Thermally Induced Deflections in Bolted Flanged Connections

2005 ◽  
Vol 127 (4) ◽  
pp. 394-401 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Akli Nechache
Keyword(s):  
Thermal Effects ◽  
Operating Temperature ◽  
Theoretical Models ◽  
Cover Plate ◽  
Joint Analysis ◽  
Temperature Profiles ◽  
Thermally Induced ◽  
Effects Of Temperature ◽  
Bolted Flange

Pressure vessel joints operating at high temperature are often very difficult to seal. The existing flange design methods do not address thermal effects other than the variation of flange material mechanical properties with temperature. It is possible to include the effects of temperature loading in joint analysis, however, presently very few guidelines exist for this type of analysis. This paper outlines the theoretical analysis used for the determination of the steady state operating temperature and deflections in bolted flange joints. It details the theoretical equations necessary to predict the temperature profiles and thermal expansion difference between the joint components necessary for the evaluation of the load redistribution for the two cases of a flange pair and a flange with a cover plate. The results from the theoretical models are verified by comparison to finite element results.

The Redistribution of Load in Bolted Gasketed Joints Subjected to Steady State Thermal Loading

2002 ◽  
Author(s):  
Akli Nechache ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Steady State ◽  
Thermal Effects ◽  
Thermal Loading ◽  
Operating Temperature ◽  
Theoretical Models ◽  
Joint Analysis ◽  
Effects Of Temperature

Pressure vessel joints operating at high temperature are often very difficult to seal. The existing flange design methods do not address thermal effects other than the variation of flange material mechanical properties with temperature. It is possible to include the effects of temperature loading in joint analysis, however, presently very few guidelines exist for this type of analysis. This paper outlines the theoretical analysis used for the determination of the steady state operating temperature and the induced loads in flange joints. It details the theoretical equations necessary to predict the temperature and the redistribution of load due to the thermal expansion of the joint components for the case of a pair flange and the case of a flange with a blind-cover. The results from the theoretical models are verified by comparison to finite element results.

The Effect of Steady State Thermal Loading on the Deflections of a Flanged Joint With a Cover Plate

2002 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Akli Nechache ◽  
Warren Brown
Keyword(s):  
Thermal Expansion ◽  
Steady State ◽  
Temperature Profile ◽  
Thermal Effects ◽  
Thermal Loading ◽  
Cover Plate ◽  
Asme Code ◽  
Effects Of Temperature ◽  
Bolted Flange

It is well recognized that bolted flange joints operating at high temperature are often very difficult to seal. The existing flange design methods including that of the ASME code do not address thermal effects other than the variation of flange and bolt material mechanical properties with temperature. It is possible to include the effects of temperature loading in the flexibility analysis of the joint. However, the temperature profile to be known to determine the radial and axial thermal expansion displacements of the joint elements to be used in the analysis. This paper outlines the theoretical analysis used for the determination of the steady state operating temperature profile, the thermal expansion displacements of the joint components and the bolt load changes for the case of a flange joint with a blind cover. The results from the proposed analytical model are verified by comparison to finite element results of three different sizes of bolted joints.

An Analytical Solution for Evaluating Gasket Stress Change in Bolted Flange Connections Subjected to High Temperature Loading

2005 ◽  
Vol 127 (4) ◽  
pp. 414-422 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Akli Nechache
Keyword(s):  
Elevated Temperature ◽  
Operating Temperature ◽  
Interaction Model ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Analytical Models ◽  
Cover Plate ◽  
Thermally Induced ◽  
Internal Fluid ◽  
Bolted Flange

The tightness of bolted flanged joints subjected to elevated temperature is not properly addressed by flange design codes. The development of an analytical method based on the flexibility of the different joint components and their elastic interaction could serve as a powerful tool for elevated temperature flange designs. This paper addresses the effect of the internal fluid operating temperature on the variation of the bolt load and consequently on the gasket stress in bolted joints. The theoretical analysis used to predict the gasket load variation as a result of unequal radial and axial thermal expansion of the joint elements is outlined. It details the analytical basis of the elastic interaction model and the thermally induced deflections that are used to evaluate the load changes. Two flange joint type configurations are treated: a joint with identical pair of flanges and a joint with a cover plate. The analytical models are validated and verified by comparison to finite element results.

