1,594 research outputs found
Connecting Abaqus and CATIA V5 in product development
Abstract. In this work Abaqus software, which is used for doing finite element analysis, and the associative interface of CATIA V5 computer-aided design software and Abaqus were researched. From the associative interface, the usage with Abaqus and the usage’s requirements were researched. From Abaqus it’s usage and requirements were studied. The software was also explored by a case study. In the case study there was no need to utilize the associativity of the associative interface. The methods of research in this work were computer-aided design, finite element analysis and the connection of those through associative interface.
In this work it was clarified how the associative interface works with Abaqus by the features, and how Abaqus works by its modules. This work included a case study, in which squeezing of a cavity seal between two plastic shells was simulated. In the case study nonlinear material model for the cavity seal was used. The case study was challenging due high nonlinearity and included especially calculation time challenges. In the case study a situation occurred where the simulation did not pass every step. Because of that a decision was made to make a second finite element analysis model, where the cavity seal model was replaced by gasket model that was simpler in terms of the calculations. The old model was named as model A and the new model as model B. In case study’s results models A and B were compared, and represented shell’s strains and stress of screw towers were calculated by model B.
In the work’s discussion the benefits of associative interface with Abaqus were discussed together with an export problem which appeared during the work, a need of expert for making simulations and the change of gasket model in the case study. As conclusions it was stated of the associative interface that its very useful with Abaqus, and it does not need special skills or experience for the use. However, as a conclusion it was stated that training is needed for use of Abaqus.Abaqus ja CATIA V5 -ohjelmistojen yhdistäminen tuotekehityksessä. Tiivistelmä. Tässä työssä tutkittiin Dassault Systémesin Abaqus-ohjelmaa, jolla tehdään elementtianalyyseja sekä CATIA V5 -tietokoneavusteisen suunnitteluohjelman ja Abaquksen välistä assosiatiivista käyttöliittymää. Assosiatiivisesta käyttöliittymästä tutkittiin yhteiskäyttöä Abaquksen kanssa, ja yhteiskäytön vaatimuksia. Abaquksesta tutkittiin käyttöä ja käytön vaatimuksia. Ohjelmistoon tutustuttiin myös esimerkkitapauksen avulla. Tässä esimerkkitapauksessa ei tarvinnut hyödyntää assosiatiivisen käyttöliittymän assosiatiivisuutta. Käytettävät tutkimusmenetelmät työssä olivat tietokoneavusteinen suunnittelu, elementtianalyysi, ja tietokoneavusteisen suunnittelun ja elementtianalyysin yhdistäminen.
Työssä selvitettiin, miten assosiatiivinen käyttöliittymä toimii Abaquksen kanssa ominaisuuksittain ja miten Abaqus toimii moduuleittain. Lisäksi työ sisälsi esimerkkitapauksen, jossa simuloitiin ontelotiivisteen puristusta kahden muovikuoren väliin. Esimerkkitapauksessa käytettiin epälineaarista materiaalimallia ontelotiivisteelle. Tämä esimerkkitapaus oli vaativa ja sisälsi erityisesti laskenta-aikahaasteita. Esimerkkitapauksessa päädyttiin tilanteeseen, jossa simulaatio ei mennyt kaikkein vaiheiden läpi. Tämän takia päädyttiin tekemään toinenkin elementtianalyysimalli, jossa ontelotiivistemalli oli korvattu laskennan kannalta yksinkertaisemmalla tiivistemallilla. Vanha malli nimettiin malli A:ksi, ja uusi malli nimettiin malli B:ksi. Esimerkkitapauksen tuloksissa vertailtiin malleja A ja B, ja otettiin esiin mallilla B laskettuja kuorten venymiä ja ruuvitornien jännitystiloja.
