STUDYING ON FAILURE MECHANISM OF 2D GRANULAR COLUMNS: NUMERICAL RESULTS

The failure mechanism of granular columns and the characteristics of this failure flows have been intersted in researching in recent years. In particular, the experiments in failure mechanism and failure flow of 2D granular column are not often 2D standard. Therefore, Cuong T. Nguyen et al. (2015) conducted research this problem based on 2D standard in the laboratory and developed a numerical computation model using SPH (Smooth Particles Hydrodynamics) method (Cuong T. Nguyen et al., 2017). This model has proven the reliability by verification of calculation and experimental results. In this paper, the developed numerical model is used to perform a series of numerical experiments that some are difficult or impossible to obtain accurate results by physical experiment model to re-examine the previously identified characteristics and find out the rules more general of this failure flow.

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STUDYING ON FAILURE MECHANISM OF 2D GRANULAR COLUMNS: NUMERICAL RESULTS

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/57/6a/14177 ◽

2020 ◽

Vol 57 (6A) ◽

pp. 88

Author(s):

Cuong Tien NGUYEN

Keyword(s):

Numerical Model ◽

Numerical Computation ◽

Failure Mechanism ◽

Numerical Experiments ◽

Physical Experiment ◽

Numerical Results ◽

Experimental Results ◽

Computation Model ◽

Granular Column

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Numerical modeling of high velocity impact in sandwich panels with honeycomb core and composite skin including composite progressive damage model

Journal of Sandwich Structures & Materials ◽

10.1177/1099636218817894 ◽

2018 ◽

Vol 22 (8) ◽

pp. 2768-2795 ◽

Cited By ~ 3

Author(s):

Meysam Khodaei ◽

Mojtaba Haghighi-Yazdi ◽

Majid Safarabadi

Keyword(s):

Numerical Model ◽

Sandwich Panel ◽

Material Model ◽

Absorption Capacity ◽

Numerical Results ◽

Ballistic Impact ◽

Experimental Results ◽

Ballistic Limit ◽

Honeycomb Core ◽

Damage Initiation

In this paper, a numerical model is developed to simulate the ballistic impact of a projectile on a sandwich panel with honeycomb core and composite skin. To this end, a suitable material model for the aluminum honeycomb core is used taking the strain-rate dependent properties into account. To validate the ballistic impact of the projectile on the honeycomb core, numerical results are compared with the experimental results available in literature and ballistic limit velocities are predicted with good accuracy. Moreover, to achieve composite skin material model, a VUMAT subroutine including damage initiation based on Hashin’s seven failure criteria and damage evolution based on MLT approach modulus degradation is used. To validate the composite material model VUMAT subroutine, the ballistic limit velocities of the projectile impact on the composite laminates are predicted similar to the numerical results presented by other researchers. Next, the numerical model of the sandwich panel ballistic impact at different velocities is compared with the available experimental results in literature, and energy absorption capacity of the sandwich panel is predicted accurately. In addition, the numerical model simulated the sandwich panel damage mechanisms in different stages similar to empirical observations. Also, the composite skin damages are investigated based on different criteria damage contours.

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Numerical computation of wetting angles of Sn–(3−x)Ag–0.5Cu−x(Bi,In) quaternary Pb-free solder alloy systems on Cu substrate

International Journal of Modern Physics C ◽

10.1142/s0129183120501193 ◽

2020 ◽

Vol 31 (09) ◽

pp. 2050119

Author(s):

Ahmet Mustafa Erer ◽

Mukaddes Ökten Turacı

Keyword(s):

