Finite Element Stress Analysis of Composite Sucker Rods

2003 ◽  
Vol 125 (4) ◽  
pp. 299-303 ◽  
Author(s):  
Eyassu Woldesenbet
Keyword(s):  
Finite Element ◽  
High Stress ◽  
Experimental Tests ◽  
Fatigue Loading ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Composite Rod ◽  
Rod System ◽  
Sucker Rod ◽  
2D And 3D

Analysis of polymer-matrix composite sucker rod systems using finite element methods is performed. Composite sucker rods used in oil production fail mainly due to fatigue loading. In majority of cases, the failure is in the region of the joint where the composite rod and the steel endfitting meet. 2D and 3D Finite Element Analysis and experimental tests are carried out in order to observe the stress distribution and to find the regions of stress concentrations inside the endfitting. The causes of failure of the composite sucker rods are identified as high transverse compressive stress caused by overloading that results in the crushing of the rod, and high stress concentrations present at the grooves of the endfitting that initiate premature cracks. Based on the result of this study, enhanced design of the composite sucker rod system can be accomplished.

Enhancement of Composite Sucker Rods for Use in the Oil Industry

2002 ◽  
Author(s):  
Eyassu Woldesenbet
Keyword(s):  
Finite Element ◽  
Fatigue Cracks ◽  
High Stress ◽  
Experimental Tests ◽  
Fatigue Loading ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Rod System ◽  
Sucker Rod ◽  
2D And 3D

Analysis of polymer-matrix composite sucker rod systems using finite element methods is performed. Composite sucker rods fail mainly due to fatigue loading. In majority of cases, the failure is in the region of the joint where the composite rod and the steel endfitting meet. 2D and 3D Finite Element Analysis and experimental tests are carried out in order to observe the stress distribution and to find the regions of stress concentrations inside the endfitting. The causes of fatigue failure of the composite sucker rods are identified. These are overloading of the rod causing high transverse compressive stress that results crushing of the rod, and high stress concentrations present at the grooves of the endfitting that initiate premature fatigue cracks. Based on the result of this study, enhanced design of the composite sucker rod system can be accomplished.

Testing of In-Plane Shear Properties under Fatigue Loading

1995 ◽  
Vol 14 (9) ◽  
pp. 965-987 ◽  
Author(s):  
Larry B. Lessard ◽  
Olivia P. Eilers ◽  
Mahmood M. Shokrieh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
High Stress ◽  
Fatigue Loading ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Plane Shear ◽  
Shear Properties ◽  
Notched Specimens

A two-dimensional finite element analysis is performed in order to analyze and improve the performance of the three-rail shear test specimen as prescribed by the ASTM Standard Guide for testing of in-plane shear properties of composite laminates [1]. Of main interest is the location of high-magnitude stresses in the matrix direction that affect the fatigue life of the specimen. Through finite element analysis, the optimal specimen configuration is determined by inserting slots in the positions at which there are stress concentrations. This has the effect of transferring the location of high stress away from critical areas, thus increasing the fatigue life of the specimen. The results are verified by three-rail shear tests performed for both standard un-notched and new notched specimens. The notched specimens show great improvement in both static strength and fatigue life.

Interfacial Delamination Near Solder Bumps and UBM in Flip-Chip Packages

2000 ◽  
Vol 123 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Yu Gu ◽  
Toshio Nakamura ◽  
William T. Chen ◽  
Brian Cotterell
Keyword(s):  
Finite Element ◽  
Energy Release ◽  
Flip Chip ◽  
Cell Model ◽  
High Stress ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Unstable Crack ◽  
Solder Bumps ◽  
Energy Release Rates