Työn käsittelyosuudessa käsiteltiin assosiatiivisen käyttöliittymän hyötyjä Abaquksen kanssa, työtä tehdessä ilmenneeseen tiedonvienti ongelmaan, asiantuntijan tarvetta esimerkkitapauksen simulaatiota tehdessä ja tiivistemallin vaihtoa työssä. Johtopäätöksinä assosiatiivisesta käyttöliittymästä todettiin, että se on Abaquksen kanssa hyvin käyttökelpoinen, eikä tarvitse erikoisosaamista tai -kokemusta käyttöä varten. Johtopäätöksenä Abaquksesta todettiin, että se tarvitsee käyttöä varten kouluttautumista
Towards machines that understand people
The ability to estimate the state of a human partner is an insufficient basis on which to build cooperative agents. Also needed is an ability to predict how people adapt their behavior in response to an agent's actions. We propose a new approach based on computational rationality, which models humans based on the idea that predictions can be derived by calculating policies that are approximately optimal given human‐like bounds. Computational rationality brings together reinforcement learning and cognitive modeling in pursuit of this goal, facilitating machine understanding of humans
Pedestrian crossing decisions can be explained by bounded optimal decision-making under noisy visual perception
This paper presents a model of pedestrian crossing decisions, based on the
theory of computational rationality. It is assumed that crossing decisions are
boundedly optimal, with bounds on optimality arising from human cognitive
limitations. While previous models of pedestrian behaviour have been either
'black-box' machine learning models or mechanistic models with explicit
assumptions about cognitive factors, we combine both approaches. Specifically,
we model mechanistically noisy human visual perception and assumed rewards in
crossing, but we use reinforcement learning to learn bounded optimal behaviour
policy. The model reproduces a larger number of known empirical phenomena than
previous models, in particular: (1) the effect of the time to arrival of an
approaching vehicle on whether the pedestrian accepts the gap, the effect of
the vehicle's speed on both (2) gap acceptance and (3) pedestrian timing of
crossing in front of yielding vehicles, and (4) the effect on this crossing
timing of the stopping distance of the yielding vehicle. Notably, our findings
suggest that behaviours previously framed as 'biases' in decision-making, such
as speed-dependent gap acceptance, might instead be a product of rational
adaptation to the constraints of visual perception. Our approach also permits
fitting the parameters of cognitive constraints and rewards per individual, to
better account for individual differences. To conclude, by leveraging both RL
and mechanistic modelling, our model offers novel insights about pedestrian
behaviour, and may provide a useful foundation for more accurate and scalable
pedestrian models
Aqueous and non-aqueous microchip electrophoresis with on-chip electrospray ionization mass spectrometry on replica-molded thiol-ene microfluidic devices
This work describes aqueous and non-aqueous capillary electrophoresis on thiol-ene-based microfluidic separation devices that feature fully integrated and sharp electrospray ionization (ESI) emitters. The chip fabrication is based on simple and low-cost replica-molding of thiol-ene polymers under standard laboratory conditions. The mechanical rigidity and the stability of the materials against organic solvents, acids and bases could be tuned by adjusting the respective stoichiometric ratio of the thiol and allyl ("ene") monomers, which allowed us to carry out electrophoresis separation in both aqueous and non-aqueous (methanol- and ethanol-based) background electrolytes. The stability of the ESI signal was generallyPeer reviewe
Laser Spectroscopy of Niobium Fission Fragments: First Use of Optical Pumping in an Ion Beam Cooler Buncher
A new method of optical pumping in an ion beam cooler buncher has been developed to selectively enhance ionic metastable state populations. The technique permits the study of elements previously inaccessible to laser spectroscopy and has been applied here to the study of Nb. Model independent mean-square charge radii and nuclear moments have been studied for Nb to cover the region of the N=50 shell closure and N≈60 sudden onset of deformation. The increase in mean-square charge radius is observed to be less than that for Y, with a substantial degree of β softness observed before and after N=60
Citizen Attitudes to Farm Animals in Finland – A Population-Based Study
