Simulation of a Full-Scale CO2 Fracture Propagation Test

2018 ◽  
Author(s):  
Gaute Gruben ◽  
Stephane Dumoulin ◽  
Håkon Nordhagen ◽  
Morten Hammer ◽  
Svend T. Munkejord
Keyword(s):  
Fluid Dynamics ◽  
Numerical Model ◽  
Numerical Study ◽  
Crack Opening ◽  
Fracture Propagation ◽  
Full Scale ◽  
Coupling Scheme ◽  
Outer Diameter ◽  
Fe Model ◽  
Set Up

In this study, we present results from a numerical model of a full-scale fracture propagation test where the pipe sections are filled with impure, dense liquid-phase carbon dioxide. All the pipe sections had a 24″ outer diameter and a diameter/thickness ratio of ∼32. A near symmetric telescopic set-up with increasing toughness in the West and East directions was applied. Due to the near symmetric conditions in both set-up and results, only the East direction is modelled in the numerical study. The numerical model is built in the framework of the commercial finite element (FE) software LS-DYNA. The fluid dynamics is solved using an in-house computational fluid dynamics (CFD) solver which is coupled with the FE solver through a user-defined loading subroutine. As part of the coupling scheme, the FE model sends the crack opening profile to the CFD solver which returns the pressure from the fluid. The pipeline is discretized by shell elements, while the backfill is represented by the smoothed-particle hydrodynamics (SPH) method. The steel pipe is described by the J2 constitutive model and an energy-based fracture criterion, while the Mohr-Coulomb material model is applied for the backfill material. The CFD solver applies a one-dimensional homogeneous equilibrium model where the thermodynamic properties of the CO2 are represented by the Peng-Robinson equation-of-state (EOS). The results from the simulations in terms of crack velocity and pressure agree well with the experimental data for the low and medium toughness pipe sections, while a conservative prediction is given for the high-toughness section. Further work for strengthening the reliability of the model to predict the arrest vs. no-arrest boundary of a running ductile fracture is addressed.

scholarly journals A Simplified Finite Element Approach for Modeling of Multilayer Plates

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Taiyou Liu ◽  
Xinbo Ma ◽  
Pak Kin Wong ◽  
Jing Zhao ◽  
Zhengchao Xie ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Reference Value ◽  
Fe Model ◽  
Practical Applications ◽  
Aerospace Applications ◽  
Equivalent Bending Stiffness ◽  
Element Approach ◽  
Set Up ◽  
Transverse Response

The multilayer plate has a great potential for automotive and aerospace applications. However, the complexity in structure and calculation of the response impede the practical applications of multilayer plates. To solve this problem, this work proposes a new plate finite element and a simplified finite element (FE) model for multilayer plates. The proposed new plate finite element consists of the shear and extension strains in all layers. The multilayer structure with the proposed new plate finite element is regarded as a reference to calculate the reference value of the transverse response. The simplified FE model of multilayer plates is proposed based on the equivalent bending stiffness by curve fitting of the reference value of the transverse response. Numerical study shows that this approach can be used to set up the simplified FE model of multilayer plates.

scholarly journals A Hybrid BEM-CFD Virtual Blade Model to Predict Interactions between Tidal Stream Turbines under Wave Conditions

2020 ◽  
Vol 8 (12) ◽  
pp. 969
Author(s):  
Nicolo’ Lombardi ◽  
Stephanie Ordonez-Sanchez ◽  
Stefania Zanforlin ◽  
Cameron Johnstone
Keyword(s):  
Numerical Study ◽  
Experimental Tests ◽  
Full Scale ◽  
Small Scale ◽  
Ansys Fluent ◽  
Narrow Channels ◽  
Tidal Turbine ◽  
Performance Deterioration ◽  
Set Up ◽  
Blade Model

