Investigation of Dynamic Photoelasticity Based on a Three-Dimensional Model

2011 ◽  
Vol 83 ◽  
pp. 261-266
Author(s):  
Bin Li ◽  
Guo Biao Yang ◽  
Fan Ni ◽  
Qi Rong Zhu
Keyword(s):  
Boundary Conditions ◽  
High Speed ◽  
Three Dimensional ◽  
Green Laser ◽  
Structure Design ◽  
Dynamic Photoelasticity ◽  
Three Dimensional Model ◽  
Design And Optimization ◽  
True Value ◽  
Dimensional Models

Dynamic photoelasticity has been widely utilized to investigate the phenomena generated by impact loading. The dynamic parameters of structures, such as propagation of stress wave and stress concentration, are obtained through this method, which provide guidelines for structure design and optimization. In the previous studies, two-dimensional models are wildly used by researchers. In these models, the inaccuracy of the boundary conditions leads to error amplification during the conversion of the tested results into real ones. In this study of dynamic photoelasticity, three-dimensional models are used. An improved digital dynamic photoelastic system is also adopted to calculate elastic wave propagation in the medium, where the diode-pumped solid-state green laser and high-speed CCD are used as light source luminaries and recording system respectively. Based on these models, where the boundary conditions approach to true value, the resulting data are higher in resolution than is possible with other experimental techniques. This method has been adopted and tested successfully by generating better results with less amplification of errors.

CFD Simulation of Particle Transport and Dispersion in Indoor Environment by Human Walking

2012 ◽  
Author(s):  
Iman Goldasteh ◽  
Goodarz Ahmadi ◽  
Andrea Ferro
Keyword(s):  
Particulate Matter ◽  
High Speed ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Study Data ◽  
Turbulent Dispersion ◽  
Experimental Chamber ◽  
Indoor Environments ◽  
Three Dimensional Model ◽  
Particle Resuspension

Particle resuspension is an important source of particulate matter in indoor environments that significantly affects the indoor air quality and could potentially have adverse effect on human health. Earlier efforts to investigate indoor particle resuspension hypothesized that high speed airflow generated at the floor level during the gate cycle is the main cause of particle resuspension. The resuspended particles are then assumed to be dispersed by the airflow in the room, which is impacted by both the ventilation and the occupant movement, leading to increased PM concentration. In this study, a three dimensional model of a room was developed using FLUENT™ CFD package. A RANS approach with the RNG k-ε turbulence model was used for simulating the airflow field in the room for different ventilation conditions. The trajectories of resuspended particulate matter were computed with a Lagrangian method by solving the equations of particle motion. The effect of turbulent dispersion was included with the use of the eddy lifetime model. The resuspension of particles due to gait cycle was estimated and included in the computational model. The dispersion and transport of particles resuspended from flooring as well as particle re-deposition on flooring and walls were simulated. Particle concentrations in the room generated by the resuspension process were evaluated and the results were compared with experimental chamber study data as well as simplified model predictions, and good agreement was found.

scholarly journals Processing Three-Dimensional Models of Archaeological Artifacts

2021 ◽  
Vol 20 (7) ◽  
pp. 48-61
Author(s):  
Pavel V. Chistyakov ◽  
Ekaterina N. Bocharova ◽  
Ksenia A. Kolobova
Keyword(s):  
Three Dimensional ◽  
3D Models ◽  
International Standards ◽  
Post Processing ◽  
Three Dimensional Model ◽  
Scaled Model ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Dimensional Models ◽  
Three Dimensional Models

