Abstract: Dynamic behavior of two types of martensitic transformations during tensile deformation
of Cu-Al-Ni shape memory alloy single crystal has been investigated using an acoustic emission
waveform analysis. Two kinds of martensitic transformations consist of β1 ⇔ β1′ (structural change
of DO3 to 18R) and β1 ⇒ γ1′ (structural change of DO3 to 2H), each of which is called super-elastic
and thermo-elastic martensitic transformations, respectively. These two types of martensitic
transformations could be obtained during tensile deformation because of different heat treatment.
The rise time at the source (the source rise time) in finite elastic solid by the modified Takashima’s
method was analyzed using the acoustic emission waveform detected during the martensitic
transformation. The mean source rise time to the γ1′ phase was smaller than that to the β1′ phase
before yielding and became the same after yielding. The former result means that the nucleation of
the γ1′ phase is faster than that of the β1′ phase because of different crystallographic structure. The
latter result is that the growth rate of the γ1′ phase is the same as that of the β1′ phase.
Abstract: The relationship between acoustic emission and internal friction is investigated during
cyclic deformation of copper single- and poly-crystals at intermediate amplitudes. Good agreement
between these two phenomena has been demonstrated in all materials tested as long as the stress
relaxation occurs uniformly within the sample whereas the difference between them becomes
pronounced when strain/fracture localisation takes place. The similarity between acoustic emission
and internal friction can be extended to materials deforming without appreciable plastic deformation,
such as metal matrix composites where the main source of stress relaxation and strain accumulation is
the particle breakage. The significance of the relation between internal friction and acoustic emission
for understanding of fundamentals of AE is discussed.
Abstract: Acoustic emission (AE) is an attractive technique for the structural health monitoring
(SHM) of aerospace systems. To reach its full potential in this role a quantitative approach must be
adopted to study damage mechanisms in composite materials.
In this paper, some of the practical issues regarding acoustic emission testing in composites are
addressed. A model describing Lamb wave propagation through plates is described and used to
make phase velocity and attenuation measurements in both aluminium and carbon fibre reinforced
plastic plates. Results are then implemented in the frequency domain to conduct an experimental
study of normal incidence Lamb wave reflections. Comparisons are made with finite element
analysis (FEA) models with good results.
Abstract: Large structural composite sandwich panels (approx. 2x4 m2) were found to have cracks
in the honeycomb core. The core was made out of a number of Nomex honeycomb blocks having
different densities. These were first machined and adhesively bonded into the final shape. The
CFRP skins were then added and the sandwich panel was cured in an autoclave applying elevated
temperature and pressure.
Acoustic emission monitoring was done during 17 hours of processing in the autoclave using a six
channel AE system. AE events from cracking of the honeycomb core were registered and could be
identified in time and space. The results from AE monitoring were very useful for modifying the
process parameters and overcome the cracking of the core.
Abstract: Cost-effective and reliable damage detection is critical for the utilization of composite
materials due to the relatively localised nature of damage formation and the resultant reduction in
structural integrity. Of the methods available, Acoustic Emission (AE) is considered as one
potential technology for on-line and in situ monitoring of structural degradation of composite
Purpose of this work was to study the interaction between embedded PVDF (polyvinylidene
fluoride) transducers and composite samples as well as detect and characterize the failure
mechanisms in aramid/epoxy flexural test specimens using acoustic emission data obtained by
embedded PVDF film sensors. Furthermore, it has been realized a comparison with surface
mounted PVDF data. Results of our previous works (Caneva et al., 2005) dealing with monitoring
tensile and flexural behaviour of glass/epoxy composites enabled to extend this methodology to
The use of Acoustic Emission and Scanning Electron Microscopy (SEM) observations enabled
to identify and understand the failure mechanisms of the composites tested. Furthermore,
satisfactory results of this work highlighted that the application of PVDF shows promise as a
suitable acoustic emission transducer for fibrous composite materials.
Abstract: Steel cables play an indispensable role in a number of rather diverse fields of
applications. They are extensively used in suspension and stay cables bridges. It is important to be
able to detect as precociously as possible the defects affecting their performance. They can present
a healthy aspect over their observable lengths and be damaged in the hidden parts (anchorages). In
this present study, Acoustic Emission (AE) is used in order to detect and to locate broken wires in
the anchorage zones.
