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.

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.

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.

scholarly journals Theoretical and Experimental Research of The Stability of The Eccentrically Loaded Steel Columns with Variable Cross–Section

2018 ◽  
Vol 7 (3.2) ◽  
pp. 458
Author(s):  
Gennady Trusov ◽  
Vladimir Ruban
Keyword(s):  
Cross Section ◽  
Research Work ◽  
Variable Cross Section ◽  
Suggested Method ◽  
National Standards ◽  
Discrete Models ◽  
Practical Calculation ◽  
Variable Cross ◽  
Cross Sectional ◽  
Steel Columns

The article deals with the problem of determining the ultimate load for the eccentrically loaded steel columns with variable-cross section.The purpose of the research work is to offer an evaluation technique and practical calculation of load-bearing ability of the beam-columns with variable cross-section on the basis of numerical research, which will allow to consider the true form of element deflection curve, the effect of cross-section form, physical nonlinearity of the material, and variety of element boundary conditions. The distinctive characteristic of the suggested method is usage of the discrete models for cross-sectional parts, for the true stress-strain curves of the materials, and for the other input data. The method was tested and the results were compared to known theoretical solutions and national standards. To establish the reliability of the developed method, the experimental study of steel columns with variable cross-section was conducted. The suggested method allows to obtain column curves tables of lowering coefficients for these elements, that can be used in practice of civil engineering, and are convenient with national standards and Eurocode. 

The Changes of Internal Forces and the Reliability of Curved Bridge Taking the Cross-Sectional Design of Axial Symmetrical

2014 ◽  
Vol 587-589 ◽  
pp. 1631-1636
Author(s):  
Zheng Jiu Zhao ◽  
Jing Hong Gao
Keyword(s):  
Cross Section ◽  
Variable Cross Section ◽  
Radius Of Curvature ◽  
Variable Cross ◽  
Cross Sectional ◽  
Box Girder ◽  
Curved Bridge ◽  
The Cross ◽  
Cross Sectional Design ◽  
Bridge Models

Taking a bridge of 160m long variable cross-section prestressed continuous curved box-girder as the research object and analyzing the cross-sectional design of axis with axial symmetrical or axial non-symmetrical to research the structure forces change of the upper part of bridge in different curvature. In order to test and verify the variable cross-section of prestressed continuous curved box-girder bridge is safe and reliable via cross-sectional design with axial symmetrical instead of axial non-symtrical within a radius of curvature of the interval. Creating the straight bridge and curved bridge models with different radius of curvature in same span by Midas/Civil to compare their structure forces.

Solar Concentrator Structural Optimization: A Variable Beam Cross Section Design

2017 ◽  
Author(s):  
Moucun Yang ◽  
Yuezhao Zhu ◽  
Wei Fu ◽  
Garth Pearce ◽  
Robert A. Taylor
Keyword(s):  
Structural Optimization ◽  
Cross Section ◽  
Cost Savings ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Maximum Displacement ◽  
Cross Sectional ◽  
Optical Efficiency ◽  
Box Structure ◽  
Section Design

The design and construction of solar concentrators heavily affects their cost, heat utilization and optical efficiency. Current trough concentrators support the reflector with an equivalent uniform beam configured from a metal grid sub-structure. Under gravity and wind loads, the support-structure stress distribution varies as a function of position of the structure and the tracking angle. In the conventional design, there is ample surplus stiffness and strength designed into some beams of the structure, which increases the overall weight and cost of the structure. This paper describes an approach towards structural optimization of trough concentrators (with the Eurotrough design taken as an example, that means that the safety factors and structure is similar with Eurotrough design) using a variable cross section beam. The main improvement of this approach comes from keeping the beams rigid and strong near the two ends (at the torque box structure) while allowing the middle of the structure to be relatively weak. Reducing the cross-sectional area of the central beams not only reduces amount of material needed for the structure but also reduces the deflection of the reflector. The simulated results show that the concentrator’s structural weight (including the torque box, endplates and cantilever arms) and the maximum displacement of the reflector are reduced about 15.3% (about 151.2kg per 12-metre long element) and 15.5%, respectively. This represents a meaningful capital and installation cost savings while at the same time improving the optical efficiency.

