Strain Reversal in Actuated Origami Structures

The experimental and numerical study of the effects of the recrystallization behavior of austenite model alloys during hot plate rolling on reverse rolling is the main goal of the paper. The computer models that are currently applied for simulation of reverse rolling are not strain-path-sensitive, thus leading to overestimation of the processing parameters outside the accepted process window (e.g., deformation in the partial austenite recrystallization region). Therefore, in this work, a particular focus is put on the investigation of strain path effects that occur during hot rolling and their influence on the microstructure evolution and mechanical properties of microalloyed austenite. Both experimental and numerical techniques are employed in this study, taking advantage of the integrated computational material engineering concept. The combined isotropic–kinematic hardening model is used for the macroscale predictions to take into account softening effects due to strain reversal. The macroscale model is additionally enriched with the full-field microstructure evolution model within the cellular automata framework. Examples of obtained results, highlighting the role of the strain reversal on the microstructural response, are presented within the paper. The combination of the physical simulation of austenitic model alloys and computer modeling provided new insights into optimization of the processing routes of advanced high-strength steels (AHSS).

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A comparison of the mechanical behaviour of an AA1050 and a low carbon steel deformed upon strain reversal

Acta Materialia ◽

10.1016/j.actamat.2004.10.046 ◽

2005 ◽

Vol 53 (4) ◽

pp. 1005-1013 ◽

Cited By ~ 59

Author(s):

G. Vincze ◽

E.F. Rauch ◽

J.J. Gracio ◽

F. Barlat ◽

A.B. Lopes

Keyword(s):

Carbon Steel ◽

Mechanical Behaviour ◽

Low Carbon Steel ◽

Low Carbon ◽

Strain Reversal

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Development of Failure Criteria for Predicting Tearing of Wrinkled Pipe

2010 8th International Pipeline Conference, Volume 4 ◽

10.1115/ipc2010-31117 ◽

2010 ◽

Author(s):

Arman Uddin Ahmed ◽

J. J. Roger Cheng ◽

Joe Zhou

Keyword(s):

Equivalent Plastic Strain ◽

Failure Criteria ◽

Numerical Analyses ◽

Fe Model ◽

Load History ◽

Key Factors ◽

Cross Sectional ◽

Damage Initiation ◽

Scale Test ◽

Strain Reversal

Onshore steel pipelines, particularly buried in cold region, often subjected to extreme geo-environmental conditions, where significant inelastic deformation may occur resulting in localized wrinkles. Under continued deformation, there is a possibility of excessive cross-sectional deformation at wrinkle locations, eventually leading to fracture or damage in the pipe wall. A recent field fracture and failed laboratory specimens under monotonic load history address the necessity of conducting a comprehensive research program to better understand this unique failure mode. Initial results have indicated that even under monotonic loading, significant strain reversals can occur at sharp fold of the wrinkle. These strain reversals were identified as one of the key factors to trigger this unique failure mechanism. This paper addresses the development of failure criteria used in the finite element (FE) model of plain pipes subjected to sustained monotonic axial and bending deformation with or without internal pressure. In conjunction with the strain reversal criterion, the critical equivalent plastic strain was used as the fracture or damage initiation limit in the numerical analyses. Results obtained from the full-scale test of an NPS16 pipe were used to calibrate the FE model. Results obtained from the numerical analyses have shown that the proposed criteria predict the onset of fracture at sharp fold of the wrinkle with reasonable accuracy.

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Improved refined plastic hinge analysis accounting for strain reversal

Engineering Structures ◽

10.1016/s0141-0296(98)00079-0 ◽

2000 ◽

Vol 22 (1) ◽

pp. 15-25 ◽

Cited By ~ 11

Author(s):

Seung-Eock Kim ◽

Moon Kyum Kim ◽

Wai-Fah Chen

Keyword(s):

Plastic Hinge ◽

Strain Reversal

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A Step Forward in the Understanding of the Strain Reversal Effect on the Recrystallization Kinetics after Hot Working

Materials Science Forum ◽

10.4028/www.scientific.net/msf.715-716.643 ◽

2012 ◽

Vol 715-716 ◽

pp. 643-648

Author(s):

D. Jorge-Badiola ◽

J.L. Lanzagorta ◽

Isabel Gutiérrez

Keyword(s):

