Mechanical Numerical Analysis for L-Shape Traffic Signs Bar with Variable Cross-Section

2013 ◽  
Vol 444-445 ◽  
pp. 1250-1254
Author(s):  
Ben Ning Qu ◽  
Ran Guo ◽  
Bang Cheng Yang
Keyword(s):  
Finite Element ◽  
Theoretical Calculation ◽  
Cross Section ◽  
Simulation Analysis ◽  
Element Model ◽  
Thin Wall ◽  
Variable Cross ◽  
Axial Line ◽  
Traffic Sign ◽  
Cross Sectional

L-shape traffic sign bar is composed of a stand column and a cantilever bar using bolted connection. The cross-section of stand column and a cantilever bar is closed thin wall with regular octagon and their cross sectional area is variable along axial line. The finite element simulation analysis for the bar is done under gravities and wind loads. Three-dimensional finite element model of bar is set up and stress field and displacement field is given under different load and their combination. Stress and displacement values of key parts are extracted and compared with theoretical calculation. Indicates that the theoretical calculation and finite element calculation is correct.

Mechanical Calculation Model for L-Shape Traffic Signs Bar with Variable Cross-Section

2013 ◽  
Vol 444-445 ◽  
pp. 1001-1006
Author(s):  
Ben Ning Qu ◽  
Bang Cheng Yang ◽  
Ran Guo
Keyword(s):  
Cross Section ◽  
Variable Cross Section ◽  
Calculation Model ◽  
Thin Wall ◽  
Variable Cross ◽  
Axial Line ◽  
Traffic Sign ◽  
Cross Sectional ◽  
Bolted Connection ◽  
Calculation Results

L shape traffic sign bar is composed of a stand column and a cantilever bar using bolted connection. The cross-section of stand column and a cantilever bar is closed thin wall with regular octagon and their cross sectional area is variable along axial line. The calculation formulas of stress for cantilever bar, stand column and flange bolts and calculation formulas of deformation for L rod are derived under gravities and wind loads, which provide theoretical basis for the design and use of L-shape bar. Calculation results using these formulas by comparison with finite element calculation results verify the correctness.

Transmission Loss of Variable Cross Section Apertures

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
J. Li ◽  
L. Zhou ◽  
X. Hua ◽  
D. W. Herrin
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Sound Propagation ◽  
Transmission Loss ◽  
Element Model ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Cross Sectional ◽  
Radiation Impedance ◽  
The Cross

Openings in enclosures or walls are frequently the dominant path for sound propagation. In the current work, a transfer matrix method is used to predict the transmission loss of apertures assuming that the cross-sectional dimensions are small compared with an acoustic wavelength. Results are compared with good agreement to an acoustic finite element approach in which the loading on the source side of the finite element model (FEM) is a diffuse acoustic field applied by determining the cross-spectral force matrix of the excitation. The radiation impedance for both the source and termination is determined using a wavelet algorithm. Both approaches can be applied to leaks of any shape and special consideration is given to apertures with varying cross section. Specifically, cones and abrupt area changes are considered, and it is shown that the transmission loss can be increased by greater than 10 dB at many frequencies.

scholarly journals Coupled Bending-Bending-Torsion Vibration of a Pre-Twisted Beam with Aerofoil Cross-Section by the Finite Element Method

2003 ◽  
Vol 10 (4) ◽  
pp. 223-230
Author(s):  
Bulent Yardimoglu ◽  
Daniel J. Inman
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Higher Order ◽  
Coupling Coefficients ◽  
Cross Sectional ◽  
Torsion Vibration ◽  
Proper Order ◽  
Proposed Model

