C214 Proposal of Limit Moment Equation Applicable to Planar/Non-Planar Flaw in Wall Thinned Pipes under Bending

2011 ◽  
Vol 2011.16 (0) ◽  
pp. 309-312
Author(s):  
Masataka TSUJI ◽  
Toshiyuki MESHII
Keyword(s):  
Moment Equation ◽  
Planar Flaw

scholarly journals Proposal of Limit Moment Equation Applicable to Planar/Non-Planar Flaw in Wall Thinned Pipes Under Bending

2011 ◽  
Author(s):  
Masataka Tsuji ◽  
Toshiyuki Meshii
Keyword(s):  
Experimental Observation ◽  
Fracture Mode ◽  
Bending Moment ◽  
Moment Equation ◽  
Planar Flaw

In this paper, limit bending moment equation applicable to all types of planar and non-planar flaw in wall thinned straight pipes under bending was proposed. An idea to rationally classify planar/non-planar flaw in wall thinned pipes was proposed, based on the experimental observation focused on the fracture mode. The results point out the importance to distinguish axially and circumferentially long flaws in wall thinned pipes.

Moment equation for the packed column with spherical composites

1993 ◽  
Vol 10 (4) ◽  
pp. 240-243
Author(s):  
In-Soo Park ◽  
Dae-Young Ahn
Keyword(s):  
Packed Column ◽  
Moment Equation

Large-amplitude undulatory fish swimming: fluid mechanics coupled to internal mechanics

1999 ◽  
Vol 202 (23) ◽  
pp. 3431-3438 ◽  
Author(s):  
T.J. Pedley ◽  
S.J. Hill
Keyword(s):  
Vortex Ring ◽  
Large Amplitude ◽  
Muscle Activation ◽  
Bending Moment ◽  
Hydrodynamic Pressure ◽  
Moment Equation ◽  
Panel Method ◽  
The Body ◽  
Undulatory Swimming ◽  
Body Theory

The load against which the swimming muscles contract, during the undulatory swimming of a fish, is composed principally of hydrodynamic pressure forces and body inertia. In the past this has been analysed, through an equation for bending moments, for small-amplitude swimming, using Lighthill's elongated-body theory and a ‘vortex-ring panel method’, respectively, to compute the hydrodynamic forces. Those models are outlined in this review, and a summary is given of recent work on large-amplitude swimming that has (a) extended the bending moment equation to large amplitude, which involves the introduction of a new (though probably usually small) term, and (b) developed a large-amplitude vortex-ring panel method. The latter requires computation of the wake, which rolls up into concentrated vortex rings and filaments, and has a significant effect on the pressure on the body. Application is principally made to the saithe (Pollachius virens). The calculations confirm that the wave of muscle activation travels down the fish much more rapidly than the wave of bending.

INVESTIGATION OF THE INFLUENCE OF THE ELBOW JOINT REACTION ON THE PREDICTED MUSCLE FORCES USING DIFFERENT OPTIMIZATION FUNCTIONS

2009 ◽  
Vol 12 (01) ◽  
pp. 31-43 ◽  
Author(s):  
Rositsa T. Raikova
Keyword(s):  
Objective Function ◽  
Elbow Joint ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Biomechanical Model ◽  
Moment Equation ◽  
Muscle Forces ◽  
Joint Stability ◽  
Biarticular Muscles ◽  
Joint Reaction

Less attention is paid to joint reactions when optimization tasks are solved aiming to predict individual muscle forces driving a biomechanical model. The reactions are important, however, for joint stability and for prevention from injuries, especially for fast motions and submaximal loading. The purpose of the paper is to investigate the influence of the joint reaction as a criterion in an objective function and to study the possibilities for prediction of antagonistic co-contraction. Planar elbow flexions in the sagittal plane with duration from 0.4 to 2 s are simulated, and muscle forces and elbow joint reaction are calculated solving numerically optimization tasks formulated for models with one (elbow moment equation only) and two (elbow and shoulder moment equations) degrees of freedom (DOF). The objective function is a weighted sum of muscle forces and joint reaction raised to different powers. The following conclusions can be made: (1) if the joint reaction is included in the objective function, antagonistic co-contraction can be predicted even for 1 DOF model; in some situations the use of such objective function can destroy the synergistic muscles' action; (2) the prediction of antagonistic muscles' co-contraction for 2 DOF model depends on the way the biarticular muscles are modeled, and this is valid for both dynamic and quasistatic conditions; if there are no biarticular muscles, antagonistic co-contraction cannot be predicted in one joint using popular objective functions, like minimum of sum of muscle forces or muscle stresses raised to a power.

