scholarly journals A Comprehensive Analytical Dynamic Model of a T-Beam

2019 ◽  
Vol 24 (No 1) ◽  
pp. 139-149 ◽  
Author(s):  
Andrew J. Hull ◽  
Daniel Perez ◽  
Donald L. Cox
Keyword(s):  
Wave Propagation ◽  
Dynamic Model ◽  
Plane Motion ◽  
Three Dimensions ◽  
Symmetric Model ◽  
Algebraic Equations ◽  
Element Analysis ◽  
T Beam ◽  
The Web ◽  
Analytical Dynamic

This paper derives a comprehensive analytical dynamic model of a T-shaped beam that includes in-plane and outof-plane vibrations for mid-frequency range analysis, defined here as approximately 1 kHz to 10 kHz. The web, right part of the flange, and left part of the flange of the T-beam are modelled independently with two-dimensional elasticity equations for the in-plane motion and the classical flexural plate equation for the out-of-plane motion. The differential equations are solved with unknown wave propagation coefficients multiplied by circular spatial domain functions, which are inserted into equilibrium and continuity equations at the intersection of the web and flange and into boundary conditions at the edges of the system resulting in 24 algebraic equations. These equations are solved to yield the wave propagation coefficients and this produces a solution to the displacement field in all three dimensions. An example problem is formulated and compared to solutions from Bickford beam theory and finite element analysis. Higher order branch waves are discussed and a simplified symmetric model is presented.

scholarly journals A High-Frequency Model of a Circular Beam with a T-Shaped Cross Section

Acoustics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 295-336
Author(s):  
Andrew Hull ◽  
Daniel Perez
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Cross Section ◽  
High Frequency ◽  
Algebraic Equations ◽  
Frequency Range ◽  
Linear Algebraic Equations ◽  
Circular Beam ◽  
The Web ◽  
Shaped Cross Section

This paper derives an analytical model of a circular beam with a T-shaped cross section for use in the high-frequency range, defined here as approximately 1 to 50 kHz. The T-shaped cross section is composed of an outer web and an inner flange. The web in-plane motion is modeled with two-dimensional elasticity equations of motion, and the left portion and right portion of the flange are modeled separately with Timoshenko shell equations. The differential equations are solved with unknown wave propagation coefficients multiplied by Bessel and exponential spatial domain functions. These are inserted into constraint and equilibrium equations at the intersection of the web and flange and into boundary conditions at the edges of the system. Two separate cases are formulated: structural axisymmetric motion and structural non-axisymmetric motion and these results are added together for the total solution. The axisymmetric case produces 14 linear algebraic equations and the non-axisymmetric case produces 24 linear algebraic equations. These are solved to yield the wave propagation coefficients, and this gives a corresponding solution to the displacement field in the radial and tangential directions. The dynamics of the longitudinal direction are discussed but are not solved in this paper. An example problem is formulated and compared to solutions from fully elastic finite element modeling. It is shown that the accurate frequency range of this new model compares very favorably to finite element analysis up to 47 kHz. This new analytical model is about four magnitudes faster in computation time than the corresponding finite element models.

Governance Disclosure on the Internet by Leading Indian Public Sector Companies

Think India ◽  
2019 ◽  
Vol 22 (2) ◽  
pp. 174-187
Author(s):  
Harmandeep Singh ◽  
Arwinder Singh
Keyword(s):  
Public Sector ◽  
Financial Information ◽  
Three Dimensions ◽  
The Internet ◽  
Web Pages ◽  
Non Profit ◽  
Index Approach ◽  
Significant Difference ◽  
Governance Disclosure ◽  
The Web

