Analytical Models for Seabed Interaction Effects on Steel Catenary Riser in Touchdown Zone

2013 ◽  
Author(s):  
Kosar Rezazadeh ◽  
Yong Bai ◽  
Jiwei Tang ◽  
Liang Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
System Performance ◽  
Analytical Models ◽  
System Response ◽  
Complex Nature ◽  
Element Analysis ◽  
Steel Catenary Riser ◽  
Steel Catenary Risers ◽  
Seabed Interaction

The complex nature of seabed interaction with steel catenary risers (SCR) in touch down zone (TDZ) of SCRs makes serious difficulties for engineering design industry. Design must ensure that the curvature remains well within elastic limits, and that fatigue damage remains acceptable during the life. Analytical methods, despite it is limited in the accuracy because of idealizations of the system response, it offers a first step in assessing the system performance. The paper compares the results of different seabed interaction models with those from finite element analysis to evaluate the accuracy and consistency of solutions for initial design assumptions and fatigue assessment.

scholarly journals Finite Element Analysis of the Parthenon marble block- steel clamp system response under acceleration

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 155
Author(s):  
Zacharias Vangelatos ◽  
Michail Delagrammatikas ◽  
Olga Papadopoulou ◽  
Charalampos Titakis ◽  
Panayota Vassiliou
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Engineering ◽  
Conservation Status ◽  
Intrinsic Stress ◽  
System Response ◽  
Confined Space ◽  
Structural System ◽  
Element Analysis ◽  
Scientific Fields

<p class="Abstract">Finite element analysis is employed to investigate the mechanical behaviour and failure scenarios of the marble block–steel clamp ancient masonry system utilised in the Parthenon (Athens Acropolis) under static loading analysis. The input data for the model are acquired by the laboratory testing of early 20th century restoration steel clamps, such as through tensile strength measurements and metallography, as well as bibliographic sources from various scientific fields (i.e. material properties, archaeometry, restoration, structural engineering and geology). Two different embedding materials (Portland cement mortar and lead), used for the nesting of the clamps, are examined under bending or stretching, induced by acceleration forces. The conservation status of the materials is taken into account by employing an intrinsic stress, as is the case when corrosion products build up in a confined space. The aim of this work is to provide a tool for the assessment of the conservation potential of the marble blocks in parts of the monument that require specific attention. Simulation results indicate the resilience of the Parthenon’s structural system under most examined scenarios and highlight the importance of intrinsic stresses, the existence of which may lead to the fracture of the marble blocks under otherwise harmless loading conditions.</p>

Finite Element Analysis of Embedded Parts with Big-Diameter Reinforcing Bar under Shear Force

2010 ◽  
Vol 452-453 ◽  
pp. 509-512
Author(s):  
Yao Guo Zhu ◽  
Qing Xiang Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Force ◽  
Three Dimensional ◽  
Interaction Force ◽  
Internal Force ◽  
Shear Capacity ◽  
System Response ◽  
Element Analysis ◽  
Reinforcing Bar

Nowadays embedded parts which connect steel members with concrete structures have frequently emerged in civil engineering; however the existing design code for embedded parts cannot satisfy the increasing demand of engineering as it was derived from limited experiments. In the paper, a finite element study on embedded parts with big-diameter reinforcing bars under shear force is conducted. The aim of the study was to fully investigate the mechanical performances of embedded parts under shear force using a three-dimensional finite element analysis with the help of a commercial software ANSYS. Cross-section internal force of anchor bar, embedded part deformation, interaction force between anchor bar and concrete, and friction force were investigated in order to well know the system response. The results show that the shear capacity of embedded part obtained from finite element analysis is conservative.

