Multiaxial Creep of 2618 Aluminum under Proportional Loading Steps.

1982 ◽  
Author(s):  
Jow-Lian Ding ◽  
William N. Findley
Keyword(s):  
Proportional Loading ◽  
Multiaxial Creep

Creep-Fatigue Strength of Sn-8Zn-3Bi Solder Under Multiaxial Loading

Materials ◽  
2005 ◽  
Author(s):  
Takaei Yamamoto ◽  
Takamoto Itoh ◽  
Masao Sakane ◽  
Hiroshi Sasaki ◽  
Kazuhiko Shuto ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Torsion Test ◽  
Multiaxial Loading ◽  
Strain Wave ◽  
Proportional Loading ◽  
Strain Waves ◽  
Creep Fatigue ◽  
Multiaxial Creep ◽  
Strain Hold

This paper describes the multiaxial creep-fatigue of Sn-8Zn-3Bi solder in proportional and non-proportional loadings. Push-pull and reversed torsion tests were carried in proportional test using fast-fast, slow-fast, fast-slow, slow-slow and strain-hold waves. Non-proportional tests were also carried out using box, step and circle strain waves. In proportional test, smallest creep-fatigue lives were observed in push-pull slow-fast test. Creep-fatigue lives in reversed torsion test were longer by a factor of 2 than those in push-pull test compared with the same strain wave. Non-proportional loading reduced the creep-fatigue life. Circle strain wave showed the smallest fatigue life in non-proportional loading. A non-proportional strain proposed by the authors correlated all the proportional and non-proportional fast-fast data within a factor of two scatter band.

scholarly journals Evaluation of Multiaxial Creep-fatigue Strength for High Chromium Steel under Non-proportional Loading

2019 ◽  
Vol 300 ◽  
pp. 07002
Author(s):  
Yuuki Kasamuta ◽  
Fumio Ogawa ◽  
Takamoto Itoh ◽  
Hiroyasu Tanigawa
Keyword(s):  
Chromium Steel ◽  
Fatigue Tests ◽  
Proportional Loading ◽  
High Chromium ◽  
Nuclear Fusion Reactor ◽  
Life Evaluation ◽  
Creep Fatigue ◽  
Strain Paths ◽  
Multiaxial Creep ◽  
Failure Life

This study discusses the result of creep-fatigue tests of a high-chromium steel, F82H which was designed as blanket structural materials of nuclear fusion reactor, carried out at room temperature to 823K in air. Strain paths applied were a push-pull loading and a circle loading in which normal and shear strain have 90 degree phase difference. The holding times used were 180 s and 600 s. Moreover, an evaluation of failure life by taking into account intensities of creep and non-proportionality is discussed based on both the life evaluation proposed by Itoh, et al and method of modified universal slopes. Availability of the equation for the life evaluation was confirmed by comparison with conventional universal slope method.

Multiaxial Creep of 2618 Aluminum Under Proportional Loading Steps

1984 ◽  
Vol 51 (1) ◽  
pp. 133-140 ◽  
Author(s):  
J.-L. Ding ◽  
W. N. Findley
Keyword(s):  
Strain Hardening ◽  
Kinematic Hardening ◽  
Superposition Principle ◽  
Viscoelastic Model ◽  
Creep Recovery ◽  
Strain Component ◽  
Proportional Loading ◽  
Dependent Strain ◽  
Stress States ◽  
Multiaxial Creep

Creep data of 2618-T61 aluminum alloy under multistep multiaxial proportional loadings at 200°C (392°F) are reported. Two viscoplastic flow rules were developed using constant stress creep and creep recovery data. One was based on the accumulated strain (isotropic strain hardening), and the other on a tensorial state varible (kinematic hardening). Data were represented by two models: a nonrecoverable viscoplastic model, and a viscous-viscoelastic model in which the time-dependent strain was resolved into recoverable (viscoelastic) and nonrecoverable components. The modified superposition principle was used to predict the viscoelastic strain component under variable stress states. The experiments showed that the viscous-viscoelastic model with either isotropic strain hardening or kinematic hardening gave very good predictions of the material responses. Isotropic strain hardening was best in some step-down stress states. The viscoelastic component accounted for not only the recovery strain but also the transient creep strain upon reloadings and step-up loadings.

scholarly journals Buckling Behavior of FG-CNT Reinforced Composite Conical Shells Subjected to a Combined Loading

