Multiscale Analysis of Acoustic Emission during Plastic Flow of Al and Mg Alloys: From Microseconds to Minutes

2014 ◽  
Vol 783-786 ◽  
pp. 204-209 ◽  
Author(s):  
Mikhail Lebyodkin ◽  
Ivan V. Shashkov ◽  
Tatiana Lebedkina ◽  
Vladimir S. Gornakov
Keyword(s):  
Plastic Deformation ◽  
Acoustic Emission ◽  
Plastic Flow ◽  
Nonlinear Dynamical Systems ◽  
Crystal Defects ◽  
Mg Alloys ◽  
Collective Effects ◽  
Experimental Conditions ◽  
Nonlinear Dynamical ◽  
Individual Crystal

Recent studies of plastic deformation using high-resolution experimental techniques bear witness that deformation processes are often characterized by collective effects emerging on an intermediate scale between the scales describing the dynamics of individual crystal defects or the macroscopic plastic flow. In particular, the acoustic emission (AE) reveals intermittency of plastic deformation in various experimental conditions, which is manifested by the property of scale invariance, a characteristic feature of self-organized phenomena. Some materials, e.g., Al or Mg alloys, display a macroscopic discontinuity of plastic flow due to the Portevin-Le Chatelier effect or twinning. These materials are therefore of special interest for the study of collective effects in plasticity. The present work reviews the results of a multiscale investigation of AE accompanying plastic deformation of such model alloys. The AE is analyzed by methods borrowed from the theory of nonlinear dynamical systems, including statistical and multifractal analyses.

scholarly journals Кинетика развития паттернов макролокализации пластического течения металлов

2018 ◽  
Vol 60 (7) ◽  
pp. 1358
Author(s):  
Л.Б. Зуев ◽  
С.А. Баранникова ◽  
Б.С. Семухин
Keyword(s):  
Plastic Deformation ◽  
Acoustic Emission ◽  
Plastic Strain ◽  
Plastic Flow ◽  
Strain Localization ◽  
Plastic Distortion ◽  
Localization Zone ◽  
Distortion Tensor ◽  
The Relationship

AbstractThe features of the macroscopic inhomogeneity of plastic deformation in the form of autowaves with a pulsating amplitude are analyzed, and data on the localization of sources of acoustic emission at different stages of plastic flow in the stretching of fcc mono- and polycrystals are presented. The relationship between the local components of the plastic distortion tensor in the strain localization zone is traced. The role of acoustic phenomena accompanying the localization of plastic strain in the development of the process of plastic deformation is considered.

Synergetics and Acoustic Emission Approach for Crazing Nonlinear Dynamical Systems

2020 ◽  
Vol 30 (03) ◽  
pp. 2050043
Author(s):  
Guodong Gao ◽  
Yongming Xing
Keyword(s):  
Acoustic Emission ◽  
Dynamical Systems ◽  
Nonlinear Dynamical Systems ◽  
Chaotic Behavior ◽  
The Self ◽  
Self Organization ◽  
Mathematical Explanation ◽  
Theoretical Derivation ◽  
Nonlinear Dynamical ◽  
Loading Mode

This paper reports that synergetics are used to analyze the crazing evolution. On this basis, chaotic effect is explored. The chaos equation is established and verified. The theoretical derivation are consistent with the experimental results. We design a special specimen with a special loading mode, the transient monitoring function of acoustic emission (AE) technology is used to track and detect the crazing inside the PMMA in real time, and the experiments show that synergetics can explain the crazing properties of polymer. Importantly, the mathematical explanation is also given. The AE analysis, synergetics, and craze photo reached a conclusion that the crazing has chaotic behavior. After analyzing the AE events and crazing at different stress levels, the accuracy of synergetic approach for crazing is verified. By studying the course of AE events and crazing, the self-organization effect is proposed. The research results will provide data support for the application of PMMA in ship, aircraft, and precision instruments.

