Distortion of U-Channel Sections in Plastic Bending

1999 ◽  
Vol 121 (2) ◽  
pp. 208-213 ◽  
Author(s):  
K. A. Stelson ◽  
A. Kramer
Keyword(s):  
Material Properties ◽  
Energy Minimization ◽  
Plastic Bending ◽  
Circular Arc ◽  
Channel Section ◽  
Analytical Expression ◽  
Flat Base ◽  
Thin Walled ◽  
Good Agreement

When a thin-walled U-channel section is plastically bent, considerable in-plane distortion occurs. The initially flat base of the U is deformed into a circular arc. The sides remain perpendicular to the base so that an angle between the sides develops. In this paper, an analytical expression for the amount of distortion is derived based on energy minimization. The expression is purely geometrical indicating that distortion should not depend on material properties. The theory is compared with fourpoint bending experiments of thin-walled channels, with good agreement found.

Residual Stresses Due to Circumferential Welds

1973 ◽  
Vol 95 (4) ◽  
pp. 233-237 ◽  
Author(s):  
S. Vaidyanathan ◽  
A. F. Todaro ◽  
I. Finnie
Keyword(s):  
Residual Stresses ◽  
Material Properties ◽  
Residual Stress Distribution ◽  
Flat Plates ◽  
Circumferential Welds ◽  
Butt Weld ◽  
State Of Stress ◽  
Axisymmetric Shells ◽  
Thin Walled ◽  
Good Agreement

The residual stress distribution produced by a circumferential weld between axisymmetric shells (cylinders, spheres, cones, etc.) is quite different from that due to a butt weld between two flat plates. The reason for this difference is pointed out and it is shown that the state of stress in thin-walled shells may be estimated from that in a plate. Since a simple approximate method for predicting residual stresses in a butt-welded flat plate is available, it is possible to estimate the stresses due to a circumferential weld from the welding conditions and certain material properties. Experimental results show good agreement with the predictions.

scholarly journals SLENDER THIN‐WALLED BOX COLUMNS SUBJECTED TO COMPRESSION AND BENDING

2010 ◽  
Vol 16 (2) ◽  
pp. 179-188 ◽  
Author(s):  
Luka Pavlovčič ◽  
Bernadette Froschmeier ◽  
Ulrike Kuhlmann ◽  
Darko Beg
Keyword(s):  
Material Properties ◽  
Local Buckling ◽  
Steel Plates ◽  
Test Results ◽  
Initial Imperfections ◽  
Euler Buckling ◽  
Thin Walled ◽  
Full Scale Tests ◽  
Box Columns ◽  
Good Agreement

This paper deals with tests on slender thin‐walled box columns, susceptible to instability of both types: to global Euler buckling as well as to local buckling of steel plates. Eight full‐scale tests were carried out with different global slenderness of welded and cold‐formed columns subjected to centric and eccentric compression. For the purpose of profound numerical simulations of tests, material properties were also tested, and the initial column geometry and residual stresses were carefully measured. The results of FEA simulations show good agreement with the test results. On verified numerical model the influence of different initial imperfections was studied. Santrauka Straipsnyje nagrinejami liaunuju dežinio skerspjūvio kolonu, jautriu abieju tipu nepastovumui ‐ bendrajam klupumui pa‐gal Euleri ir plieniniu plokšteliu vietiniam klupumui, eksperimentai. Buvo atlikti aštuoni centriškai ir ekscentriškai gniuždomu virintinio ir šaltai lankstyto skerspjūvio ivairaus liaunio kolonu natūriniai bandymai. Siekiant nuodugniai atlikti skaitini bandymu modeliavima, taip pat bandymu nustatytos mechanines plieno savybes ir kruopščiai išmatuoti visi pradiniai geometriniai nuokrypiai ir liekamieji itempiai. Skaitinio modeliavimo baigtiniu elementu metodu ir natūriniu bandymu rezultatai nedaug skiriasi. Tikrinamuoju skaitiniu modeliu buvo nagrinetas ivairiu pradiniu geometriniu netikslumu poveikis.

