The Impact of Qualified Bolting Specialists on the Safe, Reliable Assembly and Operation of Bolted Flanged Connections

2015 ◽  
Author(s):  
A. Fitzgerald (Jerry) Waterland ◽  
David Lay ◽  
Michael Dodge
Keyword(s):  
Work Force ◽  
Pressure Vessels ◽  
Bolted Joints ◽  
Critical Area ◽  
Bolted Joint ◽  
Learning Program ◽  
Guideline Document ◽  
The Impact ◽  
Joint Assembly

Why do we certify welders but require no evidence of training or competence from those performing the critical bolted flanged joint assembly of pressure vessels and piping throughout the same industries? To remedy this situation ASME has recently released the first comprehensive standard in ASME PCC-1-2013 Appendix A that establishes uniform criteria, not just for the quality of the bolted joints but for the workers who assemble them. To support this critical training and qualification standard, ASME Training & Development has created a unique blended learning program for pipe fitters and mechanics to become Qualified Bolting Specialists (QBS), per the requirements outlined in PCC-1-2013 Appendix A. The purpose of this technical presentation is to explain the opportunities presented by this new standard and how industry can benefit from a better-trained work force in this critical area of bolted joint assembly. The authors have been integrally involved in the development of both the PCC-1 guideline document, and the ASME qualification program, and can authoritatively answer industry’s questions.

Impact Fracture of Jointed Steel Plates of Bolted Joint of Cars

2014 ◽  
Vol 566 ◽  
pp. 232-237
Author(s):  
H. Ambarita ◽  
M. Daimaruya ◽  
H. Fujiki
Keyword(s):  
Tensile Strength ◽  
Shear Test ◽  
Fracture Criterion ◽  
Shear Fracture ◽  
Impact Fracture ◽  
Bolted Joints ◽  
Steel Plates ◽  
Bolted Joint ◽  
Car Body ◽  
The Impact

The present study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of a lap bolted joint used in the suspension parts of a car body. For the accurate prediction of crash characteristics of car bodies by computer-aided engineering (CAE), it is also necessary to examine the behaviour and fracture of the jointed steel plates subjected to impact loads. Although the actual impact fracture of jointed steel plates of a lap bolted joint in cars is complicated, for simplifying it is classified into the shear fracture and the extractive fracture of jointed steel plates. Three kinds of steel plates, i.e., common steel with the tensile strength of 270 MPa and two high tensile strength steels with the tensile strength of 440 and 590 MPa level used for vehicles, are examined. In the impact shear test, the specimens are made of two plates and jointed by a bolt, and in the impact extractive test the specimens are made of a plate and drilled in the centre for a bolt. The impact shear test of jointed steel plates of lap bolted joints is performed using a modified split Hopkinson bar apparatus, while the impact extractive one is performed using one-bar method. Numerical simulations by a FEM code LS-DYNA are also carried out in order to understand the mechanism of shearing and extractive fractures process of jointed steel plates. The obtained results suggest that a stress-based fracture criterion may be developed for the impact shearing and extractive fractures of jointed steel plates of lap bolted joints used in a car body.

Thread Friction Torque in Bolted Joints

2005 ◽  
Vol 127 (4) ◽  
pp. 387-393 ◽  
Author(s):  
Sayed A. Nassar ◽  
Payam H. Matin ◽  
Gary C. Barber
Keyword(s):  
Friction Coefficient ◽  
Current Practice ◽  
Weighted Average ◽  
High Accuracy ◽  
Friction Torque ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Average Value ◽  
Highly Sensitive

In this paper, formulas are developed for the calculation of the effective thread friction radius in fasteners, in order to determine the thread friction torque component. Due to the lack of exact formulas in the literature, current practice uses the average value of the minor and major thread radii, as an approximation, for determining the thread friction torque component. Results provided by these formulas are compared with those given by the current practice that uses the average value of the minor and major thread radii, instead of the exact value. It is well known that the torque-tension relationship in threaded fastener applications is highly sensitive to the friction torque components: between threads, and under the turning fastener head or nut. Even moderate variations or inaccuracies in determining the friction torque components would significantly impact the fastener tension and the joint clamp load. High accuracy in the estimation of the friction torque components is critical, as it directly affects the reliability, safety, and the quality of bolted assemblies. This analysis focuses on the thread friction torque component. The new formulas for the thread friction radius are developed for a mathematical model of a bolted joint using five assumed scenarios of the contact pressure between male and female threads. Because of the fact that the variation in the sliding speed of various points on a thread surface is insignificant, a uniform thread friction coefficient is used in the analysis. However, a contact area weighted average value is used for the thread friction coefficient. Numerical results and error analysis are presented in terms of a single nondimensional variable, namely, the ratio between the major and minor thread radii.

