Comparative Study of Flange-to-Seal Contact Couplings With Bolt Relaxation Under Creep Condition

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Jianfeng Mao ◽  
Weizhe Wang ◽  
Yingzheng Liu ◽  
Junhui Zhang
Keyword(s):  
Comparative Study ◽  
Creep Strength ◽  
Creep Condition ◽  
Contact Stresses ◽  
High Temperature Strength ◽  
Steam Turbines ◽  
Element Analysis ◽  
Creep Limit ◽  
Flange Thickness ◽  
Bolted Flange

Future coal-fired steam turbines promise increased efficiency and low emissions. However, this comes at the expense of increased thermal load from higher inlet steam temperatures and pressures leading to severe creep that significantly influences the sealing behavior and high temperature strength of bolted flange-seal couplings. Flanges with different thicknesses were employed for a comparative study. The important stress/creep values in the flanges and U-type seals had been obtained for variations in flange thickness and bolt relaxation while maintaining other leading parameters constant. The variation of contact stresses due to creep deformation plays an important role in achieving a leak proof sealing. In this paper, a two-dimensional finite element analysis of bolted flange-seal couplings has been carried out by taking the relaxation of bolt stress under full-loading turbine service. The creep strength of flanges and U-type seals are investigated by Cocks–Ashby (C–A) equivalent strain method. The multiaxial state of stresses is considered in this method by using C–A multiaxial coefficient. According to ASME allowable creep limit, the C–A equivalent strains of three flange-seal couplings are evaluated and compared. Furthermore, based on the results of contact stresses, the creep behavior of U-type seals is analyzed varying flange thickness. Finally, analysis shows that the thinner flange-seal coupling has larger long-term contact stress, while the U-type seal with the thicker flange has the least creep strength.

Comparative Study of Flange-to-Seal Contact Couplings With Bolt Relaxation Under Creep Condition

2013 ◽  
Author(s):  
Jianfeng Mao ◽  
Junhui Zhang ◽  
Weizhe Wang
Keyword(s):  
Comparative Study ◽  
Creep Strength ◽  
Creep Condition ◽  
Contact Stresses ◽  
High Temperature Strength ◽  
Steam Turbines ◽  
Element Analysis ◽  
Creep Limit ◽  
Flange Thickness ◽  
Bolted Flange

Future coal-fired steam turbines promise increased efficiency and low emissions. However, this comes at the expense of increased thermal load from higher inlet steam temperatures and pressures leading to severe creep that significantly influences the sealing behavior and high temperature strength of bolted flange-seal couplings. Flanges with different thicknesses were employed for a comparative study. The important stress/creep values in the flanges and U-type seals had been obtained for variations in flange thickness and bolt relaxation whilst maintaining other leading parameters constant. The variation of contact stresses due to creep deformation plays an important role in achieving a leak proof sealing. In this paper, a two-dimensional finite element analysis (FEA) of bolted flange-seal couplings has been carried out by taking the relaxation of bolt stress under full-loading turbine service. The creep strength of flanges and U-type seals are investigated by Cocks-Ashby (C-A) equivalent strain method. The multiaxial state of stresses is considered in this method by using C-A multiaxial coefficient. According to ASME allowable creep limit, the C-A equivalent strains of three flange-seal couplings are evaluated and compared. Furthermore, based on the results of contact stresses, the creep behavior of U-type seals is analyzed varying flange thickness. Finally, analysis shows that the thinner flange-seal coupling has larger long-term contact stress, while the U-type seal with the thicker flange has the least creep strength.

WIELAND DURO TZM

Alloy Digest ◽  
2020 ◽  
Vol 69 (12) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Creep Strength ◽  
Recrystallization Temperature ◽  
High Temperature Strength ◽  
Powder Metal ◽  
Temperature Performance ◽  
Titanium Zirconium

Abstract Wieland Duro TZM is a molybdenum-titanium-zirconium-carbon alloy produced from pressed-and-sintered billets. Compared to unalloyed molybdenum, it exhibits higher recrystallization temperature and enhanced high-temperature strength and creep strength. Wieland Duro TZM is typically used between 700 and 1400 °C (1290 and 2550 °F) in a non-oxidizing environment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance as well as machining and powder metal forms. Filing Code: Mo-20. Producer or source: Wieland Duro GmbH.

