Combined Effects of Tube Projection, Initial Tube-Tubesheet Clearance, and Tube Material Strain Hardening on Rolled Joint Strength

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
N. Merah ◽  
A. Al-Aboodi ◽  
A. N. Shuaib ◽  
Y. Al-Nassar ◽  
S. S. Al-Anizi
Keyword(s):  
Finite Element ◽  
Strain Hardening ◽  
Contact Pressure ◽  
Joint Strength ◽  
Element Model ◽  
Design Parameters ◽  
Radial Clearance ◽  
Tube Material ◽  
Element Analysis ◽  
Interfacial Pressure

The tube-to-tubesheet joint strength is measured in terms of interfacial pressure between the tube’s outer surface and tubesheet bore. The strength of a rolled joint is influenced by several design parameters, including the type of tube and tubesheet materials, initial tube projection, and the initial radial clearance between the tube and tubesheet, among other factors. This paper uses finite element analysis (FEA) to evaluate the effect of several parameters on the strength of rolled joints having large overtolerances, a situation that applies to used equipment. An axisymmetric finite element model based on the sleeve diameter and rigid tube expanding roller concepts was used to analyze the effects of tube projection, initial tube-tubesheet clearance, and tube material strain-hardening property on the deformation behavior of the rolled tube and on the strength of the tube-tubesheet joint. The FEA results show that for zero tube projection (flush) the initial clearance effect is dependent on the strain-hardening capability of the tube material. For low strain-hardening tube material the interfacial pressure remains constant well above the Tubular Exchanger Manufacturer’s Association maximum overtolerance. A drastic reduction in joint strength is observed at high values of radial clearances. The cut-off clearance (clearance at which the interfacial pressure starts to drop) is found to vary linearly with the tube material hardening level, and the contact stress increases slightly for moderate strain-hardening tube materials but shows lower cut-off clearance levels. Furthermore, with flush tubes the maximum contact pressure occurs close to the secondary face (at the end of rolling) while for joints with initial tube projection the contact pressure shows two maxima occurring near the primary and the secondary faces. This is attributed to the presence of two elbows in tube deformation near the primary and secondary faces. The average interfacial pressure increased with increasing projection length for all clearances. Tube material strain hardening enhances the interfacial pressure in a similar fashion for all initial tube projection lengths considered in the analysis.

Modeling the Effects of Initial Tube-Tubesheet Clearance, Wall Reduction and Material Strain Hardening on Rolled Joint Strength

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
A. Al-Aboodi ◽  
N. Merah ◽  
A. R. Shuaib ◽  
Y. Al-Nassar ◽  
S. S. Al-Anizi
Keyword(s):  
Finite Element ◽  
Strain Hardening ◽  
Contact Pressure ◽  
Joint Strength ◽  
Design Parameters ◽  
Radial Clearance ◽  
Residual Pressure ◽  
Tube Material ◽  
Noticeable Effect ◽  
Interfacial Pressure

The tube-to-tubesheet joint strength is measured in terms of residual contact pressure between the tube’s outer surface and tubesheet hole surfaces. The joint integrity is affected by several design parameters, including the type of tube and tubesheet materials, the level of expansion, and the initial radial clearance between the tube and tubesheet. In the present work, an axisymmetric finite element model based on the sleeve diameter and rigid roller concepts is developed. The model has been used to evaluate the combined effects of clearance, wall reduction level, and strain hardening of tube and tubesheet materials on the interfacial pressure between tube and tubesheet. The finite element results show that the initial clearance effect is dependent on the strain hardening capability of the tube material. For low strain hardening tube materials, the interfacial pressure remains almost constant well above the Tubular Exchanger Manufacturing Association maximum radial over tolerance of 0.0254mm(0.001in.). These results are validated by the experimental data developed during the research program. As expected, a drastic reduction in joint strength is observed at high values of radial clearances. The cutoff clearance (clearance at which the interfacial pressure starts to drop) is found to vary linearly with tube material hardening level. The residual pressure is found to increase slightly for moderate strain hardening tube materials but shows lower cutoff clearances. Wall reductions ranging from 1% to 12% were utilized in calculating the contact pressure as a function of radial clearance. The results show that for low strain hardening materials the optimum value of residual contact stress is obtained for the industry recommended value of 5%. Finally, because of the absence of plastic deformation in the ligament, the level of tubesheet material strain hardening does not have any noticeable effect on the joint strength.

