The Folding of Triangulated Cylinders, Part III: Experiments

1996 ◽  
Vol 63 (1) ◽  
pp. 77-83 ◽  
Author(s):  
S. D. Guest ◽  
S. Pellegrino
Keyword(s):  
Experimental Investigation ◽  
Computational Models ◽  
Computational Simulation ◽  
Geometric Imperfections ◽  
Cylindrical Structure ◽  
Truss Model

This paper describes an experimental investigation of a type of foldable cylindrical structure, first presented in two earlier papers. Three cylinders of this type were designed and manufactured, and were then tested to find the force required to fold them. The results from these tests show some discrepancies with an earlier computational simulation, which was based on a pin-jointed truss model of the cylinders. Possible explanations for these discrepancies are explored, and are then verified by new simulations using computational models that include the effect of hinge stiffness, and the effect of geometric imperfections.

Appraisal of Allowable Loads by Simplified Rules

1986 ◽  
Vol 108 (2) ◽  
pp. 131-137
Author(s):  
D. Moulin
Keyword(s):  
Experimental Investigation ◽  
Plastic Region ◽  
Thin Structures ◽  
Geometric Imperfections ◽  
Buckling Behavior ◽  
Simplified Method ◽  
Post Buckling ◽  
Initial Geometric Imperfections ◽  
Fast Breeder Reactors ◽  
Breeder Reactors

This paper presents a simplified method to analyze the buckling of thin structures like those of Liquid Metal Fast Breeder Reactors (LMFBR). The method is very similar to those used for the buckling of beams and columns with initial geometric imperfections, buckling in the plastic region. Special attention is paid to the strain hardening of material involved and to possible unstable post-buckling behavior. The analytical method uses elastic calculations and diagrams that account for various initial geometric defects. An application of the method is given. A comparison is made with an experimental investigation concerning a representative LMFBR component.

scholarly journals Population Dynamics Based on Resource Availability & Founding Effects: Live & Computational Models

2016 ◽  
Vol 78 (5) ◽  
pp. 396-403 ◽  
Author(s):  
Samuel Potter ◽  
Rebecca M. Krall ◽  
Susan Mayo ◽  
Diane Johnson ◽  
Kim Zeidler-Watters ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Computer Literacy ◽  
Computational Models ◽  
Computational Simulation ◽  
School Science ◽  
Simulation Software ◽  
High School Science ◽  
Initial Population ◽  
College Level ◽  
Factors Affecting

With the looming global population crisis, it is more important now than ever that students understand what factors influence population dynamics. We present three learning modules with authentic, student-centered investigations that explore rates of population growth and the importance of resources. These interdisciplinary modules integrate biology, mathematics, and computer-literacy concepts aligned with the Next Generation Science Standards. The activities are appropriate for middle and high school science classes and for introductory college-level biology courses. The modules incorporate experimentation, data collection and analysis, drawing conclusions, and application of studied principles to explore factors affecting population dynamics in fruit flies. The variables explored include initial population structure, food availability, and space of the enclosed population. In addition, we present a computational simulation in which students can alter the same variables explored in the live experimental modules to test predictions on the consequences of altering the variables. Free web-based graphing (Joinpoint) and simulation software (NetLogo) allows students to work at home or at school.

scholarly journals A Neurocomputational Theory of Nightmares: The role of formal properties of nightmare images

2021 ◽  
Author(s):  
Patrick McNamara ◽  
Wesley J Wildman ◽  
George Hodulik ◽  
David Rohr
Keyword(s):  
Individual Difference ◽  
Parameter Space ◽  
Computational Models ◽  
Computational Simulation ◽  
Time Varying ◽  
Individual Difference Variables ◽  
Image Characteristics ◽  
Nightmare Disorder ◽  
Formal Properties

Abstract Study Objectives To test and extend Levin & Nielsen’s (2007) Affective Network Dysfunction (AND) model with nightmare disorder (ND) image characteristics, and then to implement the extension as a computational simulation, the Disturbed Dreaming Model (DDM). Methods We used AnyLogic V7.2 to computationally implement an extended AND model incorporating quantitative effects of image characteristics including valence, dominance, and arousal. We explored the DDM parameter space by varying parameters, running approximately one million runs, each for one month of model time, varying pathway bifurcation thresholds, image characteristics, and individual-difference variables to quantitively evaluate their combinatory effects on nightmare symptomology. Results The DDM shows that the AND model extended with pathway bifurcations and image properties is computationally coherent. Varying levels of image properties we found that when nightmare images exhibit lower dominance and arousal levels, the ND agent will choose to sleep but then has a traumatic nightmare, whereas, when images exhibit greater than average dominance and arousal levels, the nightmares trigger sleep-avoidant behavior, but lower overall nightmare distress at the price of exacerbating nightmare effects during waking hours. Conclusions Computational simulation of nightmare symptomology within the AND framework suggests that nightmare image properties significantly influence nightmare symptomology. Computational models for sleep and dream studies are powerful tools for testing quantitative effects of variables affecting nightmare symptomology and confirms the value of extending the Levin & Nielsen AND model of disturbed dreaming/ND.

