Analytical Limit Load Procedure for The Axial Complex Shaped Defect in a Pressurized Pipe

2021 ◽  
Author(s):  
Igor Orynyak ◽  
Julia Bai ◽  
Roman Mazuryk
Keyword(s):  
General Procedure ◽  
Limit Load ◽  
Admissible Solution ◽  
Experimental Comparison ◽  
Physical Parameters ◽  
Equilibrium Equations ◽  
Axial Complex ◽  
The Difference ◽  
Full Scale Tests ◽  
Distribution Of Stress

Abstract The paper is devoted to elaboration of the analytical O-procedure for limit load analysis of complex shaped axial defect in a pressurized pipe. It is based on the classical lower bound theorem of the theory of plasticity, and consists in construction of the statically admissible solution, where distribution of stress satisfies to the equilibrium equations and strength conditions. O-procedure is an optimization process to get the most favorable stress distribution for providing the maximal pressure. It allows to explicitly account for the variable geometrical and physical parameters. Contrary to other approaches, the derived formula for rectangular defect is only a particular case of the general procedure application. Four different methods for the complex defects are compared. They are: first, ASME, A-, rectangular defect formula combined with RSTRENG, R-, procedure, i.e., A-R approach; second, PCORRC, P-, formula with R-procedure, P-R approach; third, Orynyak's, O-, formula with R-procedure, O-R approach; and fourth, our universal O-procedure. The verification begins for rectangular defects where both theoretical and experimental comparison is performed for A-, P-, and O- formulas. The difference between them is small, provided that all three employ the same characteristic of material, here the ultimate strength. Then theoretical comparison for A-R, P-R, O-R approaches and O-procedure is performed for the artificial complex defects, for two symmetrical rectangular defects, for triangular defect. Experimental comparison between four methods is made based on the well-known University of Waterloo full scale tests.

scholarly journals Nonlinear stability of two-layer shallow water flows with a free surface

2020 ◽  
Vol 476 (2236) ◽  
pp. 20190594
Author(s):  
Francisco de Melo Viríssimo ◽  
Paul A. Milewski
Keyword(s):  
Free Surface ◽  
Initial Data ◽  
Nonlinear Stability ◽  
Mathematical Proof ◽  
Passive Layer ◽  
Physical Parameters ◽  
Immiscible Fluid ◽  
Dimensional System ◽  
The Cauchy Problem ◽  
The Difference

The problem of two layers of immiscible fluid, bordered above by an unbounded layer of passive fluid and below by a flat bed, is formulated and discussed. The resulting equations are given by a first-order, four-dimensional system of PDEs of mixed-type. The relevant physical parameters in the problem are presented and used to write the equations in a non-dimensional form. The conservation laws for the problem, which are known to be only six, are explicitly written and discussed in both non-Boussinesq and Boussinesq cases. Both dynamics and nonlinear stability of the Cauchy problem are discussed, with focus on the case where the upper unbounded passive layer has zero density, also called the free surface case. We prove that the stability of a solution depends only on two ‘baroclinic’ parameters (the shear and the difference of layer thickness, the former being the most important one) and give a precise criterion for the system to be well-posed. It is also numerically shown that the system is nonlinearly unstable, as hyperbolic initial data evolves into the elliptic region before the formation of shocks. We also discuss the use of simple waves as a tool to bound solutions and preventing a hyperbolic initial data to become elliptic and use this idea to give a mathematical proof for the nonlinear instability.

scholarly journals Acoustic Characterization of Some Steel Industry Waste Materials

2021 ◽  
Vol 11 (13) ◽  
pp. 5924
Author(s):  
Elisa Levi ◽  
Simona Sgarbi ◽  
Edoardo Alessio Piana
Keyword(s):  
Thermal Characteristic ◽  
Environmental Benefits ◽  
Acoustic Properties ◽  
Physical Parameters ◽  
Industry Waste ◽  
Acoustic Characterization ◽  
Minimization Procedure ◽  
The Difference ◽  
By Products