Tidal turbine array optimization is crucial for the further development of the marine sector. It has already been observed that tidal turbines within an array can be heavily affected by excessive aerodynamic interference, thus leading to performance deterioration. Small-scale experimental tests aimed at understanding the physical mechanisms of interaction and identifying optimal distances between machines can be found in the literature. However, often, the relatively narrow channels of laboratories imply high blockage ratios, which could affect the results, making them unreliable if extrapolated to full-scale cases. The main aim of this numerical study was to analyze the effects of the blockage caused by the laboratory channel walls in cases of current and also current surface waves. For this purpose, the performance predictions achieved for two turbines arranged in line for different lateral offsets in case of a typical laboratory scale were compared to the predictions obtained for a full scale, unconfined environment. The methodology consisted in the adoption a hybrid Blade Element Momentum–Computational Fluid Dynamics (BEM-CFD) approach, which was based on the Virtual Blade Model of ANSYS-Fluent. The results indicate that (1) the performance of a downstream turbine can increase up to 5% when this has a lateral separation of 1.5D from an upstream device in a full-scale environment compared to a misleading 15% calculated for the laboratory set-up, and (2) the relative fluctuations of power and thrust generated by waves are not significantly affected by the domain dimensions.

scholarly journals Experimental and Numerical Study of At-Rest Lateral Earth Pressure of Overconsolidated Sand

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Magdi El-Emam
Keyword(s):  
Numerical Model ◽  
Numerical Study ◽  
Retaining Wall ◽  
Earth Pressure ◽  
System A ◽  
Lateral Earth Pressure ◽  
Backfill Soil ◽  
Load Cells ◽  
Set Up ◽  
Wall System

The paper presents a one-meter-height rigid facing panel, supported rigidly at the top and bottom to simulate nonyielding retaining wall system. A set of load cells is used to measure the horizontal force at the top and bottom of the facing panel, which is converted to equivalent horizontal earth pressure acting at the back of the wall. Another set of load cells is used to measure the vertical load at the bottom of the wall facing, both at the toe and the heel. Uniformly graded sand was used as backfill soil. The measured wall responses were used to calibrate a numerical model that used to predict additional wall parameters. Results indicated that the measured horizontal earth force is about three times the value calculated by classical at-rest earth pressure theory. In addition, the location of the resultant earth force is located closer to 0.4 H, which is higher compared to the theoretical value of H/3. The numerical model developed was able to predict the earth pressure distribution over the wall height. Test set up, instrumentation, soil properties, different measured responses, and numerical model procedures and results are presented together with the implication of the current results to the practical work.

Experimental and Numerical Study on the Mode I Delamination Toughness of Z-Pinned Composite Laminates

2009 ◽  
Vol 417-418 ◽  
pp. 185-188 ◽  
Author(s):  
Xi Tao Zheng ◽  
Lin Hu Gou ◽  
Shu Yun Han ◽  
Fan Yang
Keyword(s):  
Composite Laminates ◽  
Numerical Study ◽  
Crack Opening ◽  
Mode I ◽  
Fe Model ◽  
Cantilever Beams ◽  
Critical Crack ◽  
Delamination Toughness ◽  
Double Cantilever Beams ◽  
Mode I Delamination

An experimental investigation was performed on mode I delamination of z-pinned double-cantilever-beams (DCB) and associate z-pin bridging mechanisms. Tests were performed with ten types of samples: (1) big-pin reinforced DCB (double-cantilever-beams) with three areal densities D=2.01%, 5.15%, 8.04%, respectively; (2) median-pin reinforced DCB with three areal densities D=0.85%, 2.17%, 3.40%; (3) small-pin reinforced DCB with three areal densities D=0.25%, 0.63%, 0.90% and (4) without pin reinforced DCB specimens. Delamination tests samples were prepared from unidirectional continuous carbon fibre/epoxy prepreg (T300/TDE86), made into 3 mm thick unidirectional laminates with and without a block of Z-pins in the crack path. Fracture testing was carried out under Mode I (standard DCB test). Experiments have shown that increases in debond resistance and ultimate strength depend on the material, size, density, location of the pins and the mechanisms of pin deformation. A finite element (FE) model is developed to investigate mode I delamination toughness of z-pin reinforced composite laminates. The z-pin pullout process is simulated by the deformation of a set of non-linear springs. A critical crack opening displacement (COD) criterion is used to simulate crack growth in a DCB made of z-pinned laminates. The toughness of the structure is quantified by the energy release rate, which is calculated using the contour integral method. The FE model is verified for both unpinned and z-pinned laminates. Predicted loading forces from FE analysis are compared to available test data. Good agreement is achieved. The numerical results indicate that z-pins can greatly increase the mode I delamination toughness of the composite laminates.

