scholarly journals Hygrothermal Behaviour of Continuous Air Chambers on Stone Panels Façades through CFD and IRT

2019 ◽  
Vol 9 (15) ◽  
pp. 3001 ◽  
Author(s):  
Carlos Lerma ◽  
Ángeles Mas ◽  
Enrique Gil ◽  
Jose Vercher
Keyword(s):  
Relative Humidity ◽  
Research Work ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Qualitative And Quantitative Analysis ◽  
Air Velocity ◽  
Air Chamber ◽  
Computational Fluid Dynamics Cfd ◽  
Three Dimensional Models ◽  
Contemporary Architecture

Façades of buildings with stone cladding are widely used in contemporary architecture. This research work analyses the aerodynamic, thermal and relative humidity behaviour of this type of façade. One of the main novelties of the article is the analysis of air flow and temperature of the air chamber through finite elements with computational fluid dynamics (CFD). Ten three-dimensional models were designed to study the various parameters that influence the behaviour of the façade, including the thickness of the air chamber and the velocity of the outside air. A qualitative and quantitative analysis of temperature and humidity makes it possible to determine the areas susceptible to generating condensation. Infrared thermography (IRT) is used to obtain the actual outside temperature, which is used in the validation of finite element models. The temperature is reduced by 47% with air chambers of 3 cm instead of 1 cm with soft outside air velocity, and by up to 60% with moderate air velocity. In these cases, relative humidity increases by 96% and 74%, respectively. When the results obtained in CFD vary considerably in a particular area with respect to IRT, a possible pathology is identified. This work provides better knowledge on the durability of material and façades.

scholarly journals Study on Mechanism of Series-Flow of Pollutants between Consecutive Tunnels by Numerical Simulation

2019 ◽  
Vol 9 (19) ◽  
pp. 4125
Author(s):  
Honghu Zhang ◽  
Yunge Hou ◽  
Kaijie Wu ◽  
Tianhang Zhang ◽  
Ke Wu ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Velocity Ratio ◽  
Three Dimensional ◽  
Wall Jet ◽  
Air Velocity ◽  
Pressure Area ◽  
Computational Fluid Dynamics Cfd ◽  
Jet Theory ◽  
Jet Characteristics ◽  
Tunnel Entrance

The characteristics of series-flow between two consecutive tunnels with distance ranging from 20 m to 250 m are explored by computational fluid dynamics (CFD) parametric simulations of structure and operation parameters. The research indicates that series-flow can be considered the three-dimensional wall jet diffusion of upstream tunnel pollutants under the effects of the negative pressure area of the downstream tunnel entrance. The jet characteristics are primarily related to the tunnel distance between upstream and downstream tunnels and hydraulic diameters, and only influenced by the negative pressure in the area very close to downstream entrance where the tunnel air velocity ratio, i.e., the velocity of upstream tunnel air divided by the velocity of downstream tunnel air, decides the degree of the influence. If ignoring the effects of ambient wind and traffic flow, the series-flow ratio decreases with the increasing of parameters of the normalized tunnel distance, i.e., the tunnel distance divided by tunnel hydraulic diameter, and the tunnel air velocity ratio. Based on the three-dimensional wall jet theory, a series-flow model covering all jet characteristic sections is built. The experiment results indicate that the model applies to consecutive tunnels with any spacing and exhibits higher prediction accuracy.

Optimal Design of Conductor Clamps Based on Abaqus

2014 ◽  
Vol 915-916 ◽  
pp. 244-247
Author(s):  
Kai Liu ◽  
Ming Jiang ◽  
Fei Peng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optimal Design ◽  
Field Test ◽  
Three Dimensional ◽  
Element Model ◽  
Finite Element Models ◽  
Element Analysis ◽  
Optimal Target ◽  
Three Dimensional Models

Three dimensional models and finite element models of conductor clamps are built in software Solidworks and Abaqus. Different forces are loaded on finite element model of conductor clamps to obtain distributions of stress and displacement. Optimal design of conductor clamps is performed with finite element analysis and field test data. The results show that optimal design scheme achieves optimal target.

scholarly journals Three-dimensional Models Represent Seed Moisture Content as a Function of Relative Humidity and Temperature

HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1207-1209 ◽  
Author(s):  
Jian Fang ◽  
Frank Moore ◽  
Eric Roos ◽  
Christina Walters
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Citrullus Lanatus ◽  
Three Dimensional ◽  
Selection Criterion ◽  
Seed Storage ◽  
Response Surfaces ◽  
Seed Moisture Content ◽  
Seed Moisture ◽  
Three Dimensional Models

Seed moisture content (MC) has been considered the most important factor controlling physiological reactions in seeds, and MC changes with relative humidity (RH) and temperature (T). This relationship is revealed by studying the interaction of RH and T at equilibrium. Cucumber (Cucumis sativus L.), lettuce (Lactuca sativa L.), maize (Zea mays L.), onion (Allium cepa L.), pea (Pisum sativum L.), and watermelon (Citrullus lanatus M. & N.) seeds were equilibrated over sulfuric acid (1% RH) and various saturated salt solutions (5.5% to 93% RH) at temperatures from 5 to 50 °C. Best-fit subset models were selected from the complete third-order model MC = β0 + β1*RH + β2*T + β3*RH2 + β4*T2 + β5*RH*T + β6*RH3 + β7*T3 + β8*RH*T2 + β9*RH2*T, using Mallows' minimum Cp as the selection criterion. All six best subset models (R2, 0.98 to 0.99) had the same functional form, MC = β0 + β1*RH + β2*T + β3*RH2 + β5*RH*T + β6*RH3 + β9*RH2*T. Coefficients had essentially the same respective values among all species except onion and pea, for which some coefficients were statistically different from those of the other species (P ≤ 0.05). All models indicated that seed MC increased as RH increased and decreased as T increased; but RH had the greater influence. The inverse relationship between seed MC and T, although slight, was evident in the response surfaces. The interaction effect of RH and T on MC was significant at P ≤0.001. These results suggest that orthodox seed species respond similarly to T and RH. This in turn suggests that a common model could be developed and used for optimizing seed storage environments.

Comparative Evaluation of Finite Element Models and Types of Analyses for a Bolted Joint

2005 ◽  
Vol 127 (6) ◽  
pp. 1207-1210
Author(s):  
R. Padmaja ◽  
R. Ravinder Rao ◽  
B. Kotiveerachari ◽  
P. B. Godbole
Keyword(s):  
Finite Element ◽  
Comparative Evaluation ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Essential Difference ◽  
Bolted Joint ◽  
The Finite Element Method ◽  
Three Dimensional Models ◽  
Parametric Programs ◽  
Line Elements

The present work is aimed at evaluating different ways in which a given joint can be analyzed using the Finite Element Method. The bolt is modeled using line elements (link) or area elements (continuum) and a comparative evaluation is carried out. Each of these types is further subdivided into three categories viz., plane stress, axisymmetric, and three-dimensional models. Thus a total of six models are proposed to be analyzed and compared. As the bolt shares only a small fraction of external load in a well-tightened joint, the relative flexibility of a bracket is also studied as an example in the present work. Comparing the results of these analyses it was found that the type of model used for the bolt is more important than the type of analysis. This aspect is probed further to find the essential difference between bolt as link and bolt as continuum. The analysis is carried out using ANSYS, which enables writing many parametric programs.

Modeling of Indoor Air Quality and Comfort in the Tombs of Valley of the Kings

2005 ◽  
Author(s):  
Omar A. A. Abdel-Aziz ◽  
Essam E. Khalil
Keyword(s):  
Air Quality ◽  
Indoor Air ◽  
Three Dimensional ◽  
Design System ◽  
Wall Paintings ◽  
Governing Equations ◽  
Large Area ◽  
Air Velocity ◽  
Computational Fluid Dynamics Cfd ◽  
Selection Of

Airflow characteristics in ventilated and airconditioned spaces play an important role to attain comfort and hygiene conditions. This paper utilizes a 3D Computational Fluid Dynamics (CFD) model to assess the airflow characteristics in ventilated and air-conditioned archeological tombs of Egyptian Kings in the Valley of the Kings in Luxor, Egypt. It was found that the optimum airside design system can be attained, if the airflow is directed to pass all the enclosure areas before being extraction with careful selection of near wall velocities to avoid any wear or abrasion of the tomb-wall paintings. In this model conditioned air is allowed to enter the tomb from its entrance with a large area of admission in order to maintain low air velocity while extraction points are distributed along the tomb axis. The mode of evaluation should assess the airflow characteristics in any tomb passage according to its position in the enclosure and the thermal pattern and air quality. The Governing Equations are numerically solved in a three dimensional grid configurations at more than 500000 nodes. The paper addresses the various modeling aspects and constraints and suggests solutions that are viable and do not affect the tomb construction, interior nor sustainability.

