scholarly journals Measurement and Utilization of Acoustic Emission for the Analysis and Monitoring of Concrete Slabs on the Subsoil

2019 ◽  
Author(s):  
Luboš Pazdera ◽  
Radim Cajka ◽  
Libor Topolář ◽  
Pavlina Mateckova ◽  
Vlastimil Bilek ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Experimental Program ◽  
Concrete Slabs ◽  
Engineering Structures ◽  
Steel Fibre Reinforced Concrete ◽  
Material Optimization ◽  
Displacement Sensors ◽  
Load Carrying ◽  
Non Destructive ◽  
Typical Measurement

The article deals with the field of use of acoustic emission (AE) measurement in engineering structures. The research particularly focuses on the assessment of acoustic emission during an experimental test of the load-carrying capacity of concrete slabs on the ground. A wider field of research includes structural and material optimization of advanced engineering structures. The tests of concrete slabs are then carried out in an alternate solution which differs in the used concrete or steel fibre reinforced concrete (FRC). The experimental program then includes typical measurement methods using displacement sensors and strain gauges. Non-destructive methods of measurement including acoustic emission have been used with an eye to the configuration of the experiment and deeper understanding of the actual behaviour and damage to the structure allowing for subsequent optimization and non-linear simulation of slab computation. The aim of the submitted article is to present and assess the acoustic emission as a non-destructive method which can be used to detect damage and determine the load-bearing capacity of the selected type of a FRC structure.

Acoustic Emission Characterization of Damage Patterns in Composite Scarf Joints Using Unsupervised Learning

2020 ◽  
Author(s):  
D. Xu ◽  
Z. P. Chen ◽  
P. F. Liu ◽  
J. H. Wu ◽  
P. Jiao ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Acoustic Emission ◽  
Composite Structures ◽  
Tensile Loading ◽  
Matrix Cracking ◽  
Interface Debonding ◽  
Engineering Structures ◽  
Damage Pattern ◽  
Damage Initiation ◽  
Non Destructive

Abstract Interest in damage detection and damage pattern recognition of engineering structures by non-destructive techniques has been increasingly growing. As a non-destructive technique, acoustic emission (AE) has developed rapidly to detect dynamic defects and their evolution behaviors of composite structures, based on the transient elastic waves produced by rapid energy release due to the geometry change of structures. In this paper, AE technology is utilized to monitor the real-time condition of the composite scarf joint (SJ) under tensile loading. First, after AE signal acquisition, dimensionality reduction of eight AE features is realized by employing principal component analysis such that the Curse of Dimensionality can be avoided. Second, feature selection is continued by introducing two evaluation indexes, i.e., correlation coefficient and Laplacian score. Third, after the optimal cluster number is determined, damage pattern recognition is accomplished by introducing k-means++ algorithm which explores the distribution of each pattern in the space constructed by four informative AE features. Based on the clustering results, damage initiation and evolution in SJ specimens under tensile loading are subsequently explored. The shear failure of the adhesive layer which is a characteristic damage pattern for SJ specimens shows a relatively-high activity after the early stage. Matrix cracking and fiber/matrix interface debonding are two fundamental damage patterns which keep active in the whole process.

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