scholarly journals Utilizing a Simple Numerical Model in Discrete Element Analysis to Simulate Flow Time and Number Tests of Asphalt Mixes

2014 ◽  
Vol 11 (2) ◽  
pp. 39
Author(s):  
A.M.A. Abdo
Keyword(s):  
Numerical Models ◽  
Discrete Element ◽  
Flow Time ◽  
Two Dimensions ◽  
Particle Flow Code ◽  
Test Results ◽  
Element Analysis ◽  
Asphalt Mixes ◽  
User Friendly ◽  
Simple Numerical Model

During the past decades, many numerical models have been used to predict responses of asphalt mixes under different types of loading. Some of these models were simple due to practicality but overestimated the response of asphalt mixes. On the other hand, sophisticated but effective numerical models have been developed to address the shortcomings of the simpler models, and were used mostly in finite element analysis (FEA). However, these models were complicated and not user friendly. Recently, the approach of the discrete element method (DEM) was adopted. Unlike traditional FEA, DEM can simulate crack propagation by allowing the separation of elements in the simulated models. Understanding these challenges, this study was initiated to investigate the utilization of a simple visco-elasto-plastic model that had been used successfully in predicting deformation in asphalt mixes using the DEM embedded in Particle Flow Code in Two Dimensions (PFC2D) software simulations. Simulation results, when compared to flow time (FT) and number (FN) test results, showed that this model could simulate actual tests, thus predicting deformation of asphalt mixes using the DEM on a larger scale. 

Utilization of Modern Test Methods and Analyses for Pressure Vessel and Piping Gasket Design

2007 ◽  
Author(s):  
Rita J. Daugherty ◽  
Nancy J. Burkhart ◽  
Lonnie K. Bolin
Keyword(s):  
Pressure Vessel ◽  
State Of The Art ◽  
Test Methods ◽  
Test Results ◽  
Element Analysis ◽  
Vessel Sealing ◽  
Fea Modeling ◽  
Practical Information ◽  
Gasket Material ◽  
User Friendly

Modern, state-of-the-art equipment was recently introduced to the marketplace which allows gasket material manufacturers, fabricators, and end users to test gasket materials and analyze gasket behavior more accurately and precisely than ever before. Previous methods lacked the sophistication of this equipment, or conversely were so complex that the methods were not user friendly. Therefore, this research focuses on providing data from new equipment using newly adopted standards and applying this information to an operational bolted gasketed joint. In addition, the paper describes the test methods, summarizes and analyzes the test results, and discusses incorporating the data into Finite Element Analysis (FEA) modeling of a gasketed joint. The intent of the work is to provide practical information about the behavior of compressed non-asbestos type gaskets under varying conditions, examining this ubiquitous material and how it provides a seal, while elucidating the problems and pitfalls of pressure vessel sealing.

Application of the Discrete Element Method (DEM) to Evaluate Pipeline Response to Slope Movement

2016 ◽  
Author(s):  
Abdelfettah Fredj ◽  
Aaron Dinovitzer ◽  
Amir Hassannejadasl ◽  
Richard Gailing ◽  
Millan Sen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Discrete Element Method ◽  
Land Surface ◽  
Numerical Models ◽  
Discrete Element ◽  
Slope Movement ◽  
Ground Movement ◽  
Element Analysis ◽  
Element Method

The long linear nature of buried pipelines results in the risk of interaction with a range of geotechnical hazards including active slopes and land surface subsidence areas. Ground movement induced by these geotechnical hazards can subject a pipeline to axial, lateral flexural, and vertical flexural loading. The techniques to predict pipeline displacements, loads, stresses or strains are not well described in design standards or codes of practice. The results of geotechnical site observation, successive in-line inspection or pipeline instrumentation are used to infer pipeline displacement or strain accumulation and these techniques are often augmented through the application of finite element analysis. The practice of using finite element analysis for pipe-soil interaction has developed in recent years and is proving to be a useful tool in evaluating the pipeline behavior in response to ground movement. This paper considers pipeline response to geotechnical hazard-induced loading scenarios related to slope movement transverse to the pipeline axis. The details of the three-dimensional LS-DYNA-based BMT pipe-soil interaction model employing a discrete element method (DEM) are presented in this paper. The validation of the numerical models through comparison with medium-scale physical pipe-soil interaction tests are described to demonstrate that the models are capable of accurately simulating real world events. The models are further calibrated for nominal soil types to replicate the pipe-soil load displacement properties outlined in ASCE guideline recommendations by developing responses that closely agree with these results from the physical trials and engineering judgement. The utility of advanced pipe-soil interaction modelling in supporting strain-based pipeline integrity management or design is demonstrated by presenting the results of geotechnical hazard numerical simulations. These simulations are used to describe the sensitivity of pipeline displacements and strains to the demands of these geotechnical events and develop relationships between the geotechnical event key parameters and pipeline response.

