Viscoplastic Collapse of Thin-Walled Tubes Under Cyclic Bending

1998 ◽  
Vol 120 (4) ◽  
pp. 287-290 ◽  
Author(s):  
Wen-Fung Pan ◽  
Yung-Shun Her
Keyword(s):  
Cross Section ◽  
304 Stainless Steel ◽  
Experimental Result ◽  
Metal Tube ◽  
Controlled Experiments ◽  
Cyclic Bending ◽  
Tube Cross Section ◽  
Thin Walled ◽  
Number Of Cycles ◽  
Tubular Specimens

This paper presents the experimental result on the response and stability of thin-walled tubes subjected to cyclic bending with different curvature-rates. The curvature-ovalization measurement apparatus, designed by Pan et al. (1998), was used for conducting the present curvature-controlled experiments on thin-walled tubular specimens of 304 stainless steel. It is observed that the higher the applied curvature-rate, the greater is the degree of hardening of metal tube. However, the ovalization of tube cross-section increases when the applied curvature-rate increases. Furthermore, due to the higher degree of the ovalization of tube cross-section for higher curvature-rates under cyclic bending, the number of cycles to produce buckling is correspondingly reduced.

Effects of Notch Depth and Direction on Stability of Local Sharp-Notched Circular Tubes Subjected to Cyclic Bending

2018 ◽  
Vol 18 (07) ◽  
pp. 1850099 ◽  
Author(s):  
Kuo-Long Lee ◽  
Kao-Hua Chang ◽  
Wen-Fung Pan
Keyword(s):  
Analytical Data ◽  
Cyclic Hardening ◽  
Notch Depth ◽  
Steel Tubes ◽  
Element Analysis ◽  
Cyclic Bending ◽  
Tube Cross Section ◽  
Number Of Cycles ◽  
The Moment ◽  
The Relationship

Cyclic bending of tubes leads to progressive ovalization of the tube cross-section, and persistent cycling causes catastrophic buckling of the tube. This paper presents the response and stability of SUS304 stainless steel tubes with local sharp-notched depths of 0.2, 0.4, 0.6, 0.8, and 1.0[Formula: see text]mm and notch directions of 0[Formula: see text], 30[Formula: see text], 60[Formula: see text], and 90[Formula: see text] under cyclic bending. The experimental results reveal that the moment–curvature relationship first exhibits cyclic hardening and then a steady loop after a few cycles. Because the notches are small and localized, notch depth and direction show minimal influence on the moment–curvature relationship. In contrast, the ovalization–curvature relationship demonstrates an increasing and ratcheting pattern along with the bending cycle, whereas notch depth and direction show a strong influence on this relationship. Finite-element analysis via ANSYS is used to simulate the moment–curvature and ovalization–curvature relationships, and an empirical model is proposed to simulate the relationship between the controlled curvature and number of cycles required to ignite buckling. The experimental and analytical data agree well with each other.

Anisotropic Nonlinear Kinematic Hardening Rule Parameters From Reversed Proportional Axial-Torsional Cycling

1999 ◽  
Vol 122 (1) ◽  
pp. 18-28 ◽  
Author(s):  
J. C. Moosbrugger
Keyword(s):  
Kinematic Hardening ◽  
Transverse Isotropy ◽  
Cyclic Plasticity ◽  
304 Stainless Steel ◽  
Hardening Rule ◽  
Thin Walled ◽  
Hardening Rules ◽  
Type 304 ◽  
Type 304 Stainless Steel ◽  
Tubular Specimens

A procedure for determining parameters for anisotropic forms of nonlinear kinematic hardening rules for cyclic plasticity or viscoplasticity models is described. An earlier reported methodology for determining parameters for isotropic forms of uncoupled, superposed Armstrong-Frederick type kinematic hardening rules is extended. For this exercise, the anisotropy of the kinematic hardening rules is restricted to transverse isotropy or orthotropy. A limited number of parameters for such kinematic hardening rules can be determined using reversed proportional tension-torsion cycling of thin-walled tubular specimens. This is demonstrated using tests on type 304 stainless-steel specimens and results are compared to results based on the assumption of isotropic forms of the kinematic hardening rules. [S0094-4289(00)00301-7]