The present study deals with a finite element model for coupled bending-bending-torsion vibration analysis of a pretwisted Timoshenko beam with varying aerofoil cross-section. The element derived in this paper has two nodes, with seven degrees of freedom at each node. The nodal variables are transverse displacements, cross-section rotations and the shear angles in two planes and torsional displacement. The advantage of the present element is the exclusion of unnecessary derivatives of fundamental nodal variables, which were included to obtain invertable square matrix by other researchers, by choosing proper displacement functions and using relationship between cross-sectional rotation and the shear deformation. Element stiffness and mass matrices are developed from strain and kinetic energy expressions by assigning proper order polynomial expressions for cross-section properties and considering higher order coupling coefficients. The correctness of the present model is confirmed by the experimental results available in the literature. Comparison of the proposed model results with those in the literature indicates that a faster convergence is obtained. The results presented also provide some insights in the formulation by clearly indicating that higher order coupling terms have considerable influence on the natural frequencies.

A Slice Finite Element Model for Bending Analysis of Curved Beams

2011 ◽  
Vol 338 ◽  
pp. 282-285 ◽  
Author(s):  
Wen Guang Jiang ◽  
Li Juan Yan
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Finite Element Modelling ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Curved Beams ◽  
Pure Bending ◽  
Cross Sectional ◽  
Bending Analysis ◽  
Constraint Equations

The pure bending analysis of curved beams may be performed by finite element modelling of only a representative slice sector of the beam cross-section, by establishing exact deformation relationships between degrees of freedom of corresponding nodes on the corresponding artificial cross-sectional boundaries. These deformation relationships can be conveniently realized using constraint equations between nodal degrees of freedom. Numerical example has been given to demonstrate the accuracy and effectiveness of the proposed method.

scholarly journals Coupled Bending-Bending-Torsion Vibration of a Rotating Pre-Twisted Beam with Aerofoil Cross-Section and Flexible Root by Finite Element Method

2004 ◽  
Vol 11 (5-6) ◽  
pp. 637-646 ◽  
Author(s):  
Bulent Yardimoglu ◽  
Daniel J. Inman
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Centrifugal Force ◽  
Axial Stress ◽  
Element Model ◽  
Torsional Stiffness ◽  
Extended Model ◽  
Beam Model ◽  
Cross Sectional

The purpose of this paper is to extend a previously published beam model of a turbine blade including the centrifugal force field and root flexibility effects on a finite element model and to demonstrate the performance, accuracy and efficiency of the extended model for computing the natural frequencies. Therefore, only the modifications due to rotation and elastic root are presented in great detail. Considering the shear center effect on the transverse displacements, the geometric stiffness matrix due to the centrifugal force is developed from the geometric strain energy expression based on the large deflections and the increase of torsional stiffness because of the axial stress. In this work, the root flexibility of the blade is idealized by a continuum model unlike the discrete model approach of a combination of translational and rotational elastic springs, as used by other researchers. The cross-section properties of the fir-tree root of the blade considered as an example are expressed by assigning proper order polynomial functions similar to cross-sectional properties of a tapered blade. The correctness of the present extended finite element model is confirmed by the experimental and calculated results available in the literature. Comparisons of the present model results with those in the literature indicate excellent agreement.

1D Finite Element Model for Tapered Cross-Section Steel-Concrete Composite Material Beam

2016 ◽  
Vol 723 ◽  
pp. 807-812
Author(s):  
Jun Xia ◽  
Z. Shen ◽  
Kun Liu
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Finite Element Model ◽  
Cross Section ◽  
Structural Engineering ◽  
Kinematic Model ◽  
Element Model ◽  
High Order ◽  
Variable Cross ◽  
Interlayer Slip

The flexural and dynamic behavior of tapered cross-section steel-concrete composite material beams frequently used in structural engineering is strongly influenced by the type of shear connection between the steel beam and the concrete slab. The numerical model must account for the partial interaction (interlayer slip) in order to get accurate analytical predictions. The 1D high order finite element model for variable cross-section steel-concrete composite beams with interlayer slip were established in this paper. The displacement field of kinematic model is obtained by introducing the constraint condition on interface between those two components based on classical Newmark model. The high order finite element with 16 degrees of freedom (DOF) is chosen to overcome the slip-locking problem in low order finite element which has been reported in published literatures so much. The established element can be used in flexural and dynamic analysis of tapered cross-section steel-concrete composite material beams directly.

