scholarly journals Brazier Effect of Thin Angle-Section Beams under Bending

2018 ◽  
Vol 10 (9) ◽  
pp. 3047
Author(s):  
Zhiguang Zhou ◽  
Liuyun Xu ◽  
Chaoxin Sun ◽  
Songtao Xue
Keyword(s):  
Nonlinear Response ◽  
Beam Theory ◽  
Bending Moment ◽  
Numerical Results ◽  
Experimental Results ◽  
Angle Section ◽  
Thin Walled ◽  
The Moment ◽  
Good Agreement ◽  
Brazier Effect

Thin-walled section beams have Brazier effect to exhibit a nonlinear response to bending moments, which is a geometric nonlinearity problem and different from eigenvalue problem. This paper is aimed at investigating the Brazier effect in thin-walled angle-section beams subjected to pure bending about its weak axis. The derivation using energy method is presented to predict the maximum bending moment and section deformation. Both numerical analyses and experimental results were used to show the validity of the proposed formula. Numerical results show that the boundary condition can influence the results due to the end effect, and that the influence tends to be negligible when the length of angle beam goes up to 30 times as the length of beam side. When the collapse in experiments is governed by Brazier flattening, the moment vs. curvature curve deviates significantly from the linear beam theory, but coincides well with the proposed formula in consideration of the restraint due to limited span of experimental setup. It can be concluded that the proposed formula shows good agreement with numerical results and experimental results.

Failure of Thin-Walled Pipes With D/T up to 140 and Conclusions for the Design Codes

2016 ◽  
Author(s):  
Henry Schau ◽  
Lilit Mkrtchyan ◽  
Michael Johannes
Keyword(s):  
Yield Stress ◽  
Bending Moment ◽  
Bending Stress ◽  
Dynamic Analyses ◽  
Asme Code ◽  
Stress Intensification Factor ◽  
Thin Walled ◽  
The Moment ◽  
Outside Diameter ◽  
Good Agreement

The influence of imperfections on the instability bending moment of thin-walled straight pipes with D/t-ratios (D - outside diameter, t - wall thickness) up to 140 is determined using nonlinear Finite Element (FE) analyses. The analyses show that the type and size of the imperfection, the D/t ratio and the material properties have significant influences on the instability moment. The nominal bending stress of pipes (yield stress 500 MPa) with D/t > 70 and an ovality of 0.5% is smaller than the yield stress at the instability point. That means, the failure occurs by buckling in the elastic range of the nominal bending stress. In static analyses the moment decreases abruptly after reaching the instability moment. In the dynamic analyses the pipe jumps abruptly to the state with smaller moment. The obtained results are applied to calculate the B2 index for pipes with D/t ≤ 140. The B2 indices for thin-walled straight pipes with D/t > 40 are considerably higher than 1.0. In general, there is a good agreement between the calculated B2 values and the values of the ASME Code. A correction factor for higher temperatures is not necessary. The allowable moments calculated with the B2 index and the stress intensification factor i are compared. The bending moments from disabled thermal expansion and anchor movements have the same effect on the failure due to (plastic) buckling as the primary moments and must be taken into account.

scholarly journals Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

2016 ◽  
Vol 61 (2) ◽  
pp. 1003-1008 ◽  
Author(s):  
A. Dziubińska ◽  
A. Gontarz ◽  
K. Dziedzic
Keyword(s):  
Qualitative Research ◽  
Finite Element ◽  
Magnesium Alloy ◽  
Numerical Results ◽  
Experimental Results ◽  
Az31 Magnesium Alloy ◽  
Forming Process ◽  
Closed Die Forging ◽  
Selection Of ◽  
Good Agreement

AbstractThe paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

Analytical Model for a Superelastic SMA Beam

2017 ◽  
Author(s):  
N. V. Viet ◽  
Wael Zaki ◽  
Rehan Umer
Keyword(s):  
Analytical Model ◽  
Bending Moment ◽  
Analytical Relation ◽  
Beam Model ◽  
Element Analysis ◽  
Austenitic Phase ◽  
Martensite Variant ◽  
The Moment ◽  
Reversible Phase ◽  
Good Agreement