Distortion of Rectangular Tubes in Stretch Bending

2002 ◽  
Vol 124 (4) ◽  
pp. 886-890 ◽  
Author(s):  
Hong Zhu ◽  
Kim A. Stelson
Keyword(s):  
Internal Pressure ◽  
Energy Minimization ◽  
Stretch Bending ◽  
Rectangular Tube ◽  
Side Walls ◽  
Thin Walled ◽  
Analytical Expressions ◽  
Rectangular Tubes ◽  
Good Agreement

During stretch bending, considerable in-plane distortion occurs when a thin-walled rectangular tube is plastically bent. To minimize the distortion, fixed walls are used to limit the bulging of the side walls of the tube. Internal pressure can also be used to compensate for distortion. In this paper, analytical expressions for the amount of distortion and the needed internal pressure are derived based on energy minimization. The theory is in fairly good agreement with experiments.

Torsional Stiffness of a Thin-Walled Beam Braced by Pinned or Rigidly Fixed Transverse Diaphragms

1973 ◽  
Vol 15 (5) ◽  
pp. 351-356
Author(s):  
T. Harrison ◽  
J. M. Siddall
Keyword(s):  
Experimental Evidence ◽  
Theoretical Work ◽  
Torsional Stiffness ◽  
Cross Sectional ◽  
Cross Sectional Profile ◽  
Thin Walled ◽  
Sectional Profile ◽  
Good Agreement

The torsional stiffness of a thin-walled beam of open cross-sectional profile braced by evenly spaced transverse diaphragms is studied. Diaphragms rigidly fixed or attached by frictionless pins are treated and it is seen that, in either case, the only effect is to modify the St Venant torsional constant for the thin-walled beam. The theoretical work is supported by experimental evidence from two braced perspex channels which simulate the two assumed methods of attaching the diaphragms. Good agreement is demonstrated.

Device Modeling of a-Si:H Alloy Solar Cells: Calibration Procedure for Determination of Model Input Parameters

1998 ◽  
Vol 507 ◽  
Author(s):  
M. Zeman ◽  
R.A.C.M.M. Van Swaaij ◽  
E. Schroten ◽  
L.L.A. Vosteen ◽  
J.W. Metselaar
Keyword(s):  
Solar Cell ◽  
Material Properties ◽  
Calibration Procedure ◽  
Model Parameters ◽  
Model Input ◽  
A Value ◽  
Input Parameters ◽  
Simulated Material ◽  
Good Agreement

ABSTRACTA calibration procedure for determining the model input parameters of standard a-Si:H layers, which comprise a single junction a-Si:H solar cell, is presented. The calibration procedure consists of: i) deposition of the separate layers, ii) measurement of the material properties, iii) fitting the model parameters to match the measured properties, iv) simulation of test devices and comparison with experimental results. The inverse modeling procedure was used to extract values of the most influential model parameters by fitting the simulated material properties to the measured ones. In case of doped layers the extracted values of the characteristic energies of exponentially decaying tail states are much higher than the values reported in literature. Using the extracted values of model parameters a good agreement between the measured and calculated characteristics of a reference solar cell was reached. The presented procedure could not solve directly an important issue concerning a value of the mobility gap in a-Si:H alloys.

scholarly journals Strength of Thin-Walled Lipped Channel Section Columns with Shell-Shaped Curved Grooves

2018 ◽  
Vol 08 (04) ◽  
pp. 508-523
Author(s):  
Koki Hoshide ◽  
Mitao Ohga ◽  
Pang-jo Chun ◽  
Tsunemi Shigematsu ◽  
Sinichi Kawamura
Keyword(s):  
Channel Section ◽  
Thin Walled

Computer-Aided Visioplasticity Solution to Axisymmetric Extrusion Through Curved Boundaries