A 2-legged XY parallel flexure motion stage with minimised parasitic rotation

2014 ◽  
Vol 228 (17) ◽  
pp. 3156-3169 ◽  
Author(s):  
Guangbo Hao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Design Approach ◽  
Analytical Models ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Motion Range ◽  
Cross Axis

XY compliant parallel manipulators (aka XY parallel flexure motion stages) have been used as diverse applications such as atomic force microscope scanners due to their proved advantages such as eliminated backlash, reduced friction, reduced number of parts and monolithic configuration. This paper presents an innovative stiffness centre based approach to design a decoupled 2-legged XY compliant parallel manipulator in order to better minimise the inherent parasitic rotation and have a more compact configuration. This innovative design approach makes all of the stiffness centres, associated with the passive prismatic (P) modules, overlap at a point that all of the applied input forces can go through. A monolithic compact and decoupled XY compliant parallel manipulator with minimised parasitic rotation is then proposed using the proposed design approach based on a 2-PP kinematically decoupled translational parallel manipulator. Its load–displacement and motion range equations are derived, and geometrical parameters are determined for a specified motion range. Finite element analysis comparisons are also implemented to verify the analytical models with analysis of the performance characteristics including primary stiffness, cross-axis coupling, parasitic rotation, input and output motion difference and actuator nonisolation effect. Compared with the existing XY compliant parallel manipulators obtained using 4-legged mirror-symmetric constraint arrangement, the proposed XY compliant parallel manipulators based on stiffness centre approach mainly benefits from fewer legs resulting in reduced size, simpler modelling as well as smaller lost motion. Compared with existing 2-legged designs with the conventional arrangement, the present design has smaller parasitic rotation, which has been proved from the finite element analysis results.

scholarly journals Biomechanical effects of Skeletally anchored Class III elastics on the maxillofacial complex: a 3D finite element analysis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Priyank Rai ◽  
Dhiraj Garg ◽  
Tulika Tripathi ◽  
Anup Kanase ◽  
Gayatri Ganesh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Models ◽  
Class Iii ◽  
Maxillary Expansion ◽  
Element Analysis ◽  
3D Finite Element ◽  
3D Finite Element Analysis ◽  
Skeletal Class ◽  
Computed Tomography Images

Abstract Background Although, the outcomes and changes in the maxillofacial complex after the application of intraoral bone anchored Class III elastics, have been reported by multiple clinical studies, there was no finite element study to assess and evaluate the stress pattern and displacement on maxillomandibular complex with bimaxillary anchorage. The present study aims to evaluate the biomechanical effects on maxillomandibular complex of Skeletally anchored Class III elastics with varying angulations using the 3D finite element analysis. Methodology Two 3-dimensional analytical models were developed using the Mimics 8.11 (Materialise: Leuven, Belgium) and ANSYS software Version 12.1 (ANSYS Inc, Canonsburg, PA, USA) from sequential computed tomography images taken from a Skeletal Class III subject. The models were meshed into 465,091 tetrahedral elements and 101,247 nodes. Intraoral mechanics for skeletally anchored maxillary protraction (I-SAMP) were applied on two models i.e. A and B (without and with maxillary expansion respectively) between miniplates on maxilla and mandible on both right and left sides with three different angulations of forces—10°, 20° and 30°). Results Although the craniomaxillary complex in both the models (A and B) displaced forward while demonstrating rotations in opposite directions, the displacements and rotations decreased gradually with the increase of the angle of load application from 10° to 30°. The mandible rotated clockwise in both the simulations, but the displacement of mandibular surface landmarks was higher in Simulation A. However, the antero-inferior displacement of the glenoid fossa was higher in Simulation B than in A. Conclusion Significant displacement of maxillofacial sutures and structures was witnessed with I-SAMP with maxillary expansion and Class III elastics for correction of Skeletal Class III with maxillary retrognathism. Thus, I-SAMP with maxillary expansion is a desired protocol for treatment of maxillary retrognathism. However, the prescribed angulation of the Class III elastics should be as low as possible to maximise the desired effects.

A Rational Approach to Automated Pre- and Post-Processing of Offshore Structure Global Strength Finite Element Analysis

2011 ◽  
Author(s):  
Zhiyong Yang ◽  
Otto DaSilva
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rational Approach ◽  
Strength Analysis ◽  
Complex Nature ◽  
Post Processing ◽  
Offshore Structure ◽  
Element Analysis ◽  
Finite Element Software ◽  
Global Strength