We propose an analytical model for a superelastic shape memory alloy (SMA) beam. The model considers reversible phase transformation between austenite and a single martensite variant driven by mechanical loading/unloading. In particular, we consider a cantilever beam subjected to a concentrated transverse force acting at the tip. The force is gradually increased from zero to a maximum value sufficient to cause complete transformation of the initially austenitic phase into martensite away from the beam core. The force is then gradually removed, resulting in complete strain recovery. In each stage of the loading/unloading process, an analytical relation is established between bending moment and curvature in terms of position along the axis of the beam. The model is compared to a uniaxial numerical beam model and to finite element analysis (FEA) results for the same beam in 3D, with very good agreement in each case. The moment-curvature relation is then integrated to obtain a nonlinear expression for the deflection and stress distribution in terms of position along the length of the beam. The expression is validated against 3D simulation results.

Two Secondary Effects in Bending of Slit Thin-Walled Tubes

1966 ◽  
Vol 33 (1) ◽  
pp. 75-78 ◽  
Author(s):  
F. P. J. Rimrott
Keyword(s):  
Cross Section ◽  
Circular Tube ◽  
Bending Moment ◽  
Approximate Equation ◽  
Neutral Axis ◽  
Secondary Effects ◽  
Theoretical Predictions ◽  
Thin Walled ◽  
Brazier Effect ◽  
Free Edges

During bending of a slit, thin-walled circular tube two secondary effects are observed to occur simultaneously. One, the so-called Brazier effect, occurs in thin-walled tubes generally when they are subjected to bending, and consists of an ovaling of the cross section. The second effect is a peculiarity of slit tubes only and manifests itself as an overlap of the free edges. The severity of both effects depends upon the location of the slit. The bending moment and the radial and tangential displacements have been determined as function of the curvature for four different slit locations with respect to the neutral axis. The value of the curvature at instability has also been derived. Subsequently an approximate equation has been obtained for the cantilever. The results of experiments on a cantilever are compared with the theoretical predictions.

scholarly journals The Effect of Transverse Shear in Symmetric and Asymmetric End Notch Flexure Tests–Analytical and Numerical Modeling

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3046
Author(s):  
Konrad Dadej ◽  
Paolo Sebastiano Valvo ◽  
Jarosław Bieniaś
Keyword(s):  
Transverse Shear ◽  
Beam Theory ◽  
Bending Moment ◽  
Pure Mode ◽  
Planar Shear ◽  
Transverse Shearing ◽  
Numerical Finite Element ◽  
Rigid Interface ◽  
Moment State ◽  
Good Agreement

This paper focuses on the effects of transverse shear and root rotations in both symmetric and asymmetrical end-notched flexure (AENF) interlaminar fracture toughness tests. A theoretical model is developed, whereas the test specimen is subdivided into four regions joined by a rigid interface. The differential equations for the deflection and rotations of each region are solved within both the Euler–Bernoulli simple beam theory (SBT) and the more refined Timoshenko beam theory (TBT). A concise analytical equation is derived for the AENF deflection profile, compliance, and transverse shearing forces as a function of the specimen geometry, stacking sequence, delamination length, and fixture span. Modeling results are compared with numerical finite element analyses, obtaining a very good agreement. Performed analyses suggest that even in the case of symmetrical and unidirectional laminates considered as pure mode II fracture, a complex compression/tension and bending moment state is present, as well as a slight contribution of anti-planar shear at the vicinity of the crack tip.

scholarly journals The Effects of Projectile Speed and Medium Resistance in Ricochet off Sand

1981 ◽  
Vol 23 (2) ◽  
pp. 69-75 ◽  
Author(s):  
Y. L. Baif ◽  
W. Johnson
Keyword(s):  
Aluminium Alloy ◽  
Impact Angle ◽  
Considerable Change ◽  
Numerical Results ◽  
Experimental Results ◽  
Proposed Model ◽  
Medium Resistance ◽  
Static Resistance ◽  
Good Agreement

It has been observed experimentally that when a sphere ricochets off water or sand the critical impact angle depends on the impinging velocity. To explain this, a model is developed which takes into account the weight of the sphere and the static resistance of the medium into which penetration occurs. The proposed model can also treat processes in which the angle of impact is large and where the velocity of the sphere undergoes considerable change. Projectile trajectories which have been calculated for various conditions are presented and discussed. Numerical results for steel, aluminium alloy, and lead spheres are in good agreement with such experimental results as are available.