The Determination of Load Changes in Bolted Gasketed Joints Subjected to Elevated Temperature

2003 ◽  
Author(s):  
Akli Nechache ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Elevated Temperature ◽  
Operating Temperature ◽  
Interaction Model ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Analytical Models ◽  
Cover Plate ◽  
Thermally Induced ◽  
Internal Fluid

The tightness of bolted flanged joints subjected to elevated temperature is not properly addressed by flange design codes. The development of an analytical method based on the flexibility of the different joint components and their elastic interaction could serve as a powerful tool for elevated temperature flange designs. This paper addresses the effect of the internal fluid operating temperature on the variation of the bolt load and consequently on the gasket stress in bolted joints. The theoretical analysis used to predict the gasket load variation as a result of a temperature change is outlined. It details the analytical basis of the elastic interaction model and the thermally induced deflections that are used to evaluate the load changes. Two flange joint type configurations are treated; a joint with identical pair of flanges and a joint with a cover plate. The analytical models are validated and verified by comparison to finite element results.

scholarly journals Numerical analysis of thermal stresses in a new design of microtubular stack

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Paulina Pianko-Oprych ◽  
Tomasz Zinko ◽  
Zdzisław Jaworski
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Thermal Stresses ◽  
Operating Temperature ◽  
Electrical Energy ◽  
Numerical Approach ◽  
Thermal Gradients ◽  
Temperature Profiles ◽  
Species Concentration ◽  
Thermally Induced ◽  
Computational Fluid Dynamics Cfd

AbstractMicrotubular Solid Oxide Fuel Cells (mSOFCs) are one of the most promising and efficient devices that convert chemical energy of fuels into electrical energy. However, mSOFC stacks work at high operating temperature over 650°C, which leads to thermally induced mechanical stresses and in consequence may cause failure of stack components. In order to reduce the local thermal gradients and prevent high stresses in the stack components, it is desirable to study the effect of stack design on its performance. For this purpose a 3D numerical approach was developed to estimate thermal expansion of fuel cell inside an mSOFC stack and to reduce the associated experimental efforts and costs. Initially, a Computational Fluid Dynamics (CFD) model was used to calculate the temperature and species concentration profiles. During the second modeling step temperature profiles were used in the thermo-mechanical model to calculate the thermal stress distribution in the mSOFC stack. The results maximum thermal axial elongation that equals 1.4 mm for the mSOFC stack. The modelled maximum radial elongation was equal to 0.5 mm in the contact areas of the cylindrical housing and manifolds on the fuel inlet side.

scholarly journals The Concept of Accuracy Analysis of the Vertical Displacements Gained from the Hydrostatic Levelling Systems’ Measurements

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4842
Author(s):  
Waldemar Kamiński
Keyword(s):  
Accuracy Assessment ◽  
Theoretical Models ◽  
Vertical Displacement ◽  
Serial Connection ◽  
Vertical Displacements ◽  
Comprehensive Determination ◽  
The One ◽  
The Individual ◽  
Reference Sensor

Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the controlled points (CPs). The reference sensor is the one that is placed at the point that (in theoretical assumptions) is not a subject to vertical displacements and the displacements of controlled points are determined according to its height. The hydrostatic levelling rule comes from the Bernoulli’s law. While using the Bernoulli’s principle in hydrostatic levelling, the following components have to be taken into account: atmospheric pressure, force of gravity, density of liquid used in sensors places at CPs. The parameters mentioned above are determined with some mean errors that influence on the accuracy assessment of vertical displacements. In the subject’s literature, there are some works describing the individual accuracy analyses of the components mentioned above. In this paper, the author proposes the concept of comprehensive determination of mean error of vertical displacement (of each CPs), calculated from the mean errors’ values of components dedicated for specific HLS. The formulas of covariances’ matrix were derived and they enable to make the accuracy assessment of the calculations’ results. The author also presented the subject of modelling of vertical displacements’ gained values. The dependences, enabling to conduct the statistic tests of received model’s parameters, were implemented. The conducted tests make it possible to verify the correctness of used theoretical models of the examined object treated as the rigid body. The practical analyses were conducted for two simulated variants of sensors’ connections in HLS. Variant no. I is the sensors’ serial connection. Variant no. II relies on the connection of each CPs with the reference sensor. The calculations’ results show that more detailed value estimations of the vertical displacements can be obtained using variant no. II.

scholarly journals Towards a self-consistent analysis of the anisotropic galaxy two- and three-point correlation functions on large scales: application to mock galaxy catalogues

2020 ◽  
Author(s):  
Naonori S Sugiyama ◽  
Shun Saito ◽  
Florian Beutler ◽  
Hee-Jong Seo
Keyword(s):  
Correlation Functions ◽  
Hubble Parameter ◽  
Theoretical Models ◽  
Practical Method ◽  
Acoustic Oscillation ◽  
Nonlinear Damping ◽  
Joint Analysis ◽  
Angular Diameter Distance ◽  
Point Correlation ◽  
Parameter Constraints

