Failure analysis of CF/epoxy hollow beam components using digital image correlation and acoustic emission analyses

Understanding the damage and failure of carbon/glass epoxy hybrid woven composites under tensile loading based on acoustic emission signals is a challenging task in their practical uses. In this study, an approach based on fuzzy c-means algorithm is proposed to process the acoustic emission signals from tensile loading of composites monitored by combining acoustic emission technology and digital image correlation method. The results show that the acoustic emission signals from tensile loading can be divided into three clusters. The three clusters correspond to three kinds of damage modes including matrix cracking, fiber/matrix debonding, delamination, and fiber breakage. By comparing the acoustic characteristics of these classes, a correlation procedure between the clusters and the damage mechanisms observed is proposed. Meanwhile, it can be found that debonding and fiber break signals for glass fiber correspond to a lower frequency range than that for carbon fiber. Moreover, the method combining acoustic emission and digital image correlation can effectively monitor the damage process of the specimen both on the inside and outside, which can provide a reference for the health monitoring of composite structure.

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Mechanical Behavior of Differently Oriented Electron Beam Melting Ti–6Al–4V Components Using Digital Image Correlation

Journal of Engineering Materials and Technology ◽

10.1115/1.4040553 ◽

2018 ◽

Vol 141 (1) ◽

Cited By ~ 4

Author(s):

Edel Arrieta ◽

Mohammad Haque ◽

Jorge Mireles ◽

Calvin Stewart ◽

Cesar Carrasco ◽

...

Keyword(s):

Electron Beam ◽

Digital Image Correlation ◽

Failure Analysis ◽

Digital Image ◽

Electron Beam Melting ◽

Measuring Method ◽

Image Correlation ◽

Layer By Layer ◽

Strain Fields ◽

Shear Effects

Mechanical properties of additive manufactured metal components can be affected by the orientation of the layer deposition. In this investigation, Ti–6Al–4V cylindrical specimens were fabricated by electron beam melting (EBM) at four different build angles (0 deg, 30 deg, 60 deg, and 90 deg) and tested as per ASTM E8 Standard Test Methods for Tension Testing of Metallic Materials. With the layer-by-layer fabrication suggesting granting anisotropic properties to the builds, strain fields were recorded by digital image correlation (DIC) in the search for shear effects under uniaxial loads. For the validation of this measuring method, axial strains were measured with a clip extensometer and a virtual extensometer, simultaneously. Failure analysis of the specimens at different orientations was conducted to evidence the recording of shear strain fields. The failure analysis included fractography, optical micrographs of the microstructure distribution, and failure profiles displaying different failure features associated with the layering orientation. Additionally, an experimental study case of how the failure mode of components can potentially be designed from the fabrication process is presented. At the end, remarks about the shear effects found, and an insight of the possibility of designing components by failure for safer structures are discussed.

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Monitoring Shear Behavior of Prestressed Concrete Bridge Girders Using Acoustic Emission and Digital Image Correlation

Sensors ◽

10.3390/s20195622 ◽

2020 ◽

Vol 20 (19) ◽

pp. 5622 ◽

Cited By ~ 1

Author(s):

Fengqiao Zhang ◽

Gabriela I. Zarate Garnica ◽

Yuguang Yang ◽

Eva Lantsoght ◽

Henk Sliedrecht

Keyword(s):

Acoustic Emission ◽

Digital Image Correlation ◽

Digital Image ◽

Prestressed Concrete ◽

Field Testing ◽

Image Correlation ◽

Bridge Girders ◽

Concrete Bridge ◽

Displacement Sensors ◽

Prestressed Concrete Bridge

In the Netherlands, many prestressed concrete bridge girders are found to have insufficient shear–tension capacity. We tested four girders taken from a demolished bridge and instrumented these with traditional displacement sensors and acoustic emission (AE) sensors, and used cameras for digital image correlation (DIC). The results show that AE can detect cracking before the traditional displacement sensors, and DIC can identify the cracks with detailed crack kinematics. Both AE and DIC methods provide additional information for the structural analysis, as compared to the conventional measurements: more accurate cracking load, the contribution of aggregate interlock, and the angle of the compression field. These results suggest that both AE and DIC are suitable options that warrant further research on their use in lab tests and field testing of prestressed bridges.

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