Strain Path ◽

Static Recrystallization ◽

Equivalent Strain ◽

Hot Working ◽

Material Behaviour ◽

Reversal Effect ◽

Recrystallization Kinetics ◽

Strain Axis ◽

Strain Reversal ◽

Strain Transients

A reversion of the strain produces a modification of the static recrystallization kinetics. Initially, the reversion increases the recrystallization time, that reaches a maximum at a certain strain, and decreases again for increasing reverse strains. This transient on recrystallization kinetics develops over a strain interval similar to that of the microstructural and stress-strain transients. At strains beyond the transient, the reversion can be regarded as a shift on the strain axis. However, at the authors knowledge there is no formulation able to describe the material behaviour during the transient. The present work introduces an equivalent strain concept based on the substructural dissolution/build-up processes taking place as a result of the strain reversal. This formulation allows including the effect of the strain path on recrystallization models.

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The effect of residual stresses and strain reversal on the fracture toughness of TiAl alloys

Materials Science and Engineering A ◽

10.1016/j.msea.2017.10.010 ◽

2018 ◽

Vol 709 ◽

pp. 17-29 ◽

Cited By ~ 12

Author(s):

Fritz Appel ◽

Jonathan D.H. Paul ◽

Peter Staron ◽

Michael Oehring ◽

Otmar Kolednik ◽

...

Keyword(s):

Fracture Toughness ◽

Residual Stresses ◽

Tial Alloys ◽

Strain Reversal

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Plastic Flow and Grain Refinement under Simple Shear-Based Severe Plastic Deformation Processing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.604-605.171 ◽

2008 ◽

Vol 604-605 ◽

pp. 171-178 ◽

Cited By ~ 8

Author(s):

Dmitry Orlov ◽

Yoshikazu Todaka ◽

Minoru Umemoto ◽

Yan Beygelzimer ◽

Z. Horita ◽

...

Keyword(s):

Grain Refinement ◽

High Pressure Torsion ◽

Equivalent Strain ◽

Severe Plastic Deformation Processing ◽

Structure Evolution ◽

Twist Extrusion ◽

High Purity Aluminum ◽

Strain Reversal ◽

Deformation Modes ◽

Loading Scheme

In the present work, effects of loading scheme and strain reversal on structure evolution are studied by using high pressure torsion (HPT) and twist extrusion (TE) techniques. High purity aluminum (99.99%) was processed at room temperature up to a total average equivalent strain of ~4.8 by TE and HPT with two deformation modes: monotonic and reversal deformation with a step of 12˚ rotation. It was revealed that microstructural change with straining observed in pure Al was a common consequence of the SPD processing and was not affected significantly by the loading scheme. At the same time, it was found that strain reversal retarded grain refinement in comparison with monotonic deformation.

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On the Effect of Strain Reversal on Static Recrystallisation and Strain-Induced Precipitation Process Kinetics in Microalloyed Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.715-716.655 ◽

2012 ◽

Vol 715-716 ◽

pp. 655-660 ◽

Cited By ~ 5

Author(s):

K. Muszka ◽

Lin Sun ◽

Bradley P. Wynne ◽

Eric J. Palmiere ◽

W.M. Rainforth

Keyword(s):

Dislocation Density ◽

Strain Path ◽

Microalloyed Steel ◽

Microalloyed Steels ◽

Precipitation Process ◽

Flow Curves ◽

Process Kinetics ◽

Nb Microalloyed Steel ◽

Strain Reversal ◽

The Difference

Recent observations show that the strain reversal affects significantly and in a complex way both the static recrystallisation (SRX) and strain-induced precipitation (PPT) kinetics in Nb-microalloyed steel. It is already known that the recrystallisation stagnation is a consequence of the competition between the driving pressure for recrystallisation and the pinning pressure caused by the strain-induced precipitation of Nb (C,N) precipitates. Both of these parameters depend in turn on the local dislocation density. Thus, it is expected that a variation of the local dislocation density due to reversal of the strain will affect at the same time the local driving and the pinning pressures, which will cause the difference in the hardening levels. In the present paper, the influence of strain path change on microstructure evolution and mechanical behaviour in Nb-microalloyed steel (API X-70 grade) was studied. The deformation schedules were designed in order to investigate an effect of strain reversal on both static recrystallisation and strain-induced precipitation process kinetics. Flow curves recorded during deformation of X-70 steel showed clear influence of applied strain path on both static recrystallisation kinetics and strain-induced precipitation process.

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