scholarly journals Discrete Element Analysis of Indirect Tensile Fatigue Test of Asphalt Mixture

2019 ◽  
Vol 9 (2) ◽  
pp. 327 ◽  
Author(s):  
Xuelian Li ◽  
Xinchao Lv ◽  
Xueying Liu ◽  
Junhong Ye
Keyword(s):  
Fatigue Test ◽  
Asphalt Mixture ◽  
Discrete Element ◽  
Particle Flow Code ◽  
Displacement Curve ◽  
Distribution Characteristics ◽  
Load Curve ◽  
Element Analysis ◽  
Tensile Fatigue ◽  
Indirect Tensile

In order to investigate the damage to microstructure and some other micromechanical responses during a fatigue test on asphalt mixture, Particle Flow Code (PFC) was used to reconstruct a two-dimensional discrete element model of asphalt mixture, based on computed tomography (CT) images and image-processing techniques. The indirect tensile fatigue test of asphalt mixture was simulated with this image-based microstructural model, and verified in the laboratory. It was found that there were four stages during the fatigue failure: no crack, crack initiation, crack developing, and interconnected crack. Cracks mainly developed between the aggregate and asphalt mortar, near the loading axis. The corresponding stages of failure, the developing trend and the distribution characteristics of the cracks matched well with those in the laboratory test. Furthermore, the trends of both the time-load curve and time-displacement curve from the simulation test were also consistent with those from the experimental test. In short, the distribution characteristics of cracks and internal forces of asphalt mixture show that it is feasible to simulate the fatigue performance of the asphalt mixture by a discrete element method (DEM).

Section bending resistance of new Hybrid Double-I-Box Beams

2018 ◽  
Vol 21 (11) ◽  
pp. 1676-1695 ◽  
Author(s):  
MS Deepak ◽  
VM Shanthi
Keyword(s):  
Numerical Models ◽  
Torsional Rigidity ◽  
Local Buckling ◽  
Steel Structures ◽  
Test Results ◽  
Design Standards ◽  
Element Analysis ◽  
Box Beam ◽  
Bending Resistance ◽  
Moment Of Resistance

This article contains original works of testing and numerical validation on section bending resistance of new innovative built-up thin-walled metal Hybrid Double-I-Box Beam sections when subjected to local buckling. The cross section of Hybrid Double-I-Box Beam section is distinctive, which has advantages of both an ‘I’ section and a closed-box section. A total of 24 sections in three series that includes 8 homogeneous sections and 16 hybrid sections were tested under four-point bending. The varying parameters considered in the test specimens were as follows: first, hybrid parameter ratio, that is, yield strengths of flange steel to web steel (Φh = fyf/fyw); second, the ratio of breadth to the overall depth (B/D) of the section; and third, the flange thickness (tf). The moment-resisting capacity of these built-up sections are high due to the presence of more material at the flanges. The closed box-web portion provides higher torsional rigidity. From the test results, it was found that the hybrid sections have higher bending resistance capacity than the homogeneous sections, so technically gains more strength to weight. The increase in B/D ratio gained the increase in both major and minor axis bending resistance. The intermediate flange stiffener which alters the flange plate slenderness (λpf) had a significant effect on the local buckling resistance of the flange plate. Verification of numerical models followed by a parametric study was undertaken using ABAQUS finite element analysis software. The test results obtained were compared with the predicted design moment of resistance (Mc,Rd) as per Eurocode design standards EN 1993-1-3: 2006-Design of Steel Structures for Cold-Formed Steel Members and Sheeting and the adequacy is confirmed.

scholarly journals Discrete Element Analysis of High-Pressure Zones of Sea Ice on Vertical Structures

2021 ◽  
Vol 9 (3) ◽  
pp. 348
Author(s):  
Xue Long ◽  
Lu Liu ◽  
Shewen Liu ◽  
Shunying Ji
Keyword(s):  
High Pressure ◽  
Sea Ice ◽  
Failure Mode ◽  
Contact Area ◽  
Loading Rate ◽  
Discrete Element ◽  
Offshore Platforms ◽  
Marine Structures ◽  
Element Analysis ◽  
Ice Pressure