From a circular economy perspective, the acoustic characterization of steelwork by-products is a topic worth investigating, especially because little or no literature can be found on this subject. The possibility to reuse and add value to a large amount of this kind of waste material can lead to significant economic and environmental benefits. Once properly analyzed and optimized, these by-products can become a valuable alternative to conventional materials for noise control applications. The main acoustic properties of these materials can be investigated by means of a four-microphone impedance tube. Through an inverse technique, it is then possible to derive some non-acoustic properties of interest, useful to physically characterize the structure of the materials. The inverse method adopted in this paper is founded on the Johnson–Champoux–Allard model and uses a standard minimization procedure based on the difference between the sound absorption coefficients obtained experimentally and predicted by the Johnson–Champoux–Allard model. The results obtained are consistent with other literature data for similar materials. The knowledge of the physical parameters retrieved applying this technique (porosity, airflow resistivity, tortuosity, viscous and thermal characteristic length) is fundamental for the acoustic optimization of the porous materials in the case of future applications.

scholarly journals ELECTROKINETIC PHENOMENA

1931 ◽  
Vol 14 (5) ◽  
pp. 563-573 ◽  
Author(s):  
H. A. Abramson ◽  
E. B. Grossman
Keyword(s):  
Streaming Potential ◽  
Experimental Comparison ◽  
Consistent Difference ◽  
Real Difference ◽  
Electrokinetic Phenomena ◽  
Egg Albumin ◽  
Streaming Potentials ◽  
The Difference

1. The conditions are described which are necessary for the comparison of certain types of electrokinetic potentials. An experimental comparison is made of (a) electrophoresis of quartz particles covered with egg albumin; and (b) similar experiments by Briggs on streaming potentials. A slight, consistent, difference is found between the electrophoretic potential and the streaming potential. This difference is probably due to the difference in the protein preparations used rather than to real difference in the electrophoretic and streaming potentials. 2. Data are given which facilitate the measurements and enhance the precision of the estimation of electrical mobilities of microscopic particles.

Aerodynamic Data for Two Variants of Root Turbine Blade Sections for a 54″ Turbine Rotor Blade

2014 ◽  
Author(s):  
David Šimurda ◽  
Martin Luxa ◽  
Pavel Šafařík ◽  
Jaroslav Synáč ◽  
Bartoloměj Rudas
Keyword(s):  
Limit Load ◽  
Axial Direction ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Angle Of Incidence ◽  
Flow Angle ◽  
Turbine Rotor Blade ◽  
Blade Cascade ◽  
The Difference ◽  
Kinetic Energy Loss

Aerodynamic investigations were performed on planar blade cascades representing two alternative root sections of rotor blades 54″ in length with straight fir-tree root. Each of the variants was designed for different number of blades in the rotor. This paper presents the results of measurements showing the dependency of the kinetic energy loss coefficient and the exit flow angle on the exit isoentropic Mach number and the angle of incidence. Images of the flow fields are also presented. The experimental data is analyzed to assess and document the difference between the two root section designs. Results show that requirement of straight fir tree root leading to high design incidence angles significantly limit operation range. Also in case of root sections with high exit Mach numbers a limit load conditions are an issue. In order to utilize available pressure drop blade cascade throat/pitch ratios should be kept as high as possible which favorites variant with lower number of blades and higher outlet metal angle (relative to axial direction).

scholarly journals Research on the Difference of Physical Parameters of Concrete in Saline-alkali Environment

2020 ◽  
Vol 143 ◽  
pp. 01014
Author(s):  
Yumao Qi ◽  
Junge Huang ◽  
Yu Liu ◽  
Jian Pei
Keyword(s):  
Reinforced Concrete ◽  
Sodium Sulfate ◽  
Rock Specimen ◽  
Test Block ◽  
Control Group ◽  
Physical Parameters ◽  
Significant Difference ◽  
Specimen Test ◽  
Water Test ◽  
The Difference