Abstract We establish a practical method for the joint analysis of anisotropic galaxy two- and three-point correlation functions (2PCF and 3PCF) on the basis of the decomposition formalism of the 3PCF using tri-polar spherical harmonics. We perform such an analysis with MultiDark Patchy mock catalogues to demonstrate and understand the benefit of the anisotropic 3PCF. We focus on scales above 80 h−1 Mpc, and use information from the shape and the baryon acoustic oscillation (BAO) signals of the 2PCF and 3PCF. We also apply density field reconstruction to increase the signal-noise ratio of BAO in the 2PCF measurement, but not in the 3PCF measurement. In particular, we study in detail the constraints on the angular diameter distance and the Hubble parameter. We build a model of the bispectrum or 3PCF that includes the nonlinear damping of the BAO signal in redshift space. We carefully account for various uncertainties in our analysis including theoretical models of the 3PCF, window function corrections, biases in estimated parameters from the fiducial values, the number of mock realizations to estimate the covariance matrix, and bin size. The joint analysis of the 2PCF and 3PCF monopole and quadrupole components shows a $30\%$ and $20\%$ improvement in Hubble parameter constraints before and after reconstruction of the 2PCF measurements, respectively, compared to the 2PCF analysis alone. This study clearly shows that the anisotropic 3PCF increases cosmological information from galaxy surveys and encourages further development of the modeling of the 3PCF on smaller scales than we consider.

scholarly journals Solubilization of Trans-Resveratrol in Some Mono-Solvents and Various Propylene Glycol + Water Mixtures

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3091
Author(s):  
Mohammed Ghazwani ◽  
Prawez Alam ◽  
Mohammed H. Alqarni ◽  
Hasan S. Yusufoglu ◽  
Faiyaz Shakeel
Keyword(s):  
Propylene Glycol ◽  
Mole Fraction ◽  
Bioactive Compound ◽  
Theoretical Models ◽  
Solubility Parameters ◽  
Hansen Solubility Parameters ◽  
Neat Water ◽  
Dissolution Properties ◽  
Hansen Solubility

This research deals with the determination of solubility, Hansen solubility parameters, dissolution properties, enthalpy–entropy compensation, and computational modeling of a naturally-derived bioactive compound trans-resveratrol (TRV) in water, methanol, ethanol, n-propanol, n-butanol, propylene glycol (PG), and various PG + water mixtures. The solubility of TRV in six different mono-solvents and various PG + water mixtures was determined at 298.2–318.2 K and 0.1 MPa. The measured experimental solubility values of TRV were regressed using six different computational/theoretical models, including van’t Hoff, Apelblat, Buchowski–Ksiazczak λh, Yalkowsly–Roseman, Jouyban–Acree, and van’t Hoff–Jouyban–Acree models, with average uncertainties of less than 3.0%. The maxima of TRV solubility in mole fraction was obtained in neat PG (2.62 × 10−2) at 318.2 K. However, the minima of TRV solubility in the mole fraction was recorded in neat water (3.12 × 10−6) at 298.2 K. Thermodynamic calculation of TRV dissolution properties suggested an endothermic and entropy-driven dissolution of TRV in all studied mono-solvents and various PG + water mixtures. Solvation behavior evaluation indicated an enthalpy-driven mechanism as the main mechanism for TRV solvation. Based on these data and observations, PG has been chosen as the best mono-solvent for TRV solubilization.

Combined Experimentaland Theoretical Determination of the Atomic Structure of the (310) Twin in NB

1991 ◽  
Vol 238 ◽  
Author(s):  
Geoffrey H. Campbells ◽  
Wayne E. King ◽  
Stephen M. Foiles ◽  
Peter Gumbsch ◽  
Manfred Rühle
Keyword(s):  
High Resolution ◽  
Theoretical Models ◽  
High Resolution Electron Microscopy ◽  
Interatomic Potentials ◽  
Image Simulation ◽  
Theoretical Determination ◽  
Atomic Structures ◽  
Resolution Electron ◽  
High Resolution Images

ABSTRACTA (310) twin boundary in Nb has been fabricated by diffusion bonding oriented single crystals and characterized using high resolution electron microscopy. Atomic structures for the boundary have been predicted using different interatomic potentials. Comparison of the theoretical models to the high resolution images has been performed through image simulation. On the basis of this comparison, one of the low energy structures predicted by theory can be ruled out.

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