The model of plastic deformation and failure of solids

2021 ◽  
pp. 75-83
Author(s):  
L.B. Zuev ◽  
◽  
V.V. Gorbatenko ◽  
L.V. Danilova ◽  
◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Acoustic Emission ◽  
Plastic Flow ◽  
Work Hardening ◽  
Scale Level ◽  
Macroscopic Scale ◽  
Deformation And Failure ◽  
New Model ◽  
Hardening Law

The new model is proposed to explain localized plasticity and failure development in solids. This is based on the idea about the interaction of plasticity acts with acoustic emission pulses. They are generated in the course of the elementary plasticity acts. It is shown experimentally that plastic flow is always localized on the macroscopic scale level. The distribution of localization in the volume has the form of different autowave processes and depends on the work hardening law.

scholarly journals Complexity and Anisotropy of Plastic Flow of α-Ti Probed by Acoustic Emission and Local Extensometry

2018 ◽  
Author(s):  
Mikhail Lebyodkin ◽  
Kékéli Amouzou ◽  
Tatiana Lebedkina ◽  
Thiebaud Richeton ◽  
Amandine Roth
Keyword(s):  
Acoustic Emission ◽  
Plastic Flow ◽  
Micromechanical Model ◽  
Local Strain ◽  
Simultaneous Recording ◽  
Distribution Functions ◽  
Crystal Defects ◽  
Dislocation Dynamics ◽  
Dislocation Glide ◽  
Deformation Curves

Current progress in the prediction of mechanical behavior of solids requires understanding of spatiotemporal complexity of plastic flow caused by self-organization of crystal defects. It may be particularly important in hexagonal materials because of their strong anisotropy and combination of different mechanisms of plasticity, such as dislocation glide and twinning. These materials often display complex behavior even on the macroscopic scale of deformation curves, e.g., a peculiar three-stage elastoplastic transition, the origin of which is a matter of debates. The present work is devoted to a multiscale study of plastic flow in α-Ti, based on simultaneous recording of deformation curves, 1D local strain field, and acoustic emission (AE). It is found that the average AE activity also reveals three-stage behavior, but in a qualitatively different way depending on the crystallographic orientation of the sample axis. On the finer scale, the statistical analysis of AE events and local strain rates testifies to an avalanche-like character of dislocation processes, reflected in power-law probability distribution functions. The results are discussed from the viewpoint of collective dislocation dynamics and are confronted to predictions of a recent micromechanical model of Ti strain hardening.

scholarly journals Plasticity: from Crystal Lattice to Macroscopic Phenomena

2021 ◽  
Vol 22 (1) ◽  
pp. 3-57
Author(s):  
L. B. Zuev ◽  
S. A. Barannikova ◽  
V. I. Danilov ◽  
V. V. Gorbatenko
Keyword(s):  
Experimental Investigation ◽  
Plastic Deformation ◽  
Acoustic Emission ◽  
Plastic Flow ◽  
Basic Assumption ◽  
Nonequilibrium Systems ◽  
Flow Localization ◽  
Quasi Particle ◽  
Proposed Model ◽  
Flow Evolution

New representations concerning plasticity physics in crystals are discussed. The model of plastic flow is suggested, which can describe its main regularities. With the use of the experimental investigation, it is shown that the plastic flow localization plays the role in the evolution of plastic deformation. Obtained data are explained with the application of the principles of nonequilibrium-systems’ theory. The quasi-particle is introduced for the description of plasticity phenomenon. It is established the relation between plasticity characteristics of metals and their position in Periodic table of the elements. A new model is elaborated to address localized plastic-flow evolution in solids. The basic assumption of the proposed model is that the elementary plasticity acts evolving in the deforming of medium would generate acoustic emission pulses, which interact with the plasticity carriers and initiate new elementary shears. As found experimentally, the macrolocalization of plastic flow involves a variety of autowave processes. To address the phenomenon of localized plastic-flow autowaves, a new quasi-particle called ‘autolocalizon’ is introduced; the criterion of validity of the concept is assessed.

MANUFACTURE INVESTIGATION OF CARTRIDGE WITH BOTTOM-MOST PART FLANGE BY DIRECT EXTRUSION WITH COUNTERPUNCH. REPORT 13. DETERMINATION OF DEFORMED STATE UNDER STRAITENED EXTRUSION IN FOURTH CENTRAL AREA OF PLASTIC DEFORMATION

2020 ◽  
Vol 0 (4) ◽  
pp. 43-51
Author(s):  
A. L. Vorontsov ◽  
◽  
I. A. Nikiforov ◽  
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Central Area ◽  
Direct Extrusion ◽  
Deformed State ◽  
Cumulative Deformation ◽  
The Given ◽  
General Method

Formulae have been obtained that are necessary to calculate cumulative deformation in the process of straitened extrusion in the central area closed to the working end of the counterpunch. The general method of plastic flow proposed by A. L. Vorontsov was used. The obtained formulae allow one to determine the deformed state of a billet in any point of the given area. The formulae should be used to take into account the strengthening of the extruded material.

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