Investigation of Integral Composite T-Joints under Mixed Mode Loading

2018 ◽  
Vol 774 ◽  
pp. 197-202 ◽  
Author(s):  
Felix Nolte ◽  
André Hannig ◽  
Peter Horst
Keyword(s):  
Mixed Mode ◽  
Numerical Results ◽  
Experimental Results ◽  
Mixed Mode Loading ◽  
Load Case ◽  
T Joints ◽  
Test Fixture ◽  
Good Agreement

This paper presents experimental and numerical results on the deformations and failureof integral composite T-joints subjected to a realistic combined tensile and bending (mixed mode)load case. For this reason, standard pull-off and mixed mode load cases are experimentally studiedby means of a novel test fixture which keeps the force angle constant to the T-joint’s base and allowsfor repositioning of the specimen in order to minimize constraining forces. Two types of specimenswith varying deltoid radius are investigated. Additionally, kinematically nonlinear numerical simulationsare performed to locate damage onset and deformations of the specimens. It is found that thesimulations are in good agreement with the experimental results.

Modeling of tensile and bending properties of biaxial weft knitted composites

2015 ◽  
Vol 22 (3) ◽  
pp. 303-313 ◽  
Author(s):  
Ozgur Demircan ◽  
Shinsuke Ashibe ◽  
Tatsuya Kosui ◽  
Asami Nakai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Beam Theory ◽  
Experimental Results ◽  
Composite Panel ◽  
The Finite Element Method ◽  
Bending Properties ◽  
Bending Modulus ◽  
Laminate Beam ◽  
Good Agreement

AbstractWithin the scope of experiments, the effect of aramid and glass yarns as stitch and biaxial (warp and weft) yarns in the biaxial weft knitted (BWK) composite was compared. After production of four types of composite panel using the hand lay-up method, the tensile and bending properties of the BWK composites were investigated both experimentally and numerically. The composite with the glass stitch and biaxial yarns exhibited higher tensile and bending properties than did the composite with the aramid stitch and biaxial yarns. The good agreement between the experimental results and the numerical results validated the applicability of the finite-element method for the BWK composites. The laminate beam theory was utilized as another modeling method for calculation of the bending modulus.

General Correlations and Selection Procedures for Flow in Polyethylene Tubes With Uniformly Spaced Wall Orifices

1991 ◽  
Vol 113 (1) ◽  
pp. 98-103 ◽  
Author(s):  
E. Brundrett
Keyword(s):  
Data Base ◽  
Numerical Procedure ◽  
Experimental Results ◽  
Selection Procedures ◽  
Supply Pressure ◽  
Swirl Angle ◽  
Thin Walled ◽  
Predicted Values ◽  
Good Agreement ◽  
Economical Performance

A previously described experimentally based numerical procedure is used to characterize the flow in thin walled polyethylene tubes with uniformly spaced wall orifices (polytubes). The procedure evaluates the required supply pressure for specified geometry, supply flow, and supply swirl angle; and then predicts the pressure and discharge profiles along the polytube. The predicted values are in good agreement with reported experimental results and are used to develop a data base of the most significant ranges of polytube and supply parameters. Then, explicit design correlations and recommendations are obtained for satisfactory and economical performance.

Analysis of thin-walled frames considering joint flexibilities

2007 ◽  
Vol 221 (10) ◽  
pp. 1221-1229 ◽  
Author(s):  
P R Marur
Keyword(s):  
Beam Theory ◽  
Frame Structure ◽  
Elastic Response ◽  
Joint Flexibility ◽  
One Dimensional ◽  
Static And Dynamic Analysis ◽  
Out Of Plane ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Good Agreement

TAnalytical models are developed for static and dynamic analysis of thin-walled frames representing the automotive side structures. The model is based on one-dimensional beam theory that considers joint flexibility to compute stiffness and frequency response of the whole frame structure. The computed out-of-plane displacements under static and impact loading are in good agreement with those obtained from the shell finite element method. Using the validated analytical model, the influence of joint flexibility on the elastic response of the side structure is studied.

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