FIFTH CANADIAN CONFERENCE ON NONDESTRUCTIVE ... - IAEA

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a) enables an A/E monitor system to be a part of, or stand alone as, a
structural integrity monitoring system; and/or
b) permits A/E monitoring for process control operations.
Hence, unlike conventional inspection type A/E monitoring, the source and
characteristics of the acoustic emission within a subject structure must be
learned before a continuous A/E monitoring is commissioned. Further, once
continuous monitoring begins, this interpretive function is further refined
in recognition of unique service or operational environments. This can
also be expressed as allowing experience while monitoring a subject
structure (learning curve) to improve the reliability of results. These
results (or output) of the system are presented to otherwise unskilled A/E
operators, or as control signals to other equipment. In addition, the
results of this form of continuous monitoring may be interfaced with other
monitoring functions. The most promising of which has been vibration
analysis; but temperature, pressure, strain, etc. can also be incorporated.
4. Application:
From a technical point of view, the number of applications for continuous
A/E monitoring are considerable. Three applications are currently under
investigation, and at least one other will be undertaken when resources
permit. The structures investigated to date have been a cross country
transmission pipeline, an inlet manifold to a thermal power boiler, and a
semi-submersible drilling platform. In each case, a metallurgical study is
conducted under laboratory conditions using the materials (steel types and
damage mechanisms) that make up the subject structure. Also, acoustic
emission data is collected from the structure, and this information is
combined to program the microprocessor supported surveillance units and the
computer based controller. The pipeline application has involved field
testing of the system hardware, and preliminary results have been very
positive.
Other structures that are readily applicable to continuous A/E monitoring
are:
a) Plant wide piping systems (steam lines);
b) Pressure vessels (pulp digestors, mixing vessels, packed reaction
towers);
c) Boilers and heat exchangers (deairators, manifolds);