In order to better study the corrosion of concrete in saline-alkali area, the model tests of concrete and reinforced concrete with different ions and different ion concentrations were constructed. Taking the test blocks mixed with water as the control group, the resistance and polarizability of the test block during the maintenance period were measured by rock specimen tester and rock specimen test frame. The one-way variance analysis of the measured values of each test block was carried out by spss software, investigating the difference of electrical parameters of each concrete. The results show that there is significant difference in the resistance between the clear water concrete test block and the 3% sodium sulfate concrete test block at the level of significance ≤ 0.05. For reinforced concrete test blocks, the resistivity difference between water test block and 3% sodium sulfate test block and 6% sodium sulfate test block is not significant, and the resistivity difference between water test block and 15% sodium sulfate test block and 3% sodium chloride test block is significant. No matter concrete or reinforced concrete, the polarizability of test blocks mixed with water and test blocks mixed with each solution is significantly different. Therefore, the polarizability parameters can be used to distinguish whether the concrete is corroded by salt and alkali. It is feasible to use polarizability parameter to detect concrete erosion by salt and alkali.

scholarly journals An Experimental Comparison of the Impact of ‘Warning’ and ‘Health Star Rating’ FoP Labels on Adolescents’ Choice of Breakfast Cereals in New Zealand

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1545 ◽  
Author(s):  
Robert Hamlin ◽  
Benjamin Hamlin
Keyword(s):  
New Zealand ◽  
Experimental Comparison ◽  
Vienna Convention ◽  
Single Star ◽  
Star Rating ◽  
Stop Sign ◽  
Significant Difference ◽  
Nutritional Label ◽  
The Difference ◽  
The Impact

This research investigated the performance of the red, octagonal Vienna Convention traffic ‘STOP’ sign as a front of pack (FoP) warning nutritional label. While the Vienna Convention traffic light system is an established FoP label, the potential of the ‘STOP’ sign in the role has not been investigated. The performance of the ‘STOP’ label was compared with that of a single star (low nutritional value) Australasian Health Star Rating (HSR) label using a fractionally replicated Latin square design. The labels were presented on choice diads of cold breakfast cereal packets. The sample of 240 adolescents aged 16–18 was drawn from a secondary school in the South Island of New Zealand. A large and significant main effect was observed at the p < 0.01 level for the difference between the ’STOP’ sign and the control condition (no nutritional FoP label), and at p < 0.05 for the difference between the HSR and the ‘STOP’ label. There was no significant difference between the HSR FoP and the control condition. A significant non-additivity (interaction) (p < 0.01) was also observed via the fractional replication. The results indicate that the Vienna Convention ‘STOP’ sign is worthy of further research with regard to its potential as an FoP nutritional label.

scholarly journals Physical parameters and chemical abundances of Planetary Nebulae in the large Magellanic Cloud

1997 ◽  
Vol 180 ◽  
pp. 471-471 ◽  
Author(s):  
R. E. Carlos Reyes ◽  
J. E. Steiner ◽  
F. Elizalde
Keyword(s):  
Planetary Nebulae ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Physical Parameters ◽  
Chemical Abundances ◽  
The Difference

In the present work we have computed the physical parameters and chemical abundances for 45 planetary nebulae (PN) in the Large Magellanic Cloud (LMC) using the photoionization code CLOUDY, developed by Ferland (1993). CLOUDY is used as a subroutine in the code DIANA, developed by Elizalde & Steiner (1996), which minimises indices that measures the difference between the calculated and real nebula.

scholarly journals Variations of the snow physical parameters and their effects on albedo in Sapporo, Japan

