A New Approach to Stress Analysis of Various Wound Vessels

1994 ◽  
Vol 116 (4) ◽  
pp. 359-364 ◽  
Author(s):  
P. S. Huang ◽  
C. R. Friedrich
Keyword(s):  
Axial Load ◽  
Weighting Factor ◽  
Pressure Vessels ◽  
New Approach ◽  
Filament Wound ◽  
Analysis Technique ◽  
Flat Steel ◽  
Filament Wound Vessel ◽  
Theoretical Analyses ◽  
Good Agreement

As the width of windings of wound pressure vessels increases, the vessels are categorized as filament-wound, ribbon-wound, thin plate-wound, and finally the conventional multilayered vessels. The filament-wound vessel is one of the wound vessels with small winding width. A multilayered vessel can be regarded as one where the winding width is very great. Based on winding width, the other types of wound vessels are structurally situated between the filament-wound vessel and the multilayered vessel. As the winding width increases, the stress state in the windings gradually changes from purely biaxial to triaxial, and the windings are able to carry more axial load. Therefore, the windings and the inner shell of any wound vessel should mechanically behave in a state between that of the filament-wound and nonwound multilayered vessels, depending on winding width. By utilizing an analysis technique, analogous to mathematical interpolation, a new approach for calculating stresses for various wound vessels has been developed. The technique uses the stresses in the filament-wound vessel and of the multilayered vessel with the same dimensions, and compensates for the winding width through the use of a weighting factor. Comparisons between theoretical analyses and experiments are given for flat steel ribbon-wound vessels. The results show that the calculated stresses at the inside surface of inner shell are in very good agreement with published experimental data.

Stress Analysis of Pressure Vessel With Wound-Flat Steel Ribbons

1992 ◽  
Vol 114 (1) ◽  
pp. 94-100 ◽  
Author(s):  
P. S. Huang ◽  
G. Zhu
Keyword(s):  
Stress Analysis ◽  
Pressure Vessel ◽  
Mechanical Model ◽  
Axial Load ◽  
Pressure Vessels ◽  
Strengthening Effect ◽  
Republic Of China ◽  
Axial Strength ◽  
Flat Steel ◽  
Spiral Angle

Pressure vessels with wound-flat steel ribbons, also called ribbon-wound vessels, have excellent engineering and economic advantages and are widely used in the People’s Republic of China. A brief description of the structure and characteristics, and a comparison between the ribbon-wound technique with other methods are given. In this paper, a new mechanical model for the ribbons, in which the axial displacement and change of spiral angle are taken into account, is put forward. Then the universal formulas for the ribbon are obtained and a precise stress analysis of the vessel is presented. The spring effect of the ribbon layers has a great strengthening effect on the axial strength of the vessel and enables the vessel to support axial load. A formula for the spring effect is suggested. A comparison between theory and test is made, and the results are excellent.

scholarly journals A NEW APPROACH TO DYNAMIC FINITE-SIZE SCALING

2003 ◽  
Vol 14 (07) ◽  
pp. 945-954 ◽  
Author(s):  
MEHMET DİLAVER ◽  
SEMRA GÜNDÜÇ ◽  
MERAL AYDIN ◽  
YİĞİT GÜNDÜÇ
Keyword(s):  
Three Dimensional ◽  
Finite Size ◽  
Taylor Series Expansion ◽  
Scaling Behavior ◽  
Dynamic Scaling ◽  
Finite Size Scaling ◽  
New Approach ◽  
Size Scaling ◽  
Dynamic Exponent ◽  
Good Agreement

In this work we have considered the Taylor series expansion of the dynamic scaling relation of the magnetization with respect to small initial magnetization values in order to study the dynamic scaling behavior of two- and three-dimensional Ising models. We have used the literature values of the critical exponents and of the new dynamic exponent x0 to observe the dynamic finite-size scaling behavior of the time evolution of the magnetization during early stages of the Monte Carlo simulation. For the three-dimensional Ising model we have also presented that this method opens the possibility of calculating z and x0 separately. Our results show good agreement with the literature values. Measurements done on lattices with different sizes seem to give very good scaling.

