scholarly journals Approbation of an effective method for dynamic calculation of the steel and concrete bridge span

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Vladimir Safronov ◽  
Andrei Antipov
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Full Scale ◽  
Design Stage ◽  
Dynamic Calculation ◽  
Dynamic Component ◽  
Static Tests ◽  
Moving Vehicle ◽  
Bridge Structures ◽  
Dynamic Quality

Problem statement. The article describes the method and results of determining the dynamic response of a continuous steel-reinforced concrete span of a road bridge to the passage of heavy vehicles, which is focused on the use of finite element computing systems. The data of dynamic calculations are compared with those obtained during full-scale dynamic tests of the operated structure. Results. Modern algorithms for dynamic calculation of continuous bridge structures on the action of sprung vehicles are analyzed, which allow taking into account the irregularities on the roadway, the influence of wheel bearing point movements on the vibrations of moving vehicles. It describes the sequence of performing dynamic calculations using modal analysis blocks and dynamic calculation of KE-complexes for a system of moving non-inert loads, followed by calculating the dynamic component of deflections and forces of elements of the bridge structure, taking into account the inertia of the vehicle and unevenness on the roadway. According modal analysis of steel-concrete span structures road bridge operated by means of spatial finite element calculation schemes are determined by their own shape supporting structure, which are then used for dynamic calculations in a moving inertial load. The results of dynamic calculations of the operated road bridge on the action of a three-axle truck moving at a constant speed are presented. Calculated deflections are compared with those obtained during full-scale static tests of the bridge. Numerical calculations estimate the effect of speed, roadway irregularities, and feedback between the vibrations of the bridge and the moving vehicle. Conclusion. The proposed method of dynamic calculation of bridge structures allows evaluating the dynamic quality of transport structures at the design stage and making optimal design decisions.

Dynamic Analysis of Elastic Structures on Spreadsheet

2012 ◽  
Author(s):  
J.-M. Rambach
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Modal Analysis ◽  
Safety Assessment ◽  
Degrees Of Freedom ◽  
Vertical Plane ◽  
Design Stage ◽  
Margin Assessment ◽  
Sensitivity Studies ◽  
Stick Model

It is recalled the interest of modal analysis of heavy structures on stick model with reduced number of degrees-of-freedom (DOF), at every age of the structure: at the presizing stage, at the design stage, for assessing the results given by large tridimensional Finite Element (FE) models, and at every further seismic review (Seismic Margin Assessment studies, Seismic Probabilistic Safety Assessment studies). This article indicates a practical means for a simple programing of a modal analysis based FE code on spreadsheet able to handle up to 50 DOF. The beams, of Timoshenko’s type, are supposed moving along a vertical plane, with 2 DOF per node: the horizontal translational DOF and the rotational DOF around the horizontal axis perpendicular to the vertical plane. The analysis follows the classical steps of any FE code. The programing of such dynamic modal analysis on a spreadsheet is besides quite easy and provides a very convenient tool i) for the intimate understanding of the dynamic behavior of structures ii) for any accurate modal analysis and iii) for any sensitivity studies.

scholarly journals A Damage Detection Algorithm Utilizing Dynamic Displacement of Bridge under Moving Vehicle

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Zhen Sun ◽  
Tomonori Nagayama ◽  
Di Su ◽  
Yozo Fujino
Keyword(s):  
Damage Detection ◽  
Engineering Practice ◽  
Beam Model ◽  
Dynamic Component ◽  
Dynamic Displacement ◽  
Moving Vehicle ◽  
Finite Element Software ◽  
Damage Location ◽  
Bridge Structures ◽  
Damage Extent

A damage detection method is proposed, which utilizes dynamic displacement of bridge structures under moving vehicle. The problem is first elaborated with closed-form solution of dynamic displacement, which is decomposed into quasi-static component and dynamic component. Dynamic curvature is defined as second derivative of the dynamic displacement for detecting damage location and estimating damage extent. Damage is modeled by local reduction of stiffness in this paper. Numerical study was conducted on a simply supported beam to verify the proposed method. Vehicle model is analyzed with Newmark’s method using Matlab to obtain the contact force acting on the bridge. Beam model is established in commercial finite element software ABAQUS. The effects of road surface roughness and vehicle-bridge interaction are both considered in the analysis. In order to identify damage location and extent, dynamic curvature was calculated with midspan displacement. Parametric study on measurement noise level, damage location, damage extent, and multiple damage cases is performed, and the analysis results show both reliability and efficacy of this method in damage detection of bridge structures. At last, conclusions are drawn for its application to bridges in engineering practice.

