Stability analysis of soil–steel structures

1986 ◽  
Vol 13 (3) ◽  
pp. 319-326 ◽  
Author(s):  
Abdelrahim K. Dessouki ◽  
Gerard R. Monforton
Keyword(s):  
Plastic Hinge ◽  
High Stress ◽  
Steel Structures ◽  
Element Analysis ◽  
Interface Elements ◽  
State Highway ◽  
Quadrilateral Elements ◽  
Failure Loads ◽  
Soil Media ◽  
Strain Relationship

A finite element analysis to predict the instability of soil–steel structures is presented. For the steel segment, beam–column elements that accommodate geometric nonlinearity as well as plastic hinge formation are used. Constant and linear strain triangular and quadrilateral elements simulate the soil media in conjunction with spring-type interface elements. A hyperbolic stress–strain relationship models the soil remote from the conduit; an elastoplastic soil model is chosen for regions of high stress gradients above and around the conduit. The formulation is capable of following the initiation and propagation of failure in the soil and its effect on the conduit stability. Analytical failure loads are compared with experimental results and those predicted by the Ontario Highway Bridge Design Code (OHBDC) and the American Association of State Highway and Transportation Officials (AASHTO) specifications.

Finite element analysis of soil–steel structures

1983 ◽  
Vol 10 (2) ◽  
pp. 287-294 ◽  
Author(s):  
Hisham Hafez ◽  
George Abdel-Sayed
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computation Time ◽  
Steel Structures ◽  
Nonlinear Behaviour ◽  
Construction Simulation ◽  
Element Analysis ◽  
Interface Elements ◽  
State Highway ◽  
Strain Relationship

The present paper introduces some improvements in the finite element analysis of soil–steel structures. It applies two-noded spring-type interface elements and accounts for the compaction effects during construction simulation. The analyses are performed in increments using a hyperbolic stress–strain relationship for the nonlinear behaviour of the soil and take into account the shear or tension failure in the soil elements. Also, a combination of constant and compatible linear strain elements for soil is used to increase the accuracy of the analysis around the conduit while keeping the storage requirement and computation time for the numerical solution manageable.The analytical results show satisfactory agreement with those obtained experimentally. They also show that the American Association of State Highway and Transportation Officials (AASHTO) provisions overestimate the thrust due to live load and underestimate the thrust due to dead load. A better comparison is found with the Ontario Highway Bridge Design Code (OHBDC).

Étude par éléments finis du comportement à l'arrachement des ancrages injectés dans le roc

1990 ◽  
Vol 17 (2) ◽  
pp. 129-141 ◽  
Author(s):  
Brahim Benmokrane
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rock Mass ◽  
Field Tests ◽  
Element Analysis ◽  
Great Cost ◽  
Quadrilateral Elements ◽  
Failure Loads ◽  
Rock Anchors ◽  
Éléments Finis

The uplift behavior of grouted rock anchors is little known despite their increasing use within the last few years and during which their field of application has been greatly broadened. The behavior of anchors is usually controlled at great cost after installation through field tests. Generally, their design is based on experience and an engineer with lesser experience finds it extremely difficult to design one. Furthermore, present methods for dimensioning anchors generally result in oversizing the anchors' grouted length without a corresponding improvement in the safety factor. To provide a more fundamental approach to designing grouted rock anchors, a finite element analysis of the uplift behavior has been carried out. The results of the analysis using isoparametric quadrilateral elements with eight nodes are presented in this article. Results of failure loads and modes obtained from anchors installed in the field are well predicted by the model. Key words: rock mass, grouted anchor, cement grout, finite elements, uplift of an anchor.

scholarly journals Analysis of the Seismic Performance of Site-Bolted Beam to Column Connections in Modularized Prefabricated Steel Structures

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Xuechun Liu ◽  
Xiaoxiong Cui ◽  
Zhiwei Yang ◽  
Xinxin Zhan
Keyword(s):  
Plastic Deformation ◽  
Failure Mode ◽  
Seismic Performance ◽  
Plastic Hinge ◽  
Ductile Failure ◽  
Steel Structures ◽  
Hysteretic Behavior ◽  
Element Analysis ◽  
Skeleton Curve ◽  
Moderate Earthquake

This paper proposes a site-bolted connection that is suitable for modularized prefabricated steel structures. Excellent ductility is achieved by various structural measures. Six connection specimens with different parameters were subjected to quasi-static loading tests and finite element analysis (FEA) to determine the seismic performance of the proposed connection (e.g., hysteretic behavior, skeleton curve, ductility, and failure mode). The results of the tests and FEA showed that the connection underwent sufficient plastic deformation under cyclic loading and that its ultimate rotation angle could reach 0.09 rad. A clear plastic hinge formed on the beam before the connection failed, which suggests a ductile failure mode. The connection exhibited a wide hysteresis loop, which indicated good seismic performance. The results also showed that the connection does not slip under small earthquakes and could dissipate energy through slippage in the connection region under a moderate earthquake and through slippage in the connection region as well as plastic deformation at the beam end under a severe earthquake. The number of bolts was the main parameter that affected the seismic performance of the connection. The test and FEA results demonstrated that all six specimens had excellent seismic and ductile performance and an exceptional plastic rotation capacity.

