scholarly journals Damage Evolution Analysis in a “Spaghetti” Bridge Model Using the Acoustic Emission Technique

2021 ◽  
Vol 11 (6) ◽  
pp. 2718
Author(s):  
Boris Nahuel Rojo Tanzi ◽  
Mario Sobczyk ◽  
Tiago Becker ◽  
Luis Alberto Segovia González ◽  
Sabrina Vantadori ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Geometric Distribution ◽  
Frequency Variation ◽  
Loading Test ◽  
Evolution Analysis ◽  
Bridge Model ◽  
Theoretical Predictions ◽  
Damage Process ◽  
Damage Processes ◽  
Ae Signals

This paper applies the Acoustic Emission (AE) Technique to analyze the damage process in a one-meter span bridge model that was built from spaghetti sticks during a loading test. The AE signals are analyzed in terms of four coefficients that are evaluated as predictors of structure failure, with frequency variation appearing to be the strongest indicator of instability. The AE data are also compared to theoretical predictions that are given by the Bundle Model, confirming that underlying general patterns in damage processes are highly influenced by the geometric distribution of the structure and the loading pattern that is applied to it.

scholarly journals Acoustic emission method as a tool for the assessment of influence of the temperature variation on destructive processes created in early age concrete

2019 ◽  
Vol 284 ◽  
pp. 07002 ◽  
Author(s):  
Magdalena Bacharz ◽  
Wiesław Trąmpczyński ◽  
Barbara Goszczyńska
Keyword(s):  
Acoustic Emission ◽  
Blast Furnace ◽  
Temperature Variation ◽  
Early Age ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Damage Process ◽  
Early Age Concrete ◽  
Damage Processes ◽  
Blast Furnace Cement

During the early age concrete treatment (curing and hardening) the damage process appears i.e., microcracks in the cement paste, propagation of internal microcracks, and formation of microcracks on the surface of concrete that affect concrete. It can be the serious source that initiate cracks that will propagate in the further loading stage, thereby affecting the overall strength and durability of structures. Hence, it is quite important to have a tool to identify the damage processes created up during the early age concrete treatment. The Identification of Active Damage Processes (IADP) acoustic emission method, modified to suit the tests on non-loaded concrete, was applied to determine and locate the damage processes that appears during the hardening conditions taking into account the temperature fluctuations on which construction structures are exposed (constant temperature of 22ºC or cyclic temperature variations in the range -5ºC/+42ºC) in non-loaded concrete produced with basalt aggregate and blast furnace cement. It is shown that the modified IADP method, can be used to assess the influence of the temperature variation on damage process in early age non-loaded concrete. As an example, concrete produced with basalt aggregate and blast furnace cement was used.

NON-DESTRUCTIVE EVALUATION AND STRENGTH CHARACTERISTICS OF CFRP WITH HEAT DAMAGE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4285-4290 ◽  
Author(s):  
JIN WOOK KIM ◽  
YOUNG UN KIM ◽  
CHANG KWON MOON ◽  
SEOK HWAN AHN ◽  
KI WOO NAM
Keyword(s):  
Acoustic Emission ◽  
Structural Integrity ◽  
Matrix Cracking ◽  
Fracture Mechanisms ◽  
Heat Damage ◽  
Time Frequency ◽  
Reinforced Plastic ◽  
Damage Process ◽  
Distinct Frequency ◽  
Ae Signals

In this study, the heat-damage process of a carbon fiber reinforced plastic (CFRP) under monotonic tensile loading was characterized by acoustic emission. Additionally, epoxy specimens and prepreg specimens were used to determine the characteristics of acoustic emission (AE) signals of epoxy and fiber, respectively. The AE characteristics of CFRP showed three types of distinct frequency regions. Time-frequency analysis methods were employed for the analysis of fracture mechanisms in CFRP such as matrix cracking, debonding and fiber fracture. To evaluate the cumulative counts of AE signals, it seems that the results can be applied usefully to guarantee structural integrity and/or to the survey of destruction of the structure with heat-damage, that was made to the composite materials.

Comparative Analysis of AE Signals from Damage Processes of Concrete Using Different Sensors

2012 ◽  
Vol 204-208 ◽  
pp. 3169-3173
Author(s):  
Yan Wang ◽  
Zheng Zheng Xu ◽  
Yao Wang ◽  
Gui Juan Lu ◽  
Hai Tao Zhao
Keyword(s):  
Main Research ◽  
Axial Tension ◽  
Different Types ◽  
Tension And Compression ◽  
Concrete Damage ◽  
Damage Process ◽  
Ae Signal ◽  
Concrete Testing ◽  
Damage Processes ◽  
Ae Signals

Choosing appropriate acoustic emission (AE) sensors is crucial for the research of concrete damage failure processes using AE technology. In this paper, concrete testing under axial tension and compression is used as the main research method, and the choices of AE sensors in monitoring the fracture process of concrete are studied using digital parameters-waveform AE acquire system and four different types of AE sensors. The result showed that the broadband sensor received more signals and their frequency is wider, Broadband sensor shows certain technical advantage in monitoring the damage process of concrete under different stress conditions, embodied as collecting wider frequency range of AE signal, especially the high frequency produced in the anaphase of loading.