scholarly journals Comparative Analysis of Static and Dynamic Performance of Nonpneumatic Tire with Flexible Spoke Structure

2020 ◽  
Vol 66 (7-8) ◽  
pp. 458-466
Author(s):  
Zifeng Zhang ◽  
Hongxun Fu ◽  
Xuemeng Liang ◽  
Xiaoxia Chen ◽  
Di Tan
Keyword(s):  
Finite Element ◽  
Dynamic Performance ◽  
Research Work ◽  
Three Dimensional ◽  
Static Condition ◽  
Finite Element Models ◽  
Radial Tire ◽  
Ground Pressure ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Based on ABAQUS software, the three-dimensional finite element models of 195/50R16 radial tire and three kinds of nonpneumatic tire, i.e., spoke plate, honeycomb and grid type, are established, and the static and dynamic performance of the four finite element models of tire are analysed. The results show that in the static condition analysis, the ground pressure of the nonpneumatic tire is distributed on both sides of the tread; the stress concentration of the nonpneumatic tire mainly occurs in the grounding area near the support spoke; the deformation area of nonpneumatic tire mainly appears in the area of grounding and adjacent to the grounding spoke; In the analysis of the tire’s steady rolling condition, the ground imprint of a nonpneumatic tire is similar to that of a bar rectangle, and the ground pressure distribution is relatively uniform. The static and dynamic characteristics of honeycomb nonpneumatic tire are close to that of a radial tire. The research work of this paper will provide some reference for the structural design and parameter optimization of nonpneumatic tires.

scholarly journals The integration of computer aided design and finite element analysis tools using a logic based approach

2002 ◽  
Author(s):  
◽  
Jason David De Beer
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Element Analysis ◽  
Computer Aided ◽  
Virtual Prototypes ◽  
Three Dimensional Models ◽  
Aided Design ◽  
Analysis Models

Today's powerful computer-aided engineering (CAE) products have reached ground breaking levels of sophistication when compared with the almost archaic technology used by our predecessors. Engineers are able to develop complex three-dimensional models, or virtual prototypes, using powerful 3D modelling capabilities, and from these models, generate manufacturing drawings, motion analysis models, and even finite element models.

Plastic replicas as three-dimensional models of pulps

1975 ◽  
Vol 39 (8) ◽  
pp. 544-546
Author(s):  
HL Wakkerman ◽  
GS The ◽  
AJ Spanauf
Keyword(s):  
Three Dimensional ◽  
Dimensional Models ◽  
Three Dimensional Models

Validation of a Belt Model for Prediction of Hub Forces from a Rolling Tire4

2009 ◽  
Vol 37 (2) ◽  
pp. 62-102 ◽  
Author(s):  
C. Lecomte ◽  
W. R. Graham ◽  
D. J. O’Boy
Keyword(s):  
Internal Pressure ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Prediction Method ◽  
Analytical Models ◽  
Beam Model ◽  
Impedance Boundary ◽  
Bending Waves ◽  
Tire Rotation ◽  
Three Dimensional Models

Abstract An integrated model is under development which will be able to predict the interior noise due to the vibrations of a rolling tire structurally transmitted to the hub of a vehicle. Here, the tire belt model used as part of this prediction method is first briefly presented and discussed, and it is then compared to other models available in the literature. This component will be linked to the tread blocks through normal and tangential forces and to the sidewalls through impedance boundary conditions. The tire belt is modeled as an orthotropic cylindrical ring of negligible thickness with rotational effects, internal pressure, and prestresses included. The associated equations of motion are derived by a variational approach and are investigated for both unforced and forced motions. The model supports extensional and bending waves, which are believed to be the important features to correctly predict the hub forces in the midfrequency (50–500 Hz) range of interest. The predicted waves and forced responses of a benchmark structure are compared to the predictions of several alternative analytical models: two three dimensional models that can support multiple isotropic layers, one of these models include curvature and the other one is flat; a one-dimensional beam model which does not consider axial variations; and several shell models. Finally, the effects of internal pressure, prestress, curvature, and tire rotation on free waves are discussed.

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