Numerical Study of Internal Fire Whirls in a Kitchen With Ceiling Vents

2013 ◽  
Author(s):  
W. K. Chow ◽  
N. Cai ◽  
Y. Gao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Study ◽  
Air Flow ◽  
Ventilation System ◽  
Necessary Condition ◽  
Temperature Distributions ◽  
Computational Fluid Dynamics Cfd ◽  
Fire Whirl ◽  
Set Up

The characteristics of flame rotation induced by a fire at the top of kitchen stove were studied numerically with Computational Fluid Dynamics (CFD). Four cases with different locations of fire sources and vents were set up; simulations of swirling air flow and temperature distributions in the kitchen room were carried out. Ventilation by ceiling vents was identified as the necessary condition for internal fire whirl. Recommendations on the design of kitchen ventilation system were made.

CO2SAFE-ARREST: A Full-Scale Burst Test Research Program for Carbon Dioxide Pipelines — Part 3: Dispersion Modelling

2018 ◽  
Author(s):  
Ajit Godbole ◽  
Xiong Liu ◽  
Guillaume Michal ◽  
Cheng Lu ◽  
Clara Huéscar Medina
Keyword(s):  
Carbon Dioxide ◽  
Fracture Propagation ◽  
Co2 Concentration ◽  
Test Site ◽  
Full Scale ◽  
Wind Speeds ◽  
Transient Nature ◽  
Set Up ◽  
Experimental Values ◽  
Carbon Dioxide Co2

The ‘CO2SafeArrest’ Joint Industry Project (JIP) was set up with the twin aims of: (1) investigating the fracture propagation and arrest characteristics of steel pipelines carrying anthropogenic carbon dioxide (CO2), and (2) investigating the dispersion of CO2 following its release into the atmosphere. The project involves two full-scale burst tests of 24-inch, X65 buried line pipes filled with a mixture of CO2 and nitrogen (N2). An overview of the CO2SafeArrest JIP and details of the fracture propagation and arrest investigation appear elsewhere in two companion papers. This paper presents the experimental investigation and computational fluid dynamics (CFD) simulations of the dispersion of CO2 following its explosive release into the atmosphere over the terrain at the test site in the first test. The setting up of the experiment and the CFD model is described in detail, including the representation of terrain topography and weather (wind) conditions, and the condition at the ‘inlet to the dispersion domain’. The modelling was carried out prior to the actual event, and simulated the dispersion of the CO2 cloud for different wind speeds and directions. This analysis confirmed that the sensor layout set up to obtain spot measurements CO2 concentration over the terrain at the site was adequate. The predicted and experimental values of CO2 concentration at the nominated locations over the duration of the dispersion were found to be in good agreement. Results of this study are expected to be used in developing a generalized model for the dispersion of CO2 and for estimating the ‘consequence distance’ for such events. It is noted that this distance is necessarily a function of time due to the highly transient nature of the event.

scholarly journals Pullout simulation of post installed chemically bonded anchors in UHPFRC

2018 ◽  
Vol 199 ◽  
pp. 11007
Author(s):  
Fabien Delhomme ◽  
Michael Brun
Keyword(s):  
Numerical Model ◽  
High Performance ◽  
Failure Modes ◽  
Numerical Study ◽  
Design Stage ◽  
Embedment Depth ◽  
Concrete Damage ◽  
Pullout Failure ◽  
Set Up ◽  
Good Agreement

An experimental and numerical study was completed in order to examine the mechanical behaviour of post-installed bonded anchors in ultra-high performance fibre reinforced concrete with a compressive strength higher than 130 MPa. The aim was to analyse the failure mechanisms in static pullout tests and to suggest a simple numerical model, which can be employed in a design stage, to reproduce the global behaviour of the anchor. The experimental observations show that a combined pullout and concrete cone failure occurred for an embedment depth of 40 mm and a steel rod failure for an embedment depth of 100 mm. The numerical model was set up using Abaqus software, by adopting the concrete damage plastic model and a surface-based cohesive behaviour for the interface concrete-anchor. The obtained failure modes and ultimate loads are in good agreement with experimental results. A minimum embedment depth of 50 mm was assessed to prevent a pullout failure of the anchor.

