Experimental Investigations and a New Numerical Model for Evolution of Formwork Pressure in SCC

2017 ◽  
Vol 42 (9) ◽  
pp. 3907-3921
Author(s):  
N. S. Saleem ◽  
M. H. Baluch ◽  
M. K. Rahman ◽  
M. Al-Osta
Keyword(s):  
Numerical Model ◽  
Experimental Investigations ◽  
Formwork Pressure

scholarly journals Fish Cells, a new zero Poisson’s ratio metamaterial—Part I: Design and experiment

2020 ◽  
Vol 31 (13) ◽  
pp. 1617-1637
Author(s):  
Mohammad Naghavi Zadeh ◽  
Iman Dayyani ◽  
Mehdi Yasaee
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Poisson’S Ratio ◽  
Structural Integrity ◽  
Structural Response ◽  
Poisson's Ratio ◽  
Experimental Investigations ◽  
Fish Cells ◽  
Force Displacement ◽  
Model Approach

A novel cellular mechanical metamaterial called Fish Cells that exhibits zero Poisson’s ratio in both orthogonal in-plane directions is proposed. Homogenization study on the Fish Cells tessellation is conducted and substantially zero Poisson’s ratio behavior in a homogenized tessellation is shown by numerical analysis. Experimental investigations are performed to validate the zero Poisson’s ratio feature of the metamaterial and obtain force–displacement response of the metamaterial in elastic and plastic zone. A detailed discussion about the effect of the numerical model approach and joints on the structural response of the metamaterial is presented. Morphing skin is a potential application for Fish Cells metamaterial because of the integration benefits of zero Poisson’s ratio design. The structural integrity of the Fish Cells is investigated by studying the stiffness augmentation under tension and in presence of constraints on transverse edges. Finally, geometrical enhancements for improved integrity of the Fish Cells are presented that result in substantially zero stiffness augmentation required for morphing skins.

The Effect of Thermal Field on the Deposition of Fe-TiC on Carbon Steel Using Laser Cladding

2010 ◽  
Author(s):  
Masoud Alimardani ◽  
Ali Emamian ◽  
Amir Khajepour ◽  
Stephen F. Corbin
Keyword(s):  
Carbon Steel ◽  
Numerical Model ◽  
Laser Cladding ◽  
Thermal Field ◽  
Deposition Process ◽  
Time Dependent ◽  
Experimental Investigations ◽  
Thermal Fields ◽  
Temperature Distributions ◽  
Laser Cladding Process

In this paper, a numerical and experimental method is used to investigate the effect of thermal fields on the deposition of Fe-TiC using the laser cladding process. Since in laser cladding temperature distributions and consequent rapid cooling rates determine the microstructure and final physical properties of the deposited layers, a 3D time-dependent numerical model is used to simulate the cladding process parallel to experimental analysis. The numerical results are used to study the temperature distributions and their evolutions throughout the deposition process. The experimental and verified numerical outcomes are then employed to study the variations of the microstructures of the deposited material as well as correlation between the formed microstructures and temperature distributions across the deposition domain. The numerical and experimental investigations are conducted through the deposition of Fe-TiC on the substrate of AISI 1030 carbon steel using a 1.1 kW fiber laser. The experimental results confirm that by increasing the substrate temperature throughout the process the distribution of the TiC particles changes along with the deposited tracks and the TiC particles start forming clusters at the top of the clad.

scholarly journals Experimental and numerical investigation of thermal flow meter

2015 ◽  
Vol 36 (3) ◽  
pp. 149-160 ◽  
Author(s):  
Artur Cebula
Keyword(s):  
Temperature Distribution ◽  
Numerical Model ◽  
Surface Temperature ◽  
Numerical Investigation ◽  
Flow Rate ◽  
Experimental Investigations ◽  
Thermal Flow ◽  
Wall Surface ◽  
Flow Meter ◽  
Calculation Results

Abstract The paper presents analytical and numerical model calculation results of the temperature distribution along the thermal flow meter. Results show a very good conformity between numerical and analytical model. Apart from the calculation results the experimental investigations are presented. The author performed the test where a temperature of duct wall surface was measured. The relation between mass flow rate in terms of the duct surface temperature difference was developed.

Experimental and Numerical Investigations of Steel Profiles with Intumescent Coating Adjacent to Space-Enclosing Elements in Fire

2015 ◽  
Vol 6 (4) ◽  
pp. 237-246 ◽  
Author(s):  
Peter Kraus ◽  
Martin Mensinger ◽  
Florian Tabeling ◽  
Peter Schaumann
Keyword(s):  
Temperature Field ◽  
Numerical Model ◽  
Fire Protection ◽  
Experimental Investigations ◽  
Expansion Process ◽  
Intumescent Coating ◽  
Numerical Investigations ◽  
Steel Members ◽  
New Development ◽  
In Fire

In this paper, the research program “Optimized use of intumescent coating systems on steel members” is presented. The aim of the project is to quantify the influence of space-enclosing elements on the thermal behavior of supporting steel members. Those elements partially result in a restrained expansion of the fire protection system. Experimental investigations on coated beams and columns directly connected to space-enclosing elements are presented. Additionally, numerical simulations are performed for temperature field calculations of steel elements with intumescent coating. As a new development, the numerical model takes into account the expansion process of the intumescent coating.