scholarly journals Performance Testing and Strength Prediction of Ceramic-to-Metal Joints

1993 ◽  
Author(s):  
J. H. Selverian ◽  
Dave A. ONeil ◽  
Shinhoo Kang
Keyword(s):  
Room Temperature ◽  
Performance Testing ◽  
Strength Prediction ◽  
High Temperature Strength ◽  
Torsional Loading ◽  
Element Analysis ◽  
Failure Theory ◽  
Brazed Joints ◽  
Temperature Shear ◽  
Shrink Fit

Brazed joints were made between silicon nitride and Ni-based and Fe-based super alloys. Room temperature shear (torsion) strengths ranged from 75–242 MPa for Si3N4-to-Incoloy 909 joints and from 30–127 MPa for the Si3N4-to-Inconel 718 joints. At 500 °C the joint strength was 120 MPa while at 650°C and 950°C the joints strengths were less than 20 MPa. These low strengths at 650°C and 950°C were attributed to a reduction in the shrink-fit and to low braze strength at these high temperatures. Finite element analysis (FEA) and a probabilistic failure theory (CARES) were used to predict the joint strengths. The predicted joint strengths agreed well with measured joint strengths in torsional loading at 20°C. Torsion tests were also performed at 650°C. Aspects of the material systems, residual stresses, mechanical behavior, and strength predictions are presented. Two new braze alloys based on the Au-Ni-Cr-Fe system were used to overcome the poor high temperature strength. Joints made with these brazes had good strength (85 MPa and 35 N-m) at 650°C.

Finite Element Analysis of a Gasketed Flange Joint Under Combined Internal Pressure and Thermal Transient Loading

2007 ◽  
Author(s):  
Muhammad Abid ◽  
Javed A. Chattha ◽  
Kamran A. Khan
Keyword(s):  
Finite Element Analysis ◽  
Steady State ◽  
Internal Pressure ◽  
Thermal Loading ◽  
Flange Joint ◽  
Element Analysis ◽  
Transient Loading ◽  
Thermal Transient ◽  
Transient Thermal ◽  
Bolted Flange

Performance of a bolted flange joint is characterized mainly by its ‘strength’ and ‘sealing capability’. A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. In the available published work, thermal behavior of the pipe flange joints is discussed under steady state loading with and without internal pressure and under transient loading condition without internal pressure. The present design codes also do not address the effects of steady state and thermal transient loading on the structural integrity and sealing ability. It is realized that due to the ignorance of any applied transient thermal loading, the optimized performance of the bolted flange joint can not be achieved. In this paper, in order to investigate gasketed joint’s performance i.e. joint strength and sealing capability under combined internal pressure and transient thermal loading, an extensive nonlinear finite element analysis is carried out and its behavior is discussed.

Development of 1500-r/min 75-Inch Ultra-Long Last Stage Blades for Nuclear Steam Turbine

2017 ◽  
Author(s):  
Deqi Yu ◽  
Jiandao Yang ◽  
Wei Lu ◽  
Daiwei Zhou ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Vibration Monitoring ◽  
Steam Turbines ◽  
Element Analysis ◽  
Rotating Blade ◽  
Lifetime Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Last Stage

The 1500-r/min 1905mm (75inch) ultra-long last three stage blades for half-speed large-scale nuclear steam turbines of 3rd generation nuclear power plants have been developed with the application of new design features and Computer-Aided-Engineering (CAE) technologies. The last stage rotating blade was designed with an integral shroud, snubber and fir-tree root. During operation, the adjacent blades are continuously coupled by the centrifugal force. It is designed that the adjacent shrouds and snubbers of each blade can provide additional structural damping to minimize the dynamic stress of the blade. In order to meet the blade development requirements, the quasi-3D aerodynamic method was used to obtain the preliminary flow path design for the last three stages in LP (Low-pressure) casing and the airfoil of last stage rotating blade was optimized as well to minimize its centrifugal stress. The latest CAE technologies and approaches of Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA) and Fatigue Lifetime Analysis (FLA) were applied to analyze and optimize the aerodynamic performance and reliability behavior of the blade structure. The blade was well tuned to avoid any possible excitation and resonant vibration. The blades and test rotor have been manufactured and the rotating vibration test with the vibration monitoring had been carried out in the verification tests.