Numerical Model ◽

Numerical Computation ◽

Solder Alloy ◽

Empirical Model ◽

Sessile Drop ◽

Sessile Drop Method ◽

Experimental Results ◽

Cu Substrate ◽

Free Solder ◽

Alloy Systems

This paper was aimed to study of the wetting angle ([Formula: see text]) of Sn–Ag–Cu, Sn–([Formula: see text])Ag–0.5Cu–([Formula: see text])Bi and Sn–([Formula: see text])Ag–0.5Cu–([Formula: see text])In ([Formula: see text], 1 and 2 in wt.%) Pb-free solder alloy systems at various temperatures (250, 280 and 310∘C) on Cu substrate in Ar atmosphere. The new Sn–([Formula: see text])Ag–0.5Cu–xBi and Sn–([Formula: see text])Ag–0.5Cu[Formula: see text]([Formula: see text]) In systems, low Ag content quaternary Pb-free solder alloys, were produced by adding 0.5%, 1% and 2% Bi and In separately to the near-eutectic Sn-3[Formula: see text]wt.%Ag–0.5[Formula: see text]wt.%Cu (SAC305) alloy. The wetting angles of new alloys, Sn[Formula: see text]2.5[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]0.5[Formula: see text]wt.%Bi (SAC-0.5Bi), Sn[Formula: see text]2[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]1[Formula: see text]wt.%Bi(SAC-1Bi), Sn[Formula: see text]1[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]2[Formula: see text]wt.%Bi(SAC-2Bi), Sn[Formula: see text]2.5[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]0.5[Formula: see text]wt.%In (SAC-0.5In), Sn[Formula: see text]2[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt.%Cu[Formula: see text]1[Formula: see text]wt.%In (SAC-1In) and Sn[Formula: see text]1[Formula: see text]wt.%Ag[Formula: see text]0.5[Formula: see text]wt%.Cu[Formula: see text]2[Formula: see text]wt.%In (SAC-2In) were measured by sessile drop method. Experimental results showed that additions of Bi and In separately to SAC305 resulted in a continuous decrease in the [Formula: see text] up to 1[Formula: see text]wt.% above which the [Formula: see text] value was increased and it is appeared that a correlation among the [Formula: see text], alloys compositions and the test temperatures exists which recommended an empirical model to estimate the [Formula: see text] at a given Bi and In content and temperature for a given alloy systems. The numerical model estimates the [Formula: see text] understandably well with the present work.

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Experimental Validation of a Dynamic Numerical Model for Timing Belt Drives Behavior Simulation

Volume 6: 8th International Power Transmission and Gearing Conference ◽

10.1115/detc2000/ptg-14408 ◽

2000 ◽

Author(s):

Lionel Manin ◽

Daniel Play ◽

Patrick Soleilhac

Keyword(s):

Numerical Model ◽

Dynamic Behavior ◽

Operation Time ◽

Transmission Error ◽

Numerical Results ◽

Experimental Results ◽

Medium Size ◽

Behavior Simulation ◽

Dynamic Transmission Error ◽

Timing Belt

Abstract The behavior of timing belts used in automotive applications have to be defined and predicted at the preliminary design phases. Numerical simulations replace progressively experimental determinations that are time and money consuming. The object of the work was to qualify from experimental results a timing belt drive numerical model. The model simulates the dynamic behavior versus time of any kind of tooth belt power transmissions. The model architecture, originalities and capabilities have been already presented, and the purpose is now to compare in details numerical and experimental results. The experimental qualification has been carried out on a laboratory test bench with a medium size engine valve controlled distribution made of 3 pulleys and a tensioner. Tensions, camshaft torque, pulleys speeds and angular acylisms, dynamic transmission error between camshaft and crankshaft pulleys have been measured. Numerous tests have been made for different running conditions by changing : speed, angular acyclism, camshaft torque, setting tension. Several phenomena and influence of parameters have been identified, as the pulley eccentricity effect on camshaft torque, span tensions, and transmission error. Part of the experimental results are used as entries of the model : camshaft torque, crankshaft instantaneous speed, transmission error due to pulley eccentricities. Further, comparisons with the numerical results were made. Experimental and numerical results of tension, angular acyclism, dynamic transmission error, versus operation time are compared for the different tests performed. The agreement is good and shows that the model developed allows to simulate dynamic behavior of timing belt with high degree of confidence.

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Numerical Analysis of Biogas Composition Effects on Combustion Parameters and Emissions in Biogas Fueled HCCI Engines for Power Generation

ASME 2011 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2011-60120 ◽

2011 ◽

Cited By ~ 1

Author(s):

Iva´n D. Bedoya ◽

Samveg Saxena ◽

Francisco J. Cadavid ◽

Robert W. Dibble

Keyword(s):