Citizen attitudes and opinions form an important driving force for improvements in the ethical status of farm animals in society. Hence, it is important to understand how attitudes to farm animals vary in society and what factors, mechanisms and social processes influence the development of these attitudes. In this study we examine the relative importance of socio-demographic background, animal related experiences and social-equality attitudes in the formation of attitudes to farm animals in Finland. The research is based on a nationwide survey (n = 1890). Our research findings suggest that female gender, young age, urban residency, a non-farming background and social-equality attitudes are linked to greater concern for farm animals. A farming background, valuing social equality, and gender have the strongest connections to farm animal attitudes, followed by age and place of residence. Having a companion animal and education level have a relatively modest connection to attitudes to farm animals. In order to accumulate comparative evidence of social-group differences in attitudes to farm animals, further research should continue to develop improved indicators for attitudes to farm animal welfare and rights. Moreover, explanations for social-group differences in citizen attitudes to farm animals should be subjected to further empirical testing.</p
Variation in the physical properties of oat groats, flakes and oat flake flour - Processability of thirty pure cultivar oat batches from Finland
The aim of this study was to understand the processability of thirty pure cultivar oat batches and how the physical properties of oat groats and flakes affect the characteristics of oat flake flour. This was conducted by investigating the relationship between the chemical composition of oats and the physical characteristics of oat groats, flakes and flours produced by industrial scale milling process. It was clearly shown that the oat batches behaved differently in the milling process and that the physical characteristics of oat groats, flakes and flours were interrelated. For example, separation of bran and endosperm particles of oat flours by dry fractionation was connected to the chemical composition as well as particle size distribution of the flours. Furthermore, it was shown that flowability properties of oat flours affect the bran-endosperm separation of oat flour by dry fractionation. This study demonstrated the role of the oat raw material in the milling process as well as the relationship between the different mill products, which deepens the understanding of oat milling process and is important when aiming at producing oat products with high quality.Peer reviewe
Non-Gaussianity from Instant and Tachyonic Preheating
We study non-Gaussianity in two distinct models of preheating: instant and
tachyonic. In instant preheating non-Gaussianity is sourced by the local terms
generated through the coupled perturbations of the two scalar fields. We find
that the non-Gaussianity parameter is given by ,
where is a coupling constant, so that instant preheating is unlikely to be
constrained by WMAP or Planck. In the case of tachyonic preheating
non-Gaussianity arises solely from the instability of the tachyon matter and is
found to be large. We find that for single field inflation the present WMAP
data implies a bound on the scale of tachyonic
instability. We argue that the tachyonic preheating limits are useful also for
string-motivated inflationary models.Comment: 12 pages, 1 figure, additional discussion, improved constraint on the
scale of tachyonic preheatin
Baryogenesis with Superheavy Squarks
We consider a setup where R-parity is violated in the framework of split
supersymmetry. The out-of-equilibrium decays of heavy squarks successfully lead
to the generation of a baryon asymmetry. We restrict the R-parity violating
couplings to the baryon number violating subset to keep the neutralino
sufficiently stable to provide the dark matter. The observed baryon asymmetry
can be generated for squark masses larger than 10^11 GeV, while neutralino dark
matter induces a stronger bound of 10^13 GeV. Some mass splitting between left-
and right-handed squarks may be needed to satisfy also constraints from gluino
cosmology.Comment: 18 pages, LaTeX, 4 figure
Mapping the proton drip line from Z=31 to Z=49
The structure of proton drip line nuclei in the 60 < A < 100 mass range is
studied with the Relativistic Hartree Bogoliubov (RHB) model. For the elements
which determine the astrophysical rapid proton capture process path, the RHB
model predicts the location of the proton drip-line, the ground-state
quadrupole deformations and one-proton separation energies at and beyond the
drip-line. The results of the present theoretical investigation are compared
with available experimental data. For possible odd-Z ground state proton
emitters, the calculated deformed single-particle orbitals occupied by the odd
valence proton and the corresponding spectroscopic factors are compared with
predictions of the macroscopic-microscopic mass model.Comment: 20 pages, LaTeX, 6 eps figs, submitted to Nucl. Phys.
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