scholarly journals High Temperature Testing and Analysis of a Class 300 Bolted Flange Joint

2014 ◽  
Author(s):  
J. Adin Mann ◽  
Jeremy Hilsabeck ◽  
Cale Mckoon
Keyword(s):  
High Temperature ◽  
Bolted Joints ◽  
Flange Joint ◽  
Simulation Approach ◽  
High Temperature Testing ◽  
Material Creep ◽  
Fea Simulation ◽  
Bolted Flange ◽  
The Impact

When class 300 flange bolted joints are held at temperatures in the material creep range, it is documented that the bolt loads can relax. Tests and analysis are being performed with the goal of developing a validated FEA simulation approach to predicting the impact of creep on the bolt loads. The bolt load and gasket geometry are evaluated upon bolt up and after being heated to 1100 deg F. Tests are performed with and without a gasket to separate the impact of the gasket relaxation and flange material creep. The results of the tests and analysis approaches will be presented. Paper published with permission.

Evaluation of Leakage Probability of Non-Asbestos Fiber Sheet Gasket at Elevated Temperature Based on Percolation Theory: Characteristics Under Internal Pressure

2011 ◽  
Author(s):  
Masahiro Hagihara ◽  
Hirokazu Tsuji ◽  
Atsushi Yamaguchi
Keyword(s):  
High Temperature ◽  
Internal Pressure ◽  
Percolation Theory ◽  
Prediction Method ◽  
Chemical Plants ◽  
Flange Joint ◽  
Rate Of Increase ◽  
Oil Plant ◽  
Fiber Sheet ◽  
Bolted Flange

A long-term life prediction method for a compressed fiber sheet gasket under a high-temperature environment is studied. Non-asbestos compressed fiber sheet gaskets are now being used as a substitute for asbestos in the bolted flange joint, for instance chemical plants and oil plant facilities. Consequently, there is a real need for a technology to predict the lifetime of non-asbestos compressed fiber sheet gaskets quantitatively. We have previously reported that the facing surface which was formed the gasket and flange was visualized with scanning acoustic tomography (SAT). Voids were observed on the facing surface of the gasket and increased with the increase in exposure time at high temperature. If a leakage path for inner fluids was created by the increasing number of voids, the leak occurs on the facing surface of the gasket surface. The probability of a leak due to voids and the lifetime of this gasket were predicted by applying the percolation theory, which describes the connectedness of voids and clusters. In this report, the influence of internal pressure of test flange joint upon the rate of increase is studied.

Flange Joint Assembly Considerations for Critical Service Connections

2006 ◽  
Author(s):  
Rod T. Mueller
Keyword(s):  
Quality Control ◽  
High Temperature ◽  
Bolted Joints ◽  
Flange Joint ◽  
Process Industries ◽  
Joint Assembly

Flange joints, especially in high temperature critical services, continue to represent one of process industry’s more significant challenges in achieving reliable leak-tight piping. The paper will provide guidelines to help the user categorize critical services where flange joints warrant particular attention in their assembly. Unlike welded piping joints, flange joints do not have specific assembly qualification procedures recognized by current piping or PV Codes. The paper presents an approach to flange assembly procedures and quality control to improve the reliability of critical service bolted joints. The importance of effective assembly crew training and qualifications will also be emphasized. While the techniques have evolved with petrochemical service applications, they would be of interest to other process industries where flange leakage is a key concern.

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 Belleville Washers to Reduce Relaxation in Bolted Flange Joints

2008 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Akli Nechache
Keyword(s):  
High Temperature ◽  
Analytical Model ◽  
Analytical Calculation ◽  
Calculation Procedure ◽  
Minimum Level ◽  
Target Value ◽  
Exact Number ◽  
Model Based ◽  
Material Creep ◽  
Bolted Flange

Bolted flange joints are prone to leakage when exposed to high temperature. In most cases this is due to relaxation that takes place as a result of material creep. One way to solve this problem is to use Belleville spring washers or longer bolt with spacers. However, there is practically no reliable analytical model that can evaluate the exact number of washers or length of the bolts required to reduce relaxation to a target minimum level. This paper describes an analytical model based on the flexibility and displacement interactions of the joint different elements including the axial rigidity of the flange and bolts, used to evaluate relaxation. The developed analytical flange model can accommodate either Belleville spring washers or longer bolts with spacer tubes to reduce the bolt load loss to a maximum target value. This model is validated by comparison with the more accurate FEA findings. Calculation examples on a bolted flanged joint are presented to illustrate the suggested analytical calculation procedure.