2007 ◽  
Vol 46 ◽  
pp. 375-381 ◽  
Author(s):  
Teruo Aoki ◽  
Hiroki Motoyoshi ◽  
Yuji Kodama ◽  
Teppei J. Yasunari ◽  
Konosuke Sugiura
Keyword(s):  
Grain Size ◽  
Near Infrared ◽  
Mineral Dust ◽  
Radiation Budget ◽  
Radiative Transfer Model ◽  
Physical Parameters ◽  
Transfer Model ◽  
Infrared Wavelengths ◽  
The Difference ◽  
Impurity Models

AbstractContinuous measurements of the radiation budget and meteorological components, along with frequent snow-pit work, were performed in Sapporo, Hokkaido, Japan, during two winters from 2003 to 2005. The measured relationships between broadband albedos and the mass concentration of snow impurities were compared with theoretically predicted relationships calculated using a radiative transfer model for the atmosphere–snow system in which different types (in light absorption) of impurity models based on mineral dust and soot were assumed. The result suggests that the snow in Sapporo was contaminated not only with mineral dust but also with more absorptive soot. A comparison of the measured relationships between broadband albedos and snow grain size for two different layers with the theoretically predicted relationships revealed that the visible albedo contains information about the snow grain size in deeper snow layers (10 cm), and the near-infrared albedo contains only surface information. This is due to the difference in penetration depth of solar radiation into snow between the visible and the near-infrared wavelengths.

scholarly journals Plastic collapse load analysis for circumferential cracked cylinder under pure torsion

2018 ◽  
Vol 192 ◽  
pp. 02023
Author(s):  
Sutham Arun ◽  
Thongchai Fongsamootr
Keyword(s):  
Limit Load ◽  
Fe Model ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Pure Torsion ◽  
Perfectly Plastic ◽  
Torsion Moment ◽  
Elastic Perfectly Plastic ◽  
Distribution Of Stress ◽  
Cracked Cylinder

This paper aims to analyze the plastic collapse moment of circumferential cracked cylinder under pure torsion using the NSC approach and 3D FE model. The material considered in this work is assumed to be elastic-perfectly plastic. The influences of geometric parameters of crack and cylinder, such as Rm/t, a/t and θ/π on solution of plastic collapse load are also investigated. The analysis shows that for the case of a/t < 0.75, the values of limit torsion moment can be estimated by NSC analysis which provides conservative results. However, for the case of deeper crack, a/t ≥ 0.75, the limit load solution predicted by NSC approach may not be safe, because the distribution of stress at yielding state does not correspond to the NSC assumption. Therefore, the approximated solution of collapse torsion moment for the case of deeper crack with a/t ≥ 0.75 is proposed based on FE analysis.

The force on an elastic singularity

1951 ◽  
Vol 244 (877) ◽  
pp. 87-112 ◽  
Keyword(s):  
Elastic Field ◽  
Image Force ◽  
Theory Of Elasticity ◽  
The Body ◽  
Total Force ◽  
Equilibrium Equations ◽  
Elastic Continuum ◽  
Foreign Atom ◽  
The Difference ◽  
Maxwell Tensor

The parallel between the classical theory of elasticity and the modern physical theory of the solid state is incomplete; the former has nothing analogous to the concept of the force acting on an imperfection (dislocation, foreign atom, etc.) in a stressed crystal lattice. To remedy this a general theory of the forces on singularities in a Hookean elastic continuum is developed. The singularity is taken to be any state of internal stress satisfying the equilibrium equations but not the compatibility conditions. The force on a singularity can be given as an integral over a surface enclosing it. The integral contains the elastic field quantities which would surround the singularity in an infinite medium, multiplied by the difference between these quantities and those actually present. The expression for the force is thus of essentially the same form whether the force is due to applied surface tractions, other singularities or the presence of the free surface of the body (‘image force’). A region of inhomogeneity in the elastic constants modifies the stress field; if it is mobile one can define and calculate the force on it. The total force on the singularities and inhomogeneities inside a surface can be expressed in terms of the integral of a ‘ Maxwell tensor of elasticity’ taken over the surface. Possible extensions to the dynamical case are discussed,

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