Dynamic Characteristics of Structure With Bolted Joint Considering Some Factors

2004 ◽  
Author(s):  
Shigeru Aoki
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Damping Ratio ◽  
Random Excitation ◽  
Pressure Vessels ◽  
Bolted Joints ◽  
Piping System ◽  
Bolted Joint ◽  
Earthquake Excitation ◽  
Applied Torque

Bolted joints are widely used for pressure vessels and piping system. Many studies on strength and stiffness of bolted joint are carried out. However, few studies on the dynamic characteristics of structure with bolted joint are carried out. The dynamic characteristics are important for design of structure subjected to earthquake excitations. In this paper, the effect of bolted joints on dynamic characteristics of structure is examined. First, the damping ratio and the natural frequency of specimens with some types of bolted joints are measured. Those are obtained for some factors, amplitude of excitation, applied torque. Obtained results are compared with those for the specimen without bolted joint. It is found that the damping ratio increases and the natural frequency becomes lower. Next, modeling of the bolted joint is presented. The bolted joint is modeled using additional mass, stiffness and damping elements. Finally, using model of bolted joint, response of the structure with bolted joint subjected to earthquake excitation is examined. Earthquake excitation is modeled as stationary random excitation. Mean square values of the response are obtained. Standard deviation of the acceleration response of the structure with bolted joint are lower than those without bolted joint.

Development of Modelling Guidelines for Stress Analysis of Pressure Vessel Bolted Closures

2010 ◽  
Author(s):  
A. Towse ◽  
A. Mills ◽  
D. Griffin ◽  
P. Hurrell ◽  
D. Rowe ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Pressure Vessels ◽  
Service Performance ◽  
Bolted Joints ◽  
Model Complexity ◽  
Bolted Joint ◽  
Joint Models ◽  
Software And Hardware ◽  
Modelling Methods

This paper describes some of the outcomes of the development of finite element modelling guidelines for the stress analysis of bolted joints in pressure vessels and piping. The modelling methods originally developed at Rolls-Royce typically used 2D axisymmetric models as this was deemed adequate at the time. However, computing software and hardware improvements have subsequently been made which enable more realistic 3D bolted joint models to be solved where a greater level of geometric detail is required. For example the bolts, nuts and perforated flanges can now be represented more realistically reducing the degree of geometric abstraction that is required. Also, modern finite element codes such as ABAQUS and ANSYS now offer gasket elements which enable the initial compression, in-service performance and unloading of the joint to be modelled more realistically. Additionally, contact techniques can also be used to simulate the axial and radial distribution of thread load in the joint which will affect the stress distribution remote from the threaded region. Consequently, the modelling guidelines have been updated and provide guidance for stress engineers to decide which degree of model complexity is warranted.

What’s New in the PCC-1-2010 Update “Guidelines for Pressure Boundary Bolted Joint Assembly”

2010 ◽  
Author(s):  
Clyde Neely ◽  
Clay Rodery
Keyword(s):  
Bolted Joints ◽  
Bolted Joint ◽  
Additional Detail ◽  
And Performance ◽  
Joint Assembly

ASME PCC-1 “Guidelines for Pressure Boundary Bolted Joint Assembly” was first published in 2000 [1]. Since that time, there have been advances in bolted joint technology and industry practices that necessitated an update of the original document. The new revision of PCC-1 [2] is over twice the length of the original document and contains many new and updated guidelines. Significant additional detail has been added to the document in an effort to provide the broadest possible array of bolted joint assembly considerations to cover situations commonly encountered in industry, and thereby improve the overall safety and performance of bolted joints. This paper identifies some of the notable changes/additions that are included in the updated document.

Employing Fuzzy Logic for a Real-time Comprehensive Quality Assessment Model of Service Providers in E-learning Environments

2010 ◽  
pp. 223-241
Author(s):  
Hamed Fazlollahtabar
Keyword(s):  
Quality Assessment ◽  
Service Providers ◽  
Assessment Model ◽  
Learning Program ◽  
Production Chain ◽  
Weakest Link ◽  
E Learning ◽  
Learning Development ◽  
The Impact

Assessing quality is obviously a key concern in many aspects of learning, education and training, so why should it be especially crucial in relation to e-learning? The e-learners, as with other distance learners, are working in isolation with limited or sometimes non-existent human support. This means that the first impact of any failure in the providers’ quality assessment regime falls directly on the e-learner. When an e-learner encounters errors caused by a failure in a providers’ quality assessment regime the impact might be immediately evident or not become evident until the learner undertakes an assessed outcome. Since e-learning development is fundamentally a team-based activity, the effectiveness or quality of an e-learning program depends on the weakest link in the production chain. E-learning exists at a point of convergence between technology based disciplines and human-centered disciplines.