Back calculation of parent austenite orientation using a clustering approach

2013 ◽  
Vol 46 (1) ◽  
pp. 210-215 ◽  
Author(s):  
V. Tari ◽  
A. D. Rollett ◽  
H. Beladi
Keyword(s):  
Face Centered Cubic ◽  
Orientation Relationships ◽  
New Approach ◽  
Austenite Grain ◽  
Parent Orientation ◽  
Back Calculation ◽  
Clustering Approach ◽  
Face Centered ◽  
Parent Austenite ◽  
Good Agreement

A new approach is presented for calculating the parent orientation from sets of variants of orientations produced by phase transformation. The parent austenite orientation is determined using the orientations of bainite variants that transformed from a single parent austenite grain. In this approach, the five known orientation relationships are used to back transform each observed bainite variant to all their potential face-centered-cubic (f.c.c.) parent orientations. A set of potential f.c.c. orientations has one representative from each bainite variant, and each set is assembled on the basis of minimum mutual misorientation. The set of back-transformed orientations with the minimum summation of mutual misorientation angle (SMMA) is selected as the most probable parent (austenite) orientation. The availability of multiple sets permits a confidence index to be calculated from the best and next best fits to a parent orientation. The results show good agreement between the measured parent austenite orientation and the calculated parent orientation having minimum SMMA.

On the Influence of a Heat Treat for an Aluminizing Progress Based on Al Microparticles Slurry for Model Ni and Ni20Cr. Experimental and Theoretical Approaches.

2012 ◽  
Vol 323-325 ◽  
pp. 373-379 ◽  
Author(s):  
B. Rannou ◽  
M. Mollard ◽  
B. Bouchaud ◽  
J. Balmain ◽  
G. Bonnet ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Substrate Surface ◽  
Single Step ◽  
Alloying Element ◽  
Aluminum Particles ◽  
New Approach ◽  
Theoretical Approaches ◽  
Barrier Coating ◽  
Coating Characteristics ◽  
Good Agreement

The use of thermal barrier coating systems allows superalloys to withstand higher operating temperatures in aeroengine turbines. Aiming at providing oxidation protection to such substrates, an aluminum-rich layer is deposited to form the α-Al2O3scale over which a ceramic layer (i.e. YSZ layer) is applied to provide thermal insulation. A new approach is now being investigated within the FP7 European project « PARTICOAT », in which a single step process is employed by applying micro-sized aluminum particles. The particles are mixed in a binder and deposited by brushing or spraying on the substrate surface. During a heat treatment, the particles sinter and oxidize to form a top coat composed of hollow con-joint alumina spheres and simultaneously, an Al-rich diffusion zone is formed in the substrate. For a better understanding of the diffusion / growth processes, preliminary tests were carried out on pure nickel and Ni20Cr model alloys prior to further application on commercial superalloys. The effect of the heat treatment on the coating characteristics (number of layers, thickness, composition, homogeneity, etc.) was particularly investigated to emphasize the mechanisms of diffusion governing the growth of the coatings. The establishment of the diffused layers occurred very readily even at intermediate temperatures (650 and 700°C). However, the layers formed did not match perfectly with the thermodynamic modeling because of the quick incorporation of Ni into molten Al at intermediate temperatures (650°C). In contrast, at higher temperatures (700 and 1100°C) the phases predicted by Thermocalc are in good agreement with the observed thickness of the diffused layers. The incorporation of Cr as an alloying element restrained Al ingress by segregation of Cr even at very low temperatures aluminizing temperatures (625°C).

A new look at filter backwash hydraulics

2001 ◽  
Vol 1 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Ömer Akgiray ◽  
Ahmet M. Saatçı
Keyword(s):  
Experimental Measurements ◽  
New Approach ◽  
Ergun Equation ◽  
Mathematical Formulas ◽  
Good Agreement ◽  
New Look

A new approach to model media expansion during filter backwash is presented. The proposed approach is based on the assumption that the Ergun equation remains valid after fluidization. Mathematical formulas are derived for predicting expanded porosity for a given backwash velocity or backwash velocity for a given expanded porosity. These formulas can be easily used by the engineer. Values predicted using the proposed approach are in good agreement with experimental measurements.

Framework for a Combined Netting Analysis and Tsai-Wu-Based Design Approach for Braided and Filament-Wound Composites

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Rifat Hossain ◽  
Jason P. Carey ◽  
Pierre Mertiny
Keyword(s):  
Composite Structures ◽  
Longitudinal Direction ◽  
Industrial Applications ◽  
Pressure Vessels ◽  
Design Tool ◽  
Combined Loading ◽  
Axially Symmetric ◽  
Reinforced Polymer ◽  
Failure Theory ◽  
Filament Wound

Axially symmetric fiber-reinforced polymer composite structures, such as pressure vessels and piping, are being widely used in different industrial applications where combined loading conditions may be applied. It is imperative to determine a suitable fiber angle, or a distribution of fiber angles, along the longitudinal direction of the structure in order to achieve best performance in terms of mechanical behavior and strength for structures subjected to combined loadings. To this end, an approach combining netting analysis and Tsai-Wu failure theory was employed as a design tool to assess critical fiber angles at which applied loadings would cause a structure to fail. Together, the proposed netting analysis and failure theory-based approach constitute a simple, expedient, and convenient design process for complex-shaped structures.