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 419 ◽  
Author(s):  
Abdullah H. Sofiyev ◽  
Francesco Tornabene ◽  
Rossana Dimitri ◽  
Nuri Kuruoglu
Keyword(s):  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Structural Response ◽  
Systematic Investigation ◽  
Functionally Graded ◽  
Combined Loading ◽  
Proportional Loading ◽  
Conical Shells ◽  
Reinforced Composite ◽  
Buckling Behavior

The buckling behavior of functionally graded carbon nanotube reinforced composite conical shells (FG-CNTRC-CSs) is here investigated by means of the first order shear deformation theory (FSDT), under a combined axial/lateral or axial/hydrostatic loading condition. Two types of CNTRC-CSs are considered herein, namely, a uniform distribution or a functionally graded (FG) distribution of reinforcement, with a linear variation of the mechanical properties throughout the thickness. The basic equations of the problem are here derived and solved in a closed form, using the Galerkin procedure, to determine the critical combined loading for the selected structure. First, we check for the reliability of the proposed formulation and the accuracy of results with respect to the available literature. It follows a systematic investigation aimed at checking the sensitivity of the structural response to the geometry, the proportional loading parameter, the type of distribution, and volume fraction of CNTs.

The Further Exploration of Applying Small-Strain and Large-Strain Formulations to SMA

2012 ◽  
Vol 529 ◽  
pp. 228-235
Author(s):  
Jie Yao ◽  
Yong Hong Zhu
Keyword(s):  
Phase Transformation ◽  
Constitutive Model ◽  
Uniaxial Tension ◽  
Driving Force ◽  
Research Team ◽  
Large Strain ◽  
Small Deformation ◽  
Small Strain ◽  
Proportional Loading ◽  
The Difference

Recently, our research team has been considering to applying shape memory alloys (SMA) constitutive model to analyze the large and small deformation about the SMA materials because of the thermo-dynamics and phase transformation driving force. Accordingly, our team use simulations method to illustrate the characteristics of the model in large strain deformation and small strain deformation when different loading, uniaxial tension, and shear conditions involve in the situations. Furthermore, the simulation result unveils that the difference is nuance concerning the two method based on the uniaxial tension case, while the large deformation and the small deformation results have huge difference based on shear deformation case. This research gives the way to the further research about the constitutive model of SMA, especially in the multitiaxial non-proportional loading aspects.

Elastic Shakedown in Pressure Vessel Components Under Non-Proportional Loading

2002 ◽  
Author(s):  
Martin Muscat ◽  
Robert Hamilton
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Pressure Vessel ◽  
Proportional Loading ◽  
Linear Superposition ◽  
Element Analysis ◽  
Mechanical Loads ◽  
Bound Theorem ◽  
Square Plate ◽  
Elastic Shakedown

Bounding techniques for calculating shakedown loads are of great importance in design since this eliminates the need for performing full elasto-plastic cyclic loading analyses. The classical Melan’s lower bound theorem is widely used for calculating shakedown loads of pressure vessel components under proportional loading. Polizzotto extended the Melan’s theorem to the case of non-proportional loading acting on a structure. This paper presents a finite element method, based on Polizzotto’s theorem, to estimate the elastic shakedown load for a structure subjected to a combination of steady and cyclic mechanical loads. This method, called non-linear superposition, is then applied to investigate the shakedown behaviour of a pressure vessel component — a nozzle/cylinder intersection and that of a biaxially loaded square plate with a central hole. Results obtained for both problems are compared with those available in the literature and are verified by means of cyclic elasto-plastic finite element analysis.

The effect of finite deformations in the elastic stability of plane frames

1962 ◽  
Vol 266 (1324) ◽  
pp. 47-67 ◽  
Keyword(s):  
Critical Load ◽  
Failure Load ◽  
Elastic Stability ◽  
Load Level ◽  
Load Factor ◽  
Proportional Loading ◽  
Arbitrary Load ◽  
Plane Frames ◽  
The Difference ◽  
Rigid Joints

The circumstances are discussed under which orthogonal relations exist between the elastic critical modes of plane frames subjected to proportional loading. Orthogonal relations may be obtained provided the loading does not produce any components of deformation associated with any of the critical modes at arbitrary levels of the load factor, and provided no part of the structure remains statically indeterminate due to bar forces when all rigid joints are replaced by pin joints. When at arbitrary load factors, the structure deforms with components associated with any of the buckling modes, the elastic failure load is not identical with the lowest elastic critical load, although for many frames the two loads may be very close. A general expression is obtained which reveals the relation between the deformations at an arbitrary load level and the deflexions given by linear analysis. The difference between the elastic failure load and the elastic critical load is discussed, and an approximate treatment applicable to certain types of frame and associated loading is developed.

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