Using detailed finite element models, a fracture analysis of solder bumps and under bump metallurgy (UBM) in flip-chip packages is carried out. Our objective is to identify likely fracture modes and potential delamination sites at or near these microstructural components. In order to study flip-chips, whose dimension spans from sub-micron thickness UBM layers to several millimeters wide package, we have applied a multi-scale finite element analysis (MS-FEA) procedure. In this procedure, initially, deformation of whole thermally loaded package is analyzed. Then, the results are prescribed as the boundary conditions in a very detailed cell model, containing a single solder bump, to investigate micro-deformation surrounding UBM. Using the models with two different scales, accurate stress fields as well as fracture parameters of various interface cracks can be determined. The MS-FEA is ideally suited for the flip-chip packages since they contain many identical solder bumps. A cell model can be repeatedly used to probe stress and fracture behaviors at different locations. The computed results show high stress concentrations near the corners of solder bumps and UBM layers. Based on the energy release rate calculations, solder bumps located near the edge of chip are more likely to fail. However, our results also suggest possible delamination growth at solder bumps near the center of chip. In addition, we have observed increasing energy release rates for longer cracks, which implies a possibility of unstable crack growth.

Effects of Lingualized and Linear Occlusion Schemes on the Stress Distribution of an Implant Retained Overdenture Using Finite Element Analysis

2015 ◽  
Author(s):  
Md Abu Hasan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Alveolar Bone ◽  
High Stress ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Molar Teeth ◽  
The Right ◽  
Mandibular Overdenture

This study compares the effects of lingualized and linear occlusion schemes on the stress distribution of an implant retained mandibular overdenture (IRO) using finite element analysis (FEA). A high fidelity solid model of mandibular overdenture incorporating cusps and fossae of occlusal surface with two anterior implants in the canine regions and residual ridge support in the posterior region of the alveolar bone was modeled in SolidWorks and imported to ANSYS for stress analysis. The load was applied vertically to the central grooves and buccal cusp tips of the premolars and molar teeth for the lingualized and linear occlusion respectively. The loading magnitudes were 200 N on the premolars and 200 N on the molar teeth with multiple contact locations. The results show that the linear occlusion scheme generated higher stress in the implants and the prosthetic bar than the lingualized occlusion. The locations of high stress concentrations were the neck of the implants and the implant-prosthetic bar intersection for both the occlusion schemes. However, in the cortical bone lingualized occlusion loading scheme generated higher stress (max principal stress) than the linear one suggesting possibility of greater bone loss. The results of this study could be used to comprehend the stress distribution in the denture teeth, base, bone-implant interface and surrounding bone for the two occlusion concepts and may be of help to the clinicians in choosing the right scheme for the edentulous patients.

Experimental and Analytical Study for Collapse Characteristics of 45 Deg Cylinder-to-Cylinder Intersections

2014 ◽  
Author(s):  
Shunji Kataoka ◽  
Takuya Sato ◽  
Takuro Honda ◽  
Masashi Takeda ◽  
Toshiya Tanimoto
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Stress ◽  
Stress Triaxiality ◽  
Local Stress ◽  
Reduction Factor ◽  
Stress Concentrations ◽  
Strength Reduction Factor ◽  
Element Analysis ◽  
Inelastic Analysis

The 45-degree laterals are widely used in pressure vessel nozzles and piping branch connections. Though the pressure design is always important for the 45-degree laterals, it is not a simple work because it has severe stress concentrations, it is difficult to weld and inspect, and there are some discrepancy between a conventional design and design by linear and nonlinear finite element analysis. In previous papers, authors studied the characteristics of both 90 degree tee and 45 degree laterals using an inelastic finite element analysis based on simplified shell element models and proposed Collapse Strength Reduction Factor (CSRF) based on an inelastic analysis were compared. In this paper, results of the burst test of 45-degree lateral and 90 degree intersection were shown. The fracture surface of 45-degree lateral was different from that of 90-degree intersection. These experimental results are compared with the inelastic finite element analysis results focusing on the local stress and strain behaviors. It was found that the magnitude of the local strain affected the burst pressure. Consideration should be given on the local failure due to excessive plastic strain under high stress triaxiality for the design of the 45-degree lateral by inelastic analysis.

