Acoustic Emission Analysis of Nanoindentation-Induced Fracture Events

2004 ◽  
Vol 841 ◽  
Author(s):  
Pawel Dyjak ◽  
Raman P. Singh
Keyword(s):  
Acoustic Emission ◽  
Brittle Materials ◽  
Signal Amplitude ◽  
Crack Arrest ◽  
Quantitative Information ◽  
Local Failure ◽  
Emission Analysis ◽  
Specimen Holder ◽  
Cube Corner ◽  
Ae Signal

ABSTRACTMonitoring of acoustic emission (AE) activity was employed to characterize the initiation and progression of local failure processes during nanoindentation-induced fracture. Specimens of various brittle materials were loaded with a cube-corner indenter and AE activity was monitored during the entire loading and unloading event using an AE transducer mounted inside the specimen holder. As observed from the nanoindentation and AE response, there were fundamental differences in the fracture behavior of the various materials. Post-failure observations were used to identify particular features in the AE signal (amplitude, frequency, rise-time) that correspond to specific types of fracture events. Furthermore, analysis of the parametric and transient AE data was used to establish the crack-initiation threshold, crack-arrest threshold, and energy dissipation during failure. It was demonstrated that the monitoring of AE signals yields both qualitative and quantitative information regarding highly local failure events in brittle materials.

Acoustic Emission Monitoring During Rupture Test of Pressure Vessel and Laboratory Fracture Test

1981 ◽  
Vol 103 (2) ◽  
pp. 191-199 ◽  
Author(s):  
N. Ohtsuka ◽  
M. Nakano ◽  
H. Ueyama
Keyword(s):  
Acoustic Emission ◽  
Signal Amplitude ◽  
Fracture Test ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Test Conditions ◽  
Significant Difference ◽  
Ae Signal ◽  
Loading Parameter ◽  
Crack Tip Opening

In order to relate the results of a field AE test on a large structure to observations made from small laboratory specimens, acoustic emission (AE) was monitored during a pressurization test on a model vessel containing several kinds of artificial defects and during laboratory tests on small specimens to simulate the defects. The active AE sources in the vessel were concentrated mainly around an artificial weld crack and a sawcut notch. The total number of AE events is compared with displacement, load, crack tip opening displacement, and AE signal amplitude under various test conditions on two types of defects. The significant difference in AE generating mechanism, size of defects, loading parameter and rate between the tests is discussed by the fracture mechanics approach.

On the Feasibility of Catastrophic Cutting Tool Fracture Prediction Via Acoustic Emission Analysis

1993 ◽  
Vol 115 (4) ◽  
pp. 390-397 ◽  
Author(s):  
J. A. Rice ◽  
S. M. Wu
Keyword(s):  
Acoustic Emission ◽  
Energy Release Rate ◽  
Energy Release ◽  
Physical Model ◽  
Release Rate ◽  
Cutting Tool ◽  
Emission Analysis ◽  
Ae Signal ◽  
Ae Signals ◽  
Acoustic Emission Analysis

The prediction of catastrophic cutting tool fracture is explored through monitoring the acoustic emission (AE) from a cutting process. A prediction parameter is derived which combines the AE signal with a physical model of a cracked tool to form an estimate of the spatial energy release rate. Monitoring the energy release rate is found to be largely dependent on the detection of crack advancement. Experiments were performed with both new and artificially cracked inserts during interrupted cutting. Epoches denoting crack advancement were detected through high time homomorphic analysis of the acquired AE signals. AE bursts prior to and leading up to fracture were analyzed for crack advancement. The calculated energy release rate was found to exponentially increase as fracture was approached. Crack advancement could be feasibly detected approximately six cuts prior to fracture.

Acoustic Emission Analysis of Fracture Events in Cu Films with W Overlayers

1999 ◽  
Vol 563 ◽  
Author(s):  
Alex A. Volinsky ◽  
William W. Gerberich
Keyword(s):  
Acoustic Emission ◽  
Energy Release ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Crack Arrest ◽  
Work Of Adhesion ◽  
Emission Analysis ◽  
Cu Films ◽  
Plastic Energy ◽  
Emission Signal

AbstractIndentation-induced delamination of thin films provides the basis for adhesion calculations. In the case of ductile Cu films plastic deformation usually prevents a film from debonding from the substrate. Deadhesion is facilitated by the use of a hard W superlayer, which promotes indenter-induced Cu film failure, increasing the delamination area by an order of magnitude. Radial as well as annular cracking acts like a secondary mechanism in the strain energy release, and can be resolved from excursions on the load-displacement curves. For the thicker Cu films no excursions were observed, though radial cracking took place. It is important to identify fracture events as they occur in order to understand the system behavior and accurately apply the analysis. An acoustic emission signal is used to detect the magnitude of fracture events in thin Cu films. For the films of different thickness from 40 nm to 3 microns the corresponding interfacial fracture energy ranged from 0.2 to over 100 J/m2. Limits of plastic energy dissipation are determined with the lower limit, the true work of adhesion, being associated with a dislocation emission criterion. Crack arrest marks were found upon the blister removal, and are proposed to represent the shape of the crack tip. Total acoustic emission energy was found to be inversely proportional to the strain energy release rate.

