Related Experiment Video
Updated: Jun 3, 2026
11:28
A Coupled Experiment-finite Element Modeling Methodology for Assessing High Strain Rate Mechanical Response of Soft Biomaterials
Published on: May 18, 2015
Multiscale modeling approach to acoustic emission during plastic deformation
Jagadish Kumar1, G Ananthakrishna
1Materials Research Centre, Indian Institute of Science, Bangalore 560012, India.
Physical Review Letters
|April 8, 2011
Summary
This study explains acoustic emission during plastic deformation using the Ananthakrishna model. It reveals how dislocation dynamics create distinct acoustic signals for different Portevin-Le Chatelier band types.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nonlinear Dynamics
Background:
- Acoustic emission is frequently observed during plastic deformation.
- The Portevin-Le Chatelier effect involves serrated yielding, characterized by distinct band propagation dynamics.
- Understanding the origin of acoustic signals in these phenomena remains a challenge.
Purpose of the Study:
- To develop a theoretical framework explaining the origin of acoustic emission during plastic deformation.
- To differentiate acoustic emission characteristics associated with different types of Portevin-Le Chatelier bands (Type A and Type C).
- To reconcile the disparate timescales of collective dislocation motion and elastic phenomena.
Main Methods:
- Utilizing the Ananthakrishna model, which captures generic features of the Portevin-Le Chatelier effect.
- Developing a framework to analyze the interplay between dislocation dynamics and elastic degrees of freedom.
- Analyzing the temporal characteristics of acoustic emission bursts in relation to stress drops.
Main Results:
- Acoustic emission bursts associated with stress drops are well-separated for Type C serrations.
- For propagating Type A bands, these distinct bursts merge into nearly continuous acoustic signals.
- Overriding bursts are observed within the continuous signal for Type A bands.
Conclusions:
- The proposed framework successfully explains the diverse acoustic emission signatures observed during plastic deformation.
- The Ananthakrishna model provides a robust basis for understanding the complex dynamics leading to acoustic emission.
- The study highlights the critical role of dislocation collective dynamics in generating measurable acoustic signals during material yielding.
Related Concept Videos
01:21Plastic Behavior
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and reloaded.
01:19Plastic Deformations
Plastic deformation represents a fundamental concept in materials science, which explains the irreversible change in the shape of a material when it experiences stress beyond its elastic capability. This phenomenon is important in structural engineering, especially in designing and analyzing cantilever beams—structures that are securely fixed at one end and bear loads at the opposite end. When these beams are subjected to loads within their elastic range, they will return to their original...
01:14Plastic Deformations
It is essential to understand how structural members behave under plastic deformation when the bending stress exceeds the material's yield strength. This state of deformation permanently alters the shape of the member, in contrast to the linear elastic behavior observed before yielding. The strain at any point in the member is expressed in terms of maximum strain. Notably, the neutral axis, which coincides with the centroid during elastic bending, shifts away from the centroid under plastic...
01:19Members Made of Elastoplastic Material
The behavior of elastoplastic materials under bending stresses, particularly in structural members with rectangular cross-sections, is crucial for predicting material responses and understanding failure modes. Initially, when a bending moment is applied, the stress distribution across the section follows Hooke's Law and is linear and elastic. This distribution means the stress increases from the neutral axis to the maximum at the outer fibers, up to the elastic limit.
As the bending moment...
As the bending moment...
01:21Plastic Deformations of Members with a Single Plane of Symmetry
When a structural member undergoes plastic deformation due to bending, it is crucial to understand the position of the neutral axis and the stress distribution. This member, characterized by a single plane of symmetry, exhibits a uniform stress distribution, with negative stress above the neutral axis and positive stress below. Notably, the neutral axis does not align with the centroid of the cross-section. This misalignment is typical in cases where the cross-section is not rectangular or...
01:20Elastic Strain Energy for Shearing Stresses
As discussed in previous lessons, strain energy in a material is the energy stored when it is elastically deformed, a concept crucial in materials science and mechanical engineering. This energy results from the internal work done against the cohesive forces within the material. When a material undergoes shearing stress and corresponding shearing strain, the strain energy density, which is the energy stored per unit volume, is calculated. Within the elastic limit, where the stress is...