scholarly journals Design Optimization for the Thin-Walled Joint Thread of a Coring Tool Used for Deep Boreholes

2020 ◽  
Vol 10 (8) ◽  
pp. 2669 ◽  
Author(s):  
Yu Wang ◽  
Chengyuan Qian ◽  
Lingrong Kong ◽  
Qin Zhou ◽  
Jinwu Gong
Keyword(s):  
Stress Distribution ◽  
Large Diameter ◽  
High Stress ◽  
Three Dimensional ◽  
Outer Diameter ◽  
Stress Concentrations ◽  
Core Drilling ◽  
Drilling Tools ◽  
Deep Boreholes ◽  
Thread Structure

Threaded joints are key components of core drilling tools. Currently, core drilling tools generally adopt the thread structure designed by the API Spec 7-1 standard. However, fractures easily occur in this thread structure due to high stress concentrations, resulting in downhole accidents. In this paper, according to the needs of large-diameter core drilling, a core barrel joint was designed with an outer diameter of Φ135 mm and a trapezoidal thread profile. Subsequently, a three-dimensional simulation model of the joint was established. The influence of the external load, connection state and thread structure on the stress distribution in the joint was analyzed through simulations, from which the optimal thread structure was determined. Finally, a connection test was carried out on the threaded joint. The stress distribution in the joint thread was indirectly studied by analyzing gas leaks (i.e., the sealing effect) under axial tension. According to the test data and the simulation results, the final joint thread structure was optimized, which lays a good foundation for the design of a core barrel.

A New Shaft Coupling Design for a High-Speed Rotor Wheel

1995 ◽  
Author(s):  
Tibor Kiss ◽  
Wing-Fai Ng ◽  
Larry D. Mitchell
Keyword(s):  
High Speed ◽  
High Stress ◽  
Critical Issue ◽  
Working Environment ◽  
Outer Diameter ◽  
Stress Concentrations ◽  
Coupling Region ◽  
Rotor Wheel ◽  
High Stress Concentration ◽  
Safety Margins

Abstract A high-speed rotor wheel for a wind-tunnel experiment has been designed. The rotor wheel was similar to one in an axial turbine, except that slender bars replaced the blades. The main parameters of the rotor wheel were an outer diameter of 10“, a maximum rotational speed of 24,000 RPM and a maximum transferred torque of 64 lb-ft. Due to the working environment, the rotor had to be designed with high safety margins. The coupling of the rotor wheel with the shaft was found to be the most critical issue, because of the high stress concentration factors associated with the conventional coupling methods. The efforts to reduce the stress concentrations resulted in an advanced coupling design which is the main subject of the present paper. This new design was a special key coupling in which six dowel pins were used for keys. The key slots, now pin-grooves, were placed in bosses on the inner surface of the hub. The hub of the rotor wheel was relatively long, which allowed for applying the coupling near the end faces of the hub, that is, away from the highly loaded centerplane. The long hub resulted in low radial expansion in the coupling region. Therefore, solid contact between the shaft and the hub could be maintained for all working conditions. To develop and verify the design ideas, stress and deformation analyses were carried out using quasi-two-dimensional finite element models. An overall safety factor of 3.7 resulted. The rotor has been built and successfully accelerated over the design speed in a spin test pit.

Effects of Weld Geometry Size on the Pressure-Bearing Capacity of an API X80 LSAW Pipe

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Gui-ying Qiao ◽  
Yu-meng Liu ◽  
Jun-si Wang ◽  
Fu-ren Xiao
Keyword(s):  
Stress Distribution ◽  
Weld Joint ◽  
Large Diameter ◽  
Three Dimensional ◽  
3D Models ◽  
Welding Parameter ◽  
Weld Geometry ◽  
Transmission Pipeline ◽  
2D And 3D ◽  
Submerged Arc

Abstract The weld joint is the weakest zone of a longitudinal-seam submerged arc welded (LSAW) pipe, which has great effects on its in-service properties and safety. The weld geometry and shape of the weld joint are important factors that affect the mechanical properties of the pipe. In this work, two-dimensional (2D) and three-dimensional (3D) finite element models (FEMs) of a large-diameter, heavy-wall API X80 LSAW pipe were established, and the stress distribution of the pipe was calculated to simulate the in-service gas transmission pipeline. Results showed that the stress distribution calculated by both 2D and 3D models are similar. Consequently, the effects of weld geometry, softening of heat affected zone (HAZ), and strength matching of the weld joint on bearing pressure capability of the pipe were analyzed, and the results showed that the bearing pressure capability of the pipe can be improved by controlling these parameters. These results are beneficial in providing references for welding parameter design and improved properties of the X80 LSAW pipe.