Parametric Studies on Bolted Flange Thermal Analysis to Improve LCF Life

2013 ◽  
Author(s):  
Mohd. Yousuf ◽  
Krishna Nelanti ◽  
Rajendra Prasad Allabanda
Keyword(s):  
Thermal Analysis ◽  
Life Stress ◽  
Low Cycle Fatigue ◽  
Aircraft Engine ◽  
Bolted Joints ◽  
Thermal Gradients ◽  
Flange Thickness ◽  
Parametric Studies ◽  
Bolted Flange ◽  
The Impact

Low cycle fatigue (LCF) life plays an important role in the design of aircraft engine components, especially that of bolted joints. Bolted joints are of critical importance in aircraft engines as they connect parts and transfer loads. In gas turbine engines, most of the bolted flanges experience high pressure loads & high thermal gradients. LCF life/stress is very sensitive to the thermal gradients encountered in flight cycle (from idle to takeoff & takeoff to landing). Accurate flange leakage modeling & accurate boundary condition estimation are critical to design. This paper emphasizes on thermal analysis of bolted flange using the finite element method. Thermal analysis results show that, during flight cycle (Accel/Decel), flange leakage is a key contributor to thermal gradients. The flange leakage is majorly influenced by the gap between the flanges. Parametric studies have been carried out to understand the impact of gap between the flanges, flange thickness and flange height on the flange thermal gradients. The results presented in this paper will be helpful to the designer in designing better bolted flange joints with improved LCF life.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. ANALYSIS OF THE COMPOSITION AND PROPERTIES OF DEFORMABLE HEAT-RESISTANT HIGH-CHROMIUM NICKEL-BASED ALLOYS FOR WELDED PARTS. ANALYSIS OF EXISTING FUELLING STATIONS TYPES AND VEHICLES USING HYDROGEN, HYDROGEN PRODUCTION AND STORING METHODS

2019 ◽  
pp. 43-48
Author(s):  
Ben Nengjun ◽  
Zhou Pengfei ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Nickel Alloys ◽  
Total Content ◽  
Operating Conditions ◽  
High Temperature Strength ◽  
High Chromium ◽  
Salt Corrosion ◽  
Tcp Phases ◽  
The Impact

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

Stochastic simulation for determining the design flood of cascade reservoir systems

2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  
Keyword(s):  
Simulation Model ◽  
Stochastic Simulation ◽  
Southern China ◽  
Flow Simulation ◽  
Simulation Method ◽  
Simulation Approach ◽  
Design Flood ◽  
Design Values ◽  
Stochastic Simulation Model ◽  
The Impact

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.

scholarly journals Temperature, Disease, and Death in London: Analyzing Weekly Data for the Century from 1866 to 1965

2021 ◽  
pp. 1-41
Author(s):  
W. Walker Hanlon ◽  
Casper Worm Hansen ◽  
Jake Kantor
Keyword(s):  
Nineteenth Century ◽  
High Temperature ◽  
Mortality Data ◽  
Late Nineteenth Century ◽  
Infant Deaths ◽  
Digestive Diseases ◽  
Late Nineteenth ◽  
The Impact ◽  
The City

Using novel weekly mortality data for London spanning 1866-1965, we analyze the changing relationship between temperature and mortality as the city developed. Our main results show that warm weeks led to elevated mortality in the late nineteenth century, mainly due to infant deaths from digestive diseases. However, this pattern largely disappeared after WWI as infant digestive diseases became less prevalent. The resulting change in the temperature-mortality relationship meant that thousands of heat-related deaths—equal to 0.9-1.4 percent of all deaths— were averted. These findings show that improving the disease environment can dramatically alter the impact of high temperature on mortality.

scholarly journals The modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo, China

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rui Zhang ◽  
Yujie Meng ◽  
Hejia Song ◽  
Ran Niu ◽  
Yu Wang ◽  
...  
Keyword(s):  
Air Pollution ◽  
High Temperature ◽  
Air Pollutants ◽  
Meteorological Data ◽  
Effect Of Temperature ◽  
Distributed Lag ◽  
Modification Effect ◽  
Incidence Risk ◽  
The Impact ◽  
The Relationship

Abstract Background Although exposure to air pollution has been linked to many health issues, few studies have quantified the modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo, China. Methods The data of daily incidence of influenza and the relevant meteorological data and air pollution data in Ningbo from 2014 to 2017 were retrieved. Low, medium and high temperature layers were stratified by the daily mean temperature with 25th and 75th percentiles. The potential modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo was investigated through analyzing the effects of air pollutants stratified by temperature stratum using distributed lag non-linear model (DLNM). Stratified analysis by sex and age were also conducted. Results Overall, a 10 μg/m3 increment of O3, PM2.5, PM10 and NO2 could increase the incidence risk of influenza with the cumulative relative risk of 1.028 (95% CI 1.007, 1.050), 1.061 (95% CI 1.004, 1.122), 1.043 (95% CI 1.003, 1.085), and 1.118 (95% CI 1.028, 1.216), respectively. Male and aged 7–17 years were more sensitive to air pollutants. Through the temperature stratification analysis, we found that temperature could modify the impacts of air pollution on daily incidence of influenza with high temperature exacerbating the impact of air pollutants. At high temperature layer, male and the groups aged 0–6 years and 18–64 years were more sensitive to air pollution. Conclusion Temperature modified the relationship between air pollution and daily incidence of influenza and high temperature would exacerbate the effects of air pollutants in Ningbo.

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