FEA of the Effects of Initial Tube-Tubesheet Clearance, Wall Reduction and Material Strain Hardening on Rolled Joint Strength

2006 ◽  
Author(s):  
A. Al-Aboodi ◽  
N. Merah ◽  
A. R. Shuaib ◽  
Y. Al-Nassar ◽  
S. S. Al-Anizi
Keyword(s):  
Strain Hardening ◽  
Contact Pressure ◽  
Joint Strength ◽  
Element Model ◽  
Design Parameters ◽  
Radial Clearance ◽  
Residual Pressure ◽  
Tube Material ◽  
Noticeable Effect ◽  
Interfacial Pressure

The tube-to-tubesheet joint strength is measured in terms of residual contact pressure between the tube’s outer surface and tubesheet hole surfaces. The joint integrity is affected by several design parameters, including the type of tube and-tubesheet materials, level of expansion and the initial radial clearance between the tube and tubesheet. In the present work, an axisymmetric finite element model based on the sleeve diameter and rigid roller concepts is developed. The model has been used to evaluate the combined effects of clearance, wall reduction level and the-strain hardening of tube and tubesheet materials on the interfacial pressure between tube and tubesheet. The FE results show that the initial clearance effect is dependent on the strain hardening capability of the tube material. For low strain hardening tube material the interfacial pressure remains almost constant well above the TEMA (Tubular Exchanger Manufacturing Association) maximum radial over tolerance of 0.0254 mm. These results are validated by the experimental data developed during the research program. As expected, a drastic reduction in joint strength is observed at high values of radial clearances. The cut-off clearance (clearance at which the interfacial pressure starts to drop) is found to vary linearly with the level tube material hardening level. The residual pressure is found to increase slightly for moderate strain hardening tube materials but shows lower cut-off clearances. Wall reductions ranging from 1% to 10% were utilized in calculating the contact pressure as a function of radial clearance. The results show that for low strain hardening materials the optimum value of residual contact stress is obtained for the industry recommended value of 5%. Finally, because of the absence plastic deformation in the ligament, the level of tubesheet material strain hardening does not have any noticeable effect to the joint strength.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

Development of a Belt Conveyor Cooling System for Concrete Aggregates

2011 ◽  
Author(s):  
Khaled I. E. Ahmed ◽  
A. M. S. Hamouda ◽  
M. S. Gadala
Keyword(s):  
Finite Element ◽  
Cooling System ◽  
Initial Conditions ◽  
Element Model ◽  
Design Parameters ◽  
Element Analysis ◽  
Conveyor System ◽  
Concrete Aggregates ◽  
Concrete Production ◽  
The Finite Element Analysis

Using hot aggregates, in concrete production, results in a drop in compressive strength of the produced concrete. Various methods have been proposed for cooling concrete aggregates. This paper proposes a new design for a conveyor system for cooling the aggregates during hot seasons. Simulation of the heat flow during the cooling process over the conveyor is analyzed with the objective of understanding the effect of the various design parameters and achieving minimum cooling time with the least possible power. A finite element model for the new design is proposed and discussed. Challenges facing numerical simulation are addressed in this paper. The results of the finite element analysis of the new design are presented for various initial conditions and cooling rates.

A frequency response function-based updating technique for the finite element model of automotive structures

2008 ◽  
Vol 222 (10) ◽  
pp. 1781-1791 ◽  
Author(s):  
D-C Lee ◽  
C-S Han
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Design Parameters ◽  
External Loading ◽  
Element Analysis ◽  
Automotive Structures ◽  
Different Types ◽  
External Loads ◽  
The Finite Element Model ◽  
Huge Variety

Today's automotive industry uses finite element analysis (FEA) in a huge variety of applications in order to optimize structures and processes before hardware is produced. Efficiencies can be enhanced and margins are reduced because the external loads and structural properties are identified with higher confidence. The accuracy of FEA predictions has become increasingly important and directly influences the competitiveness of a product on the market. Because automotive structures are under dynamic environments, the correlation on the basis of static deformations independent of the mass and damping parameters do not provide a valuable reference from the view of the dynamic characteristics. In this paper, by systematically comparing the results from analytical and experimental analysis techniques, finite element (FE) models can be validated by the deterministic and robust design on the basis of each tolerance of design parameters, and improved so that they can be used with more confidence in further analysis. Making use of different types of test datum, a recommended procedure is to use a sequence of analysis in which mass, stiffness, damping, and external loading are validated and, if necessary, updated.

Characterization of Tissue Scaffolds Fabricated by Rapid Prototyping Techniques Aided by Finite Element Analysis

2006 ◽  
Author(s):  
Andrew R. Thoreson ◽  
James J. Stone ◽  
Kurtis L. Langner ◽  
Jay Norton ◽  
Bor Z. Jang
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Cartilage Regeneration ◽  
Element Model ◽  
Tissue Scaffolds ◽  
Design Parameters ◽  
Element Analysis ◽  
Apparent Modulus ◽  
Wide Range

Numerous techniques for fabricating tissue engineering scaffolds have been proposed by researchers covering many disciplines. While literature regarding properties and efficacy of scaffolds having a single set of design parameters is abundant, characterization studies of scaffold structures encompassing a wide range of design parameters are limited. A Precision Extrusion Deposition (PED) system was developed for fabricating poly-ε-caprolactone (PCL) tissue scaffolds having interconnected pores suitable for cartilage regeneration. Scaffold structures fabricated with three-dimensional printing methods are periodic and are readily modeled using Computer Aided Design (CAD) software. Design parameters of periodic scaffold architectures were identified and incorporated into CAD models with design parameters over the practical processing range represented. Solid models were imported into a finite element model simulating compression loading. Model deformation results were used to identify apparent modulus of elasticity of the structure. PCL scaffold specimens with design parameters within the modeled range were fabricated and subjected to compression testing to physically characterize scaffold modulus. Results of physical testing and finite element models were compared to determine effectiveness of the method.