Three-Dimensional Stress Analysis and Configuration Optimization of Cross Wavy Primary Surface Recuperator for Microturbine System

2008 ◽  
Author(s):  
D. J. Zhang ◽  
M. Zeng ◽  
Q. W. Wang
Keyword(s):  
High Temperature ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Parametric Design ◽  
Minimum Principle ◽  
High Stress ◽  
Three Dimensional ◽  
Automatic Generation ◽  
Temperature And Pressure ◽  
Air Passage

Recuperator in a microturbine system, which has to work under a high temperature and high pressure condition, is a key component to improve the electricity efficiency of the system. High temperature and pressure may cause high stress inside the Cross-Wavy Primary Surface (CWPS) sheet, and it is essential to analyze the stress distribution to ensure the security while the recuperator is working. In this paper the combined thermomechanical design of a CWPS recuperator for a 100kW microturbine system is presented. With the ANSYS Parametric Design Language (APDL), calculation procedures for heat transfer and stress analysis are combined in order to perform a reliable strength prediction of the recuperator. A program has been generated, which allows the automatic generation of the numerical model, the mesh and the boundary conditions. Also with the energy minimum principle, an optimal configuration of the air and gas passages is obtained. The results show that the material of the primary sheet (0Cr18Ni11Nb) is reliable. The stress distribution changes with the different configuration of the passages. Since the air pressure is much higher than that of the exhaust gas, the configuration of the primary sheet is much better when the sectional area of the gas passage is larger than that of the air passage. If the pitch of the sheet is maintained at 2mm, the best configuration is obtained when the dimension of passage is at r = 0.35–0.42mm, R = 0.55–0.48mm.

On the Structural Response of a Flexible Pipe With Damaged Tensile Armor Wires

2011 ◽  
Author(s):  
Jose´ Renato M. de Sousa ◽  
George C. Campello ◽  
Antoˆnio Fernando B. Bueno ◽  
Eduardo Vardaro ◽  
Gilberto B. Ellwanger ◽  
...  
Keyword(s):  
Mechanical Response ◽  
High Stress ◽  
Three Dimensional ◽  
Structural Response ◽  
Experimental Tests ◽  
Element Model ◽  
Axial Stiffness ◽  
Stress Concentrations ◽  
Flexible Pipe ◽  
Flexible Pipes

This paper studies the structural response of a 6.0″ flexible pipe under pure tension considering two different situations: the pipe is intact or has five wires broken in its outer tensile armor. A three-dimensional nonlinear finite element model devoted to analyze the local mechanical response of flexible pipes is employed in this study. This model is capable of representing each wire of the tensile armors and, therefore, localized defects, including total rupture, may be adequately represented. Results from experimental tests are also presented in order to validate the theoretical estimations. The theoretical and experimental results indicate that the imposed damage reduced the axial stiffness of the pipe. High stress concentrations in the wires near the damaged ones were also observed and, furthermore, the stresses in the inner carcass and the pressure armor are affected by the imposed damage, but, on the other hand, the normal stresses in the wires of the inner tensile armor are not.

scholarly journals A Comparative Three-Dimensional Finite Element Study of Two Space Regainers in the Mixed Dentition Stage

2020 ◽  
Vol 14 (01) ◽  
pp. 107-114
Author(s):  
Mohamed Ahmed Abdel Hakim ◽  
Nagwa Mohamed Ali Khatab ◽  
Kareem Maher Gaber Mohamed ◽  
Ahmad Abdel Hamid Elheeny
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
The Other ◽  
Mixed Dentition ◽  
Von Mises Stress ◽  
Stress Concentrations ◽  
Permanent Molar ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract Objectives This study aims to compare the stress distribution and displacement that resulted from the use of a Gerber space regainer and sagittal distalizer using three-dimensional finite element analysis. Materials and Methods Three-dimensional simulated models of the appliances were developed using a software. The forces applied by the two appliances were 3N (tipping) and 15N (bodily), respectively. Displacement and von Mises stress on the compact and cancellous bone, periodontal ligament (PDL), crowns of the mandibular first, second permanent molars, and deciduous canines were calculated. Stress distribution and displacement values were measured via linear static analysis. Results Gerber space regainer showed greater displacement than that produced by the sagittal distalizer at the first permanent molar. However, such displacement was less at the other tested points when compared with that delivered by sagittal distalizer. The stresses created by Gerber appliance were higher in the crown and PDL of the deciduous canine than the crown of the first permanent molar crown. Conclusions Gerber appliance generates more distal force and less stress concentration on the crown of the mandibular first permanent molar than that created by the sagittal distalizer. On the other hand, stress concentrations produced by Gerber space regainer are found to be more on the crown and PDL of the deciduous canine. Therefore, it can be concluded that the use of Gerber appliance needs more anchorage.