scholarly journals Verification of the Façade Scaffolding Computer Model

2018 ◽  
Vol 64 (1) ◽  
pp. 41-53 ◽  
Author(s):  
P. Jamiṅska-Gadomska ◽  
J. Bẹc ◽  
T. Lipecki ◽  
A. Robak
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Computer Model ◽  
Computational Models ◽  
Full Scale ◽  
Mode Shapes ◽  
Natural Vibrations ◽  
The Real ◽  
Different Levels

AbstractThis paper presents an analysis of natural vibrations of typical façade scaffolding. Three Finite Element Method models with different levels of accuracy of the real structure of the scaffolding representation were used. Modal analysis was carried out for each of these models. The obtained frequencies and mode shapes were compared with the results from the measurements performed on the full-scale scaffolding. The authors of the paper point out the difficulties arise while modelling such structures, and suggest ways to improve the accuracy of scaffolding computational models.

Design and Finite Element Modal Analysis of 48m Composite Wind Turbine Blade

2011 ◽  
Vol 146 ◽  
pp. 170-184 ◽  
Author(s):  
M. Tarfaoui ◽  
H. Khadimallah ◽  
Abdellatif Imad ◽  
J.Y. Pradillon
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Modal Analysis ◽  
Turbine Blades ◽  
Full Scale ◽  
Wind Turbine Blades ◽  
Horizontal Axis Wind Turbine ◽  
Numerical Work ◽  
Complex Structural ◽  
Full Scale Tests

We currently notice a substantial growth in the wind energy sector worldwide. This growth is expected to be even faster in the coming years. This means that a massive number of wind turbine blades will be produced in the forthcoming years. There is a large potential for materials savings in these blades. The analysis of designed blade is done in dynamic loading. Five types of spars cross-section are taken in this work. The blade and spar are of composite material. The Finite element modal analysis of designed blade is done in ABAQUS. The scope of the present work is to investigate the structural modal analysis of full-scale 48m fiberglass composite wind turbine blades for 5MW horizontal axis wind turbine and through this to assess the potential for materials savings and consequent reductions of the rotor weight. The entire wind turbine can benefit from such weight reductions through decreased dynamics loads and thus leave room for further optimization. A numerical work has been used to address the most adequate spar shape and to get an understanding of the complex structural behavior of wind turbine blades. Five different types of structural reinforcements helping to prevent undesired structural elastic mechanisms are presented. Comparisons of the eigenfrequencies observed in the full-scale tests are presented and conclusions are drawn based on the mechanisms found.

scholarly journals Vibration Analysis of a Guitar considered as a Symmetrical Mechanical System

Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 727 ◽  
Author(s):  
Mariana D. Stanciu ◽  
Sorin Vlase ◽  
Marin Marin
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Vibration Analysis ◽  
The Body ◽  
Design Stage ◽  
Steady State Response ◽  
Eigenvalues And Eigenvectors ◽  
Element Analysis ◽  
State Response ◽  
Different Types

This paper aimed to use the symmetry that exists to the body of a guitar to ease the analysis behavior to vibrations. Symmetries can produce interesting properties when studying the dynamic and steady-state response of such systems. These properties can, in some cases, considerably decrease the effort made for dynamic analysis at the design stage. For a real guitar, these properties are used to determine the eigenvalues and eigenvectors. Finite element method (FEM) is used for a numerical modeling and to prove the theoretically determined properties in this case. In this paper, different types of guitar plates related to symmetrical reinforcement patterns were studied in terms of modal analysis performed using finite element analysis (FEA). The dynamic response differs in terms of amplitude, eigenvalues, modal shapes in accordance with number and pattern of stiffening bars. In this study, the symmetrical and asymmetric modes of modal analysis were highlighted in the case of constructive symmetrical structures.