Effective Convergence Checks for Verifying Finite Element Stresses at Three-Dimensional Stress Concentrations

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
J. R. Beisheim ◽  
G. B. Sinclair ◽  
P. J. Roache
Keyword(s):  
Finite Element ◽  
Error Estimation ◽  
A Posteriori Error Estimates ◽  
Three Dimensional ◽  
Posteriori Error ◽  
Test Problems ◽  
A Posteriori ◽  
Stress Concentrations ◽  
Element Analysis ◽  
A Posteriori Error

Current computational capabilities facilitate the application of finite element analysis (FEA) to three-dimensional geometries to determine peak stresses. The three-dimensional stress concentrations so quantified are useful in practice provided the discretization error attending their determination with finite elements has been sufficiently controlled. Here, we provide some convergence checks and companion a posteriori error estimates that can be used to verify such three-dimensional FEA, and thus enable engineers to control discretization errors. These checks are designed to promote conservative error estimation. They are applied to twelve three-dimensional test problems that have exact solutions for their peak stresses. Error levels in the FEA of these peak stresses are classified in accordance with: 1–5%, satisfactory; 1/5–1%, good; and <1/5%, excellent. The present convergence checks result in 111 error assessments for the test problems. For these 111, errors are assessed as being at the same level as true exact errors on 99 occasions, one level worse for the other 12. Hence, stress error estimation that is largely reasonably accurate (89%), and otherwise modestly conservative (11%).

Effect of Defect on Elastic/Plastic and Creep Behavior of Bone: A Finite Element Study

2007 ◽  
Author(s):  
A. Ajdari ◽  
P. K. Canavan ◽  
H. Nayeb-Hashemi ◽  
G. Warner
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Trabecular Bone ◽  
Fatigue Loading ◽  
Dimensional Structure ◽  
Plastic Behavior ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Local Bone ◽  
Osteoporotic Vertebral Fractures

Three-dimensional structure of trabecular bone can be modeled by 2D or 3D Voronoi structure. The effect of missing cell walls on the mechanical properties of 2D honeycombs is a first step towards understanding the effect of local bone resorption due to osteoporosis. In patients with osteoporosis, bone mass is lost first by thinning and then by resorption of the trabeculae [1]. Furthermore, creep response is important to analyze in cellular solids when the temperature is high relative to the melting temperature. For trabecular bone, as body temperature (38 °C) is close to the denaturation temperature of collagen (52 °C), trabecular bone creeps [1]. Over the half of the osteoporotic vertebral fractures that occur in the elderly, are the result of the creep and fatigue loading associated with the activities of daily living [2]. The objective of this work is to understand the effect of missing walls and filled cells on elastic-plastic behavior of both regular hexagonal and non-periodic Voronoi structures using finite element analysis. The results show that the missing walls have a significant effect on overall elastic properties of the cellular structure. For both regular hexagonal and Voronoi materials, the yield strength of the structure decreased by more than 60% by introducing 10% missing walls. In contrast, the results indicate that filled cells have much less effect on the mechanical properties of both regular hexagonal and Voronoi materials.

Practical Procedures for Technical and Economic Investigation of Ship Structural Details

1981 ◽  
Vol 18 (01) ◽  
pp. 51-68
Author(s):  
Donald Liu ◽  
Abram Bakker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Analysis Techniques ◽  
Structural Problems ◽  
Analysis Technique ◽  
The Finite Element Analysis ◽  
Structural Details

Local structural problems in ships are generally the result of stress concentrations in structural details. The intent of this paper is to show that costly repairs and lay-up time of a vessel can often be prevented, if these problem areas are recognized and investigated in the design stages. Such investigations can be performed for minimal labor and computer costs by using finite-element analysis techniques. Practical procedures for analyzing structural details are presented, including discussions of the results and the analysis costs expended. It is shown that the application of the finite-element analysis technique can be economically employed in the investigation of structural details.

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