EVALUATION OF PERFORMANCE OF BEAM COLUMN JOINT WITH REDUCED BEAM SECTION

2020 ◽  
Vol 9 (7) ◽  
pp. 1-10
Keyword(s):  
Cross Section ◽  
Progressive Collapse ◽  
Plastic Hinge ◽  
Beam Theory ◽  
Steel Structures ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Reduced Beam Section ◽  
Weak Beam ◽  
Beam Section

This study reviews mainly holistic design of PEB structure and comparison of behavior of reduced beam section at beam column sub assemblage. Commercial software based on finite element analysis is used for carrying out mathematical modeling and analysis. In recent construction work it is observed that during conditions like earthquake or cyclone connections fails resulting in to progressive collapse. Also it damages column resulting in failure of strong column weak beam theory. In present work after identifying problem structure is fused at connection by reducing beam cross section at location of connection. This is done by reducing cross section of beam in plan expected to result in shifting of plastic hinge from face of column. Reduced beam sections capacity is calculated by simple calculations and verifying them with moment curvature relationships at desired locations. This will concentrate on failure of fuse and not of connection during load application. Motivation of this study is to improve connection by fulfilling strong column and weak beam theory. This will motivate construction industry to utilize steel structures more often assuring repairing of structure as element failure will be dominant over failure of entire structure

Comparison on Stress Concentration Factors of Y/T Tubular Joints Between Numerical and Parametric Formulation Results

2005 ◽  
Author(s):  
Stefano Baratella ◽  
Dario Boote ◽  
Fabio Petrillo ◽  
Fabrizio Stefani
Keyword(s):  
Stress Concentration ◽  
Numerical Models ◽  
High Stress ◽  
Bending Moment ◽  
Steel Structures ◽  
Element Analysis ◽  
High Stress Concentration ◽  
Wide Range ◽  
Long Time ◽  
Stress Concentration Factors

The action of environmental loads such as wind and waves on offshore steel structures is locally emphasized by complex tubular connections, giving place to high stress concentration in correspondence of welds between pipe elements. This phenomenon, which heavily influences the fatigue life of the joint and, as a consequence, the operability of the whole platform, can be quantified by the Stress Concentration Factor. SCF can be determined either by experimental approach, numerical analysis and parametrical formulas developed mainly in the seventies-eighties by specialized authors like Kuang, Wordsworth, Smedley and Efthymiou. Even though these formulas, quoted as reference in the main world recognized rules, represented for a long time a useful tool for the designers of most projects, some discrepancies have been found to exist among them. A research has then been jointly promoted by University of Genoa and RINA Industry in order to compare the results of the parametric formulas with those coming from a finite element analysis performed on very refined numerical models made of brick elements. In this investigation attention has been focused on Y/T type joints; a wide range of configurations has been analysed by varying the most important parameters defining the geometry of the joint. Each configuration has been loaded by axial force and in/out of plane bending moment.

scholarly journals Direct plastic analysis of steel structures by flexibility-based element with initial imperfection

2018 ◽  
Author(s):  
Siu Lai Chan ◽  
Yaopeng Liu ◽  
G. P. Shu
Keyword(s):  
Plastic Hinge ◽  
High Stress ◽  
Three Dimensional ◽  
Initial Imperfection ◽  
Steel Structures ◽  
Direct Analysis ◽  
Second Order ◽  
Analysis And Design ◽  
Fiber Plastic ◽  
Plastic Analysis

Second-order direct analysis has been used in some regions for reliable analysis and design of steel structures. Currently, the stiffness-based element is widely used with accuracy improved by enforcing equilibrium along mid-span or “stations” along the member length in order to achieve equilibrium which is not guaranteed along an element. In this paper, a flexibility-based beam-column element considering member imperfection based on Hellinger-Reissner functional is developed and used for practical second-order direct analysis. This new element is a flexibility-based element with member initial bowing at the element level for direct analysis of three-dimensional frame analysis whereas previous flexibility-based elements assumed perfectly straight geometry for the element. The fiber plastic hinge approach is adopted to account for the distributed plasticity of a section. The new flexibility-based element performs excellently for modeling of members under high stress with material yielded as the conventional stiffness-based element has less accuracy when few elements are used in modeling a plastic member. This will significantly enhance accuracy and computational efficiency for direct plastic analysis which can then be more widely used in practical design. Several examples are employed to validate the accuracy and efficiency of the proposed element along this line of thought.

