Information Technology Reference
In-Depth Information
Chapter 5
Application of ICAMM to Impact-Echo
Testing
5.1 Introduction
Having information about the condition of a material is an important issue for many
industries. This is especially valued if the applied procedure is not time-consuming
and is easy to employ in the production line. This is the case of the so-called impact-
echo method, which is simply based on making an impact in the material being
analyzed. Nevertheless, the impact-echo method is essentially limited to obtaining
information about the general status of the specimen. When more detailed infor-
mation is required (e.g. kind, orientation, and dimension of the defects), other time-
consuming and more costly methods, like ultrasonic tomography, are required. In
this work, we aim to improve the capability of the impact-echo technique in order to
derive more detailed information about the possible defects of the material.
In the impact-echo technique, a material is impacted with a hammer, which
produces a response that is sensed by a mono- or multi-sensor system that is located
on the surface of the material. Thus, the surface motion resulting from the short-
duration mechanical impact can be monitored. We apply a multi-channel config-
uration with sensors located on different sides of a parallelepiped-shaped material.
This configuration allows the microstructure material response to be measured from
different planes in order to obtain a more complete examination of the underlying
wave propagation phenomenon. The impact-echo signals contain backscattering
from grain microstructure as well as information about flaws in the inspected
material [
1
]. This technique has been widely used in applications of concrete
structures in civil engineering. Cross-sectional modes in impact-echo signals have
been analyzed in elements of different shapes, such as circular and square beams,
beams with empty ducts or cement fillings, rectangular columns, post-tensed
structures, and tendon ducts. Impact-echo has been used in determining superficial
crack depth, evaluation of early-age concrete hardness, evaluation of structural
integrity, crack propagation tracing and detection of steel corrosion damage in
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