Design of Pipeline Composite Repairs: From Lab Scale Tests to FEA and Full Scale Testing

2014 ◽  
Author(s):  
Remy Her ◽  
Jacques Renard ◽  
Vincent Gaffard ◽  
Yves Favry ◽  
Paul Wiet
Keyword(s):  
Finite Element ◽  
Full Scale ◽  
Combined Loading ◽  
Material Strength ◽  
Repair System ◽  
Loading Conditions ◽  
Original Design ◽  
Composite Repair ◽  
Repair Systems ◽  
Composite Properties

Composite repair systems are used for many years to restore locally the pipe strength where it has been affected by damage such as wall thickness reduction due to corrosion, dent, lamination or cracks. Composite repair systems are commonly qualified, designed and installed according to ASME PCC2 code or ISO 24817 standard requirements. In both of these codes, the Maximum Allowable Working Pressure (MAWP) of the damaged section must be determined to design the composite repair. To do so, codes such as ASME B31G for example for corrosion, are used. The composite repair systems is designed to “bridge the gap” between the MAWP of the damaged pipe and the original design pressure. The main weakness of available approaches is their applicability to combined loading conditions and various types of defects. The objective of this work is to set-up a “universal” methodology to design the composite repair by finite element calculations with directly taking into consideration the loading conditions and the influence of the defect on pipe strength (whatever its geometry and type). First a program of mechanical tests is defined to allow determining all the composite properties necessary to run the finite elements calculations. It consists in compression and tensile tests in various directions to account for the composite anisotropy and of Arcan tests to determine steel to composite interface behaviors in tension and shear. In parallel, a full scale burst test is performed on a repaired pipe section where a local wall thinning is previously machined. For this test, the composite repair was designed according to ISO 24817. Then, a finite element model integrating damaged pipe and composite repair system is built. It allowed simulating the test, comparing the results with experiments and validating damage models implemented to capture the various possible types of failures. In addition, sensitivity analysis considering composite properties variations evidenced by experiments are run. The composite behavior considered in this study is not time dependent. No degradation of the composite material strength due to ageing is taking into account. The roadmap for the next steps of this work is to clearly identify the ageing mechanisms, to perform tests in relevant conditions and to introduce ageing effects in the design process (and in particular in the composite constitutive laws).

scholarly journals Rotor Loading Characteristics of a Full-Scale Tidal Turbine

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1035 ◽  
Author(s):  
Magnus Harrold ◽  
Pablo Ouro
Keyword(s):  
Turbulent Flows ◽  
Mechanical Loading ◽  
Full Scale ◽  
Design Stage ◽  
Flow Profile ◽  
Expected Return ◽  
Tidal Turbines ◽  
Theoretical Predictions ◽  
Tidal Turbine

Tidal turbines are subject to highly dynamic mechanical loading through operation in some of the most energetic waters. If these loads cannot be accurately quantified at the design stage, turbine developers run the risk of a major failure, or must choose to conservatively over-engineer the device at additional cost. Both of these scenarios have consequences on the expected return from the project. Despite an extensive amount of research on the mechanical loading of model scale tidal turbines, very little is known from full-scale devices operating in real sea conditions. This paper addresses this by reporting on the rotor loads measured on a 400 kW tidal turbine. The results obtained during ebb tidal conditions were found to agree well with theoretical predictions of rotor loading, but the measurements during flood were lower than expected. This is believed to be due to a disturbance in the approaching flood flow created by the turbine frame geometry, and, to a lesser extent, the non-typical vertical flow profile during this tidal phase. These findings outline the necessity to quantify the characteristics of the turbulent flows at sea sites during the entire tidal cycle to ensure the long-term integrity of the deployed tidal turbines.

scholarly journals Analysis of vibrodiagnostics methods in the technical state study of designed multimedia mobile scenes

2019 ◽  
Vol 302 ◽  
pp. 01011
Author(s):  
Marcin Łukasiewicz ◽  
Michał Liss ◽  
Natalia Dluhunovych
Keyword(s):  
Modal Analysis ◽  
Diagnostic Tests ◽  
Research Process ◽  
Technical Condition ◽  
Technical State ◽  
Normal Operation ◽  
Design Stage ◽  
Analysis Methods ◽  
State Study ◽  
Diagnostic Research

The paper presents the possibilities of using vibroacoustic methods in the study of the technical condition of designed multimedia mobile scenes. In particular, the possibility of implementing modal analysis methods in modelling and diagnostic research process has been presented. The use of virtual methods enables diagnostic tests both at the design stage and at the stage of normal operation, whereas modal methods help to explain the nature of the work of the element under investigation.

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