Biaxial Ratcheting Under Strain or Stress-Controlled Axial Cycling With Constant Hoop Stress

1994 ◽  
Vol 61 (2) ◽  
pp. 422-428 ◽  
Author(s):  
Z. Xia ◽  
F. Ellyin
Keyword(s):  
Hoop Stress ◽  
304 Stainless Steel ◽  
Test Results ◽  
Cyclic Tests ◽  
Stress Memory ◽  
Qualitative And Quantitative ◽  
Thin Walled ◽  
Tubular Specimens ◽  
Hoop Direction ◽  
Good Agreement

Strain or stress-controlled tension-compression cyclic tests were conducted on pressurized thin-walled tubular specimens of 304 stainless steel. In strain-controlled mode ratcheting strains in hoop direction, and under stress-controlled mode ratcheting in both hoop and axial directions, were observed. To predict the observed ratcheting behavior, an additional evolution rule for the stress memory surface has been introduced in the constitutive model developed recently by the authors. Qualitative and quantitative comparisons with the test results indicate a fairly good agreement in predicting ratcheting deformations.

The Influence of Diameter-to-Thickness Ratios on the Response and Collapse of Sharp-Notched Circular Tubes under Cyclic Bending

2012 ◽  
Vol 28 (3) ◽  
pp. 461-468 ◽  
Author(s):  
K.-L. Lee ◽  
C.-M. Hsu ◽  
W.-F. Pan
Keyword(s):  
Experimental Finding ◽  
Empirical Relationship ◽  
Cyclic Hardening ◽  
304 Stainless Steel ◽  
Cyclic Bending ◽  
Circular Tubes ◽  
Parallel Lines ◽  
Number Of Cycles ◽  
The Moment ◽  
Good Agreement

AbstractThis paper discusses an experimental investigation of the behavior of sharp-notched circular tubes subjected to cyclic bending. The sharp-notched circular tubes of 304 stainless steel with three different diameter-to-thickness ratios (Do / t) were tested under symmetric curvature-controlled cyclic bending. It has been shown that the moment-curvature curves exhibited the loops with cyclic hardening and gradually becoming steady after a few cycles for all tested tubes. The ovalization-curvature curves revealed unsymmetric, ratcheting and increasing behavior with the number of cycles. In addition, five almost parallel lines corresponding to five different notch depths for each Do / t ratio were found from the experimental relationship between the cyclic controlled curvature and the number of cycles necessary to produce buckling on a log-log scale. Finally, an empirical relationship was proposed so it could be used for simulating the aforementioned relationship. By comparing with the experimental finding, the derived empirical relationship was in good agreement with the experimental data.

Variation of Ovalization for Sharp-Notched Circular Tubes Under Cyclic Bending

2010 ◽  
Vol 26 (3) ◽  
pp. 403-411 ◽  
Author(s):  
K.-L. Lee ◽  
C.-Y. Hung ◽  
W.-F. Pan
Keyword(s):  
Empirical Relationship ◽  
304 Stainless Steel ◽  
Tube Bending ◽  
Steel Tubes ◽  
Cyclic Bending ◽  
Circular Tubes ◽  
Tertiary Stage ◽  
Three Stages ◽  
Number Of Cycles ◽  
Good Agreement

AbstractIn this paper, an experimental investigation on the variation of ovalization for sharp-notched circular tubes subjected to cyclic bending is discussed. The tube bending machine and curvature-ovalization measurement apparatus were used to test the unnotched and sharp-notched 304 stainless steel tubes. For sharp-notched tubes, five different notch depths (0.2, 0.4, 0.6, 0.8 and 1.0mm) were considered in this study. It was found that the experimental curve of the ovalization and the number of cycles could be divided into three stages-an initial, secondary and tertiary stage. An empirical relationship was proposed for simulating the aforementioned curve for the initial and secondary stages in this study. It has been shown that the derived empirical relationship was in good agreement with the experimental data.