Comparative Study of Acoustic Emission Characteristics for Intergranular Corrosion of 316L Stainless Steel Parent Material and Weldment

2014 ◽  
Author(s):  
Wenjie Bai ◽  
Mengyu Chai ◽  
Lichan Li ◽  
Quan Duan
Keyword(s):  
Stainless Steel ◽  
Acoustic Emission ◽  
Comparative Analysis ◽  
Intergranular Corrosion ◽  
316L Stainless Steel ◽  
Signal Amplitude ◽  
Parent Material ◽  
Ae Signal ◽  
Preliminary Corrosion ◽  
Spectrum Characteristics

The 316L stainless steel parent material and weldment specimens were made to carry out intergranular corrosion(IGC) test using the method of boiling nitric acid. During the corrosion experiment, the acoustic emission(AE) signals were collected. Through the comparative analysis of corrosion rate and metallographic structure, the results showed that the IGC of parent material and weldment can be divided into the preliminary corrosion stage and the rapid corrosion stage. The AE parameters and spectrum characteristics of the two corrosion stages of the parent material and weldment were analyzed. The results showed that: in preliminary and rapid corrosion stages, the AE signal amplitude and energy of weldment were higher than that of parent material; the spectrum characteristics of weldment was more abundant than that of parent material. Based on the results of the comparative analysis, the AE sources of parent material and weldment IGC and the possibilities of monitoring IGC using AE technique were analyzed.

Acoustic Emission From Single-Plate Martensitic Transformation

1991 ◽  
Vol 58 (4) ◽  
pp. 889-894 ◽  
Author(s):  
Xiangying Liu ◽  
Elijah Kannatey-Asibu
Keyword(s):  
Acoustic Emission ◽  
Martensitic Transformation ◽  
Growth Process ◽  
Martensite Plate ◽  
Signal Amplitude ◽  
Elastic Half Space ◽  
Plate Martensite ◽  
Single Plate ◽  
Plate Formation ◽  
Ae Signal

Martensitic transformation occurs in a diffusionless manner at high velocity, with acoustic emission (AE) being generated during the process. The AE signal contains information about the dynamic process of martensitic transformation. In this analysis, a model is developed for the AE signal, or dynamic displacement, from the transformation strains and the growth process of martensitic transformation in an elastic half-space using Green’s functions. The AE signal amplitude is found to be inversely proportional to the distance between the martensite source and the sensor, and to the duration of transformation. It also depends on the orientation of the martensite plate. The spectral bandwidth increases as the duration of plate formation decreases. In addition, raising the carbon content increases the fraction of plate martensite, and consequently the signal amplitude.

Punch Press Monitoring with Acoustic Emission (AE) Part I: Signal Characterization and Stock Hardness Effects

1983 ◽  
Vol 105 (4) ◽  
pp. 295-300 ◽  
Author(s):  
B. S. Kim
Keyword(s):  
Acoustic Emission ◽  
Shear Fracture ◽  
Signal Amplitude ◽  
Relative Timing ◽  
Component Identification ◽  
Ae Signal ◽  
Signal Characterization ◽  
Ae Counts ◽  
Three Components ◽  
Punch Press

As an integral part of the punch press monitoring research program, the Acoustic Emission (AE) signal emitted from a Minster1 #3 punch press is completely characterized in terms of signal component identification, relative timing and signal amplitude of each component. The AE signal generated during punching is found to consist of three components: initial impact, shear fracture and rupture. Effects of stock hardness are then examined in terms of relative timing and amplitude of those three components. Good correlations are found between stock hardness and the corresponding AE signals (and thus AE counts).

In-Situ Observation and Acoustic Emission Analysis for Corrosion Pitting of MgCl2 Droplet in SUS304 Stainless Steel

2012 ◽  
Vol 53 (6) ◽  
pp. 1069-1074 ◽  
Author(s):  
Mitsuharu Shiwa ◽  
Hiroyuki Masuda ◽  
Hisashi Yamawaki ◽  
Kaita Ito ◽  
Manabu Enoki
Keyword(s):  
Stainless Steel ◽  
Acoustic Emission ◽  
Emission Analysis ◽  
Sus304 Stainless Steel ◽  
Corrosion Pitting ◽  
Acoustic Emission Analysis
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