scholarly journals Finite Element Analysis and Parametric Study of Spudcan Footing Geometries Penetrating Clay Near Existing Footprints

2019 ◽  
Vol 7 (6) ◽  
pp. 175 ◽  
Author(s):  
Long Yu ◽  
Heyue Zhang ◽  
Jing Li ◽  
Xian Wang
Keyword(s):  
Bending Moment ◽  
Vertical Force ◽  
Leg Length ◽  
Element Analysis ◽  
Centrifuge Tests ◽  
Flat Base ◽  
Key Factor ◽  
The Stability ◽  
Resultant Forces ◽  
Theoretical Analyses

Most existing research on the stability of spudcans during reinstallation nearing footprints is based on centrifuge tests and theoretical analyses. In this study, the reinstallation of the flat base footing, fusimform spudcan footing and skirted footing near existing footprints are simulated using the coupled Eulerian–Lagrangian (CEL) method. The effects of footprints’ geometry, reinstallation eccentricity (0.25D–2.0D) and the roughness between spudcan and soil on the profiles of the vertical force, horizontal force and bending moment are discussed. The results show that the friction condition of the soil–footing interface has a significant effect on H profile but much less effect on M profile. The eccentricity ratio is a key factor to evaluate the H and M. The results show that the geometry shape of the footing also has certain effects on the V, H, and M profiles. The flat base footing gives the lowest peak value in H but largest in M, and the performances of the fusiform spudcan footing and the skirted footing are similar. From the view of the resultant forces, the skirted footing shows a certain potential in resisting the damage during reinstallation near existing footprints by comparing with commonly used fusiform spudcan footings. The bending moments on the leg–hull connection section of different leg length at certain offset distances are discussed.

scholarly journals Flexural-Torsional Vibration of Thin-Walled Beams Subjected to Combined Initial Axial Load and End Bending Moment: Application to the Design of Saw Tooth Blades

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Van Binh Phung ◽  
Anh Tuan Nguyen ◽  
Hoang Minh Dang ◽  
Thanh-Phong Dao ◽  
V. N. Duc
Keyword(s):  
Boundary Conditions ◽  
Axial Load ◽  
Stability Boundary ◽  
Bending Moment ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Rayleigh Method ◽  
Thin Walled ◽  
The Stability ◽  
Fixed End

The present paper analyzes the vibration issue of thin-walled beams under combined initial axial load and end moment in two cases with different boundary conditions, specifically the simply supported-end and the laterally fixed-end boundary conditions. The analytical expressions for the first natural frequencies of thin-walled beams were derived by two methods that are a method based on the existence of the roots theorem of differential equation systems and the Rayleigh method. In particular, the stability boundary of a beam can be determined directly from its first natural frequency expression. The analytical results are in good agreement with those from the finite element analysis software ANSYS Mechanical APDL. The research results obtained here are useful for those creating tooth blade designs of innovative frame saw machines.

Modeling of a Cartwheel Flexural Pivot

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Bi Shusheng ◽  
Zhao Hongzhe ◽  
Yu Jingjun
Keyword(s):  
Parametric Design ◽  
Bending Moment ◽  
Equivalent Model ◽  
Vertical Force ◽  
Element Analysis ◽  
Rotational Angle ◽  
Single Beam ◽  
Primary Motion ◽  
Center Shift ◽  
Parasitic Motion

A cartwheel flexural pivot has a small center shift as a function of loading and ease of manufacturing. This paper addresses an accurate model that includes the loading cases of a bending moment combined with both a horizontal force and a vertical force. First, a triangle flexural pivot is modeled as a single beam. Then, the model of cartwheel flexural pivot based on an equivalent model is developed by utilizing the results of the triangle pivot. The expressions for rotational displacement and center shift are derived to evaluate the primary motion and the parasitic motion; the maximum rotational angle is simply formulated to predicate the range of motion. Finally, the model is verified by finite element analysis. The relative error of the primary motion is less than 1.1% for various loading cases even if the rotational angle reaches ±20 deg, and the predicted errors for the two center shift components are less than 15.4% and 7.1%. The result shows that the model is accurate enough for designers to use for initial parametric design studies, such as for conceptual design.

scholarly journals BEHAVIOUR OF PARALLEL GIRDERS STABILISED WITH U‐FRAMES

2010 ◽  
Vol 16 (2) ◽  
pp. 197-202 ◽  
Author(s):  
Kuldeep Virdi ◽  
Walid Azzi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Buckling Analysis ◽  
Effective Length ◽  
Ultimate Capacity ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Element Analysis ◽  
Key Factor ◽  
The Stability

Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by cross‐bracing, reducing the effective length and thus increasing the ultimate capacity. U‐frames are an option often used to brace the girders, when designing through type of bridges and where overhead bracing is not practical. This paper investigates the effect of the U‐frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U‐frames. Results were extracted from finite element analysis, interpreted and conclusions drawn. Santrauka Projektuojant plienines sijas šoninis sukamasis klupumas yra svarbiausias veiksnys. Pastovumas gali būti padidintas skersiniais ryšiais, mažinančiais veikiamaji ilgi ir padidinančiais ribine galia. U‐formiai remai yra dažna priemone sijoms išramstyti, kai projektuojami tiltai, kuriu laikančiosios konstrukcijos yra virš pakloto, o viršutiniai ryšiai yra nepraktiški. Šiame straipsnyje nagrinejamas U‐formiu remu tarpatramio poveikis lygiagrečiuju siju pastovumui. Tikravertis klupumo skaičiavimas buvo atliktas esant keturiems skirtingiems U‐formiu remu tarpatramiams. Aptarti rezultatai, gauti apskaičiavus baigtinius elementus, padarytos išvados.

Analytical Modeling and Analysis of an Annulus-Shaped Flexural Pivot

2012 ◽  
Author(s):  
Yanbin Yao ◽  
Shusheng Bi ◽  
Hongzhe Zhao
Keyword(s):  
Analytical Modeling ◽  
Compliant Mechanisms ◽  
Bending Moment ◽  
Vertical Force ◽  
Rotational Stiffness ◽  
Element Analysis ◽  
Rotational Angle ◽  
Modeling And Analysis ◽  
The Finite Element Analysis ◽  
Constraint Model

Annulus-shaped flexural pivots (ASFP), composed of three or more identical leaves that are symmetrically arrayed in an annulus, can be used widely in compliant mechanisms for their excellent performances. This paper proposes the accurate load-rotation models of ASFP with three straight leaves, which include the load cases of bending moment combined with horizontal force and vertical force. Firstly, the load-rotation models of ASFP are derived based on the Beam Constraint Model (BCM). Then, the rotational stiffness and buckling characteristics are analyzed based on the derived models. Finally, the accuracy of the models is validated by the finite element analysis (FEA). The relative error of the load-rotation models is within 7% for various load cases even if the rotational angle reaches 0.07 (4°). The results show that the models are accurate enough to be used for initial parametric designing of ASFP.

Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains

2020 ◽  
pp. 136943322098170
Author(s):  
Michele Fabio Granata ◽  
Antonino Recupero
Keyword(s):  
Analytical Model ◽  
Prestressed Concrete ◽  
3D Analysis ◽  
Box Girders ◽  
Element Analysis ◽  
Cross Sectional ◽  
Interaction Domains ◽  
Global And Local ◽  
Resultant Forces

In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical model allows an easy and reliable reinforcement evaluation, in agreement with a more refined 3D analysis but with a reduced computational burden.

scholarly journals Inlay-Retained Dental Bridges—A Finite Element Analysis

2021 ◽  
Vol 11 (9) ◽  
pp. 3770
Author(s):  
Monica Tatarciuc ◽  
George Alexandru Maftei ◽  
Anca Vitalariu ◽  
Ionut Luchian ◽  
Ioana Martu ◽  
...  
Keyword(s):  
Finite Element ◽  
Young Patients ◽  
Maximum Pressure ◽  
Class Iii ◽  
Element Analysis ◽  
Dental Prostheses ◽  
Abutment Teeth ◽  
Fixed Dental Prostheses ◽  
Implant Therapy ◽  
The Stability

Inlay-retained dental bridges can be a viable minimally invasive alternative when patients reject the idea of implant therapy or conventional retained full-coverage fixed dental prostheses, which require more tooth preparation. Inlay-retained dental bridges are indicated in patients with good oral hygiene, low susceptibility to caries, and a minimum coronal tooth height of 5 mm. The present study aims to evaluate, through the finite element method (FEM), the stability of these types of dental bridges and the stresses on the supporting teeth, under the action of masticatory forces. The analysis revealed the distribution of the load on the bridge elements and on the retainers, highlighting the areas of maximum pressure. The results of our study demonstrate that the stress determined by the loading force cannot cause damage to the prosthetic device or to abutment teeth. Thus, it can be considered an optimal economical solution for treating class III Kennedy edentation in young patients or as a provisional pre-implant rehabilitation option. However, special attention must be paid to its design, especially in the connection area between the bridge elements, because the connectors and the retainers represent the weakest parts.