The study of the behaviour of a broken wire in a cable under dynamic bending contribute to
understand the origin of AE source and to discuss the necessary conditions of vibrating for
detection. In this case, the phenomene source of AE is related to interwire friction caused by the
redistribution of elastic energy on the recovery length of the broken wire and the repetition of the
process joining-slip between wires.
AE parameters are very influenced by the change of surface conditions, contact strength between
wires and the recovery length of the broken wire. Several cables are evaluated in different surface
conditions i.e. corroded, dry and oiled.
Abstract: In order to explore potential applications for Active Fiber Composite (AFC) elements
made from piezoelectric fibers for structural integrity monitoring, a model experiment for leak
testing on pipe segments has been designed. A pipe segment made of aluminum with a diameter of
60 mm has been operated with gaseous (compressed air) and liquid media (water) for a range of
operating pressures (between about 5 and 8 bar). Artificial leaks of various sizes (diameter) have
been introduced. In the preliminary experiments presented here, commercial Acoustic Emission
(AE) sensors have been used instead of the AFC elements. AE sensors mounted on waveguides in
three different locations have monitored the flow of the media with and without leaks. AE signals
and AE waveforms have been recorded and analysed for media flow with pressures ranging from
about 5 to about 8 bar. The experiments to date show distinct differences in the FFT spectra
depending on whether a leak is present or not.
Abstract: The Kaiser Effect in acoustic emission is often used for an estimation of the stress to which
rocks have been subjected. However, there are cases in which the Kaiser Effect is not clear, since the
noises due to the contact and/or the stick slip between the pre-induced fracture surfaces are measured
during the reloading process. In such cases, estimation of previous stress is difficult by the
conventional method which is based on the acoustic emission activity observed under reloading
process. In the tests for the Kaiser Effect on rocks, therefore, the noises must be eliminated from the
acoustic emission generated from newly created cracks during the second loading process. Such
techniques as analysis of the difference between the acoustic emission activity observed in the first
and second reloading and the analysis of the change in the slope of the acoustic emission amplitude
distribution have been proposed. In this paper we present a new method by which the maximum
previous stress in rocks can be directly estimated without any post signal analysis. In the new method,
simultaneous measurement of acoustic and electromagnetic emission during loading test of rock
sample is employed. The electromagnetic emission in the deformation of rock sample generates only
when the fresh surfaces due to cracking are created in the material, and the source of electromagnetic
emission is the electrification between the fresh crack surfaces. This paper describes the
simultaneous measurement of acoustic and electromagnetic emission useful for estimating the rock
Abstract: The TÜV Austria (formerly TÜV Vienna) has been testing different structures, mainly
pressure equipment, since 1977 with Acoustic Emission. I will not enumerate all the different tests,
which are more than 20.000 till today, but I will point out, how the test method has changed on
some typical tests over the years. I will also remind you on the different possibilities, which have
been offered by the rapid development of the electronic data acquisition and treatment, especially
during the last 10 – 15 years.
Abstract: In spite of the availability of very versatile analysis packages, such as VisualAE™, the
large variety of test objects that can be successfully tested by AE sometimes calls for the use of an
application dedicated analysis algorithm, especially if large numbers of similar or identical objects
shall be tested.
This can save a lot of time for data analysis and interpretation and reduce the requirements on
Those analysis algorithms can be developed by AE-experts based on AE data from a number of
test objects. Up to now, such a program had no access to real time data.
The more such a dedicated analysis
algorithm proves to be helpful and valuable
for a specific application (e.g. testing small,
buried LPG vessels), the higher the desire to
use that algorithm also in real time (i.e.
during data acquisition). This can simplify
testing and improve test control e.g. by the
application of higher sophisticated alarm
With the new Embedded Code Processor
(ECP) the user can develop and verify
software algorithms of any complexity, that
run within the environment of VisualAE™.
This tremendously accelerates the
Any result within VisualAE can be input
into the user-developed code, any new
results can be calculated, and then used by
VisualAE for filtering, data presentation and
alarm raising, if desired in combination with
the conventional results.
This paper summarizes the structure of
VisualAE in short and the intentions and
possibilities of an Embedded Code
ECP is already available and in use.