Oscillation Caused by Vortex Cavitation in a Double-Suction Volute Pump

2011 ◽  
Author(s):  
Kazuhiro Tanaka ◽  
Akira Inoue ◽  
Toshiyuki Sato ◽  
Takahide Nagahara ◽  
Masaki Fuchiwaki ◽  
...  
Keyword(s):  
Numerical Model ◽  
Multiphase Flow ◽  
Numerical Simulations ◽  
Characteristic Frequency ◽  
Experimental Investigations ◽  
Baffle Plate ◽  
Fixed Frequency ◽  
Flow Equations ◽  
Commercial Code ◽  
Collapse Process

This study highlights a mechanism of the vortex cavitation occurrence from the baffle plate, the end of the suction duct, in a double-suction volute pump and a relationship between pump oscillation and the cavitation occurrence. In this study, full 3D numerical simulations have been performed using a commercial code inside the pump from the inlet of suction duct to the outlet of delivery duct. The numerical model is based on combination of multiphase flow equations with the truncated version of Rayleigh-Plesset model predicting the complicated growth and collapse process of cavity bubbles. The vortex cavitation has the characteristic frequency based on the impeller rotation and has much influence on the pump oscillation, however at over discharge range the vortex cavitation does not collapse, because the cavitation runs into and combines with another cavitation generated in the impeller shroud, and the fixed frequency of the pump oscillation is reduced. The experimental investigations have also been performed on the cavitating flow to evaluate the numerical results and the both results agree well.

Computational and Experimental Analysis of Direct CNG Injection and Mixture Formation in a Spark Ignition Research Engine

2010 ◽  
Author(s):  
Mirko Baratta ◽  
Andrea E. Catania ◽  
Francesco C. Pesce
Keyword(s):  
Numerical Model ◽  
Combustion Chamber ◽  
Cone Angle ◽  
Combustion Process ◽  
Laser Induced Fluorescence ◽  
Operating Conditions ◽  
Design Parameters ◽  
Experimental Investigations ◽  
Injection Timing ◽  
Mixture Formation

Direct injection (DI) of compressed natural gas (CNG) under high pressure conditions is a topic of great interest, owing to its potential for improving SI engine performance and fuel consumption. However, relevant technical difficulties have yet to be resolved in order to stabilize combustion process, especially for stratified engine operating conditions. The present paper is focused on experimental and numerical investigations of the jet formation and fuel-air mixing process in a research optical-access single-cylinder engine. The engine is based on the multi-cylinder engine under development within the European Community (EC) VII Framework Program (FP) InGAS Integrated Project, and features a centrally mounted poppet-valve injector on a pent-roof combustion chamber with a bowl in piston. Experimental investigations were made by means of the planar laser-induced fluorescence technique, and revealed a cycle-to-cycle jet shape variability. In particular, for specific cylinder pressure values at the start of injection, the jet can adhere to chamber walls for a relevant number of cycles, leading to an ‘umbrella-like’ shape. This can change the mixing capabilities of the combustion chamber and cause instabilities in the combustion process. The mentioned behaviour is strongly dependent not only on the injection and cylinder pressures, but also on important design parameters, such as needle cone angle and in-chamber injector protrusion. For this reason, in order to obtain a deep insight into the injected gas behaviour on an average cycle basis, the experimental investigation was supported by a numerical analysis. Simulations were carried out by an optimized variable-density finite-volume numerical model which was built within the Star-CD environment. A previously developed and validated ‘virtual injector’ model was implemented. The outcomes of the numerical model were compared to laser-induced fluorescence images, for both stratified- and homogeneous-charge engine operating conditions and a good agreement was obtained, substantiating the reliability of the applied computational model. Then, the effects of the injector protrusion in the combustion chamber and of injection timing were analyzed, and their impact on jet stability and mixture-formation process was analyzed.

scholarly journals Experimental and numerical tests of the compaction process of loose material in the form of sawdust

2019 ◽  
Vol 254 ◽  
pp. 02042 ◽  
Author(s):  
Dominik Wilczyński ◽  
Maciej Berdychowski ◽  
Dominik Wojtkowiak ◽  
Jan Górecki ◽  
Krzysztof Wałęsa
Keyword(s):  
Numerical Model ◽  
Loose Material ◽  
Testing Machine ◽  
Experimental Tests ◽  
Experimental Investigations ◽  
Strength Testing ◽  
Compaction Process ◽  
Pine Sawdust ◽  
Cap Model ◽  
Effect Of The Composition

The paper presents experimental investigations of the compaction process of loose material in the form of sawdust. These were compacted in the sleeve-punch assembly adapted for installation on a strength testing machine. Sawdust was compacted with a force suitable to obtain the desired compressive stress in the sample cross-section. The effect of the composition of the compacted sample was investigated by adding pine sawdust to 50% of the total sample's weight. The experimental compaction process was simulated by building its numerical model using the Drucker-Prager-Cap model. Obtained results of experimental tests carried out on a strength testing machine allowed to establish a numerical model of the sawdust compaction process in the Abaqus program and to assess the possibility of using the Drucker-Prager-Cap model for numerical simulation of compaction process of loose materials in the form of sawdust.

