The Effect of Cylinder and Hub Creep on the Load Relaxation in Bolted Flanged Joints

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Akli Nechache ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Creep Behavior ◽  
Temperature Effects ◽  
Analytical Approach ◽  
Finite Element Models ◽  
Load Relaxation ◽  
3D Finite Element ◽  
Bolted Flange

The leakage tightness behavior of bolted flange joints is compromised due to the high temperature effects and, in particular, when creep of the materials of the different components of the bolted flanged joint takes place. The relaxation of bolted flanged joints is often estimated from the creep of the gasket and the bolts. The creep behavior of the flange ring, the hub, and the cylinder is often neglected. Apart from an acknowledgement of relaxation due to the creep, the designer has no specific tools to accurately assess this effect on the bolt load relaxation. The objective of this paper is to present an analytical approach capable of predicting the bolt load relaxation due to the creep of the flange ring, hub, and cylinder. The proposed approach is compared to the 3D finite element models of different size flanges. An emphasis will be put toward the importance of including creep of the hub and cylinder in high temperature flange designs.

Creep Effect of Attached Structures on Bolted Flanged Joint Relaxation

2005 ◽  
Author(s):  
Akli Nechache ◽  
Abdel-Hakim Bouzid
Keyword(s):  
High Temperature ◽  
Creep Behavior ◽  
Temperature Effects ◽  
Analytical Approach ◽  
Load Relaxation ◽  
Creep Effect ◽  
Bolted Flange

The leakage tightness behavior of bolted flange joints is compromised due to high temperature effects and in particular when creep of the materials of the different components of the bolted flanged joint take place. The relaxation of bolted flanged joints is often estimated from the creep of the gasket and the bolts. The creep behavior of the flange ring and the attached structures such as the shell and the hub is often neglected. Apart from an acknowledgement of relaxation due to creep, the designer has no specific tools to accurately assess this effect on the bolt load relaxation. The objective of this paper is to present an analytical approach capable of predicting the bolt load relaxation due to creep of the attached structures. The proposed approach is validated by comparison with 3D FE models of different size flanges. An emphasis will be put towards the importance of including creep of the attached structures in high temperature flange designs.

Creep Life Simulation and Assessment of High Temperature Piping Systems and Components

2012 ◽  
Author(s):  
Brian Rose ◽  
James Widrig
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Creep Behavior ◽  
Material Behavior ◽  
Piping System ◽  
Remaining Life ◽  
Creep Life ◽  
Element Analysis ◽  
Piping Systems

High temperature piping systems and associated components, elbows and bellows in particular, are vulnerable to damage from creep. The creep behavior of the system is simulated using finite element analysis (FEA). Material behavior and damage is characterized using the MPC Omega law, which captures creep embrittlement. Elbow elements provide rapid yet accurate modeling of pinching of piping, which consumes a major portion of the creep life. The simulation is used to estimate the remaining life of the piping system, evaluate the adequacy of existing bellows and spring can supports and explore remediation options.

EFFECT OF FACE COOLING ON WORKPIECE TEMPERATURES USING 2D AND 3D FINITE ELEMENT ANALYSIS OF CREEP-FEED GRINDING

2008 ◽  
Vol 32 (3-4) ◽  
pp. 439-452 ◽  
Author(s):  
David Anderson ◽  
Andrew Warkentin ◽  
Robert Bauer
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Contact Temperature ◽  
Grinding Wheel ◽  
Finite Element Models ◽  
3D Finite Element ◽  
Creep Feed ◽  
2D And 3D ◽  
Maximum Contact ◽  
Face Cooling

This work uses validated 2D and 3D finite element models of the creep-feed grinding operation to study the effects of face cooling on the workpiece temperatures. The results show that as the intensity of the face cooling is increased the maximum contact temperature decreases and the location of the maximum contact temperature shifts away from the finished workpiece material and towards the uncut workpiece surface. The finite element models are also used to study the maximum temperatures along the workpiece during a complete grinding pass. The temperature profiles show that there are four important temperature features on the workpiece, which are the cut-in, steady-state, temperature spike, and cut-out zones. Cut-in occurs when the grinding wheel initially engages the workpiece, steady-state occurs in the middle of the workpiece, the temperature spike occurs at the beginning of cut-out, and cut-out occurs as the grinding wheel disengages from the workpiece. Finally, the results show that face cooling need only be applied to the area immediately adjacent to the contact zone to be effective and that there is very little benefit to applying coolant to the entire front and back workpiece faces.

Sign in / Sign up

Export Citation Format

Share Document