1972 ◽  
Vol 94 (4) ◽  
pp. 1225-1230 ◽  
Author(s):  
A. H. Shabaik
Keyword(s):  
Material Properties ◽  
Extrusion Ratio ◽  
Strain Rates ◽  
Exit Section ◽  
Flow Function ◽  
Curved Boundaries ◽  
Circular Arc ◽  
Conical Die ◽  
Stress Components ◽  
Experimental Values

A procedure for smoothing the experimental values of the flow function ψ in axisymmetric extrusion through curved boundaries was developed. The analysis was applied to a 45 deg conical die with a 6:1 extrusion ratio and a circular arc of 0.33-in. radius and 0.033-in. land at the exit section. An analytical expression of ψ in terms of r and z was obtained and used in the calculation of velocity and strain rate components in axisymmetric extrusion of a superplastic of the eutectic of lead–tin. The stress components were obtained from the known values of the strain rates by considering equilibrium and plasticity equations and material properties.

Modeling of contact-induced radial cracking in ceramic bilayer coatings on compliant substrates

2003 ◽  
Vol 18 (5) ◽  
pp. 1275-1283 ◽  
Author(s):  
Chun-Hway Hsueh ◽  
Pedro Miranda
Keyword(s):  
Flexural Rigidity ◽  
Ceramic Coatings ◽  
Analytical Expression ◽  
Bilayer Coating ◽  
Compliant Substrates ◽  
Dental Crowns ◽  
Plates On Elastic Foundation ◽  
Radial Cracks ◽  
Good Agreement ◽  
Bilayer Coatings

Contact-induced radial cracking in ceramic coatings on compliant substrates was analyzed recently. Radial cracks initiate at the coating/substrate interface beneath the contact where maximum flexural tension occurs, and an analytical expression for the onset of radial cracking in monolayer coatings was formulated on the basis of the classical solution for flexing plates on elastic foundation. In the present study, the analytical expression was derived for the case of ceramic bilayer coatings on compliant substrates, which have significant applications in the structure of dental crowns. It was found that the analytical solution for bilayer-coating/substrate systems can be obtained from that of monolayer-coating/substrate systems by replacing the neutral surface position and the flexural rigidity of monolayer coating with those of bilayer coating. The predicted critical loads for initiating radial cracking were found to be in good agreement with existing measurements and finite element results for glass/alumina, glass/glass-ceramic, and glass/Y2O3-stabilized ZrO2polycrystal bilayers on polycarbonate substrates. Limitations of the present analysis are discussed.

Study on Dynamic Characteristics and Parameter Sensitivity of Three Spans Prestressed Continuous Beam

2013 ◽  
Vol 351-352 ◽  
pp. 386-391
Author(s):  
Lu Ning Shi ◽  
Hao Xiang He ◽  
Wei Ming Yan ◽  
Yan Jiang Chen ◽  
Da Zhang
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Frequency Equation ◽  
Dynamic Parameters ◽  
Continuous Beam ◽  
Analytical Expression ◽  
Beam Dynamic ◽  
Frequency Sensitivity ◽  
The Impact ◽  
Good Agreement

Established the three spans prestressed continuous beam dynamic equation, obtained analytical expression of frequency equation. To solve the frequency equation for natural frequency, and compared with the finite element numerical analysis results, the frequency both with analytical expression and with finite element are in good agreement. The formula can be obtained accurately the dynamic parameters of three spans prestressed continuous beam such as frequency. At the same time, the paper also studied the natural frequency sensitivity analysis of three spans prestressed continuous beam, and focuses on the impact on the frequency with effective prestress and prestressed eccentricity.

In-plane behavior of cold-formed thin-walled beam-columns with lipped channel section

2016 ◽  
Vol 105 ◽  
pp. 1-15 ◽  
Author(s):  
Ying-Lei Li ◽  
Yuan-Qi Li ◽  
Yan-Yong Song ◽  
Zu-Yan Shen
Keyword(s):  
Channel Section ◽  
Beam Columns ◽  
Thin Walled
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