Vibrations and Power Flows in a Coupled Beam System

2007 ◽  
Vol 129 (5) ◽  
pp. 616-622 ◽  
Author(s):  
Wen L. Li ◽  
Murilo W. Bonilha ◽  
Jie Xiao

Vibrations of and power flow between coupled beams have been the subject of many investigations, and various techniques have been developed over the years. However, most of the existing methods will require a certain level of modifications or adaptations to account for the variations in the coupling and∕or boundary conditions. In this study, a general analytical method is developed for predicting the vibrations of and power flow between two-coupled beams. The coupling between the beams is generically represented by two (translational and rotational) springs of arbitrary stiffnesses. Thus, many rigid and nonrigid connectors of practical interest can be directly taken into account. In addition, because the beams are elastically restrained at each end, the current method can be universally applied to different boundary conditions by simply varying the stiffnesses of the boundary springs. Numerical results are presented to show the excellent accuracy of the proposed approach.

Author(s):  
Wen L. Li ◽  
Murilo W. Bonilha ◽  
Jie Xiao

Vibrations of and power flows between coupled beams have been the subject of many investigations and various techniques have been developed over years. However, most of these techniques are typically proposed for a specific case that involves a particular kind of boundary conditions and/or connections. In this study, a general analytical method is developed for predicting the vibrations of and power flow between two-coupled beams. The coupling between the beams is generically represented by two (translational and rotational) springs of arbitrary stiffnesses. Thus, many rigid and non-rigid connectors of practical interest can be directly taken into account. In addition, because the beams are elastically restrained at each end, the current method can be universally applied to different boundary conditions by simply varying the stiffnesses of the boundary springs. Numerical results are presented to show the excellent accuracy of the proposed approach.


Author(s):  
رضوان جمال الأطرش ◽  
نجوى نايف شكوكاني

        الملخّص      هدف هذا البحث إبراز إمكانية التأثر العملي بأسلوب التعليل في القرآن الكريم، ومحاولة البحث في تطبيقاته في واقع العملية التعليمية من العالم والمتعلم، بحيث لم يقتصر على الدراسة اللغوية أو الأصولية النظرية؛ وخصوصاً بعد التعريف بهذا الأسلوب وأدواته وأهميته وبيان اللوازم الخاصة للعالم والمتعلم للتأثر به، وقد تم ذلك من خلال استخدام المنهج الاستقرائي بتتبع أعمال العلماء في ذلك وتم رصد أقوال المفسرين فيما يتعلق بالأساليب البيانية وآيات التعليل ووجوه الإعجاز القرآني، ومن ثم استُخدم المنهج التحليلي لإثبات ذلك الأثر وإثبات وجود إشارات وأدلة على مظاهر التأثر؛ واستنتاج حقيقة إمكانية استمرارية البحث في كل أدوات وآيات ومواضيع ذلك الأسلوب بنفس الطريقة التي تمّ طرحُها، مما يثري هذا المجال، ويفتح العقول ويدفعها للنظر والتدبر والبحث في آي القرآن، وفي كل المناحي، منطلقةً من فكر التجديد، والإفادة من مستجدات العصر وعلومه ضمن ضوابط العقيدة الغراء والشرع الحنيف. الكلمات المفتاحية: أسلوب التعليل، أدوات أسلوب التعليل، التدبر، التعليم التقليدي، أثر.  Abstract This study intends to highlight the possible practical impact of the principles of argumentation found in the Qur’an. The study attempts to apply the principles on the actual education process of the scholars and students without limiting it to linguistic studies or theoretical principles. This was done after introducing the principles of reasoning, its tools, its importance, and disclosing the special requirements for the scholars and students in order to be influenced by the latter principles.  The work used inductive method to track the works of the scholars on the subject and observe the opinions of the Qur’an-commentators in relation to principles of explanation, verses of argument, and aspects of Qur’anic Inimitability. Analytical method was used to establish the impacts of the Qur’anic arguments; to prove the presence of signs and evidences for the manifestation of the impacts; and to make the continuity of this research possible in all the tools, verses and topics related to the principles of Qur’anic argument. Among those things that enrich this work is that it opens the minds, and pushes it to ponder and study the verses of the Qur’an. For every direction it becomes the starting point for the innovative thinking, and benefit for the new age and its sciences while maintaining the harmony with the principles of creed and the true SharÊ‘ah. Keywords: Principles of Argumentation, Tools of Argumentation Principles, Thinking, Traditional Education, Effect.


2015 ◽  
Vol 15 (02) ◽  
pp. 1450040 ◽  
Author(s):  
Seyed Mojtaba Hozhabrossadati ◽  
Ahmad Aftabi Sani ◽  
Masood Mofid

This technical note addresses the free vibration problem of an elastically restrained Euler–Bernoulli beam with rotational spring-lumped rotary inertia system at its mid-span hinge. The governing differential equations and the boundary conditions of the beam are presented. Special attention is directed toward the conditions of the intermediate spring-mass system which plays a key role in the solution. Sample frequency parameters of the beam system are solved and tabulated. Mode shapes of the beam are also plotted for some spring stiffnesses.


2012 ◽  
Vol 5 (1) ◽  
pp. 3-30 ◽  
Author(s):  
G. Shephard ◽  
F. Berthiller ◽  
P. Burdaspal ◽  
C. Crews ◽  
M. Jonker ◽  
...  