Finite Element Analysis of External Prestressing Beams Made of Strain Hardening Material

2012 ◽  
Vol 166-169 ◽  
pp. 259-268 ◽  
Author(s):  
Ahmed Atta
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Hardening ◽  
High Performance ◽  
Concrete Strength ◽  
Element Model ◽  
Element Analysis ◽  
Hardening Material ◽  
External Prestressing ◽  
Prestressing Tendon

The use of finite element analysis has been widely used as a means to analyze individual elements and the effects of concrete strength under loading. This paper is a study of prestressed concrete beams made of strain hardening material called UHP-SHCC (Ultra High Performance Strain Hardening Cementitious Composite) using finite element analysis to understand their response. A finite element model is studied and compared to experimental data. The basic parameters included second order effect of prestressed beam, and prestressing tendon depths have been considered in the analysis. The present study indicated the following conclusions: the number of deviators significantly influences the ultimate capacity and the strains values of UHP-SHCC beams, the change of external prestressing tendon depth has a significant effect on the cracking load, failure load, deflection values, and ultimate stress in the tendon in case of using UHP-SHCC beams but keep the final mode of failure without change.

scholarly journals Computerized Generation and Finite Element Stress Analysis of Endodontic Rotary Files

2021 ◽  
Vol 11 (10) ◽  
pp. 4329
Author(s):  
Victor Roda-Casanova ◽  
Álvaro Zubizarreta-Macho ◽  
Francisco Sanchez-Marin ◽  
Óscar Alonso Ezpeleta ◽  
Alberto Albaladejo Martínez ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computer Aided Design ◽  
Element Model ◽  
Transverse Load ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Element Analysis ◽  
Design Skills ◽  
Von Mises

Introduction: The finite element method has been extensively used to analyze the mechanical behavior of endodontic rotary files under bending and torsional conditions. This methodology requires elevated computer-aided design skills to reproduce the geometry of the endodontic file, and also mathematical knowledge to perform the finite element analysis. In this study, an automated procedure is proposed for the computerized generation and finite element analysis of endodontic rotary files under bending and torsional conditions. Methods: An endodontic rotary file with a 25mm total length, 0.25mm at the tip, 1.20mm at 16mm from the tip, 2mm pitch and squared cross section was generated using the proposed procedure and submitted for analysis under bending and torsional conditions by clamping the last 3mm of the endodontic rotary file and applying a transverse load of 0.1N and a torsional moment of 0.3N·cm. Results: The results of the finite element analyses showed a maximum von Mises stress of 398MPa resulting from the bending analysis and a maximum von Mises stress of 843MPa resulting from the torsional analysis, both of which are next to the encastre point. Conclusions: The automated procedure allows an accurate description of the geometry of the endodontic file to be obtained based on its design parameters as well as a finite element model of the endodontic file from the previously generated geometry.

Finite Element Analysis and Design of a Trochoidal-Type Machine Without Apex Seals

1995 ◽  
Author(s):  
Kannan Venkatesh ◽  
John B. Shung
Keyword(s):  
Finite Element ◽  
Iterative Procedure ◽  
Element Model ◽  
Design Parameters ◽  
Dimensional Model ◽  
Element Analysis ◽  
Analysis And Design ◽  
Type Machine ◽  
Free Body ◽  
The Finite Element Model

Abstract A two-dimensional model for a trochoidal-type machine without apex seals using finite element method has been developed with the help of Cosmos/M V1.65, and is evaluated by using a classical free-body technique. The minimum running clearance required to avoid contact between rotor and chamber is determined by an iterative procedure using the finite element model. The variation in the minimum required running clearance with the variation in the design parameters is studied. Guidelines for using the results of this study for an optimal design of a trochoidal-type machine without apex seals are presented.

Finite Element Analysis of Bicycle Saddle Based on Ergonomics

2012 ◽  
Vol 215-216 ◽  
pp. 497-500
Author(s):  
Ying Xin ◽  
Xiu Ping Yang ◽  
Lei Zhang
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Human Body ◽  
Element Model ◽  
Circulation System ◽  
Element Analysis ◽  
Blood Circulation System ◽  
Bicycle Rider ◽  
The One ◽  
Seating Comfort

Seating comfort is an important factor for bicycle-rider. It was shown that riding on discomfort saddle could affect the blood circulation system, genitourinary system of human, and harm to their health. In this paper, detailed finite element model of seated human associated with a prototypical bicycle saddle were established, and contact pressure between human body and the saddle was analyzed quantitatively. Then two positions of the saddle were considered, which included horizontal saddle and the one with an upward degree of 15. The contact pressure and the Mises stress over the polyurethane model and the industrial polypropylene model, as well as the buttocks and the perineal area of human body were obtained. The results show that contact pressure is centralized in body's buttocks and the perineal area, especially in the buttocks. Mises stress over human is lower when the saddle is horizontal compared with the upward raked one, in other words, horizontal saddle can improve seating comfort of human.

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