scholarly journals Modeling of the sliding process in condition of disturbed soil stability

2010 ◽  
Vol 90 (1) ◽  
pp. 35-49
Author(s):  
Nedeljko Stojnic
Keyword(s):  
Urban Area ◽  
Distinct Element ◽  
Time History ◽  
Soil Stability ◽  
New Approach ◽  
Rainy Period ◽  
Disturbed Soil ◽  
Profile Line ◽  
Good Agreement ◽  
Terrain Characteristics

Main goal of this investigation is to present a mechanism, terrain shaping of a certain slope during the sliding process, in time history, up to its final form. It means that except slope material movement what is the slope composed, in time of slope occurrence is emphasized becoming of a new terrain form as a result of the process itself, too. This way of investigation definitively opens a new approach in a terrain relief form prediction depends on terrain characteristics and expecting weather occurrence. Here is analyzed a process of land crumbing and sliding on a Neogene slope at Ubilci place (part of urban area of Smederevo city), which was triggered by humane activities (undercutting of slope) and weather influence (rainy period). To present continuity flow of the slope material movement, it is used extended distinct element method. Profile line of the terrain surface which is obtained by numerical analyzes is in very good agreement with the finale profile line of the slope where a real case of crumbing and soil sliding has occurred. .

scholarly journals The seismic performance of steel encased reinforced concrete bridge piles

1983 ◽  
Vol 16 (2) ◽  
pp. 123-140
Author(s):  
R. J. T. Park ◽  
M. J. N. Priestley ◽  
W. R. Walpole
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Theoretical Investigation ◽  
Axial Load ◽  
Lateral Displacement ◽  
Load Level ◽  
Concrete Bridge ◽  
Reinforced Concrete Bridge ◽  
Outside Diameter ◽  
Good Agreement

An experimental and theoretical investigation into the seismic performance of steel encased reinforced concrete bridge piles is described. Six test units were designed, constructed and tested
under cyclic lateral displacement-controlled loading. The units had
an outside diameter of 360 mm and a steel casing thickness of 5 mm. Variables included the axial load level, inclusion or exclusion of internal reinforcing cages, and the influence of the casing continuity at he critical flexural sections. Sound seismic performance was observed in all of the models and good agreement between predicted and observed ultimate behaviour was obtained.

Optimal Winding Conditions of Flat Steel Ribbon Wound Pressure Vessels With Controllable Stresses

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Chuanxiang Zheng ◽  
Shaohui Lei
Keyword(s):  
Optimal Design ◽  
Stress Analysis ◽  
Design Method ◽  
Pressure Vessels ◽  
Layer By Layer ◽  
Shell Layer ◽  
Discrete Structure ◽  
Flat Steel ◽  
Optimal Design Method ◽  
Steel Ribbon

Stress analysis of flat steel ribbon wound pressure vessels (FSRWPVs) is very difficult because they have a special discrete structure and complex pretensions exit in the flat steel ribbons, which are wound around the inner shell layer by layer. An analytical multilayered model for stress analysis is presented in this paper, which involves the effect of prestress in every flat steel ribbon layer as well as in the inner shell. Based on this model, an optimal design method for FSRWPV is suggested, which can assure a reasonable stress level and distribution along the wall thickness during the operation. A practical example of a large FSRWPV is finally given for illustration.

Determination of Subnanosecond Fluorescence Lifetimes with a UHF Television Tuner and a cw or Mode-Locked Laser

1986 ◽  
Vol 40 (5) ◽  
pp. 683-687 ◽  
Author(s):  
Frank V. Bright ◽  
Daniel A. Wilson ◽  
Gary M. Hieftje
Keyword(s):  
High Frequency ◽  
Rhodamine 6G ◽  
Instrument Design ◽  
Fluorescence Lifetimes ◽  
New Approach ◽  
Ion Laser ◽  
Subnanosecond Fluorescence ◽  
Argon Ion ◽  
Good Agreement

An inexpensive ultra-high-frequency (UHF) television tuner and an argon-ion laser are employed for the determination of excited-state lifetimes of a series of common fluorophores. Fluorescence lifetimes are determined in the frequency domain; the results are in good agreement with previously reported values and demonstrate the utility of the new approach for subnanosecond measurements. Binary mixtures of rhodamine 6G and rose bengal can also be resolved with the use of this novel instrument design.

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