Critical Behaviour in Concrete Structures and Damage Localization by Acoustic Emission

2006 ◽  
Vol 312 ◽  
pp. 305-310 ◽  
Author(s):  
Alberto Carpinteri ◽  
Giuseppe Lacidogna ◽  
Gianni Niccolini
Keyword(s):  
Acoustic Emission ◽  
Concrete Fracture ◽  
Rc Structures ◽  
Size Dependent ◽  
Spatially Distributed ◽  
Damage Process ◽  
Non Destructive ◽  
Dependent Behaviour ◽  
Ae Signals ◽  
Fracture Processes

Extensive research and studies on concrete fracture and failure have shown that concrete should be viewed as a quasi-brittle material having a size-dependent behaviour. Numerous experimental techniques have been employed to evaluate fracture processes, and a number of modelling approaches have been developed to predict fracture behaviour. The non-destructive method based on the Acoustic Emission (AE) technique has proved highly effective, especially to check and measure the damage phenomena that take place inside a structure subjected to mechanical loading. In this paper an experimental investigation conducted on concrete and RC structures by means of the AE technique is described. The AE signals reflecting the release of energy taking place during the damage process were recorded and micro-cracking sources were localised by measuring time delays by means of spatially distributed AE sensors.

scholarly journals Mechanical Properties of Thin-Ply Composites Based on Acoustic Emission Technology

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 913
Author(s):  
Kaidong Zheng ◽  
Dongfeng Cao ◽  
Haixiao Hu ◽  
Yundong Ji ◽  
Shuxin Li
Keyword(s):  
Acoustic Emission ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Operating Conditions ◽  
Fiber Failure ◽  
Crack Propagation Resistance ◽  
Evolution Characteristics ◽  
Damage Process ◽  
Laminate Thickness ◽  
Ae Signals

Compared with standard-ply composites, thin-ply composites exhibit a superior mechanical performance under various operating conditions due to their positive size effects. Thin-ply laminate failure modes, including matrix initial damage (MID), matrix failure (MF), and fiber failure (FF), have been distinguished through a systematic acoustic emission (AE) signals analysis combined with scanning electron microscopy (SEM). First, the characteristic frequencies of various failure modes are identified based on unidirectional laminates ([90] 68 and [0] 68). Then, according to the identified frequencies corresponding to distinctive damage modes, four lay-up sequences (02[[90m/0m]ns]02, m = 1, 2, 4, 8, n × m = 16) with a constant total thickness are designed, and the effects of the number of identical plies in the laminate thickness on the damage evolution characteristics and the damage process under uniaxial tension loads are dynamically monitored. The obtained results indicate that the characteristic frequency ranges for MID, MF, and FF are identified as 0–85 kHz, 165–260 kHz, and 261–304 kHz, respectively. The thickness of identical plies has a significant effect on onset damage. With the decrease of the number of identical plies (i.e., m in the stacking sequences), the thin-ply laminates exhibit the initiation of damage suppression effects and crack propagation resistance.

scholarly journals An Experimental and Numerical Study on Acoustic Emission in the Process of Rock Damage at Different Stress Paths

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Dongxu Liang ◽  
Nong Zhang ◽  
Haoyu Rong
Keyword(s):  
Acoustic Emission ◽  
Cyclic Loading ◽  
Numerical Study ◽  
Rock Damage ◽  
Construction Design ◽  
Cyclic Loading And Unloading ◽  
Damage Process ◽  
Loading And Unloading ◽  
Loading Methods ◽  
Damage Processes

The study of the damage process of rock under external loads is good guidance for geotechnical construction design. The differences in rock damage processes and damage modes under different stress paths are rarely reported. To explore the effects of stress paths on rock damage processes, uniaxial compression experiments under three stress paths were conducted. Numerical simulation is also used to simulate the rock acoustic emission (AE) and fracture process. The results of the study indicate that the maximum acoustic emission events are at the peak of stress, and fractures are mainly formed at this stage. The peak of AE energy occurs before the peak of AE events. The damage pattern and fragmentation size of the rock are related to the way the stresses are loaded. It is noticed that there is appearance of a quiet period of AE events prior to the production of significant cracks. Minor damage to the rock is accompanied by the generation of bright white spots in the specimen, which is due to the high tensile or shear stress in the units. When the stress in these units exceeds their strength, the units break down and tiny cracks appear. As the external load increased, the cracks developed and penetrated, and the specimen was damaged. Under cyclic loading and unloading, the number of AE events increased significantly compared with the controlled displacement and controlled stress loading methods, and the radius of the AE circle became larger and the energy also increased, which indicates a greater degree of destruction of the rock under cyclic loading and unloading. The results of the study are of reference significance for rock crack propagation and fracture mode influenced by stress conditions and provide some guidance for construction design under different working conditions.