On the Assessment of Masonry Structures

2021 ◽  
Author(s):  
Mariella Diaferio ◽  
Marilena Venerito ◽  
Michele Vitti
Keyword(s):  
Numerical Model ◽  
Ground Level ◽  
Experimental Investigations ◽  
Maximum Height ◽  
Masonry Building ◽  
Safety Level ◽  
Gable Roof ◽  
Lack Of Information ◽  
Construction Techniques ◽  
Earthquake Performance

Abstract The conservation of existing masonry buildings has reached a greater attention especially in the Southern Europe, where such structures are widespread, and need a periodic check also because they are the testimony of the history and the architectural progress of these areas. However, the assessment of the earthquake performance level of these structures is rather difficult for many reasons: the lack of information, the high variability of adopted materials and construction techniques, the existence of several interventions occurred during their service life, etc. These circumstances make difficult to define an accurate numerical model of these structures, by which assess their safety level and design possible strengthening and retrofitting. The present research deals with these issues by discussing the non-destructive tests performed on a masonry building in Bari, which in the 1977 was converted in a church and dedicated to San Marco. The San Marco church is an isolated building, whose plan dimensions are 16 m × 23 m, and with a maximum height equal to 10.50m. The church stands in a seismic prone zone and is characterized at the ground level by barrel vaults in some parts and by wooden roofs in the remaining parts, and by a gable roof realized by wood. The experimental investigations are utilized to validate a numerical model of the structure.

scholarly journals Climatic Issue in an Advanced Numerical Modeling of Concrete Carbonation

2021 ◽  
Vol 13 (11) ◽  
pp. 5994
Author(s):  
Viet Duc Ngo ◽  
Ngoc Tan Nguyen ◽  
Frédéric Duprat ◽  
Ngoc Tru Vu ◽  
Viet Phuong Nguyen
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Numerical Model ◽  
Relative Humidity ◽  
Research Work ◽  
Mass Conservation ◽  
Climatic Variables ◽  
Experimental Investigations ◽  
Concrete Carbonation ◽  
Wide Range

Damage in reinforced concrete structures is frequently caused by reinforcement corrosion due to carbonation. Although a wide range of literature contributed to the concrete carbonation consisting of experimental investigations and numerical simulations, research work on a complete numerical model for concrete carbonation prediction with integrated climatic variables (e.g., temperature, relative humidity) is still a challenge. The present paper aims to propose an advanced numerical model to simulate the penetration of carbon dioxide and moisture, diffusion of calcium ions, heat transfer, and porosity modification in concrete material using COMSOL Multiphysics software. Three coupled mass conservation equations of calcium, water, and carbon dioxide are solved together with additional equations regarding the heat transfer, variation of porosity, and content of portlandite and other hydrates and calcites. In this study, the actual temporal variabilities of temperature and relative humidity in Toulouse, France, are used as a case study. The predicted results of portlandite profiles and carbonation depth are compared with the experimental data and discussed to identify the effect of climatic variables on the concrete carbonation.

Influence Imperfections on the Difference between the Numerical and Experimental Investigations of a Punching in the Central Slab-Column Connections of RC Structures

2015 ◽  
Vol 769 ◽  
pp. 264-269
Author(s):  
Barbara Wieczorek
Keyword(s):  
Numerical Model ◽  
Laboratory Tests ◽  
Progressive Collapse ◽  
Numerical Calculations ◽  
Experimental Investigations ◽  
Material Models ◽  
Rc Structures ◽  
Non Linear ◽  
Australian Standard ◽  
The Difference

This paper presents the results of laboratory tests concerning the central connection of the slab with the column, in which an additional reinforcement ensuring the structure against a progressive collapse was applied as to recommended in the standard PN-EN 1991-1-7:2008 as well as in PN-EN 1992-1-1:2008. Regulations concerning the necessity of such a reinforcement are also contained in the American and Australian standard as well as in the Bulletin FIB. The obtained results of investigations have been compared with calculations based on a spatial numerical model representing the analyzed phenomenon. The numerical model bases on predefined material models of steel and concrete, taking into account non-linear dependences of the strength of these materials. The values of displacements of the upper surface of the slab depending on the exerted load were compared with the values of numerical calculations.

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