scholarly journals Fluid dynamics in a full-scale flat sheet MBR, an experimental and numerical study

2018 ◽  
Vol 78 (10) ◽  
pp. 2077-2087
Author(s):  
Lasse Sørensen ◽  
Thomas Ruby Bentzen
Keyword(s):  
Fluid Dynamics ◽  
Numerical Study ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Full Scale ◽  
Shear Stresses ◽  
Proper Understanding ◽  
Flat Sheet ◽  
Vof Model ◽  
Wall Shear

Abstract Fluid dynamics is used for fouling mitigation in membrane bioreactors (MBRs), whereby a proper understanding of the fluid dynamics is of great interest. The influence of fluid dynamics has led to the use of computational fluid dynamics for optimizing MBR systems. In this work, a model has been validated for flat sheet membranes, with use of the Eulerian multiphase method. The model is validated against a comparable setup where the liquid velocities are measured with a laser Doppler anemometer (LDA). Furthermore, the Eulerian multiphase approach is validated against the more numerical direct volume of fluid (VOF) approach with sludge properties for the liquid, resulting in an error between the models of less than 2% for the wall shear stresses. The VOF model further showed that the horizontal components contribute significantly to the total wall shear stresses. The model has been applied to a full-scale setup for studying the effect of deflecting membranes as deflections have been seen in production. Minimizing the deflection of the membrane sheets was crucial to achieve a good operating condition as a deflection of 2 mm in a setup with a gap of 7 mm decreased the wall shear stresses with as much as 40% on average on the specific membrane surface.

scholarly journals Dynamical Studies and Numerical Study of the Pandemic Fractional COVID-19 Using the Caputo–Fabrizio Derivative

2021 ◽  
Author(s):  
Amr Mahdy ◽  
Y. A. Amer ◽  
E. S. M. Youssef ◽  
W. Adel
Keyword(s):  
Fixed Point ◽  
Numerical Model ◽  
Numerical Study ◽  
Models Of Care ◽  
Care Model ◽  
Significant Information ◽  
Proposed Model ◽  
Novel Virus ◽  
Set Up ◽  
Entire Number

Abstract In this document, we are in the process of solving and describing the engineering meaning of one of the most dangerous models that affect humans and that spreads at a tremendous speed between people. A Caputo–Fabrizio type partial request numerical model for the fractional Coronavirus model is introduced. The principal properties of the model are investigated. The presence and uniqueness of the answer for the proposed partial Coronavirus model are given through the fixed-point speculation. The mathematical propagations for the model are obtained by using explicit boundary regards. The non-number solicitation subordinate gives continuously versatile and more significant information about the multifaceted idea of the components of the proposed fractional budgetary models of care model than the entire number solicitation models set up beforehand. This new proposed model better may help to better understand the dynamic of this novel virus and may help to better control it.

Experimental and numerical study of miscible Faraday instability

2009 ◽  
Vol 628 ◽  
pp. 43-55 ◽  
Author(s):  
F. ZOUESHTIAGH ◽  
S. AMIROUDINE ◽  
R. NARAYANAN
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Numerical Study ◽  
Stable Configuration ◽  
Rectangular Cell ◽  
Diffuse Interfaces ◽  
Faraday Instability ◽  
Miscible Liquids ◽  
Set Up ◽  
Nonlinear Numerical Model

A study of the Faraday instability of diffuse interfaces between pairs of miscible liquids of different densities, by means of experiments and by a nonlinear numerical model, is presented. The experimental set-up consisted of a rectangular cell in which the lighter liquid was placed above the denser one. The cell in this initially stable configuration was then subjected to vertical vibrations. The subsequent behaviour of the ‘interface’ between the two liquids was observed with a high-speed camera. This study shows that above a certain acceleration threshold an instability developed at the interface. The amplitude of the instability grew during the experiments which then led to the mixing of the liquids. The instability finally disappeared once the two liquids were fully mixed over a volume, considerably larger than the initial diffuse region. The results of a companion two-dimensional nonlinear numerical model that employs a finite volume method show very good agreement with the experiments. A physical explanation of the instability and the observations are advanced.

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