This article provides a detailed account of the process of scanning, post-processing and further manipulation of three-dimensional models obtained with structured light scanners. Purpose. The purpose of the study is determined by the need for national archaeologists to learn the methods of three-dimensional modeling for the implementation of scientific research corresponding to international standards. Unfortunately, this direction in national archaeology began to develop in a relatively recent time and there is a lag in the application of three-dimensional modeling of national archaeology compared to the world level. Results. Any archaeological, experimental or ethnographic artifact can be used for three-dimensional scanning. To perform post-processing of three-dimensional models it is necessary to carry out primary scanning of an artifact by one of the existing algorithms. The algorithm for creating models, their positioning, simplification, saving in various formats and export is described. The main sequence of 3D models post-processing includes: processing of groups of scanned projections (their cleaning and alignment), creation of artifact model and processing/rectification of the resulting model using special software. Conclusion. As a result of correct implementation of the algorithm, the researcher receives a scaled model completely corresponding to the original artifact. Obtaining a scalable, texture-free three-dimensional model of the artifact, which fully corresponds to the original and exceeds a photograph in the quality of detail transfer, allows a scientist to conduct precise metric measurements and any procedures of non-invasive manipulation of the models. The ability to access a database of three-dimensional models of archaeological collections greatly simplifies the work of archaeologists, especially in situations when country borders are closed.

Analysis and Research of High Speed Milling of Thin-Walled Bracket Part Based on UG NX

2010 ◽  
Vol 129-131 ◽  
pp. 256-260
Author(s):  
Yi Shu Hao ◽  
Chuang Hai ◽  
Xin Xing Zhu
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Structural Features ◽  
Milling Process ◽  
Analysis Method ◽  
Three Dimensional Model ◽  
Machining Processes ◽  
Element Analysis ◽  
High Speed Milling ◽  
Tool Paths

Treating high speed milling theory as the guidance, this paper researched high speed milling process of bracket part based on UG NX. Combined with the structural features of bracket part, three dimensional model is built by UG NX CAD and machining processes are worked out after analysis. UG CAM module was applied to fabricate tool paths. At last, finite element analysis method is introduced to study the processing deformation by UG NX NASTRAN module, based on which measures to restrain processing deformations is advanced and processing sequences are optimized.

On the modeling of thermohydrodynamic and biogeochemical processes in the inland water objects

2020 ◽  
Author(s):  
Daria Gladskikh ◽  
Evgeny Mortikov ◽  
Victor Stepanenko
Keyword(s):  
Carbon Dioxide ◽  
Numerical Study ◽  
Three Dimensional ◽  
Measurement Data ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Inland Water ◽  
One Dimensional ◽  
Biochemical Processes ◽  
Dimensional Models

<p>Currently, one-dimensional and three-dimensional models are widely used to model thermohydrodynamic and biochemical processes in lakes and water rеreservoirs. One-dimensional models are highly computationally efficient and are used to parameterize land water bodies in climate models, however, when calculating large lakes and reservoirs with complex geometry, such models may incorrectly reproduce processes associated with horizontal heterogeneity. This becomes especially important for the prediction of water quality and euthrophication.</p><p>A three-dimensional model of thermohydrodynamics and biochemistry of an inland water obect is presented, which is based on the hydrostatic RANS model [1-3], and the parameterization of biochemical processes is implemented by analogy with the scheme for calculating biochemistry in the one-dimensional LAKE model [4]. Thus, the three-dimensional model is supplemented by a description of the transport of substances such as oxygen (O<sub>2</sub>), carbon dioxide (CO<sub>2</sub>), methane (CH<sub>4</sub>), as well as phyto- and zooplankton. The effect of turbulent diffusion and large-scale water movements on the distribution of a methane concentration field is studied.</p><p>To verify the calculation results, idealized numerical experiments and comparison with the measurement data on Lake Kuivajärvi (Finland) were used.</p><p>The work was supported by grants of the RF President’s Grant for Young Scientists (MK-1867.2020.5, MD-1850.2020.5) and by the RFBR (18-05-00292, 18-35-00602, 20-05-00776). <br><br>References:<br>[1] Mortikov E.V. Numerical simulation of the motion of an ice keel in stratified flow // Izv. Atmos. Ocean. Phys. 2016. 52. P. 108-115.<br>[2] Mortikov E.V., Glazunov A.V., Lykosov V.N. Numerical study of plane Couette flow: turbulence statistics and the structure of pressure-strain correlations // Russian Journal of Numerical Analysis and Mathematical Modelling. 2019. V. 34, N 2. P. 119-132.<br>[3] D.S. Gladskikh, V.M. Stepanenko, E.V. Mortikov, On the influence of the horizontal dimensions of inland waters on the thickness of the upper mixed layer. // Water Resourses. 2019. 18 pages. (submitted)<br>[4] Victor Stepanenko, Ivan Mammarella, Anne Ojala, Heli Miettinen, Vasily Lykosov, and Vesala Timo. LAKE 2.0: a model for temperature, methane, carbon dioxide and oxygen dynamics in lakes. Geoscientific Model Development, 9(5): 1977–2006, 2016.</p>

