tutkittavasta järjestelmästä mitattu ohjaussignaali sekä syötinosan jousien arvot. Järjestelmän rakenneominaisuudet saatiin suoraan valmistajan luovuttamista tiedoista. ADAMS-ohjelmistolla mallinnetussa simulaatiomallissa runko mallinnettiin joustavaksi ANSYS-ohjelmistossa, josta se siirrettiin ADAMS-ohjelmistoon. Saaduista tuloksista kävi ilmi, että osarakennetekniikkaa voidaan hyödyntää syötinosan joustavan rungon simuloinnissa. Tutkittavasta järjestelmästä mitatuissa jännityksissä ja simulaatiomalleista saaduissa jännityksissä oli eroja, mutta jännityshistorian muodot ja suuruusluokat vastasivat pääosin toisiaan. Tulosten parantamiseksi tulee selvittää lisää alkuarvoja tutkittavasta järjestelmästä ja varmistua nyt saatujen jousiparametrien oikeellisuudesta.

A Soft Contact Collision Method For Real-Time Simulation of Triangularized Geometries in Multibody Dynamics

When modeling machines in their natural working environment collisions become a very important feature in terms of simulation accuracy. By expanding the simulation to include the operation environment, the need for a general collision model that is able to handle a wide variety of cases has become central in the development of simulation environments. With the addition of the operating environment the challenges for the collision modeling method also change. More simultaneous contacts with more objects occur in more complicated situations. This means that the real-time requirement becomes more difficult to meet. Common problems in current collision modeling methods include for example dependency on the geometry shape or mesh density, calculation need increasing exponentially in respect to the number of contacts, the lack of a proper friction model and failures due to certain configurations like closed kinematic loops. All these problems mean that the current modeling methods will fail in certain situations. A method that would not fail in any situation is not very realistic but improvements can be made over the current methods.

Simuloinnin hyödyntäminen kotihoidon kehittämisessä

Ikääntyvien ihmisten kasvava määrä tulevina vuosikymmeninä kuormittaa kaupunkien kotihoitoa enenemässä määrin. Kaupunkien rajalliset resurssit ovat jo nyt koetuksella, eikä nykyiseen tilanteeseen ole nähtävissä huomattavaa parannusta tulevina vuosina. Kotihoidon henkilöstön määrää ei pystytä kasvattamaan riittävästi suhteessa kasvavien asiakasvirtojen kanssa, jotta korkea palvelun laatu voitaisiin taata myös tulevaisuudessa. Lahden kaupungin kotihoito pyrkii etsimään teknisiä ratkaisuja kotihoidon haasteisiin muun muassa kotihoidon töiden jakamiseen kehitetyllä optimointialgoritmilla sekä simuloinnilla. Tämä diplomityö käsittelee toimintatutkimuksen avulla simuloinnin tuomia hyötyjä sekä rajoitteita Lahden kotihoidon näkökulmasta. Launeen alueen kotihoidon haasteita käydään läpi neljässä eri työpajassa. Työssä esitetään Quest-simulointiohjelmiston ominaisuuksia, sekä Launeen alueen simulointimallin luomista aina suunnittelusta verifiointiin. Työn tuottama lisäarvo kotihoidon kehittämisessä tulee ilmi neljässä eri vaihtoehtoajossa kotihoitajien asiakkaalta toiselle kulkemien matkojen ja matkoihin käytettyjen aikojen mittaamisessa.

Reusable formal architectures for networked systems

Today's networked systems are becoming increasingly complex and diverse. The current simulation and runtime verification techniques do not provide support for developing such systems efficiently; moreover, the reliability of the simulated/verified systems is not thoroughly ensured. To address these challenges, the use of formal techniques to reason about network system development is growing, while at the same time, the mathematical background necessary for using formal techniques is a barrier for network designers to efficiently employ them. Thus, these techniques are not vastly used for developing networked systems. The objective of this thesis is to propose formal approaches for the development of reliable networked systems, by taking efficiency into account. With respect to reliability, we propose the architectural development of correct-by-construction networked system models. With respect to efficiency, we propose reusable network architectures as well as network development. At the core of our development methodology, we employ the abstraction and refinement techniques for the development and analysis of networked systems. We evaluate our proposal by employing the proposed architectures to a pervasive class of dynamic networks, i.e., wireless sensor network architectures as well as to a pervasive class of static networks, i.e., network-on-chip architectures. The ultimate goal of our research is to put forward the idea of building libraries of pre-proved rules for the efficient modelling, development, and analysis of networked systems. We take into account both qualitative and quantitative analysis of networks via varied formal tool support, using a theorem prover the Rodin platform and a statistical model checker the SMC-Uppaal.

A simulation model of the optimal maintenance strategy: conceptual agent-based approach

In this Master’s thesis agent-based modeling has been used to analyze maintenance strategy related phenomena. The main research question that has been answered was: what does the agent-based model made for this study tell us about how different maintenance strategy decisions affect profitability of equipment owners and maintenance service providers? Thus, the main outcome of this study is an analysis of how profitability can be increased in industrial maintenance context. To answer that question, first, a literature review of maintenance strategy, agent-based modeling and maintenance modeling and optimization was conducted. This review provided the basis for making the agent-based model. Making the model followed a standard simulation modeling procedure. With the simulation results from the agent-based model the research question was answered. Specifically, the results of the modeling and this study are: (1) optimizing the point in which a machine is maintained increases profitability for the owner of the machine and also the maintainer with certain conditions; (2) time-based pricing of maintenance services leads to a zero-sum game between the parties; (3) value-based pricing of maintenance services leads to a win-win game between the parties, if the owners of the machines share a substantial amount of their value to the maintainers; and (4) error in machine condition measurement is a critical parameter to optimizing maintenance strategy, and there is real systemic value in having more accurate machine condition measurement systems.

Potential benefits of building information modeling for building material supplier

This thesis investigated building information modeling (BIM) from a material supplier’s point of view. The objective was to gain understanding about how a building material supplier could benefit from the growing use of BIM in the AEC (architectural, engineering and construction) industry. Increasing amount of inquiries related to BIM from customers and other interest groups had awoken target company’s interest towards BIM. This thesis acts as a pre-study for the target company related to potential of BIM. First of all BIM and its meaning from a material supplier’s point of view was defined based on a literature review. To reveal the potential benefits of BIM for a material supplier a questionnaire survey and in total of 11 interviews were conducted. Based on the literature review and analyzed results it came clear that BIM offers benefits also for material suppliers. Product libraries and material databases for BIM tools can act as an important marketing channel for material suppliers. Material suppliers could also utilize the information from the BIM models to schedule their deliveries more precisely and potentially even to schedule their own production. All this needs deeper cooperation between material suppliers, contractors and other stakeholders in the AEC industry. Based on the results also first steps for the target company to utilize the growing use of BIM were defined.

Bridge over troubled water - using the CRIS in building Open Access infrastructures

Presentation at the Nordic Perspectives on Open Access and Open Science seminar, Helsinki, October 15, 2013

Building Next Generation Consortium Services – part 3: The National Metadata Repository, Discovery Service Finna, and the New Library System

Kristiina Hormia-Poutasen esitys CBUC-konferenssissa Barcelonassa 12.4.2013.

Building Next Generation Consortium Services – part 1: Background for Change

Kristiina Hormia-Poutasen esitys CBUC-konferenssissa Barcelonassa 12.4.2013.

Building Next Generation Consortium Services – part 2: Next Generation IT-services – Why, What, When?

Kristiina Hormia-Poutasen esitys CBUC-konferenssissa Barcelonassa 12.4.2013.