Longitudinal oscillation of a rod with a variable cross section

2019 ◽  
Vol 14 (2) ◽  
pp. 138-141
Author(s):  
I.M. Utyashev
Keyword(s):  
Cross Section ◽  
Natural Frequencies ◽  
Liouville Problem ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Independent Functions ◽  
The Cross ◽  
The Right

Variable cross-section rods are used in many parts and mechanisms. For example, conical rods are widely used in percussion mechanisms. The strength of such parts directly depends on the natural frequencies of longitudinal vibrations. The paper presents a method that allows numerically finding the natural frequencies of longitudinal vibrations of an elastic rod with a variable cross section. This method is based on representing the cross-sectional area as an exponential function of a polynomial of degree n. Based on this idea, it was possible to formulate the Sturm-Liouville problem with boundary conditions of the third kind. The linearly independent functions of the general solution have the form of a power series in the variables x and λ, as a result of which the order of the characteristic equation depends on the choice of the number of terms in the series. The presented approach differs from the works of other authors both in the formulation and in the solution method. In the work, a rod with a rigidly fixed left end is considered, fixing on the right end can be either free, or elastic or rigid. The first three natural frequencies for various cross-sectional profiles are given. From the analysis of the numerical results it follows that in a rigidly fixed rod with thinning in the middle part, the first natural frequency is noticeably higher than that of a conical rod. It is shown that with an increase in the rigidity of fixation at the right end, the natural frequencies increase for all cross section profiles. The results of the study can be used to solve inverse problems of restoring the cross-sectional profile from a finite set of natural frequencies.

Numerical Simulation of the Effects of Preheating on Electron Beam Additive Manufactured Ti-6Al-4V Build Plate

2016 ◽  
Vol 879 ◽  
pp. 274-278 ◽  
Author(s):  
Jun Cao ◽  
Philip Nash
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Cross Section ◽  
Element Model ◽  
Normal Direction ◽  
Thermal Residual Stresses ◽  
Longitudinal Residual Stress ◽  
Middle Cross Section

In an earlier study, a 3-D thermomechanical coupled finite element model was built and experimentally validated to investigate the evolution of the thermal residual stresses and distortions in electron beam additive manufactured Ti-6Al-4V build plates. In this study, an investigation using this robust and accurate model was focused on an efficient preheating method, in which the electron beam quickly scanned across the substrate to preheat the build plate prior to the deposition. Various preheat times, beam powers, scan rates, scanning paths and cooling times (between the end of current preheat scan/deposition layer and the beginning of the next preheat scan/deposition layer) were examined, and the maximum distortion along the centerline of the substrate and the maximum longitudinal residual stress along the normal direction on the middle cross-section of the build plate were quantitatively compared. The results show that increasing preheat times and beam powers could effectively reduce both distortion and residual stress for multiple layers/passes components.

Free Vibration Analysis for Tapered Cross-Section Steel-Concrete Composite Material Beam

2017 ◽  
Vol 893 ◽  
pp. 380-383
Author(s):  
Jun Xia ◽  
Z. Shen ◽  
Kun Liu
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Cross Section ◽  
Vibration Analysis ◽  
Free Vibration Analysis ◽  
Element Model ◽  
Composite Beams ◽  
Shear Connection ◽  
The Common ◽  
Interlayer Slip

The tapered cross-section beams made of steel-concrete composite material are widely used in engineering constructions and their dynamic behavior is strongly influenced by the type of shear connection jointing the two different materials. The 1D high order finite element model for tapered cross-section steel-concrete composite material beam with interlayer slip was established in this paper. The Numerical results for vibration nature frequencies of the composite beams with two typical boundary conditions were compared with ANSYS using 2D plane stress element. The 1D element is more efficient and economical for the common tapered cross-section steel-concrete composite material beams in engineering.

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