Numerical Model ◽

Power Output ◽

Internal Combustion Engines ◽

Numerical Results ◽

Experimental Results ◽

Combustion Stability ◽

Absolute Pressure ◽

Nox Emissions ◽

Hcci Engine ◽

Hcci Engines

This study investigates the effects of biogas composition on combustion stability for a purely biogas fueled HCCI engine. Biogas is one of the most promising renewable fuels for Combined Heat and Power systems driven by internal combustion engines. However, the high content of CO2 in biogas composition leads to low thermal efficiencies in spark ignited and dual fuel compression ignited engines. The study is divided into two parts: first experimental results on a biogas-fueled HCCI engine are used to validate a numerical model, and second the model is used to investigate how biogas composition impacts combustion stability. In the first part of the study, experimental analysis of a 4 cylinder, 1.9 L Volkswagen TDI Diesel engine running with biogas in HCCI mode has shown high gross indicated mean effective pressure (close to 8 bar), high gross indicated efficiency (close to 45%) and ultra-low NOx emissions below the US2010 limit (0.27 g/kWh). An inlet absolute pressure of 2 bar and inlet temperature of 473 K (200°C) were required for allowing HCCI combustion with a biogas composition of 60% CH4 and 40% CO2 on a volumetric basis. However, slight changes in inlet pressure and temperature caused large changes in cycle-to-cycle variations at low equivalence ratios and large changes in ringing intensity at high equivalence ratios. A numerical model is validated against these experimental results. In the second part of the study, the numerical results for varied biogas composition show that at high load limit, higher contents of CH4 in biogas composition allow advanced combustion and increased burning rates of the biogas air mixture. Higher contents of CO2 in biogas composition allow lowered ringing intensities with moderate decrease in the indicated efficiency and power output. NOx emissions are not highly affected by biogas composition, while CO and HC emissions tend to increase with higher contents of CO2. According with the numerical results, biogas composition is an effective strategy to control the onset of combustion and combustion phasing of HCCI engines running biogas, allowing more stabilized combustion at low equivalence ratios and safe operation at high equivalence ratios. The main advantages of using biogas fueled HCCI engines in CHP systems are the low sensitivity of power output and indicated efficiency to biogas composition, as well as the ultra low NOx emissions achieved for all tested compositions.

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Numerical Analysis of the Influence of the Padding-Plate on the Extended End-Plate Connection

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.578-579.505 ◽

2014 ◽

Vol 578-579 ◽

pp. 505-508

Author(s):

Shao Qin Zhang ◽

Lei Wu

Keyword(s):

Numerical Analysis ◽

Numerical Model ◽

Numerical Simulations ◽

Load Capacity ◽

Numerical Results ◽

Experimental Results ◽

End Plate ◽

Extended End Plate ◽

Plate Connection

In the present paper, we investigate the effect of a padding-plate on the behavior of extended end-plate semi-rigid connections. The numerical simulations were carried out for a standard extended end-plate connection joint without padding-plate and two connection joints with 4mm and 6mm thick padding-plates. The existing experimental results verified the validity of the numerical model. The numerical results have shown that a thin padding-plate will more or less decline the carrying load capacity of the connection joint but greatly improve the connect ductility. Filling a thin padding-plate in the end-plate connection is feasible and brings the forewarning function.

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Deformation of the Wave Field Interacting With Offshore Platforms: Comparison Between the Corresponding Results From a Numerical Model and a Wave Tank

Volume 3: Structures, Safety and Reliability ◽

10.1115/omae2016-54329 ◽

2016 ◽

Author(s):

M. Hasanat Zaman ◽

Ayhan Akinturk

Keyword(s):

Numerical Model ◽

Wave Field ◽

National Research Council ◽

Numerical Results ◽

Experimental Results ◽

Test Facility ◽

Offshore Platforms ◽

Offshore Structure ◽

Alternating Direction ◽

Tracking Devices

In the present research, a 3D dispersive numerical model has been developed and utilized to study the modification of the wave field in the presence of offshore structure. The Alternating Direction Implicit (ADI) algorithm has been employed for the solution of the governing equations. Relevant experiments are carried out in the Offshore Engineering Basin (OEB) of National Research Council (NRC) Canada. OEB is a 3D heavy duty 75m × 32m × 2.8m test facility equipped with modern data acquisition and tracking devices to record experimental data. Total 10 wave probes are deployed to measure the data at different locations in the Basin. Later the numerical results are compared with the experimental results. The comparisons of the numerical results show great agreement with the experimental results.