Assessing the Fracture and Damage Process in Recycled Aggregate Concrete under Compressive Loading by Acoustic Emission

2010 ◽  
Vol 163-167 ◽  
pp. 2528-2531
Author(s):  
Seung Hyun Ryu ◽  
Young Oh Lee ◽  
Sun Woo Kim ◽  
Hyun Do Yun
Keyword(s):  
Acoustic Emission ◽  
Nondestructive Test ◽  
Crack Growth ◽  
Compressive Loading ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Damage Process ◽  
Degree Of Damage ◽  
Ae Signals

Acoustic emission (AE) is a powerful nondestructive test that can be used to characterize cracking, growth of cracks, and the degree of damage. This technique is clearly distinguished from other nondestructive techniques as it is a nondestructive test that estimates the degree of damage to concrete. In this study, the AE signals emitted during failure, according to the strength of recycled aggregate concrete specimens was examined, in order to characterize them using existing research results and evaluation theories. In addition, it is demonstrated that AE can be utilized to identify crack source and the mechanism of crack growth, which were monitored using a software program developed from the theory of the location of the source of a microcrack.

scholarly journals Analysis of Acoustic Emission (AE) Signals for Quality Monitoring of Laser Lap Microwelding

2021 ◽  
Vol 11 (15) ◽  
pp. 7045
Author(s):  
Ming-Chyuan Lu ◽  
Shean-Juinn Chiou ◽  
Bo-Si Kuo ◽  
Ming-Zong Chen
Keyword(s):  
Stainless Steel ◽  
Acoustic Emission ◽  
Frequency Domain ◽  
Monitoring System ◽  
Welding Quality ◽  
Steel Sheets ◽  
Signal Features ◽  
Ae Signal ◽  
Laser Microwelding ◽  
Ae Signals

In this study, the correlation between welding quality and features of acoustic emission (AE) signals collected during laser microwelding of stainless-steel sheets was analyzed. The performance of selected AE features for detecting low joint bonding strength was tested using a developed monitoring system. To obtain the AE signal for analysis and develop the monitoring system, lap welding experiments were conducted on a laser microwelding platform with an attached AE sensor. A gap between the two layers of stainless-steel sheets was simulated using clamp force, a pressing bar, and a thin piece of paper. After the collection of raw signals from the AE sensor, the correlations of welding quality with the time and frequency domain features of the AE signals were analyzed by segmenting the signals into ten 1 ms intervals. After selection of appropriate AE signal features based on a scatter index, a hidden Markov model (HMM) classifier was employed to evaluate the performance of the selected features. Three AE signal features, namely the root mean square (RMS) of the AE signal, gradient of the first 1 ms of AE signals, and 300 kHz frequency feature, were closely related to the quality variation caused by the gap between the two layers of stainless-steel sheets. Classification accuracy of 100% was obtained using the HMM classifier with the gradient of the signal from the first 1 ms interval and with the combination of the 300 kHz frequency domain signal and the RMS of the signal from the first 1 ms interval.

scholarly journals Acoustic Emission Testing and Ib-Value Analysis of Ultraviolet Light-Irradiated Fiber Composites

2021 ◽  
Vol 11 (14) ◽  
pp. 6550
Author(s):  
Doyun Jung ◽  
Wonjin Na
Keyword(s):  
Acoustic Emission ◽  
Irradiation Time ◽  
Tensile Load ◽  
Failure Behavior ◽  
Value Analysis ◽  
Emission Testing ◽  
Final Failure ◽  
Acoustic Emission Testing ◽  
Woven Glass Fiber ◽  
Ae Signals

The failure behavior of composites under ultraviolet (UV) irradiation was investigated by acoustic emission (AE) testing and Ib-value analysis. AE signals were acquired from woven glass fiber/epoxy specimens tested under tensile load. Cracks initiated earlier in UV-irradiated specimens, with a higher crack growth rate in comparison to the pristine specimen. In the UV-degraded specimen, a serrated fracture surface appeared due to surface hardening and damaged interfaces. All specimens displayed a linearly decreasing trend in Ib-values with an increasing irradiation time, reaching the same value at final failure even when the starting values were different.

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