scholarly journals Stability of Embankments Resting on Foundation Soils with a Weak Layer

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 86
Author(s):  
Maurizio Ziccarelli ◽  
Marco Rosone
Keyword(s):  
Safety Factor ◽  
Failure Mechanisms ◽  
Stress And Strain ◽  
The Finite Element Method ◽  
Safety Factors ◽  
Weak Layer ◽  
Overall Stability ◽  
Undrained Conditions ◽  
Stress And Strain Distribution ◽  
Very High

The presence of weak layers in geotechnical systems, including soil or rock masses, both natural and man-made, is more frequent than is normally believed. Weak layers can affect both failure mechanisms, in drained and in undrained conditions, as well as in static and seismic conditions, and the safety factor. In the present study, conducted numerically using the finite-element method (FEM) Plaxis 2D code, the influence of a horizontal thin weak layer on stress and strain distribution, on failure mechanisms and on the overall stability of an embankment was evaluated. The results obtained prove that when the weak layer is located at a significant depth from the foundation plane, the failure mechanisms are normally mixtilinear in shape because the shear strains largely develop on the weak layer. As a result, the safety factor highly decreases compared to the same case without a weak layer. Then, in the presence of weak layers, even embankments that, if founded on homogeneous soils, would have very high global safety factors (higher than 2) can become unstable, i.e., the safety factor can become unitary. So particular attention must be paid during detail ground investigations to finding thin weak layers.

scholarly journals The finite element method in the analysis of the stress and strain distribution in polyethylene elements of hip and knee joints endoprostheses

2019 ◽  
Vol 254 ◽  
pp. 02025
Author(s):  
Marcin Nabrdalik ◽  
Michał Sobociński
Keyword(s):  
Numerical Analysis ◽  
Finite Elements ◽  
Finite Elements Method ◽  
Knee Joints ◽  
Stress And Strain ◽  
The Finite Element Method ◽  
Artificial Joints ◽  
Material Fatigue ◽  
Weak Points ◽  
Stress And Strain Distribution

The paper presents the numerical analysis of stress and strain occurring in the most wearable parts of hip and knee joints endoprostheses. The complexity of the processes taking place in both, natural and artificial joints, makes it necessary to conduct the analysis on the 3D model based on already existing mathematical models. Most of the mechanical failures in alloplasty are caused by material fatigue. To cut down the risk of it, we can either increase the fatigue resistance of the material or decrease the load strain. It is extremelly important to indicate the areas where damage or premature wear may occur. The Finite Elements Method makes it possible to calculate the stress and strain in particular elements of the tested models. All presented numerical calculations define quality conclusions concerning the influence of some parameters of endoprostheses on the values of stress and strain that are formed in polyethylene parts of endoprotheses of hip and knee joints. The obtained results help to reveal “weak points” in examined models and thus, counteract the subsequent effects resulting from premature wear of endoprosthesis elements. The numerical analysis was performed basing on the finite elements method using Autodesk Simulation Mechanical 2017 software and the ADINA 7.5.1.

In-Plane Torsion Testing of Sheet Metal

1977 ◽  
Vol 19 (5) ◽  
pp. 213-220 ◽  
Author(s):  
R. Sowerby ◽  
Y. Tomita ◽  
J. L. Duncan
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Work Hardening ◽  
Finite Element Approximation ◽  
Stress And Strain ◽  
Element Approximation ◽  
The Finite Element Method ◽  
Hardening Material ◽  
Torsion Testing ◽  
Stress And Strain Distribution

In this paper, the ‘in-plane’ torsion testing of sheet metal is examined. The test itself was first proposed by Marciniak in order to ascertain the work hardening behaviour and fracture strain of sheet metals. In the original work, the analysis was based on the assumption that the material was rigid-work hardening. The present work attempts a more rigorous solution, assuming the material to be elastic-work hardening. A finite-element approximation is employed to calculate the stress and strain distribution across the sheet metal annulus at various stages in the deformation process. A comparison is made between the results from the finite-element method and those based on a rigid-work hardening material. For certain annulus geometries, excellent agreement is obtained between both sets of results.

