Study on Acoustic Emission Signatures during the Process of Edge Chipping for Engineering Ceramics

2011 ◽  
Vol 697-698 ◽  
pp. 93-96 ◽  
Author(s):  
Xiu Jian Tang ◽  
Xin Li Tian ◽  
Jian Quan Wang ◽  
Ya Tao Mao ◽  
F.Q. Li
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Static Load ◽  
Average Frequency ◽  
Displacement Curve ◽  
Edge Chipping ◽  
Kaiser Effect ◽  
Engineering Ceramics ◽  
Highly Active ◽  
Fracture Processes

The developments of edge chipping for engineering ceramics are analyzed. An edge chipping experiment under static load is adopted to study the fracture process of edge chipping. The results show that the fracture processes of edge chipping under different edge distances are similar, which can be divided into four stages based on load-displacement curve. There is obviously Kaiser Effect during the fracture processes of edge chipping. Counts, average frequency, RMS, duration, amplitude and inverse calculation can be used to describe the process of edge chipping for engineering ceramics. Amplitude, duration and average frequency become highly active on the eve of fracture, which can be regard as the omens of edge chipping and used to predict the fracture of edge chipping.

Study on Kaiser Effect of Edge Chipping for Engineering Ceramics during their Failure Process

2011 ◽  
Vol 697-698 ◽  
pp. 152-156
Author(s):  
Xiu Jian Tang ◽  
Xin Li Tian ◽  
Zhi Yuan Wu ◽  
Bao Guo Zhang ◽  
Jian Quan Wang
Keyword(s):  
Static Load ◽  
Failure Process ◽  
Ceramic Surface ◽  
Edge Chipping ◽  
Kaiser Effect ◽  
Engineering Ceramics ◽  
Edge Distance ◽  
Mechanics Characteristic ◽  
Ae Signals ◽  
Main Factor

An edge chipping experiment under static load is adopted to study the Kaiser Effect during the failure process for engineering ceramics. The mechanisms inducing Kaiser Effect are discussed. Some AE signals during the course of Kaiser Effect are analyzed. The results show that there’s obvious Kaiser Effect during the failure process of edge chipping; count, energy and amplitude can be well used to describe the Kaiser Effect. The surface metamorphic layer remained on the ceramic surface during the course of machining is the main factor for Kaiser Effect. Edge distance and mechanics characteristic are the important factors for Kaiser Effect. The study on Kaiser Effect of edge chipping has provided some guidance to prevent edge chipping of engineering ceramics.

Study on the Relationships between Edge Distance and the Failure Process of Edge Chipping for Engineering Ceramics

2011 ◽  
Vol 314-316 ◽  
pp. 904-908
Author(s):  
Xiu Jian Tang ◽  
Xin Li Tian ◽  
Bao Guo Zhang ◽  
Keling Lin Lin
Keyword(s):  
Critical Loads ◽  
Fracture Process ◽  
Failure Process ◽  
Edge Chipping ◽  
Engineering Ceramics ◽  
Edge Distance ◽  
Critical Edge ◽  
Ae Signals ◽  
Fracture Processes ◽  
Main Factor

Edge distance is the main factor inducing edge chipping. An edge chipping experiment is designed to study the relationships between edge distance and the edge chipping from the aspect of fracture process, the load-displacement curves and AE signals are documented. The results show that the fracture processes of edge chipping at different edge distances are similar and could be divided into four stages, AE signals could reflect the fracture process features of edge chipping. As edge distance increases, the displacements of indenter and critical loads would increase correspondingly, while the peak values of count and duration would decrease. The critical edge distance for Al2O3 is about 0.75mm; the displacements of indenter would keep invariable, while the peak values of count and duration would get to the minimum.

Experimental Investigation of Low Velocity Impact and Residual Compressive Properties of Composite Laminates Based on AE

2013 ◽  
Vol 345 ◽  
pp. 214-217
Author(s):  
Shi Yan ◽  
Ying Guo ◽  
Xia Mei Lu
Keyword(s):  
Composite Laminates ◽  
Fracture Process ◽  
Peak Frequency ◽  
Low Velocity Impact ◽  
Displacement Curve ◽  
Compressive Failure ◽  
Compressive Properties ◽  
Low Velocity ◽  
Velocity Impact ◽  
Fracture Processes

The low-velocity impact and residual compressive failure processes of composite laminate were investigated by the acoustic emission (AE) technique in this paper. The AE energy, amplitude, and the peak frequency were analyzed. At the same time, combining with the load-displacement curve varying feature, the compressive fracture processes were divided into different stages to deeply understand the damaged mechanisms of the composites. Results reveal that the behavior of AE parameters described well the fracture process of the composites.

Experimental Investigation of Tensile Damage Mechanisms on 3-D Braided Composites with AE

2013 ◽  
Vol 345 ◽  
pp. 290-293 ◽  
Author(s):  
Shi Yan ◽  
Li Li Jiang ◽  
Dong Hua Li
Keyword(s):  
Fracture Process ◽  
Event Rate ◽  
Peak Frequency ◽  
Textile Composites ◽  
Displacement Curve ◽  
Braided Composites ◽  
Cumulative Energy ◽  
Damage Mechanisms ◽  
3D Braided Composites ◽  
Fracture Processes

In this paper, the fracture process of 3D four-directional carbon/epoxy braided composites with different braiding angles under the monotonic tensile loading were investigated by the acoustic emission (AE) technique. The AE cumulative energy, event rate, amplitude, and the peak frequency were analyzed. At the same time, combining with the load-displacement curve varying feature, the fracture processes were divided into different stages to deeply understand the damaged mechanisms of the textile composites. Furthermore, the fracture surfaces of the specimens were observed under optical microscopy. Results reveal that the behavior of AE parameters described well the fracture process in the 3D braided composites with different braiding angles, and the damage mechanisms of the composites can be successfully identified by AE characteristics.