Fatigue Failure Analysis Using the Theory of Critical Distance

2011 ◽  
Vol 462-463 ◽  
pp. 663-667 ◽  
Author(s):  
Ruslizam Daud ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Al Emran Ismail
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Notch Root ◽  
High Stress ◽  
Critical Distance ◽  
Future Research ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Elastic Fracture

This paper explores the initial potential of theory of critical distance (TCD) which offers essential fatigue failure prediction in engineering components. The intention is to find the most appropriate TCD approach for a case of multiple stress concentration features in future research. The TCD is based on critical distance from notch root and represents the extension of linear elastic fracture mechanics (LEFM) principles. The approach is allowing possibilities for fatigue limit prediction based on localized stress concentration, which are characterized by high stress gradients. Using the finite element analysis (FEA) results and some data from literature, TCD applications is illustrated by a case study on engineering components in different geometrical notch radius. Further applications of TCD to various kinds of engineering problems are discussed.

scholarly journals Behavior of Offshore Pile in Calcareous Sand—Case Study

2021 ◽  
Vol 9 (8) ◽  
pp. 839
Author(s):  
Tarek N. Salem ◽  
Nadia M. Elkhawas ◽  
Ahmed M. Elnady
Keyword(s):  
Load Capacity ◽  
High Stress ◽  
Embedment Depth ◽  
Shear Stresses ◽  
Northern Coast ◽  
Compression Tests ◽  
Calcareous Sand ◽  
Element Analysis ◽  
Mixing Ratios

The erosion of limestone and calcarenite ridges that existed parallel to the Mediterranean shoreline forms the calcareous sand (CS) formation at the surface layer of Egypt's northern coast. The CS is often combined with broken shells which are considered geotechnically problematic due to their possible crushability and relatively high compressibility. In this research, CS samples collected from a site along the northern coast of Egypt are studied to better understand its behavior under normal and shear stresses. Reconstituted CS specimens with different ratios of broken shells (BS) are also investigated to study the effect of BS ratios on the soil mixture strength behavior. The strength is evaluated using laboratory direct-shear and one-dimensional compression tests (oedometer test). The CS specimens are not exposed to significant crushability even under relatively high-stress levels. In addition, a 3D finite element analysis (FEA) is presented in this paper to study the degradation offshore pile capacity in CS having different percentages of BS. The stress–strain results using oedometer tests are compared with a numerical model, and it gave identical matching for most cases. The effects of pile diameter and embedment depth parameters are then studied for the case study on the northern coast. Three different mixing ratios of CS and BS have been used, CS + 10% BS, CS + 30% BS, and CS + 50% BS, which resulted in a decrease of the ultimate vertical compression pile load capacity by 8.8%, 15%, and 16%, respectively.

scholarly journals Mechanical Integrity Assessment of Two-Side Etched Type Printed Circuit Heat Exchanger with Additional Elliptical Channel

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4711
Author(s):  
Armanto P. Simanjuntak ◽  
Jae-Young Lee
Keyword(s):  
Heat Exchanger ◽  
Stress Intensity ◽  
Maximum Stress ◽  
High Stress ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Printed Circuit ◽  
Mechanical Integrity ◽  
Finite Element Analysis Simulation ◽  
Maximum Stress Intensity

Printed circuit heat exchangers (PCHEs) are often subject to high pressure and temperature difference between the hot and cold channels which may cause a mechanical integrity problem. A conventional plate heat exchanger where the channel geometries are semi-circular and etched at one side of the stacked plate is a common design in the market. However, the sharp edge tip channel may cause high stress intensity. Double-faced type PCHE appears with the promising ability to reduce the stress intensity and stress concentration factor. Finite element analysis simulation has been conducted to observe the mechanical integrity of double-etched printed circuit heat exchanger design. The application of an additional ellipse upper channel helps the stress intensity decrease in the proposed PCHE channel. Five different cases were simulated in this study. The simulation shows that the stress intensity was reduced up to 24% with the increase in additional elliptical channel radius. Besides that, the horizontal offset channels configuration was also investigated in this study. Simulation results show that the maximum stress intensity of 2.5 mm offset configuration is 9% lower compared to the maximum stress intensity of 0 mm offset. This work proposed an additional elliptical upper channel with a 2.5 mm offset configuration as an optimum design.

Delamination of Laminate Plates

2014 ◽  
Vol 969 ◽  
pp. 97-100 ◽  
Author(s):  
Eva Kormaníková
Keyword(s):  
Finite Element Analysis ◽  
Mixed Mode ◽  
Plate Theory ◽  
Laminate Plate ◽  
Element Analysis ◽  
Interface Elements ◽  
First Order ◽  
Plate Elements ◽  
Interface Modeling ◽  
Shear Deformable

The paper deals with numerical modeling of delamination of laminate plate consists of unidirectional fiber reinforced layers. The methodology adopts the first-order shear laminate plate theory and fracture and contact mechanics. There are described sublaminate modeling and delamination modeling by the help of finite element analysis. With the interface modeling there is calculated the energy release rate along the lamination front. Numerical results are given for mixed mode delamination problems by implementing the method in a 2D finite analysis, which utilizes shear deformable plate elements and interface elements. Numerical example is done by the commercial ANSYS code.

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