Offshore structure global strength analysis based on finite element plate model is a requirement for today’s classification societies and designers. Wave, wind, current loads have to be applied to the global strength model as a pre processing step to allow the analysis to take place. After the analysis, code checking must be performed to verify if the structure meets class or other requirements. Due to its complex nature, a large amount of engineering hours have to be spent for the pre and post processing. This is not only lengthy if performed manually or semi-automatically, but also mistake prone. General guidelines from classification societies exist, but general purpose commercial software is scarce and often still requires significant amount of engineering time to perform these tasks. This paper shows a rational approach to automate the pre and post processing of offshore structure global strength finite element analysis. Utilizing the FEMAP Application Program Interface (API), a complete automatic pre and post processing is implemented in one integrated program, Exmar Design Suite (EDS). The program will load the model from WAMIT generated wave pressure, apply internal pressure induced from motions to internal tanks, and also apply other environmental loads. After the finite element analysis, the program can execute strength code checking including yielding and buckling for the model. Both beam and stiffened plate panels can be identified using an automatic search algorithm, which is not a function available for general finite element software. The panels and beams are then checked against various common codes such as API/AISC/ABS/DNV. In addition, fatigue analysis can also be performed in either spectral or simplified approach. The benefits of automation are timesaving, accuracy and reliability. It also makes the check of whole model possible. Instead of relying more on “screening” or experience based structure check, engineers will have more confidence in the results by going through the whole model.

Development of A Three-Dimensional Membrane Element for the Finite Element Analysis of Tires

1991 ◽  
Vol 19 (1) ◽  
pp. 23-36 ◽  
Author(s):  
K. Ishihara
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computing Time ◽  
Three Dimensional ◽  
Complex Nature ◽  
Element Formulation ◽  
Membrane Element ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Modeling Strategy

Abstract A three-dimensional membrane element was developed for the finite element analysis of tires. In general, the three-dimensional finite element analysis of tires uses a lot of computing time because of the complex nature of the problem. Major sources of complexity are, for example, nonlinearities in kinematics, material properties, boundary conditions, and the multilayer structure which is inherent to the tire. One of the ways to overcome this situation can be in the modeling strategy. This paper describes an approach where the cord-rubber composite components of the tire are modeled by membrane elements. The number of nodes required in the tire model using this strategy is considerably reduced, without any loss of accuracy, compared with models in which only ordinary solid elements are used. The nonlinear finite element formulation, numerical examples, and a comparison of the results with those obtained from models using solid elements and experimental values are given in the paper.

scholarly journals Wrinkling of a stiff thin film bonded to a pre-strained, compliant substrate with finite thickness

2016 ◽  
Vol 472 (2192) ◽  
pp. 20160339 ◽  
Author(s):  
Yinji Ma ◽  
Yeguang Xue ◽  
Kyung-In Jang ◽  
Xue Feng ◽  
John A. Rogers ◽  
...  
Keyword(s):  
Thin Film ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Thickness ◽  
Analytical Models ◽  
Thickness Effect ◽  
Element Analysis ◽  
Compliant Substrate ◽  
Tensile Stiffness ◽  
The Finite Element Analysis

A stiff thin film bonded to a pre-strained, compliant substrate wrinkles into a sinusoidal form upon release of the pre-strain. Many analytical models developed for the critical pre-strain for wrinkling assume that the substrate is semi-infinite. This critical pre-strain is actually much smaller than that for a substrate with finite thickness (Ma Y et al. 2016 Adv. Funct. Mater. ( doi:10.1002/adfm.201600713 )). An analytical solution of the critical pre-strain for a system of a stiff film bonded to a pre-strained, finite-thickness, compliant substrate is obtained, and it agrees well with the finite-element analysis. The finite-thickness effect is significant when the substrate tensile stiffness cannot overwhelm the film tensile stiffness.

Measurements of Dielectric Properties for Intense Heating Applications

1996 ◽  
Vol 430 ◽  
Author(s):  
J. M. Borrego ◽  
K. A. Connor ◽  
J. Braunstein
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dielectric Properties ◽  
Wave Structure ◽  
Analytical Models ◽  
Dielectric Measurements ◽  
Element Analysis ◽  
Measurement Apparatus

AbstractDielectric measurements for frequencies in the tens of gigahertz are discussed. Interpretation of measurements obtained for mixtures are presented based on some simple analytical models and finite-element analysis of the wave structure in the measurement apparatus.

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