scholarly journals Strain rate–dependent mechanical metamaterials

2020 ◽  
Vol 6 (25) ◽  
pp. eaba0616 ◽  
Author(s):  
S. Janbaz ◽  
K. Narooei ◽  
T. van Manen ◽  
A. A. Zadpoor
Keyword(s):  
Strain Rate ◽  
Viscoelastic Properties ◽  
Computational Models ◽  
Geometric Imperfections ◽  
Rate Dependent ◽  
Instability Modes ◽  
Mechanical Metamaterials ◽  
Unique Strain ◽  
Different Levels ◽  
Static Nature

Mechanical metamaterials are usually designed to exhibit novel properties and functionalities that are rare or even unprecedented. What is common among most previous designs is the quasi-static nature of their mechanical behavior. Here, we introduce a previously unidentified class of strain rate-dependent mechanical metamaterials. The principal idea is to laterally attach two beams with very different levels of strain rate-dependencies to make them act as a single bi-beam. We use an analytical model and multiple computational models to explore the instability modes of such a bi-beam construct, demonstrating how different combinations of hyperelastic and viscoelastic properties of both beams, as well as purposefully introduced geometric imperfections, could be used to create robust and highly predictable strain rate-dependent behaviors of bi-beams. We then use the bi-beams to design and experimentally realize lattice structures with unique strain rate-dependent properties including switching between auxetic and conventional behaviors and negative viscoelasticity.

scholarly journals Simulation Experiment Description Markup Language (SED-ML) Level 1 Version 3 (L1V3)

2018 ◽  
Vol 15 (1) ◽  
Author(s):  
Frank T. Bergmann ◽  
Jonathan Cooper ◽  
Matthias König ◽  
Ion Moraru ◽  
David Nickerson ◽  
...  
Keyword(s):  
Time Course ◽  
Computational Models ◽  
Simulation Experiment ◽  
Computational Simulation ◽  
Biological Research ◽  
Markup Language ◽  
Formal Representation ◽  
Post Process ◽  
Experiment Description ◽  
Level 1

AbstractThe creation of computational simulation experiments to inform modern biological research poses challenges to reproduce, annotate, archive, and share such experiments. Efforts such as SBML or CellML standardize the formal representation of computational models in various areas of biology. The Simulation Experiment Description Markup Language (SED-ML) describes what procedures the models are subjected to, and the details of those procedures. These standards, together with further COMBINE standards, describe models sufficiently well for the reproduction of simulation studies among users and software tools. The Simulation Experiment Description Markup Language (SED-ML) is an XML-based format that encodes, for a given simulation experiment, (i) which models to use; (ii) which modifications to apply to models before simulation; (iii) which simulation procedures to run on each model; (iv) how to post-process the data; and (v) how these results should be plotted and reported. SED-ML Level 1 Version 1 (L1V1) implemented support for the encoding of basic time course simulations. SED-ML L1V2 added support for more complex types of simulations, specifically repeated tasks and chained simulation procedures. SED-ML L1V3 extends L1V2 by means to describe which datasets and subsets thereof to use within a simulation experiment.

scholarly journals Computational simulation of fracture behaviour in auxetic cellular structure by multiaxial loading

2019 ◽  
Vol 300 ◽  
pp. 03001
Author(s):  
Branko Nečemer ◽  
Janez Kramberger ◽  
Nejc Novak ◽  
Srečko Glodež
Keyword(s):  
Computational Model ◽  
Cellular Structure ◽  
Computational Models ◽  
Fracture Behaviour ◽  
Computational Simulation ◽  
Tangential Direction ◽  
Multiaxial Loading ◽  
Loading Conditions ◽  
Normal Contact ◽  
Auxetic Structure