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2010 and mid-2011. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Analytical methods for mycotoxins continue to be developed and published. Despite much interest in immunochemical methods and in the rapid development of LC-MS methodology, more conventional methods, sometimes linked to novel clean-up protocols, have also been the subject of research publications over the above period. Occurrence of mycotoxins falls outside the main focus of this review; however, where relevant to analytical method development, this has been mentioned.


2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Konstantin I. Matveev ◽  
Sungmin Jung

The subject of this paper is modeling of low-amplitude acoustic fields in enclosures with nonuniform medium and boundary conditions. An efficient calculation method is developed for this class of problems. Boundary conditions, accounting for the boundary-layer losses and movable walls, are applied near solid surfaces. The lossless acoustic wave equation for a nonuniform medium is solved in the bulk of the resonator by a finite-difference method. One application of this model is for designing small thermoacoustic engines. Thermoacoustic processes in the regular-geometry porous medium inserted in resonators can be modeled analytically. A calculation example is presented for a small-scale thermoacoustic engine coupled with an oscillator on a flexing wall of the resonator. The oscillator can be used for extracting mechanical power from the engine. A nonuniform wall deflection may result in a complicated acoustic field in the resonator. This leads to across-the-stack variations of the generated acoustic power and local efficiency of thermoacoustic energy conversion.


2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Hui Shi ◽  
Teijun Yang ◽  
Shiliang Jiang ◽  
W. L. Li ◽  
Zhigang Liu

Effects of curvature upon the vibration characteristics of doubly curved shallow shells are assessed in this paper. Boundary conditions of the shell are generally specified in terms of distributed elastic restraints along the edges. The classical homogeneous boundary supports can be easily simulated by setting the stiffnesses of restraining springs to either zero or infinite. Vibration problems of the shell are solved by a modified Fourier series method that each of the displacements is invariably expressed as a simple trigonometric series which converges uniformly and acceleratedly over the solution domain. All the unknown expansion coefficients are treated equally as a set of independent generalized coordinates and solved using the Rayleigh-Ritz technique. The current method provides a unified solution to the vibration problems of curved shallow shells involving different geometric properties and boundary conditions with no need of modifying the formulations and solution procedures. Extensive tabular and graphical results are presented to show the curvature effects on the natural frequencies of the shell with various boundary conditions.


2011 ◽  
Vol 1 (32) ◽  
pp. 67
Author(s):  
Boyang Jiang ◽  
James Kaihatu

As the forecasting models become more sophisticated in their physics and possible depictions of the nearshore hydrodynamics, they also become increasingly sensitive to errors in the inputs, such as errors in the specification of boundary information (lateral boundary conditions, initial boundary conditions, etc). Evaluation of the errors on the boundary is less straightforward, and is the subject of this study. The model under investigation herein is the Delft3D modeling suite, developed at Deltares (formerly Delft Hydraulics) in Delft, the Netherlands. Coupling of the wave (SWAN) and hydrodynamic (FLOW) model requires care at the lateral boundaries in order to balance run time and error growth. To this extent, we will use perturbation method and spatio-temporal analysis method such as Empirical Orthogonal Function (EOF) analysis to determine the various scales of motion in the flow field and the extent of their response to imposed boundary errors.


2021 ◽  
Vol 27 (8) ◽  
pp. 1894-1910
Author(s):  
Marzhinat I. KANKULOVA ◽  
Sabina Z. OSMANOVA

Subject. This article examines the business processes of treasury control in the course of authorizing budget expenditures of the subject of the Russian Federation. Objectives. The article aims to develop recommendations for improving the business processes of treasury execution of budget expenditures of the subject of the Russian Federation. Methods. For the study, we used the methods of formalization, analysis and synthesis, induction and deduction, comparison, observation, and other general scientific theoretical and empirical research methods. Results. The article identifies reserves for increasing the potential of treasury control of the financial body of the Russian Federation subject by modifying the functionality of the budget process automated information system. It offers recommendations to increase the number of transactions for which extensive documentary control is carried out, while reducing the labor costs for performing the same type of current operations. Conclusions and Relevance. The proposals to optimize treasury control are in line with the solution of common tasks for the development of modern technologies for budget execution based on digitalization and automation of budget procedures. The results obtained may be of practical interest to the financial authorities of the Russian Federation constituent entities (municipalities) that implement their budgets independently through the current budget account opened at the Federal Treasury.


2015 ◽  
Vol 61 (3) ◽  
pp. 149-168
Author(s):  
A. Szychowski

AbstractBuckling of the stiffened flange of a thin-walled member is reduced to the buckling analysis of the cantilever plate, elastically restrained against rotation, with the free edge stiffener, which is susceptible to deflection. Longitudinal stress variation is taken into account using a linear function and a 2nd degree parabola. Deflection functions for the plate and the stiffener, adopted in the study, made it possible to model boundary conditions and different buckling modes at the occurrence of longitudinal stress variation. Graphs of buckling coefficients are determined for different load distributions as a function of the elastic restraint coefficient and geometric details of the stiffener. Exemplary buckling modes are presented.


1981 ◽  
Vol 77 (3) ◽  
pp. 311-321 ◽  
Author(s):  
H.G. Davies ◽  
M.A. Wahab
Keyword(s):  

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