scholarly journals The effect of flexural–torsional buckling on the stability of timber members: a case study

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Osama A. B. Hassan
Keyword(s):  
Axial Compression ◽  
Bending Moment ◽  
List Type ◽  
Torsional Buckling ◽  
Solution Methods ◽  
Simplified Solution ◽  
The Stability ◽  
Flexural Torsional Buckling ◽  
Building Engineering

Abstract This study investigates the stability of timber members subjected to simultaneously acting axial compression and bending moment, with possible risk for torsional and flexural–torsional buckling. This situation can occur in laterally supported members where one side of the member is braced but the other side is unbraced. In this case, the free side will buckle out of plane while the braced side will be prevented from torsional and flexural–torsional buckling. This problem can be evident for long members in timber-frame structures, which are subjected to high axial compression combined with bending moments in which the member is not sufficiently braced at both sides. This study is based on the design requirement stated in Eurocode 5. Solution methods discussed in this paper can be of interest within the framework of structural and building Engineering practices and education in which the stability of structural elements is investigated. Article Highlights This case study investigates some design situations where the timber member is not sufficiently braced. In this case, a stability problem associated with combined torsional buckling and flexural buckling can arise. The study shows that the torsional and/or flexural–torsional buckling of timber members can be important to control in order to fulfil the criteria of the stability of the member according to Eurocode 5 and help the structural engineer to achieve safer designs. The study investigates also a simplified solution to check the effect of flexural torsional buckling of laterally braced timber members.

scholarly journals Sustainable Measures for Protection of Structures Against Earthquake Induced Liquefaction

2021 ◽  
Author(s):  
Gopal S. P. Madabhushi ◽  
Samy Garcia-Torres
Keyword(s):  
Soil Liquefaction ◽  
Excess Pore Pressure ◽  
Economic Losses ◽  
Element Analysis ◽  
Centrifuge Testing ◽  
Centrifuge Tests ◽  
Liquefiable Soil ◽  
Recent Earthquakes ◽  
Excess Pore Pressures ◽  
Excess Pore

AbstractSoil liquefaction can cause excessive damage to structures as witnessed in many recent earthquakes. The damage to small/medium-sized buildings can lead to excessive death toll and economic losses due to the sheer number of such buildings. Economic and sustainable methods to mitigate liquefaction damage to such buildings are therefore required. In this paper, the use of rubble brick as a material to construct earthquake drains is proposed. The efficacy of these drains to mitigate liquefaction effects was investigated, for the first time to include the effects of the foundations of a structure by using dynamic centrifuge testing. It will be shown that performance of the foundation in terms of its settlement was improved by the rubble brick drains by directly comparing them to the foundation on unimproved, liquefiable ground. The dynamic response in terms of horizontal accelerations and rotations will be compared. The dynamic centrifuge tests also yielded valuable information with regard to the excess pore pressure variation below the foundations both spatially and temporally. Differences of excess pore pressures between the improved and unimproved ground will be compared. Finally, a simplified 3D finite element analysis will be introduced that will be shown to satisfactorily capture the settlement characteristics of the foundation located on liquefiable soil with earthquake drains.

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

Release Profile of a Model Protein Drug Depending on the Stability of Microspheres Based on Polyelectrolyte Complex

2007 ◽  
Vol 342-343 ◽  
pp. 505-508
Author(s):  
Sung Won Kim ◽  
Yun Sik Nam ◽  
Yeon Jin Min ◽  
Jong Ho Kim ◽  
Kwang Meyong Kim ◽  
...  
Keyword(s):  
Polyelectrolyte Complex ◽  
Coating Layer ◽  
Great Influence ◽  
Release Profile ◽  
Core Material ◽  
Glycol Chitosan ◽  
The Core ◽  
Key Factor ◽  
Model Protein ◽  
The Stability

Stability and disintegration of natural polyelectrolyte complex microspheres for protein drugs delivery have been extensively investigated because of their great influence on the drug release patterns. In this study, we tested stability of microspheres with alginate (Alg) core layered by either chitosan (Chi) or glycol chitosan (GChi) by examining release profiles of fluorophorelabeled bovine serum albumin (BSA) and lysozyme (Lys) from the microspheres. While GChi shell was disintegrated quickly, Chi-shell microspheres showed good stability in PBS. Disintegration of the coated layer induced the core material instable. The results indicated that while the charges of the shell material provided additional diffusion barrier against the protein release, the key factor to hold the proteins inside the microspheres was the integrity of the outer coating layer.

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