Evaluation of Composite Structures by Stress- Wave-Factor and Acoustic Emission

1981 ◽  
pp. 450-462 ◽  
Author(s):  
Allen T. Green
Keyword(s):  
Acoustic Emission ◽  
Stress Wave ◽  
Composite Structures ◽  
Stress Wave Factor

scholarly journals Damage Characterisation in Composite Laminates Using Vibro-Acoustic Technique

2021 ◽  
pp. 275-282
Author(s):  
Kristian Gjerrestad Andersen ◽  
Gbanaibolou Jombo ◽  
Sikiru Oluwarotimi Ismail ◽  
Yong Kang Chen ◽  
Hom Nath Dhakal ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Stress Wave ◽  
Composite Structures ◽  
Impact Damage ◽  
Test Sample ◽  
Ultrasonic Technique ◽  
Low Velocity ◽  
Acoustic Testing ◽  
Set Up ◽  
Stress Wave Factor

AbstractThe need to characterise in-service damage in composite structures is increasingly becoming important as composites find higher utilisation in wind turbines, aerospace, automotive, marine, among others. This paper investigates the feasibility of simplifying the conventional acousto-ultrasonic technique set-up for quick and economic one-sided in-service inspection of composite structures. Acousto-ultrasonic technique refers to the approach of using ultrasonic transducer for local excitation while sensing the material response with an acoustic emission sensor. However, this involves transducers with several auxiliaries. The approach proposed herewith, referred to as vibro-acoustic testing, involves a low level of vibration impact excitation and acoustic emission sensing for damage characterisation. To test the robustness of this approach, first, a quasi-static test was carried out to impute low-velocity impact damage on three groups of test samples with different ply stacking sequences. Next, the vibro-acoustic testing was performed on all test samples with the acoustic emission response for the samples acquired. Using the acoustic emission test sample response for all groups, the stress wave factor was determined using the peak voltage stress wave factor method. The stress wave factor results showed an inverse correlation between the level of impact damage and stress wave factor across all the test sample groups. This corresponds with what has been reported in literature for acousto-ultrasonic technique; thus demonstrating the robustness of the proposed vibro-acoustic set-up. Structural health monitoring, impact damage, acousto-ultrasonic testing, non-destructive testing.

Acoustic Emission-Based Experimental Analysis of Mechanical Stress Wave in IGBT Device

2020 ◽  
Vol 20 (11) ◽  
pp. 6064-6074 ◽  
Author(s):  
Mengchuan Li ◽  
Yunze He ◽  
Zhiqiang Meng ◽  
Jun Wang ◽  
Xiang Zou ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Mechanical Stress ◽  
Stress Wave ◽  
Experimental Analysis

Acoustic Emission Source Characterisation in Large-Scale Composite Structures

2011 ◽  
Vol 70 ◽  
pp. 381-386 ◽  
Author(s):  
Mark J. Eaton ◽  
Rhys Pullin ◽  
C.A. Featherston ◽  
Karen M. Holford
Keyword(s):  
Acoustic Emission ◽  
Damage Detection ◽  
Composite Structures ◽  
Large Scale ◽  
Amplitude Ratio ◽  
Matrix Cracking ◽  
Out Of Plane ◽  
Critical Components ◽  
Observed Damage ◽  
Buckling Test

Damage detection and location in aerospace composites is currently of great interest in the research community and is being driven by the need to reduce weight of commercial aircrafts and hence make substantial environmental improvements. The increased use of composites as safety critical components has led to the need for development of structural health monitoring (SHM) systems. Acoustic Emission (AE) offers an excellent potential for delivering the necessary information of damage detection to maintenance engineers in terms of location however there are currently no methodologies that can use AE signals to characterise damage sources. This paper explores a methodology for damage characterisation based on measuring the amplitude ratio (MAR) of the two primary plate wave modes, to allow identification of in-plane (matrix cracking) and out-of-plane sources (delamination). Results from a large-scale buckling test show good correlation between signal characterization and observed damage mechanisms.

Factors Influencing the Ultrasonic Stress Wave Factor Evaluation of Composite Material Structures

1986 ◽  
Vol 8 (1) ◽  
pp. 18 ◽  
Author(s):  
KL Reifsnider ◽  
GP Sendeckyj ◽  
SS Wang ◽  
TT Chiao ◽  
W Feng ◽  
...  
Keyword(s):  
Composite Material ◽  
Stress Wave ◽  
Factors Influencing ◽  
Factor Evaluation ◽  
Stress Wave Factor

Automated Damage Detection in Composite Components Using Acoustic Emission

2013 ◽  
Vol 569-570 ◽  
pp. 80-87 ◽  
Author(s):  
Rhys Pullin ◽  
Matthew R. Pearson ◽  
Mark J. Eaton ◽  
Carol A. Featherston ◽  
Karen M. Holford ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Health Monitoring ◽  
Composite Structures ◽  
Impact Damage ◽  
Turbine Blades ◽  
Fatigue Loading ◽  
Potential Method ◽  
Base Line ◽  
Wind Turbine Blades ◽  
Ae Signals

The ability of a Structural Health Monitoring (SHM) system to automatically identify damage in a composite structure is a vital requirement demanded by end-users of such systems. This paper presents the demonstration of a potential method. A composite fatigue specimen was manufactured and initially tested at 1Hz for 1000 cycles. Acoustic emission (AE) signals were recorded for complete fatigue cycles periodically in order to establish a base-line associated with undamaged specimens. The specimen was then subjected to impact damage to create barely-visible impact damage (BVID) and subjected to further fatigue cycles with acoustic emission recorded until failure. The data was subsequently analysed using a range of techniques including basic RMS signal levels and frequency-based analysis. At various stages during the test, C-scanning was used to validate the results obtained. Results demonstrated that AE is capable of detecting BVID in composite materials under fatigue loading. The proposed method has wide applicability to composite structures which are subjected to cyclic loading, such as wind turbine blades.

Basic NDE of Some Nano Composites

2002 ◽  
Author(s):  
Emmanuel Ayorinde ◽  
Sadikul Islam ◽  
Hassan Mahfuz ◽  
Ronald Gibson ◽  
Feizhong Deng ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Composite Structures ◽  
Mechanical Test ◽  
Test Methods ◽  
Nano Composites ◽  
Nano Materials ◽  
Sandwich Composites ◽  
The World ◽  
The Matrix ◽  
Slender Structures

The influence of the nano-sized particulate or slender structures admixed into the material of regular composite structures of various architectures is being enthusiastically studied in many places across the world, but the study is yet in its infancy because there are so many aspects to be investigated. This work is basically on foam-cored structural sandwich composites, and even here there are many variables involved, for example the nano-enhancer can be introduced into the reinforcement, the matrix or the foam. The focus of the work is on some possible effects of the presence of the nano-materials on the NDE process in testing these composites. Acoustic emission is emphasized in these studies, as it appears to hold promise for non-destructively testing materials of this nature, and basic and standard mechanical test methods are employed.

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