A Study on Application of the Honeycomb Structure in the Large-Scaled Parts

2010 ◽  
Vol 426-427 ◽  
pp. 525-528
Author(s):  
F.H. Yin ◽  
H. Guo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain Distribution ◽  
Large Scale ◽  
Honeycomb Structure ◽  
Theoretical Research ◽  
Stress And Strain ◽  
The Finite Element Method ◽  
Simulation Results ◽  
Stress And Strain Distribution

The Application of honeycomb structure was studied for the large-scaled structures in the paper. Stress and strain distribution of different nephogram structure is gained by the finite element method (FEM), the simulation results are discussed. Based on above-mentioned analysis, the evaluation of distortion is accomplished. The research provides a useful reference for the design of large-scale structure; it has had a certain project practical value and theoretical research value academically.

A Mountain Highway Slope Stability Analysis

2012 ◽  
Vol 241-244 ◽  
pp. 1562-1566
Author(s):  
Ling Jun Zhong ◽  
Jie Liu ◽  
Dong Dong Yang ◽  
Li Feng ◽  
Hang Hang Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Slope Stability ◽  
Plastic Zone ◽  
Safety Factor ◽  
Slope Stability Analysis ◽  
Stress And Strain ◽  
The Finite Element Method ◽  
Element Method

Through the analysis of its geology and geomorphology to calculate the relevant parameters , some hidden problems of slope stability of the mountain road are calculated and analyzed by the finite element method for solving the slope stress and strain and the analysis results of plastic zone , which confirms the slope stability conclusions drawn by the safety factor .

Effect of pipe expansion on the redistribution of residual stresses after molding

2020 ◽  
Vol 10 (2) ◽  
pp. 122-126
Author(s):  
Nikolay A. Makhutov ◽  
◽  
Dmitry A. Neganov ◽  
Eugeny P. Studenov ◽  
◽  
...  
Keyword(s):  
Residual Stresses ◽  
Strain Distribution ◽  
Strain State ◽  
Stress And Strain ◽  
Cylindrical Shape ◽  
Pipe Material ◽  
Pipe Expansion ◽  
Calculation Results ◽  
Residual Deformations ◽  
Stress And Strain Distribution

In the factory, pipes for trunk oil and oil product pipelines are obtained by molding and welding. To ensure a cylindrical shape and reduce technological residual stresses, expansion technology is used. Pipe expansion causes a significant change in the values of residual deformations and stresses. The article presents both the calculation results and graphs regarding stress and strain distribution during bending of the stock and their redistribution after expansion. Based on the calculation results, the final total values of residual stresses and residual deformations caused by bending and expansion were stated to be important components of the stress-strain state observed in pipelines being operated under cyclic loading, as well as those used in assessing how degradation affects the ductility of the pipe material. These factors were concluded as being reasonably taken into account when performing verification calculations regarding long-running pipelines if, based on their diagnostics and analysis, their state does not meet modern strength requirements.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

Research of Stress Transfer Area and its Length Prediction of Single-Lap Adhesive Joint

2010 ◽  
Vol 129-131 ◽  
pp. 680-685
Author(s):  
Wei Ping Ouyang ◽  
Jian Ping Lin ◽  
Zhi Guo Lu
Keyword(s):  
Shear Stress ◽  
Adhesive Joint ◽  
Stress Transfer ◽  
Uniaxial Tensile ◽  
Stress And Strain ◽  
Significant Implication ◽  
Transfer Length ◽  
Fem Model ◽  
Strain Fracture ◽  
Stress And Strain Distribution

obtaining the law of stress and strain distribution of loaded adhesive joint has significant implication for joint design and its strength prediction. The dynamic FEM model of uniaxial tensile adhesive joint was established, in which strain fracture criteria is adopted. It can be observed from the FEM results that: lapped area of the joint bears shear stress primarily, the adherend areas located away from the lapped area bear steady tensile stress mainly and the adherend areas adjacent to lapped area endure tensile and shear stress simultaneously. Based on stress distribution characters, the joint was divided into three areas (lapped area, stress transfer area and uniform stress area) and an analytical model predicting the length of stress transfer areas was developed. DIC technology was applied to measure the whole field strain of the joint. It can be seen from the DIC results that the joints area division and the model of predicting the length of stress transfer length are feasible.

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