A Finite Element Analysis of the Human Temporomandibular Joint

1994 ◽  
Vol 116 (4) ◽  
pp. 401-407 ◽  
Author(s):  
J. Chen ◽  
Liangfeng Xu
Keyword(s):  
Finite Element ◽  
Temporomandibular Joint ◽  
Reaction Force ◽  
Element Model ◽  
Contact Stresses ◽  
Element Analysis ◽  
Tensile Stresses ◽  
Reaction Forces ◽  
Von Mises ◽  
Von Mises Stresses

A 2-D finite element model of the human temporomandibular joint (TMJ) has been developed to investigate the stresses and reaction forces within the joint during normal sagittal jaw closure. The mechanical parameters analyzed were maximum principal and von Mises stresses in the disk, the contact stresses on the condylar and temporal surfaces, and the condylar reactions. The model bypassed the complexity of estimating muscle forces by using measured joint motion as input. The model was evaluated by several tests. The results demonstrated that the resultant condylar reaction force was directed toward the posterior side of the eminence. The contact stresses along the condylar and temporal surfaces were not evenly distributed. Separations were found at both upper and lower boundaries. High tensile stresses were found at the upper boundaries. High tensile stresses were found at the upper boundary of the middle portion of the disk.

Finite Element Analysis of the Effect of Surface Hardening Depth in Port Crane Wheel

2011 ◽  
Vol 291-294 ◽  
pp. 3282-3286 ◽  
Author(s):  
Jiang Wei Wu ◽  
Peng Wang
Keyword(s):  
Finite Element ◽  
Surface Hardening ◽  
Three Dimensional ◽  
Element Model ◽  
Contact Stresses ◽  
Numerical Results ◽  
Element Analysis ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In port crane industry, the surface hardening technique is widely used in order to improve the strength of wheel. But the hardening depth is chosen only by according to the experience, and the effect of different hardened depths is not studied theoretically. In this paper, the contact stresses in wheel with different hardening depth have been analyzed by applying three-dimensional finite element model. Based on this model, the ANSYS10.0 finite element software is used. The elastic wheel is used to verify the numerical results with the Hertz’s theory. Three different hardening depths, namely 10mm, 25mm and whole hardened wheel, under three different vertical loads were applied. The effect of hardening depth of a surface hardened wheel is discussed by comparing the contact stresses and contact areas from the numerical results.

Bolted Flange Joint Made of Glass Fibre Reinforced Polymer (GFRP) for Oil and Gas Pipelines

2018 ◽  
Author(s):  
Muhsin Aljuboury ◽  
Md Jahir Rizvi ◽  
Stephen Grove ◽  
Richard Cullen
Keyword(s):  
Glass Fibre ◽  
Oil And Gas ◽  
High Strength ◽  
Flange Joint ◽  
Element Analysis ◽  
Glass Fibre Reinforced Polymer ◽  
Linear Behaviour ◽  
Glass Fibre Reinforced ◽  
Gasket Material ◽  
Bolted Flange

The objective of this work is an experimental and numerical investigation for a bol Richard Cullen ted composite flange connection for composite pipes, which are used in the oil and gas applications, and obtain a joint with high strength and high corrosion resistance. For the experimental part, we have designed and manufactured the required mould, which ensures the quality of the composite materials and controls its surface grade. Based on the ASME Boiler and Pressure Vessel Code, Section X, this GFRP flange has been fabricated using biaxial glass fibre braid and polyester resin in a vacuum infusion process. Numerically, an investigation is carried out using 3D finite element analysis (FEA) of a bolted GFRP flange joint including flange, pipe, gasket and bolts. This model has taken into account the orthotropy of the GFRP material and the non-linear behaviour of the rubber gasket material for both the loading and non-loading conditions. Furthermore, the leakage propagation between the flange and the gasket has also been simulated in this investigation by using the pressure-penetration criteria PPNC in ANSYS. Finally, the flange has been tested under the internal pressure and the agreement between the experimental and numerical results is excellent.

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