Efficient Assembly of Pressure Vessel Bolted Joints

2004 ◽  
Author(s):  
Warren Brown
Keyword(s):  
Pressure Vessel ◽  
Experimental Results ◽  
Bolted Joints ◽  
Effect Of Temperature ◽  
Bolted Joint ◽  
Joint Integrity ◽  
Selection Of ◽  
Joint Assembly

This paper details the results of recent testing and experience into the assembly of bolted joints. Pressure boundary bolted joint assembly procedures are examined and details are presented that result in a reduction in the required effort to assemble any given joint by more than 50%. The selection of correct assembly load levels is addressed and suggestions for joint integrity improvement are made. Experimental results are also presented on the use of bolt lubricants and the effect of temperature on the lubricant properties.

Dynamic Characteristics of Structures With Bolted Joint

2002 ◽  
Author(s):  
Shigeru Aoki
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Random Vibration ◽  
Damping Ratio ◽  
Pressure Vessels ◽  
Bolted Joints ◽  
Simplified Model ◽  
Piping System ◽  
Bolted Joint ◽  
Acceleration Response

Bolted joints are widely used for pressure vessels and piping system. Many studies on strength of bolted joint are carried out. However, few studies on dynamic characteristics of structure with bolted joint are carried out. In this paper, the effect of bolted joints on dynamic characteristics of structure is examined. First, the damping ratio and the natural frequency of specimens with some types of bolted joints are measured. Obtained results are compared with those for the specimen without bolted joint. It is found that damping ratio increases and the natural frequency becomes lower. Next, the effect of bolted joint on random vibration response of structure using simplified model is examined. Standard deviation of acceleration response of structure with bolted joint is lower than that of structure without bolted joint.

scholarly journals Solving the Puzzle of Bolted Joints

2011 ◽  
Vol 133 (06) ◽  
pp. 48-52
Author(s):  
Edward Hayman ◽  
Clyde Neely
Keyword(s):  
Best Practices ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Flange Joint ◽  
Unit Load ◽  
Bolt Stress ◽  
Torque Values ◽  
Bolted Flange ◽  
Joint Integrity ◽  
Joint Assembly

This article discusses the various ways of solving the puzzle of bolted joint assembly. In 2001, The PCC-1-2000 Guidelines for Pressure Boundary Bolted Flange Joint Assembly presented with knowledge and practices specific to the assembly of bolted flange joints. The puzzle solution that came from this box was the most definitive to date and allowed those dealing with bolted joints to assemble the variables by methods that had been used successfully for many years by many people. This document is helping people across industry not only to assemble bolted flange joints, but also to establish joint integrity programs, procedures, and best practices. PCC-1-2010 shifts the emphasis to gasket stress and gasket type and provides instruction and information pertinent to bolt torque values. The 2010 document contains, for instance, a whole section on bolt stress—the unit load that should be put on the bolts—and includes tables as well.

On the Use of Shape Memory Alloy Studs to Recover Load Loss in Bolted Joints

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Nazim Ould-Brahim ◽  
Abdel-Hakim Bouzid ◽  
Vladimir Brailovski
Keyword(s):  
Shape Memory ◽  
Analytical Model ◽  
Experimental Studies ◽  
Thermal Exposure ◽  
Element Model ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Creep Properties ◽  
Material Creep ◽  
Joint Assembly

Creep is an important factor that contributes to the clamp load loss and tightness failure of bolted joints with and without gaskets over time. Retightening of the joint can be expensive and time consuming; therefore, it is an undesirable solution. Currently, most efforts are put towards reducing load losses directly by tightening to yield, improving material creep properties, or making joint less rigid. An alternative solution of current interest is the use of bolts in shape memory alloys (SMAs). However, very few experimental studies are available, which demonstrate the feasibility of these alloys. The objective of this study is to explore the benefit of shape memory and superelasticity behavior of an SMA stud to recover load losses due to creep and thermal exposure of a gasket in a bolted-joint assembly. This paper explores several venues to investigate and model the thermomechanical behavior of a bolted joint with a nickel–titanium SMA stud. A stiffness-based analytical model which incorporates the Likhachev model of SMA is used as a representation of an experimental bolted-joint assembly. Based on this model, the rigidity of the experimental setup is optimized to make the best use of the SMA properties of the stud. This analytical model is compared with a finite element model, which also implements the Likhachev's material law. Finally, an experimental test bench with a relatively low stiffness representative of standard flanges is used, with and without gaskets to demonstrate the ability of the SMA stud to recover load losses due to gasket creep.

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