Nowadays, internet satisfying people with different services related to different fields. The profit, as well as non-profit organization, uses the internet for various business purposes. One of the major is communicated various financial as well as non-financial information on their respective websites. This study is conducted on the top 30 BSE listed public sector companies, to measure the extent of governance disclosure (non-financial information) on their web pages. The disclosure index approach to examine the extent of governance disclosure on the internet was used. The governance index was constructed and broadly categorized into three dimensions, i.e., organization and structure, strategy & Planning and accountability, compliance, philosophy & risk management. The empirical evidence of the study reveals that all the Indian public sector companies have a website, and on average, 67% of companies disclosed some kind of governance information directly on their websites. Further, we found extreme variations in the web disclosure between the three categories, i.e., The Maharatans, The Navratans, and Miniratans. However, the result of Kruskal-Wallis indicates that there is no such significant difference between the three categories. The study provides valuable insights into the Indian economy. It explored that Indian public sector companies use the internet for governance disclosure to some extent, but lacks symmetry in the disclosure. It is because there is no such regulation for web disclosure. Thus, the recommendation of the study highlighted that there must be such a regulated framework for the web disclosure so that stakeholders ensure the transparency and reliability of the information.

scholarly journals Numerical Investigation on Hydrodynamic Performance of a Portable AUV

2021 ◽  
Vol 9 (8) ◽  
pp. 812
Author(s):  
Lin Hong ◽  
Renjie Fang ◽  
Xiaotian Cai ◽  
Xin Wang
Keyword(s):  
Numerical Investigation ◽  
Dynamic Model ◽  
Autonomous Underwater Vehicle ◽  
Dynamic Performance ◽  
Plane Motion ◽  
Hydrodynamic Performance ◽  
Wave Forces ◽  
Modeling And Control ◽  
Experiment Platform ◽  
Cfd Method

This paper conducts a numerical investigation on the hydrodynamic performance of a portable autonomous underwater vehicle (AUV). The portable AUV is designed to cruise and perform some tasks autonomously in the underwater world. However, its dynamic performance is strongly affected by hydrodynamic effects. Therefore, it is crucial to investigate the hydrodynamic performance of the portable AUV for its accurate dynamic modeling and control. In this work, based on the designed portable AUV, a comprehensive hydrodynamic performance investigation was conducted by adopting the computational fluid dynamics (CFD) method. Firstly, the mechanical structure of the portable AUV was briefly introduced, and the dynamic model of the AUV, including the hydrodynamic term, was established. Then, the unknown hydrodynamic coefficients in the dynamic model were estimated through the towing experiment and the plane-motion-mechanism (PMM) experiment simulation. In addition, considering that the portable AUV was affected by wave forces when cruising near the water surface, the influence of surface waves on the hydrodynamic performance of the AUV under different wave conditions and submerged depths was analyzed. Finally, the effectiveness of our method was verified by experiments on the standard models, and a physical experiment platform was built in this work to facilitate hydrodynamic performance investigations of some portable small-size AUVs.

scholarly journals Locally Corroded Stiffener Effect on Shear Buckling Behaviors of Web Panel in the Plate Girder

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Jungwon Huh ◽  
In-Tae Kim ◽  
Jin-Hee Ahn
Keyword(s):  
Corrosion Damage ◽  
Element Analysis ◽  
Buckling Strength ◽  
Lower Shear ◽  
Out Of Plane ◽  
Shear Buckling ◽  
Buckling Failure ◽  
Plane Displacement ◽  
The Web ◽  
Plate Girder

The shear buckling failure and strength of a web panel stiffened by stiffeners with corrosion damage were examined according to the degree of corrosion of the stiffeners, using the finite element analysis method. For this purpose, a plate girder with a four-panel web girder stiffened by vertical and longitudinal stiffeners was selected, and its deformable behaviors and the principal stress distribution of the web panel at the shear buckling strength of the web were compared after their post-shear buckling behaviors, as well as their out-of-plane displacement, to evaluate the effect of the stiffener in the web panel on the shear buckling failure. Their critical shear buckling load and shear buckling strength were also examined. The FE analyses showed that their typical shear buckling failures were affected by the structural relationship between the web panel and each stiffener in the plate girder, to resist shear buckling of the web panel. Their critical shear buckling loads decreased from 82% to 59%, and their shear buckling strength decreased from 88% to 76%, due to the effect of corrosion of the stiffeners on their shear buckling behavior. Thus, especially in cases with over 40% corrosion damage of the vertical stiffener, they can have lower shear buckling strength than their design level.

