scholarly journals The Influence of Base Layer Thickness in Flexible Pavements

2021 ◽  
Vol 11 (6) ◽  
pp. 7904-7909
Author(s):  
M. A. S. Hadi ◽  
M. H. Al-Sherrawi
Keyword(s):  
Vertical Displacement ◽  
Flexible Pavement ◽  
Base Layer ◽  
The Finite Element Method ◽  
Layer Depth ◽  
Analysis And Design ◽  
The Past ◽  
Stress Levels ◽  
Elastic Characteristics ◽  
Element Method

Flexible pavement design and analysis were carried out in the past with semi-experimental methods, using elastic characteristics of pavement layers. Due to the complex interferences between various layers and their time consumption, the traditional pavement analysis, and design methods were replaced with fast and powerful methods including the Finite Element Method (FEM) and the Discrete Element Method (DEM). FEM requires less computational power and is more appropriate for continuous environments. In this study, flexible pavement consisting of 5 layers (surface, binder, base, subbase, and subgrade) had been analyzed using FEM. The ABAQUS (6.14-2) software had been utilized to investigate the influence of the base layer depth on vertical stresses and displacements. Three different thicknesses were adopted (10, 20, and 30cm) with constant other pavement layer thicknesses. The results of this study showed that the stress levels at the top of the base layer increased by about 37% when the thickness of this layer increased from 10cm to 30cm, while the stress levels at the top of the subbase layer decreased by about 64%. When the base layer increased from 10 to 20, from 20 to 30, and from 10 to 30cm the vertical displacement decreased by 18%, 24%, and 37% respectively.

Renewed Inflation of Krafla Caldera, Iceland, since 2018: Sensitivity of Ground Deformation to lateral variation in Earth structure and architecture of the magmatic system explored with the Finite Element Method

2020 ◽  
Author(s):  
Chiara Lanzi ◽  
Vincent Drouin ◽  
Siqi Li ◽  
Freysteinn Sigmundsson ◽  
Halldor Geirsson ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Properties ◽  
Ground Deformation ◽  
Vertical Displacement ◽  
Magma Source ◽  
The Finite Element Method ◽  
Spherical Source ◽  
Horizontal Displacements ◽  
Element Method

<p>The Krafla volcanic area in Northern Volcanic Zone of Iceland was characterized by deflation starting in 1989, suggesting a general pressure decrease and/or volume contraction at depth, which then exponentially decayed until having no significant deformation since around 2000.  In summer 2018, the volcano behaviour changed to inflation as observed both by Global Navigation Satellite System (GNSS) geodesy  and Sentinel-1 satellite radar interferometry (InSAR). Inflation since 2018 occurs at a rate of 10-14 mm/yr, centered in the middle of the caldera. No significant change in seismicity has occurred in the area in 2018, but seismic moment release ocurrs at a higher rate since middle 2019. Gravity stations in the area were remeasured in November 2019 for allowing comparison with earlier observations, and for providing reference for later studies. Initial modelling of the geodetic data is carried out assuming that the deformation is caused by a spherical source of pressure in an uniform elastic half-space. The result suggests that the deformation can be broadly explained by a single source of magma inflow at depth around 3.9-7.5 km, with the best-fit value around 4-4.5 km. We also apply the Finite Element Method (FEM) to additionally consider modification of the deformation field caused by Earth’s elastic heterogeneities and the uncertain geometry and  depth of the magma source. A set of FEM models are built with the COMSOL Multiphysics software in a 50x50 km domain where we test three different geometries of the source: a spherical source (radius 1000 km), a prolate ellipsoid,  and an oblate ellipsoid (sill-like) source, at 2.5, 4.0 and 5.5 km of depth. We also build a model to test how the vertical and horizontal displacements may be influenced by different elastic properties (e.g. Young’s modulus; about an order of magnitude different within a caldera boundary) for these sources. The results show that lateral variations in material properites can have a significant influence on ground deformation. Low-value Young’s inside caldera boundaries compared to higher values outside caldera boundaries will in particular influence the vertical displacement: the vertical displacement is about half of of what it is the original modelling.  The ratio of vertical to horizontal displacements will thus also be modified. This can in turn influence the inferred magma source geometry as it depends on the displacement ratios. The outcome of our study will provide better constrain for the elastic properties in Krafla area, and help understand the magma intrusion rate in the area.</p>

Dynamic Analysis of Cold-Rolling Process Using the Finite-Element Method

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Sajan Kapil ◽  
Peter Eberhard ◽  
Santosha K. Dwivedy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Governing Equation ◽  
Degrees Of Freedom ◽  
Vertical Displacement ◽  
Work Roll ◽  
Equation Of Motion ◽  
Element Formulation ◽  
The Finite Element Method ◽  
Element Method

In this work, the finite-element method (FEM) is used to develop the governing equation of motion of the working roll of a four-high rolling mill and to study its vibration due to different process parameters. The working roll is modeled as an Euler Bernoulli beam by taking beam elements with vertical displacement and slope as the nodal degrees-of-freedom in the finite-element formulation. The bearings at the ends of the working rolls are modeled using spring elements. To calculate the forces acting on the working roll, the interaction between the working roll and the backup roll is modeled by using the work roll submodel, and the interaction between the working roll and the sheet is modeled by using the roll bite submodel (Lin et al., 2003, “On Characteristics and Mechanism of Rolling Instability and Chatter,” ASME J. Manuf. Sci. Eng., 125(4), pp. 778–786). Nodal displacements and velocities are obtained by using the Newmark Beta method after solving the governing equation of motion of the working roll. The transient and steady-state variation of roll gap, exit thickness profile, exit stress, and sheet force along the length of the strip have been found for different bearing stiffnesses and widths of the strip. By using this model, one can predict the shape of the outcoming strip profile and exit stress variation which will be useful to avoid many defects, such as edge buckling or center buckling in rolling processes.

scholarly journals Analysis Beam-Column Cellular By Finite Element Method

10.29007/s1rd ◽  
2022 ◽  
Author(s):  
Minh Duc Nguyen ◽  
Thai Hien Nguyen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Web Openings ◽  
Telephone Networks ◽  
The Past ◽  
Post Buckling ◽  
The Subject ◽  
Element Method

Nowadays in the construction of modem buildings, it is necessary to accommodate pipes and ducts necessary services, such as air conditioning, water supply, sewerage, electricity, computer networks, and telephone networks. Cellular members – steel I‐ shaped structural elements with circular web openings at regular intervals – have been used as beams for more than 35 years now. Although in the past already a large deal of research was performed into the subject of the behavior of cellular beams, almost no attention has been paid to the application of cellular members as columns. The column will be analyzed using the finite element method to calculate the critical load and compared with the Eurocode3 standard, web-post buckling, and frame using cellular member by FEM.

Application Analysis of Finite Element Method in the Calculation of Foundation Pit Excavation

2014 ◽  
Vol 898 ◽  
pp. 395-398
Author(s):  
Shan Shan Xu ◽  
Wei Wei Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
The Finite Element Method ◽  
Foundation Pit ◽  
Finite Element Software ◽  
The Past ◽  
Application Analysis ◽  
Practical Engineering ◽  
Contact Relation ◽  
Element Method

This paper introduces the finite element method theory of foundation pit excavation, on the basis of summarizing the past experience, combined with the mechanical property of engineered soil, by using a variety of contact relation provided by the finite element software, select the appropriate unit to simulate the foundation pit excavation model scientific and reasonable. It has a very important guiding significance in practical engineering.

Sign in / Sign up

Export Citation Format

Share Document