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.

scholarly journals Investigation on Acoustic Emission Kaiser Effect and Frequency Spectrum Characteristics of Rock Joints Subjected to Multilevel Cyclic Shear Loads

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Zhiqiang Hou ◽  
Changhong Li ◽  
Zhengyang Song ◽  
Yonggang Xiao ◽  
Chen Qiao ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Cyclic Loading ◽  
Frequency Spectrum ◽  
Rock Joints ◽  
Displacement Curve ◽  
Kaiser Effect ◽  
Cyclic Shear ◽  
Shear Damage ◽  
Spectrum Characteristics ◽  
Felicity Ratio

Rock joints have obvious acoustic emission (AE) Kaiser effect and Felicity effect under multilevel cyclic shear conditions. The TFD-20H/50J rock shear apparatus was used to carry out cyclic loading and unloading joint shear tests, and the acoustic emission parameters and frequency spectrum characteristics of the whole shearing process were analyzed. The results show that, under the cyclic loading, the shear stress-displacement curve forms several cyclic hysteresis loops, and the number of loops increases with the increase of normal stress. With the cycles increase, the shear damage gradually increases, and the Felicity ratio gradually decreases. The Felicity ratio at the final shear failure moment is about 0.94~0.99. The ratio of the RA value (rise time/amplitude) and the average frequency value (RA-AF) is used to classify the cracking mode of the joint sample. There are two AE crack signal types (tensile type and shear type) during shear damage. The peak frequency is displayed as high, medium, and low three frequency bands, which are distributed in the range of 0~35 kHz, 35~122 kHz, and 122~300 kHz, respectively. Both low-frequency and high-frequency signals account for less than 10%, and medium-frequency signals account for more than 90%. The research of the AE monitoring signals of multilevel shear behaviors can help understand the shear-friction mechanisms of rock joints.

Energy Characteristics Analysis of Engineering Ceramics during the Process of Edge Chipping Based on AE

2013 ◽  
Vol 770 ◽  
pp. 170-174
Author(s):  
Xiu Jian Tang ◽  
Bao Guo Zhang ◽  
Xin Li Tian ◽  
Ze Yun Zhou ◽  
Hui Ge
Keyword(s):  
Acoustic Emission ◽  
Failure Process ◽  
Cumulative Energy ◽  
Edge Chipping ◽  
Energy Characteristics ◽  
Engineering Ceramics ◽  
Experiment System ◽  
Micro Cracks ◽  
Characteristics Analysis ◽  
Cracks Propagation

To study the failure process of edge chipping for engineering ceramics, a method of energy analysis is used. Acoustic emission parameters such as energy, cumulative energy and amplitude collected in the experiment system are analyzed in this paper. The results show that energy and cumulative energy change little, amplitude changes among 40dB to 60dB before fracturing; the main reason for these is the micro-cracks propagation. While edge chipping engenders, energy, cumulative energy and amplitude would increase sharply and reach to the maximums; the main reason for these is the macro-cracks coming into being, and lots of energy release out. The change regulars of different parameters have reflected types of acoustic emission source. The method of energy could reveal the fracture mechanism of edge chipping for engineering ceramics well.

Evaluation of the mechanical properties of Inconel 718 to SCM 440 dissimilar friction welding through real-time monitoring of the acoustic emission system

2021 ◽  
pp. 146442072199383
Author(s):  
Yu Sik Kong ◽  
Muralimohan Cheepu ◽  
Jin-Kyung Lee
Keyword(s):  
Acoustic Emission ◽  
Friction Welding ◽  
Inconel 718 ◽  
Low Voltage ◽  
Dissimilar Materials ◽  
Average Frequency ◽  
Very High Frequency ◽  
Cumulative Count ◽  
Emission System ◽  
Very High

Friction welding was chosen for its versatility in the joining of dissimilar materials with high quality. The aim of this study is to determine the optimal welding conditions for attaining quality joints by using online monitoring of acoustic emission system signals. During friction welding, the formation of cracks, defects, or any abnormalities in the joining process which have a detrimental effect on the joints quality was identified. The most widely used materials in the aerospace industry—Inconel 718 and molybdenum steel—were joined by friction welding. The precision of the joints, internal defects, and quality are major concerns for aerospace parts. The results of the present research determined the optimal welding conditions for high tensile strength by nondestructively inducing acoustic emission signals. During friction time and upset time periods, the typical waveforms and frequency spectrum of the acoustic emission signals were recorded, and their energy level, average frequency, cumulative count, and amplitude were analyzed. Both cumulative count and amplitude were found to be useful parameters for deriving the optimal welding conditions. In the initial stage of friction welding, a very high voltage of continuous form was generated with frequency characteristics of 0.44 MHz and 0.54 MHz. The signals generated during the upset stage had a low voltage, but a very high frequency of 1.56 MHz and 1.74 MHz with a burst-type signal. The amplitude of the signal generated for the optimally welded joints was about 100 dB at the friction time and about 45 dB at the upset time.

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.

Sign in / Sign up

Export Citation Format

Share Document