Limit Loads for Laterally Loaded I-Section Beams With Consideration of Shear

2003 ◽  
Vol 47 (02) ◽  
pp. 83-91
Author(s):  
L. Belenkiy ◽  
Y. Raskin
Keyword(s):  
Physical Model ◽  
Limit Load ◽  
Nonlinear Finite Element ◽  
Shear Forces ◽  
Element Analysis ◽  
Limit Loads ◽  
Closed Form Solutions ◽  
Engineering Technique ◽  
Laterally Loaded ◽  
The Web

The paper examines an effect of shear forces on limit load for I-section beams carrying later alloads. The problem is solve don the basis of a physical model, which enables one to take into account the effect of a resistance of beam flanges to the plastic shears train in the web of the beam. The physical model for the evaluation of limit loads was veriŽed using nonlinear finite element analysis. An engineering technique for the calculation of limit loads for shiphull beams subjected to large shear forces was developed using this model. As illustrative examples, the paper shows the application of the proposed technique to obtain closed-form solutions for the prediction of limit loads.

Axial Wave Propagation in Infinitely Long Periodic Curved Panels

2003 ◽  
Vol 125 (1) ◽  
pp. 24-30 ◽  
Author(s):  
C. Pany ◽  
S. Parthan
Keyword(s):  
Wave Propagation ◽  
Natural Frequencies ◽  
Propagation Constant ◽  
Infinite Length ◽  
Approximate Methods ◽  
Bending Vibration ◽  
Element Analysis ◽  
Curved Panel ◽  
Propagation Of Waves ◽  
Curved Panels

Propagation of waves along the axis of the cylindrically curved panels of infinite length, supported at regular intervals is considered in this paper to determine their natural frequencies in bending vibration. Two approximate methods of analysis are presented. In the first, bending deflections in the form of beam functions and sinusoidal modes are used to obtain the propagation constant curves. In the second method high precision triangular finite elements is used combined with a wave approach to determine the natural frequencies. It is shown that by this approach the order of the resulting matrices in the FEM is considerably reduced leading to a significant decrease in computational effect. Curves of propagation constant versus natural frequencies have been obtained for axial wave propagation of a multi supported curved panel of infinite length. From these curves, frequencies of a finite multi supported curved panel of k segments may be obtained by simply reading off the frequencies corresponding to jπ/kj=1,2…k. Bounding frequencies and bounding modes of the multi supported curved panels have been identified. It reveals that the bounding modes are similar to periodic flat panel case. Wherever possible the numerical results have been compared with those obtained independently from finite element analysis and/or results available in the literature.

scholarly journals Development of an Analytical Dynamic Model of a Vibro-Compactor Used in Carbon Anode Production

2013 ◽  
pp. 1111-1115
Author(s):  
Fatma Rebaïne ◽  
Mohamed Bouazara ◽  
Daniel Marceau ◽  
Duygu Kocaefe ◽  
Brigitte Morais
Keyword(s):  
Dynamic Model ◽  
Carbon Anode ◽  
Analytical Dynamic

scholarly journals Performance Testing of Web Map Services tn three Dimensions – X, Y, Scale

2013 ◽  
Vol 21 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Dušan Cibulka
Keyword(s):  
Performance Testing ◽  
Service Performance ◽  
Performance Characteristics ◽  
Three Dimensions ◽  
Web Mapping ◽  
Practical Experiment ◽  
Web Map ◽  
Open Geospatial Consortium ◽  
Map Service ◽  
The Web

Abstract The paper deals with the performance testing of web mapping services. The paper describes map service tests in which it is possible to determine the performance characteristics of a map service, depending on the location and scale of the map. The implementation of the test is tailored to the Web Map Service specifications provided by the Open Geospatial Consortium. The practical experiment consists of testing the map composition acquired from OpenStreetMap data for the area of southwestern Slovakia. These tests permit checking the performance of services in different positions, verifying the configuration of services, the composition of a map, and the visualization of geodata. The task of this paper is to also highlight the fact that it is not sufficient to only interpret a map service performance with conventional indicators. A map service’s performance should be linked to information about the map’s scale and location.

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