Correlation between Parameters of Acoustic Emission and Fracture Characteristics Obtained from Three-Point Bending Test

2015 ◽  
Vol 1124 ◽  
pp. 231-236
Author(s):  
Libor Topolář ◽  
Luboš Pazdera
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Emission Method ◽  
Fracture Characteristics ◽  
Three Point Bending ◽  
Experimental Tool ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission method is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

Effect of Concrete Mixture Composition on Acoustic Emission and Fracture Parameters Obtained from Three-Point Bending Test

2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Mixture Composition ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

An Experimental Study on Acoustic Emission Signals during the Three-Point Bending Fracture Test

2014 ◽  
Vol 1000 ◽  
pp. 281-284 ◽  
Author(s):  
Michal Matysík ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Hana Šimonová ◽  
Tomáš Vymazal ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Fracture Test ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Experimental Tool ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture test of specimens of concrete. Much has been said in literature about the fracture energy of concrete and its importance. Acoustic emission is an experimental tool well suited for monitoring fracture processes. Quantitative acoustic emission techniques were used to measure micro fracture properties. For three different concrete mixtures typical acoustic emission patterns were identified in the acoustic emission records to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviours. The results obtained in the laboratory are useful to understand the various stages of micro-cracking activity during the fracture process in quasi-brittle materials such as concrete and extend them for field applications.

The Effect of Concrete Quality on the Acoustic Emission Parameters during Three-Point Bending Fracture Test

2014 ◽  
Vol 897 ◽  
pp. 149-152 ◽  
Author(s):  
Michal Matysík ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Tomáš Vymazal ◽  
Iveta Plšková
Keyword(s):  
Acoustic Emission ◽  
Large Scale ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Fracture Test ◽  
Opening Displacement ◽  
Three Point Bending ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture

Acoustic emission is an experimental tool well suited for monitoring fracture processes. The paper presents experiment focused on analysing acoustic emission signals captured during three-point bending fracture test of specimens of concrete. Quantitative acoustic emission techniques were used to measure micro fracture properties. For three different concrete mixtures typical acoustic emission patterns were identified in the acoustic emission records to further describe the under-the-stress behaviour and failure development. If we have a better understanding of the relationships between micro structural events and macroscopic behaviour we can better formulate predictive models for large-scale structural performance and reliability. An understanding of microstructureperformance relationships is the key to true understanding of material behaviours. Three-point bending fracture tests were conducted on these specimens and load versus crack mouth opening displacement (Load-CMOD) diagrams were recorded during the testing.

Influence of Aeration of Concrete on Acoustic Emission and Fracture Mechanical Parameters Obtained from Three-Point Bending Tests

2015 ◽  
Vol 1124 ◽  
pp. 237-242
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák ◽  
Petr Daněk ◽  
Zbyněk Keršner ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Mechanical Parameters ◽  
Bending Tests ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Acoustic Emission Sensors ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Mechanical Parameters

This paper examines the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with similar water-cement ratio, but one set of specimens was prepared from aerated concrete. The acoustic emission method is an experimental tool well suited for monitoring fracture processes in material. The typical parameters of acoustic emission signals were identified from the acoustic emission records for two different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The crack growth was continuously monitored using four acoustic emission sensors mounted on the specimen. The acoustic emission results are accompanied by selected fracture mechanical parameters determined via evaluation of load versus displacement diagrams recorded during three-point bending fracture tests.

Three-Point Bending Test Evaluation of Concrete Specimens by Non-Traditional Analysis of Acoustic Emission Method

2016 ◽  
Vol 837 ◽  
pp. 198-202
Author(s):  
Luboš Pazdera ◽  
Libor Topolář ◽  
Tomáš Vymazal ◽  
Petr Daněk ◽  
Jaroslav Smutny
Keyword(s):  
Acoustic Emission ◽  
Signal Analysis ◽  
Measurement Data ◽  
Bending Test ◽  
Test Evaluation ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Three Point Bending ◽  
Time Frequency ◽  
Emission Signal

The aim of the paper is focused on the analysis of the mechanical properties of the concrete specimens with plasticizer at three point bending test by the signal analysis of the acoustic emission signal. The evaluations were compared the measurement and the results obtained with theoretical presumptions. The Joint Time Frequency Analysis applied on measurement data and its evaluation is described. It is well known that the Acoustic Emission Method is a very sensitive method to determine active cracks into structure. However, evaluation of acoustic emission signals is very difficult. A non-traditional method was used to signal analysis of burst acoustic emission signals recorded during three point bending test.