A computational simulation of fracture behaviour in auxetic cellular structure, subjected to multiaxial loading is presented in this paper. A fracture behaviour of the 3D (three-dimensional) chiral auxetic structure under multiaxial loading conditions was studied. The computational models were used to study the geometry effect of the unit cell on the Poisson’s ratio and fracture behaviour of the analysed chiral auxetic structure. A 3D computational model was built using FEM-code LS DYNA. The discrete computational model of chiral auxetic structure was built using beam finite elements. The lattice model of the analysed auxetic structure was positioned between rigid plates and assembled in a way to simulate a hydro-compression loading conditions. Between the contacting surfaces interactions in normal (contact) and tangential direction (friction) with the node-to-surface approach were simulated. A developed computational model offers insight in the fracture behaviour of considered auxetic cellular structure and helps to better understanding their crushing behaviour under impact multiaxial loading.

A Flexible Scheme to Model the Cognitive Influence on Emotions in Autonomous Agents

2018 ◽  
Vol 12 (4) ◽  
pp. 81-100
Author(s):  
Sergio Castellanos ◽  
Luis-Felipe Rodríguez
Keyword(s):  
Computational Models ◽  
Autonomous Agents ◽  
Computational Simulation ◽  
Cognitive Model ◽  
Human Information Processing ◽  
Appraisal Theory ◽  
Cognitive Mechanisms ◽  
Integrative Framework ◽  
Cognitive Components ◽  
Cognitive Information

Autonomous agents (AAs) are designed to embody the natural intelligence by incorporating cognitive mechanisms that are applied to evaluate stimuli from an emotional perspective. Computational models of emotions (CMEs) implement mechanisms of human information processing in order to provide AAs for a capability to assign emotional values to perceived stimuli and implement emotion-driven behaviors. However, a major challenge in the design of CMEs is how cognitive information is projected from the architecture of AAs. This article presents a cognitive model for CMEs based on appraisal theory aimed at modeling AAs' interactions between cognitive and affective processes. The proposed scheme explains the influence of AAs' cognition on emotions by fuzzy membership functions associated to appraisal dimensions. The computational simulation is designed in the context of an integrative framework to facilitate the development of CMEs, which are capable of interacting with cognitive components of AAs. This article presents a case study and experiment that demonstrate the functionality of the proposed models.

Ultrathin undoped tetrahedral amorphous carbon films: thickness dependence of the electronic structure and implications for their electrochemical behaviour

2015 ◽  
Vol 17 (14) ◽  
pp. 9020-9031 ◽  
Author(s):  
V. S. Protopopova ◽  
N. Wester ◽  
M. A. Caro ◽  
P. G. Gabdullin ◽  
T. Palomäki ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Electronic Structure ◽  
Physical Properties ◽  
Amorphous Carbon ◽  
Electrode Material ◽  
Electrochemical Behaviour ◽  
Computational Simulation ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon

Complex experimental investigation of the physical properties of prospective electrode material based on Ti/ta-C bilayers in relation to their electrochemical behaviour, supported by computational simulation.

scholarly journals Computational simulation of soybean particles flow in a hopper using computational fluid dynamics (CFD) and discrete elements method (DEM)

2020 ◽  
Vol 9 (8) ◽  
pp. e448985463
Author(s):  
Jéssica Aparecida Apolinário de Paula ◽  
Érica Victor de Faria ◽  
Ana Christina Pitard Lima ◽  
José Luiz Vieira Neto ◽  
Kássia Graciele dos Santos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Models ◽  
Solid Phase ◽  
Computational Simulation ◽  
Fluid Phase ◽  
Discrete Elements ◽  
Granular Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
The Subject

The hoppers are the most common structures used in storage units for agricultural products such as grains and cereals. The soybean, which is one of the most common products in Brazil spend most of their time in a hopper between the stages of picking and shipment. Problems such as damage to the hopper structures during the outflow are factors that have been the subject of studies using computational models. Computational Fluid Dynamics (CFD) has played a big role in gas-solid systems study, together with the Discrete Element Method (DEM). This method manages both fluid phase as the solid phase, which in this case is granular, through the Eulerian and Lagrangian approach. The DEM is based on the interaction between the particles and each one is separately monitored. This work aims to calibrate the parameters of the spring-dashpot model, in the granular dynamics of fluids study, which influences the contact between the soy particles in the silo. For this purpose, a comparison was made of the experimental discharge time of soybeans into a hopper, with the time resulting from 27 simulations generated by a central composite design (CCD). Through the analysis of the simulations and statistics, it was possible to identify the factors that influence whether or not the time of discharge and establish a calibration of these parameters that best describe the experimental results.

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