In cold regions, ice pressure poses a serious threat to the safe operation of ship hulls and fixed offshore platforms. In this study, a discrete element method (DEM) with bonded particles was adapted to simulate the generation and distribution of local ice pressures during the interaction between level ice and vertical structures. The strength and failure mode of simulated sea ice under uniaxial compression were consistent with the experimental results, which verifies the accuracy of the discrete element parameters. The crushing process of sea ice acting on the vertical structure simulated by the DEM was compared with the field test. The distribution of ice pressure on the contact surface was calculated, and it was found that the local ice pressure was much greater than the global ice pressure. The high-pressure zones in sea ice are mainly caused by its simultaneous destruction, and these zones are primarily distributed near the midline of the contact area of sea ice and the structure. The contact area and loading rate are the two main factors affecting the high-pressure zones. The maximum local and global ice pressures decrease with an increase in the contact area. The influence of the loading rate on the local ice pressure is caused by the change in the sea ice failure mode. When the loading rate is low, ductile failure of sea ice occurs, and the ice pressure increases with the increase in the loading rate. When the loading rate is high, brittle failure of sea ice occurs, and the ice pressure decreases with an increase in the loading rate. This DEM study of sea ice can reasonably predict the distribution of high-pressure zones on marine structures and provide a reference for the anti-ice performance design of marine structures.

scholarly journals Discrete element analysis of the punching behaviour of a secured drapery system: from laboratory characterization to idealized in situ conditions

2021 ◽  
Author(s):  
Antonio Pol ◽  
Fabio Gabrieli ◽  
Lorenzo Brezzi
Keyword(s):  
Mechanical Response ◽  
Steel Wire ◽  
Discrete Element ◽  
Wire Mesh ◽  
Steel Plates ◽  
Loading Conditions ◽  
Element Analysis ◽  
In Situ Conditions ◽  
Wire Meshes

AbstractIn this work, the mechanical response of a steel wire mesh panel against a punching load is studied starting from laboratory test conditions and extending the results to field applications. Wire meshes anchored with bolts and steel plates are extensively used in rockfall protection and slope stabilization. Their performances are evaluated through laboratory tests, but the mechanical constraints, the geometry and the loading conditions may strongly differ from the in situ conditions leading to incorrect estimations of the strength of the mesh. In this work, the discrete element method is used to simulate a wire mesh. After validation of the numerical mesh model against experimental data, the punching behaviour of an anchored mesh panel is investigated in order to obtain a more realistic characterization of the mesh mechanical response in field conditions. The dimension of the punching element, its position, the anchor plate size and the anchor spacing are varied, providing analytical relationships able to predict the panel response in different loading conditions. Furthermore, the mesh panel aspect ratio is analysed showing the existence of an optimal value. The results of this study can provide useful information to practitioners for designing secured drapery systems, as well as for the assessment of their safety conditions.

Finite Element Analysis of Reinforced Concrete Beams with Exterior FRP Shell

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Contact Interface ◽  
Accurate Calculation ◽  
Element Analysis

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.

Analysis of Heat Transfer through PVC Window Profile Reinforced with Ti6Al4V Alloy

2016 ◽  
Vol 687 ◽  
pp. 236-242 ◽  
Author(s):  
Piotr Lacki ◽  
Judyta Różycka ◽  
Marcin Rogoziński
Keyword(s):  
Heat Transfer ◽  
Titanium Alloy ◽  
Thermal Insulation ◽  
Numerical Models ◽  
Characteristic Temperature ◽  
Permanent Deformation ◽  
Transfer Coefficients ◽  
Element Analysis ◽  
Ti6al4v Titanium Alloy ◽  
Characteristic Points

This requires the use of additional reinforcement in order to prevent excessive or permanent deformation of PVC windows. In the paper particular attention was devoted to space located in a corrosive environment exposed to chemical agents. For this purpose, proposed to change the previously used steel profiles reinforcements made of Ti6Al4V titanium alloy corrosion-resistant in the air, at sea and many types of industrial atmosphere. Analysis of the thermal insulation properties of PVC windows with additional reinforcement of profile Ti6Al4V titanium alloy was performed. PVC window set in a layer of thermal insulation was analyzed. Research was conducted using Finite Element Analysis. Numerical models and thermal calculations were made in the program ADINA, assuming appropriate material parameters. The constant internal temperature of 20 ̊ and an outer-20 ̊ was assumed. The course of temperature distribution in baffle in time 24 hours and graphs of characteristic points was obtained. The time of in which followed the steady flow of heat, as well as the course of isotherm of characteristic temperature in the baffle was determined. On the basis of numerical analysis obtained vector distribution of heat flux q [W/m2] and was determined heat transfer coefficients U [W/m2K] for the whole window with titanium reinforcement . All results were compared with the model of PVC windows reinforced with steel profile.

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