A three-dimensional model of Hamilton Harbour incorporating spatial distribution of transient surface drag

1978 ◽  
Vol 5 (4) ◽  
pp. 479-488 ◽  
Author(s):  
William James ◽  
Basem Eid
Keyword(s):  
Boundary Conditions ◽  
Transport Model ◽  
Three Dimensional ◽  
Layered System ◽  
Surface Boundary ◽  
Hydrodynamic Equations ◽  
Three Dimensional Model ◽  
Surface Drag ◽  
Hamilton Harbour ◽  
Surface Boundary Conditions

This paper discusses the formulation of surface boundary conditions for a three-dimensional transport model for shallow lakes, specifically for Hamilton Harbour. The same hydrodynamic equations that describe the circulation of the ocean and the Great Lakes were used in this study. However, the boundary conditions (bed topography, shoreline configuration, and surface and bottom shear stress fields) have bigger effects on circulation in shallow enclosed lakes.In this study the flow is assumed to be incompressible and in hydrostatic equilibrium. A layered system is used in which the lake is considered to consist of a number of unequal layers in the vertical. The hydrodynamic equations are integrated vertically over each layer, and both vertical and horizontal eddy viscosities are introduced.The over-water wind stress is determined using the logarithmic wind velocity distribution and Von Karman's integral equation for turbulent flow over a rough movable surface of variable roughness, in conjunction with equations for wind–wave generation. Thus the wind drag coefficient is determined as a function of wind and wave characteristics, and is time- and space-dependent.

Structure Design and FE Analysis of a Newly Basketball Wheelchair

2008 ◽  
Vol 44-46 ◽  
pp. 685-690
Author(s):  
Lei Lei ◽  
Tian Min Guan ◽  
Li Jun Shan
Keyword(s):  
Three Dimensional ◽  
Work Conditions ◽  
Structure Design ◽  
Human Engineering ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Engineering Theory ◽  
Development Level ◽  
The Finite Element Analysis

Based on the human engineering theory the structure of the new Basketball wheelchair is designed. And the three dimensional model is drawn by means of the PRO/E software after the design. Next, the finite element analysis computation on the wheelchair structure is completed under the four work conditions by I-DEAS software. The result shows that its intensity satisfies the operation requirements and proves that the new Basketball wheelchair is comfortable, safe and reliable. The research of this paper has a more vital significance for enhancing the performance of basketball wheelchair and the development level of sport wheelchair.

Finite Element Static Analysis of YP2080 Automatic Hydraulic Press

2014 ◽  
Vol 556-562 ◽  
pp. 1046-1049
Author(s):  
Dong Qing Lv
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Three Dimensional ◽  
Hydraulic Press ◽  
Stress And Strain ◽  
Design And Optimization ◽  
Dimensional Models ◽  
Three Dimensional Models

The paper took 2080 tons automatic hydraulic tile press as the research object, completed the finite element static analysis of its beam and base. Established their three-dimensional models with CAD software Pro/ENGINEER, and then analyzed the stress and transfiguration with CAE software ANSYS. Studied the distribution of the stress and strain, and found their maximum and location. The result can provide some good reference for design and optimization.

Study on the Application of Computer Three-Dimensional Model's Simulation Functions

2013 ◽  
Vol 443 ◽  
pp. 27-30
Author(s):  
Qin Gu
Keyword(s):  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Simulation Functions ◽  
Dimensional Models ◽  
Three Dimensional Models

In this paper, the simulation functions of computer three-dimensional model as well as the advantages in the simulated application are briefly introduced, and also the application of the three-dimensional models simulation functions to the different industries is discussed in details.

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