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.

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 Analysis of Combined Bolted Flange Joints under High Temperature

2014 ◽  
Vol 624 ◽  
pp. 187-192
Author(s):  
He Hui Wang ◽  
Yan Zhang
Keyword(s):  
High Temperature ◽  
Loading Condition ◽  
Film Stress ◽  
Load Relaxation ◽  
Tightening Force ◽  
Element Simulation ◽  
Sealing Performance ◽  
Creep Analysis ◽  
Sealing Pressure ◽  
Bolted Flange

The tightness of bolted flange joints will weaken due to the loss of bolt load as a result of creep under high temperature. There exists no mature calculation procedure that can accounts for creep. Based on the finite element simulation of a combined flanged joint under four various conditions, the strength integrity and sealing performance of it are evaluated according to the code JB4732-2005. The results show that the integrity and tightness of the combined flanged joint under pre-loading condition, pressure condition and operating condition (except local film stress) meet requirements. However, more than 50% of the bolt load relaxation is found due to creep, part of the gasket residual stress is lower than the required minimum sealing pressure. It can lead to leakage. Bigger bolt pre-tightening force, materials with good creep relaxation resistance and hot-tighting method are recommended to reduce the influence of creep.

High temperature creep behavior of thixoformed nickel-based superalloy parts

2021 ◽  
pp. 141216
Author(s):  
Guanfei Xiao ◽  
Jufu Jiang ◽  
Ying Wang ◽  
Yingze Liu ◽  
Ying Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Creep Behavior ◽  
High Temperature Creep ◽  
Temperature Creep ◽  
Nickel Based Superalloy

scholarly journals Environmental effects on photosynthetic capacity of bean genotypes

2004 ◽  
Vol 39 (7) ◽  
pp. 615-623 ◽  
Author(s):  
Rafael Vasconcelos Ribeiro ◽  
Mauro Guida dos Santos ◽  
Gustavo Maia Souza ◽  
Eduardo Caruso Machado ◽  
Ricardo Ferraz de Oliveira ◽  
...  
Keyword(s):  
High Temperature ◽  
Natural Condition ◽  
Temperature Effects ◽  
Environmental Changes ◽  
Photosynthetic Capacity ◽  
Photosynthetic Apparatus ◽  
Co2 Assimilation ◽  
Fluorescence Yield ◽  
Environmental Condition ◽  
Response Curves

Photosynthetic responses to daily environmental changes were studied in bean (Phaseolus vulgaris L.) genotypes 'Carioca', 'Ouro Negro', and Guarumbé. Light response curves of CO2 assimilation and stomatal conductance (g s) were also evaluated under controlled (optimum) environmental condition. Under this condition, CO2 assimilation of 'Carioca' was not saturated at 2,000 µmol m-2 s-1, whereas Guarumbé and 'Ouro Negro' exhibited different levels of light saturation. All genotypes showed dynamic photoinhibition and reversible increase in the minimum chlorophyll fluorescence yield under natural condition, as well as lower photosynthetic capacity when compared with optimum environmental condition. Since differences in g s were not observed between natural and controlled conditions for Guarumbé and 'Ouro Negro', the lower photosynthetic capacity of these genotypes under natural condition seems to be caused by high temperature effects on biochemical reactions, as suggested by increased alternative electron sinks. The highest g s values of 'Carioca' were observed at controlled condition, providing evidences that reduction of photosynthetic capacity at natural condition was due to low g s in addition to the high temperature effects on the photosynthetic apparatus. 'Carioca' exhibited the highest photosynthetic rates under optimum environmental condition, and was more affected by daily changes of air temperature and leaf-to-air vapor pressure difference.

High Temperature Effects in Li-Doped ZnO Thin Films

2004 ◽  
Vol 63 (1) ◽  
pp. 209-213 ◽  
Author(s):  
A. DEYNEKA ◽  
Z. HUBICKA ◽  
M. CADA ◽  
G. SUCHANECK ◽  
M. SAVINOV ◽  
...  
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Temperature Effects ◽  
Zno Thin Films ◽  
Doped Zno
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