First and Second Order Elastoplastic Analyses of Thin-Walled Metal Members using Generalized Beam Theory

2018 ◽  
Author(s):  
Miguel Abambres
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Cross Section ◽  
Beam Theory ◽  
Second Order ◽  
Flow Rule ◽  
Non Linear ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalized Beam Theory

Original Generalized Beam Theory (GBT) formulations for elastoplastic first and second order (postbuckling) analyses of thin-walled members are proposed, based on the J2 theory with associated flow rule, and valid for (i) arbitrary residual stress and geometric imperfection distributions, (ii) non-linear isotropic materials (e.g., carbon/stainless steel), and (iii) arbitrary deformation patterns (e.g., global, local, distortional, shear). The cross-section analysis is based on the formulation by Silva (2013), but adopts five types of nodal degrees of freedom (d.o.f.) – one of them (warping rotation) is an innovation of present work and allows the use of cubic polynomials (instead of linear functions) to approximate the warping profiles in each sub-plate. The formulations are validated by presenting various illustrative examples involving beams and columns characterized by several cross-section types (open, closed, (un) branched), materials (bi-linear or non-linear – e.g., stainless steel) and boundary conditions. The GBT results (equilibrium paths, stress/displacement distributions and collapse mechanisms) are validated by comparison with those obtained from shell finite element analyses. It is observed that the results are globally very similar with only 9% and 21% (1st and 2nd order) of the d.o.f. numbers required by the shell finite element models. Moreover, the GBT unique modal nature is highlighted by means of modal participation diagrams and amplitude functions, as well as analyses based on different deformation mode sets, providing an in-depth insight on the member behavioural mechanics in both elastic and inelastic regimes.

scholarly journals Factors Affecting the Compression and Energy Absorption Properties of Small-Sized Thin-Walled Metal Tubes

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiaoqin Hao ◽  
Jia Yu ◽  
Weidong He ◽  
Yi Jiang
Keyword(s):  
Energy Absorption ◽  
Simulation Models ◽  
Simulation Method ◽  
Engineering Practice ◽  
Small Ring ◽  
Metal Tube ◽  
Absorption Properties ◽  
Factors Affecting ◽  
Thin Walled ◽  
Hollow Metal

To solve the problem of the effective cushioning of fast-moving mechanical components in small ring-shaped spaces, the factors affecting the compression and energy absorption properties of small-sized hollow metal tubes were studied. Simulation models were constructed to analyse the influences of tube diameter, wall thickness, relative position, and number of stacked components on the compression and energy absorption properties. The correctness of the simulation method and its output were verified by experiments, which proved the effectiveness of compression and energy absorption properties of small-sized thin-walled metal tubes. The research provides support for the application of metal tube buffers in armament launch technology and engineering practice.

Application of the Equivalent Transformation Layering Calculation Model in Heavy Cross-Section FGCs - Axis-Symmetrical Mechanics Problems

2005 ◽  
Vol 475-479 ◽  
pp. 1533-1536
Author(s):  
Liu Ding Tang ◽  
Xue Bin Zhang ◽  
Bing Zhe Li
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Calculation Model ◽  
Functionally Graded ◽  
Equivalent Transformation ◽  
Metal Tube ◽  
Cross Sectional ◽  
Functionally Graded Composites ◽  
Graded Structure ◽  
Design And Practice

Based on equivalent transformation by means of mathematically rigorous analytics, the stress analysis of heavy cross-sectional, non-homogeneous Functionally Graded Composites (FGCs) has been performed by the layering calculation model in axis-symmetrical mechanics problems. The partially calculated results of the non-homogeneous layered thick-walled metal tube are similar to the design and practice of machine forging moulds manufactured with special welding electrodes developed by the German Capilla Company. The analysis is used complementary to the investigation of the quantitative analysis of thermo-mechanical properties, or the so-called anti-design and the optimization of the graded structure for FGCs.

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