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An implicit scheme for simulation of free surface non-Newtonian fluid flows on dynamically adapted grids

Russian Journal of Numerical Analysis and Mathematical Modelling ◽

10.1515/rnam-2021-0014 ◽

2021 ◽

Vol 36 (3) ◽

pp. 165-176

Author(s):

Kirill Nikitin ◽

Yuri Vassilevski ◽

Ruslan Yanbarisov

Keyword(s):

Free Surface ◽

Numerical Model ◽

Newtonian Fluid ◽

Viscoelastic Fluid ◽

Fluid Flows ◽

Numerical Results ◽

Implicit Scheme ◽

New Approach

Abstract This work presents a new approach to modelling of free surface non-Newtonian (viscoplastic or viscoelastic) fluid flows on dynamically adapted octree grids. The numerical model is based on the implicit formulation and the staggered location of governing variables. We verify our model by comparing simulations with experimental and numerical results known from the literature.

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Thermochemical Heat Storage in a Lab-Scale Indirectly Operated CaO/Ca(OH)2 Reactor—Numerical Modeling and Model Validation through Inverse Parameter Estimation

Applied Sciences ◽

10.3390/app11020682 ◽

2021 ◽

Vol 11 (2) ◽

pp. 682

Author(s):

Gabriele Seitz ◽

Farid Mohammadi ◽

Holger Class

Keyword(s):

Numerical Model ◽

Gas Flow ◽

Reaction Rate ◽

Heat Storage ◽

Bulk Material ◽

Fixed Bed ◽

Experimental Results ◽

Fixed Bed Reactor ◽

Thermochemical Heat Storage ◽

Speed Up

Calcium oxide/Calcium hydroxide can be utilized as a reaction system for thermochemical heat storage. It features a high storage capacity, is cheap, and does not involve major environmental concerns. Operationally, different fixed-bed reactor concepts can be distinguished; direct reactor are characterized by gas flow through the reactive bulk material, while in indirect reactors, the heat-carrying gas flow is separated from the bulk material. This study puts a focus on the indirectly operated fixed-bed reactor setup. The fluxes of the reaction fluid and the heat-carrying flow are decoupled in order to overcome limitations due to heat conduction in the reactive bulk material. The fixed bed represents a porous medium where Darcy-type flow conditions can be assumed. Here, a numerical model for such a reactor concept is presented, which has been implemented in the software DuMux. An attempt to calibrate and validate it with experimental results from the literature is discussed in detail. This allows for the identification of a deficient insulation of the experimental setup. Accordingly, heat-loss mechanisms are included in the model. However, it can be shown that heat losses alone are not sufficient to explain the experimental results. It is evident that another effect plays a role here. Using Bayesian inference, this effect is identified as the reaction rate decreasing with progressing conversion of reactive material. The calibrated model reveals that more heat is lost over the reactor surface than transported in the heat transfer channel, which causes a considerable speed-up of the discharge reaction. An observed deceleration of the reaction rate at progressed conversion is attributed to the presence of agglomerates of the bulk material in the fixed bed. This retardation is represented phenomenologically by mofifying the reaction kinetics. After the calibration, the model is validated with a second set of experimental results. To speed up the calculations for the calibration, the numerical model is replaced by a surrogate model based on Polynomial Chaos Expansion and Principal Component Analysis.

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Simulation of a Free Standing Riser Model and Validation With Experimental Results

Volume 6A: Pipeline and Riser Technology ◽

10.1115/omae2014-23309 ◽

2014 ◽

Author(s):

Marcio Yamamoto ◽

Sotaro Masanobu ◽

Satoru Takano ◽

Shigeo Kanada ◽

Tomo Fujiwara ◽

...

Keyword(s):

Numerical Simulation ◽

Numerical Analysis ◽

Previous Experiment ◽

Numerical Results ◽

Experimental Results ◽

Previous Article ◽

Scale Model ◽

Analysis Software ◽

Free Standing ◽

Reduced Scale

In this article, we present the numerical analysis of a Free Standing Riser. The numerical simulation was carried out using a commercial riser analysis software suit. The numerical model’s dimensions were the same of a 1/70 reduced scale model deployed in a previous experiment. The numerical results were compared with experimental results presented in a previous article [1]. Discussion about the model and limitations of the numerical analysis is included.

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