scholarly journals A well-balanced solver for the Saint Venant equations with variable cross-section

2015 ◽  
Vol 23 (2) ◽  
Author(s):  
Raul Borsche
Keyword(s):  
Numerical Method ◽  
Cross Section ◽  
Variable Cross Section ◽  
Test Cases ◽  
Variable Cross ◽  
Bottom Slope ◽  
Cross Sectional ◽  
Analytical Properties ◽  
Saint Venant Equations ◽  
Numerical Solver

AbstractIn this paper we construct a numerical solver for the Saint Venant equations. Special attention is given to the balancing of the source terms, including the bottom slope and variable cross-sectional profiles. Therefore a special discretization of the pressure law is used, in order to transfer analytical properties to the numerical method. Based on this approximation awell-balanced solver is developed, assuring the C-property and depth positivity. The performance of this method is studied in several test cases focusing on accurate capturing of steady states.

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.

Study on Flexible Spin-Up Maneuver with Variable Cross-Section Based on Positional FEM

2014 ◽  
Vol 670-671 ◽  
pp. 834-837
Author(s):  
Lv Zhou Ma ◽  
Yu Qin Yan ◽  
Xun Lin Diao ◽  
Jian Liu
Keyword(s):  
Cross Section ◽  
Mass Matrix ◽  
Variable Cross Section ◽  
Beam Element ◽  
Variable Cross ◽  
Lumped Mass ◽  
Nonlinear Fem ◽  
Calculation Results ◽  
Properties Of Materials ◽  
Consistent Mass Matrix

Based on positional finite element method (FEM) and MATLAB platform, program VBEP (Variable cross-section Beam Element based on Positional FEM) is compiled. Flexible spin-up maneuver is calculated. The calculation results show that positional FEM uses fewer elements and gains higher calculation precision and efficiency when compared with traditional nonlinear FEM, and that calculated quantity using lumped mass matrix is less than using consistent mass matrix about properties of materials under the same calculation precision.

Analysis of Singly Symmetric Oval Rings with Variable Cross Section

1970 ◽  
Vol 14 (03) ◽  
pp. 143-152
Author(s):  
J. E. Flaherty ◽  
W. P. Vafakos
Keyword(s):  
Cross Section ◽  
Variable Cross Section ◽  
Experimental Results ◽  
Variable Cross ◽  
Cross Sectional ◽  
Shear Loads ◽  
Good Agreement

An analysis of singly symmetric oval rings with variable cross-sectional properties, subjected to arbitrary radial and shear loads, is presented. The flange stresses in nonuniform reinforcing rings of ring-stiffened oval cylinders are obtained by assuming that such cylinders behave as composite rings. The stresses are shown to be in good agreement with available theoretical and experimental results.

Partially Vaned Diffuser With Variable Cross-Section for Centrifugal Fans

2017 ◽  
Author(s):  
Tore Fischer ◽  
Sebastian Burgmann ◽  
Manuel Rudersdorf ◽  
Joerg R. Seume
Keyword(s):  
Cross Section ◽  
Pressure Ratio ◽  
Variable Cross Section ◽  
Cross Sectional Area ◽  
Variable Cross ◽  
Centrifugal Fan ◽  
Sectional Area ◽  
Cross Sectional ◽  
Vaned Diffuser ◽  
Part Load

The present research focuses on the efficiency improvement at part-load of a centrifugal fan for a 30 kW fuel cell combined heat and power (CHP) unit. For this purpose, the fan stage is equipped with a partially vaned diffuser with a variable cross-sectional area using a moving backplate. The design and the performance of the partially vaned diffuser with a variable cross-sectional area are described in the first part of this paper. The performance results are compared to measurements of the same centrifugal fan with a vaneless diffuser carried out for the previous investigation. For the second part, the influence of the variable cross-sectional area on the diffuser flow field is investigated using optical PIV (Particle Image Velocimetry) measurements and CFD (Computational Fluid Dynamics) simulations. The combination of a variable cross-section, partially vaned diffuser was able to achieve a 10 percent increase in pressure ratio, a 5 percentage points increase in part-load efficiency while maintaining the whole operating range of the vaneless, constant cross section reference design.

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