The Coning Designs for the Micro Forming of a Surgical Slit Knife Using FE Simulations

2012 ◽  
Vol 197 ◽  
pp. 745-749
Author(s):  
Xin Wu Ma ◽  
Guo Qun Zhao ◽  
Wen Juan Li
Keyword(s):  
Stress Distribution ◽  
High Stress ◽  
Three Dimensional ◽  
Die Geometry ◽  
Strength Limit ◽  
Fe Simulations ◽  
Die Stress ◽  
Die Material ◽  
Forming Defects ◽  
Very High

This paper deals with problems in the coining process for manufacturing surgical slit knife using two-dimensional (2D) and three-dimensional (3D) finite element (FE) simulations. The FE simulations are performed to investigate the material flow, and especially stress distribution on the coining dies. The main objective of this paper is to study the feasibility of a coining process for manufacturing a given geometry of surgical slit knife without forming defects and die failure. Very high stress distribution on the coining dies is found by 2D simulations of the coining process that exceeds the strength limit of the die material. The optimum preform and preforming die geometry are determined by FE simulations in order to reduce the die stress. 3D simulations of the preforming and coining processes are conducted with the optimal design to show that the geometry of the product can be achieved without defects by the coining process.

scholarly journals Three-Dimensional Finite Element Analysis to Evaluate Stress Distribution in Tooth and Implant-Supported Fixed Partial Denture–An In Vitro Study

2020 ◽  
Vol 8 (03) ◽  
pp. 084-091
Author(s):  
Himani Jain ◽  
Tarun Kalra ◽  
Manjit Kumar ◽  
Ajay Bansal ◽  
Deepti Jain
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Alveolar Bone ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Three Dimensional Finite Element

Abstract Introduction This study was undertaken to assess the influence of different superstructure materials, when subjected to occlusal loading, on the pattern of stress distribution in tooth-supported, implant-supported, and tooth implant-supported fixed partial prostheses, using the finite element analysis with a comparative viewpoint. Materials and Methods The geometric models of implant and mandibular bone were generated. Three models were created in accordance with the need of the study. The first model was given a tooth-supported fixed partial prosthesis. The second model was given tooth implant-supported fixed partial prosthesis, and the third model was given implant-supported fixed partial prosthesis. Forces of 100 N and 50 N were applied axially and buccolingually, respectively. Results The present study compared the stresses arising in the natural tooth, implant, and the whole prostheses under simulated axial and buccolingual loading of three types of fixed partial dentures, namely, tooth-supported, tooth implant-supported, and implant-supported fixed partial dental prostheses using three different types of materials. Conclusion The pattern of stress distribution did not appear to be significantly affected by the type of prosthesis materials in all models. The maximum stress concentrations were found in the alveolar bone around the neck of the teeth and implants.

scholarly journals A Finite Element Analysis to Compare Stress Distribution on Extra-Short Implants with Two Different Internal Connections

2019 ◽  
Vol 8 (8) ◽  
pp. 1103 ◽  
Author(s):  
García-Braz ◽  
Prados-Privado ◽  
Zanatta ◽  
Calvo-Guirado ◽  
Prados-Frutos ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Axial Load ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Stress Concentrations ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Short Implants

Background: The goal of this study was to analyze the stress distribution on two types of extra-short dental implants with 5 mm of length: An internal hexagon (IH) and morse taper connection (MT). Methods: The three-dimensional model was composed of trabecular and cortical bone, a crown, an extra-short dental implant and their components. An axial load of 150 N was applied and another inclined 30° with the same magnitude. Results: Stress concentrations on the IH implant are observed in the region of the first threads for the screw. However, in the MT implant the highest stress occurs at the edges of the upper implant platform. Conclusions: In view of the results obtained in this study the two types of prosthetic fittings present a good stress distribution. The Morse taper connections presented better behavior than the internal in both loading configurations.

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.

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