The Assessment of High-Temperature Degraded Concrete Specimens of Different Mixtures by Acoustic Emission Method during Three-Point Bending Test and Pulse Velocity Method in Comparison with Destructive Tests

2017 ◽  
Vol 908 ◽  
pp. 88-93 ◽  
Author(s):  
Libor Topolář ◽  
Richard Dvořák ◽  
Luboš Pazdera
Keyword(s):  
Acoustic Emission ◽  
Building Materials ◽  
Pulse Velocity ◽  
Bending Test ◽  
Structural Components ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Three Point Bending ◽  
Live Loads ◽  
Non Destructive

One of the advantages of concrete over other building materials is its inherent fire-resistive properties. The concrete structural components still must be able to withstand dead and live loads without collapse even though the rise in temperature causes a decrease in the strength and modulus of elasticity for concrete and steel reinforcement. In addition, fully developed fires cause expansion of structural components and the resulting stresses and strains must be resisted. This paper reports the results of measurements by Acoustic Emission method during three-point bending test on concrete specimens. The Acoustic emission method is a non-destructive technique used widely for structural health monitoring purposes of structures. The sensors are mounted by beeswax on the surface of the material or structure to record the motion of the surface under the elastic excitation of the cracking sources. The concrete specimens were heated in a programmable laboratory furnace at a heating rate of 5 °C/min. The specimens were loaded at six temperatures, 200 °C, 400 °C, 600 °C, 800 °C, 1000 °C, and 1200 °C maintained for 60 minutes. The results are obtained in the laboratory.

Evaluation of Acoustic Emission Events Generated at Three Point Bending of Different Concrete Specimens by Spectral Analysis

2016 ◽  
Vol 258 ◽  
pp. 485-488
Author(s):  
Lubos Pazdera ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Jaroslav Smutny ◽  
Karel Mikulasek
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Direct Evaluation ◽  
Cement Ratio ◽  
Three Point Bending ◽  
Time Frequency ◽  
Frequency Domains ◽  
The Individual

The paper aims to the determine of the mechanical properties of the concrete specimens at three-point bending test by application of the Acoustic Emission Method. Recorded acoustic emission events generated during three-point loading have been chosen. Some frequency and joint time-frequency methods are applied to these records. Time series as acoustic emission events may be analyzed in the time, frequency, and/or time-frequency domains. The selection is based on the type of the signal in question, on the type of analysis to be used or the result achieved. In many applications, direct evaluation of the time-amplitude representation is neither easy nor advantageous. The individual mixtures were different in cement dosage and water-cement ratio based on how much the amount of cement was increased while maintaining consistency S2 according to EN 206.

scholarly journals Study on Bending Damage Constitutive Model and Mechanical Properties of Limestone Based on Acoustic Emission

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yuanshuai Zhang ◽  
Shuangying Zuo ◽  
Bo Yu ◽  
Shiwan Chen ◽  
Jienan Jia
Keyword(s):  
Acoustic Emission ◽  
Constitutive Model ◽  
Damage Evolution ◽  
Damage Variable ◽  
Bending Test ◽  
Neutral Layer ◽  
Three Point Bending ◽  
Bending Process ◽  
Damage Constitutive Model ◽  
Bending Fracture

To reveal the mechanical characteristics and damage evolution mechanism of limestone in the bending process, the cumulative acoustic emission (AE) hits were used to define the damage variable, and the rock microbody hypothesis and the Weibull distribution function were applied to further improve the damage variable. Meanwhile, the bending damage constitutive model of limestone under three-point bending was developed based on the Lemaitre strain equivalence principle and the continuum damage theory. Then, the three-point bending test with acoustic emission monitoring was carried out to verify the rationality and validity of the model. Results showed that the modified damage variable D had an exponential distribution with the strain ε, and the damage was mainly concentrated in the macrocrack propagation stage. Moreover, the bending neutral layer moved towards the compressive zone in the bending damage process. The bending neutral layer, furthermore, moved slowly a small distance at the initial stage of bending fracture but moved fast a long distance at the end stage of bending fracture. In addition, the bending damage constitutive model could be quantitatively expressed by the cumulative AE hits Np, the stress σ, the strain ε, and Young’s modulus E. The theoretical stress-strain model curves agreed well with experimental results, which demonstrated that the proposed model could capture the damage evolution of limestone reasonably in the bending process.

Evaluation of Three-Point Bending Fracture Tests of Selected Concrete: Crack Initiation and Acoustic Emission Parameters

2017 ◽  
Vol 259 ◽  
pp. 58-63
Author(s):  
Hana Šimonová ◽  
Libor Topolář ◽  
Ivana Havlíková ◽  
Michal Matysík ◽  
Petr Daněk ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Crack Initiation ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Opening Displacement ◽  
Unstable Crack ◽  
Three Point Bending ◽  
Damage Process ◽  
Fracture Tests ◽  
Bending Fracture

In this paper, authors concentrate attention on crack initiation and acoustic emission (AE) parameters obtained from records of three-point bending fracture tests on eight sets of concrete specimens with initial stress concentrator at the age of 28 days. Resistance to stable and unstable crack propagation was quantified via evaluation of load vs crack mouth opening displacement diagrams using Double-K fracture model. The AE technique was used to monitor damage process taking place during testing in specimens.

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