scholarly journals A convergence study for the Laguerre expansion in the moment equation method for neoclassical transport in general toroidal plasmas

2010 ◽  
Vol 17 (8) ◽  
pp. 082510 ◽  
Author(s):  
S. Nishimura ◽  
H. Sugama ◽  
H. Maaßberg ◽  
C. D. Beidler ◽  
S. Murakami ◽  
...  
Keyword(s):  
Moment Equation ◽  
Equation Method ◽  
Laguerre Expansion ◽  
Toroidal Plasmas ◽  
Neoclassical Transport ◽  
Convergence Study ◽  
The Moment

Fracture Failure Risk Analysis of Pressure Pipeline Containing Defects on Pile Foundation Settlement

2006 ◽  
Author(s):  
Xiang Li ◽  
Jinyang Zheng ◽  
Yujun Xie
Keyword(s):  
Risk Analysis ◽  
Failure Probability ◽  
Pile Foundation ◽  
Moment Equation ◽  
Assessment Procedure ◽  
Foundation Settlement ◽  
Disastrous Consequence ◽  
Fracture Failure ◽  
Failure Risk ◽  
Pressure Pipeline

Pile foundation settlement might cause a disastrous consequence to an in-service pressure pipeline. Flaws, which are unavoidable in the pipeline, lead to reduction of load-supporting capability and service life of the pipeline. So fracture failure risk analysis of in-service pressure pipeline is important in engineering. Failure probability of pipeline due to pile foundation settlement is computed by using the well-known safety assessment procedure R6. Three-moment equation is adopted to compute bending moment in the condition of n piles, where n is the number of piles. A numerical example was presented to illustrate the application of fracture failure risk analysis to determine the failure probability of the pressure pipeline, considering the uncertainties in various internal operating loadings and external forces, flaw sizes, material fracture toughness and flow stress. Furthermore, the failure probabilities of each defect and the whole pipeline were obtained.

A power moment reformulation of the Nikiforov–Uvarov method for exactly solvable systems

2016 ◽  
Vol 94 (4) ◽  
pp. 410-424
Author(s):  
Carlos R. Handy ◽  
Daniel Vrinceanu
Keyword(s):  
Closed Form ◽  
Discrete Spectrum ◽  
Asymptotic Form ◽  
Moment Equation ◽  
Wave Functions ◽  
Moment Equations ◽  
Power Moment ◽  
Exactly Solvable ◽  
Uvarov Method ◽  
Polynomial Expansions

Exactly solvable (ES) systems are those for which the full, discrete spectrum can be solved in closed form. In this work, we argue that a moment’s representation analysis can generate these closed-form expressions for the energy in a more direct and transparent manner than the popular Nikiforov–Uvarov (NU) procedure. NU analysis strips the asymptotic form of the physical states. We retain these to generate appropriate moment equations. We show how the form of these moment equations leads to closed-form energy expressions. The wave functions can then be generated as well. Our analysis is extendable to quasi-exactly solvable systems (QES; those for which a subset of the discrete spectrum can be generated in closed form). Two formulations are presented. One of these affirms that a previously developed, general, moment quantization procedure is exact for ES and QES states. This method is referred to as the orthogonal polynomial projection quantization method. It combines moment equation representations for physical states with weighted polynomial expansions (Handy and Vrinceanu. J. Phys. A: Math. Theor. 46, 135202 (2013). doi:10.1088/1751-8113/46/13/135202 ). We also show that in implementing any numerical search procedure to determine the quantum parameter regimes corresponding to ES or QES states, our procedure is more reliable (i.e., numerically stable) than using a Hill determinant formulation. We develop our formalism, demonstrate its effectiveness, and prove its equivalence to the NU approach for ES systems.

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