Detecting and locating damage initiation and progression in full-scale sandwich composite fuselage panels using acoustic emission

2012 ◽  
Vol 47 (13) ◽  
pp. 1643-1664 ◽  
Author(s):  
Frank A Leone ◽  
Didem Ozevin ◽  
Jonathan Awerbuch ◽  
Tein-Min Tan
2008 ◽  
Author(s):  
Frank A. Leone, Jr. ◽  
Didem Ozevin ◽  
Valery Godinez ◽  
Bao Mosinyi ◽  
John G. Bakuckas, Jr. ◽  
...  

2015 ◽  
Vol 50 (4) ◽  
pp. 447-469 ◽  
Author(s):  
Jonathan Awerbuch ◽  
Frank A Leone ◽  
Didem Ozevin ◽  
Tein-Min Tan
Keyword(s):  

2021 ◽  
Vol 79 (1) ◽  
pp. 61-77
Author(s):  
A Jayababu ◽  
V Arumugam ◽  
B Rajesh ◽  
C Suresh Kumar

This work focuses on the experimental investigation of indentation damage resistance in different stacking sequences of glass/epoxy composite laminates under cyclic loading on normal (0°) and oblique (20°) planes. The stacking sequence, such as unidirectional [0]12, angle ply [±45]6S, and cross ply [0/90]6S, were subjected to cyclic indentation loading and monitoring by acoustic emission testing (AE). The laminates were loaded at the center using a hemispherical steel indenter with a 12.7 mm diameter. The cyclic indentation loading was performed at displacements from 0.5 to 3 mm with an increment of 0.5 mm in each cycle. Subsequently, the residual compressive strength of the post-indented laminates was estimated by testing them under in-plane loading, once again with AE monitoring. Mechanical responses such as peak load, absorbed energy, stiffness, residual dent, and damage area were used for the quantification of the indentation-induced damage. The normalized AE cumulative counts, AE energy, and Felicity ratio were used for monitoring the damage initiation and propagation. Moreover, the discrete wavelet analysis of acoustic emission signals and fast Fourier transform enabled the calculation of the peak frequency content of each damage mechanism. The results showed that the cross-ply laminates had superior indentation damage resistance over angle ply and unidirectional (UD) laminates under normal and oblique planes of cyclic loading. However, the conclusion from the results was that UD laminates showed a better reduction in residual compressive strength than the other laminate configurations.


2021 ◽  
Vol 5 (8) ◽  
pp. 221
Author(s):  
Janna Krummenacker ◽  
Joachim Hausmann

This study investigates the damage initiation in short glass fiber-reinforced polyamide 6.6 under fatigue loading using acoustic emission analysis. An optimized specimen geometry was developed to meet the specific requirements of this testing method, at the same time allowing further micromechanical studies. Specimens were preloaded with tensile–tensile fatigue loading, varying the maximum stress and the number of load cycles. Subsequently, the acoustic emission signals in residual strength tests were compared to those of undamaged specimens. The idea behind this approach is that only the damage that has not already occurred under fatigue load can be recorded in the residual strength tests. Using the analysis of acoustic energy, a stress threshold for damage initiation was identified. Furthermore, with tension–tension fatigue tests, the SN curve of the material was determined to estimate the lifetime for the identified stress threshold. The presented approach allows us to estimate a so-called endurance limit of short glass fiber-reinforced polyamide 6.6.


2019 ◽  
Vol 18 ◽  
pp. 843-848 ◽  
Author(s):  
Ekaterina M. Zubova ◽  
Tatyana V. Tretyakova ◽  
Valery E. Wildemann

Author(s):  
Pankaj R Jaiswal ◽  
R Iyer Kumar ◽  
M Saeedifar ◽  
MN Saleh ◽  
Geert Luyckx ◽  
...  

The increasing interest for the application of adhesive joints in naval superstructures motivates researchers to gain an in-depth understanding of the mechanical behaviour and failure mechanisms of these joints. This work reports on an experimental study of the deformation behaviour and damage evolution of a full-scale multi-material joint using different instrumentation techniques. Adhesively bonded joints of steel to sandwich panel components have been subjected to quasi-static tensile tests during which the global deformation of the joint and local strain distributions were monitored using digital image correlation (DIC). During one particular tensile test, fibre optic Bragg sensors (FBG) were also applied to the specimen’s surface at different locations in order to quantify the evolution of local strains. Additionally, acoustic emission (AE) sensors were installed in order to monitor damage initiation and evolution with increasing levels of imposed deformation. This test showcased adhesive failure at the interface of the steel adherend and the adhesive, while cohesive failure was observed within the adhesive and skin failure at the interface between adhesive and the composite skin of the sandwich panel. The post-mortem observed failures modes were compared to the acoustic events that originated during the test due to damage initiation and propagation within the joint. The evolution of the different sensor signals, i.e. the damage expressed as cumulative AE energy and local strains measured with Bragg sensors and DIC, are mutually compared and acceptable correlation is found.


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