504
Z. Wu et al.
Truss structure is a common type of crane boom structure. It is often used in
crawler crane, wheel crane, tower crane, portal crane and other cranes. The truss
structure is complex, and composed of upper chord, lower chord and web rod. And
the web rod is divided into oblique web rod and straight web rod. As the truss boom
is mostly welded by K-type, T-type and other types of pipe joints, there are a large
number of welds. Also, due to its large slenderness of the member itself and its large
structure, it is difficult to detect its defects or may be missing by using the normal
method.
The nondestructive testing techniques used in cranes ordinary are visual inspection, ultrasonic flaw detection, stress testing, etc., which will be conducted for
sampling parts of steel structure. But this method only can detect in a small range
with low speed and low efficiency, also do not have the ability to discover early
damage. It is easy to cause missed inspection, and the inspection cost is higher. The
cracks are one of the familiar faults in crane structures. The acoustic emission (AE)
is a supplemental technique for the testing. The activity defects in the whole structure can be found in once loading test, and also can be supervised on line, which
will reduce the inspecting cycle, cost and has potential of early damage forecasting
[1–5]. Therefore, the purpose of this study was to explore the feasibility of applying
acoustic emission technology to detect and evaluate the structural integrity of the
crawler crane truss beam.
At present, the research and application of acoustic emission of crane steel beam
is mainly box beam, and the study on truss beam structure is rarely reported. In order
to achieve the purpose of acoustic emission technology in crane field inspection, it is
necessary to study the acoustic emission characteristics of defects on the crane truss
beam.
In this paper, the acoustic emission attenuation characteristics and source location
characteristics of truss beam are studied firstly. And then, the three-point bending test
is carried out on the crane truss beam, and the acoustic emission signal is collected
by the acoustic emission instruments during the test. Through the test, the AE characteristics of the destructive test process of the truss beam are obtained, including
the characteristics of AE parameters, frequency spectrum and location. The results
of this study provide a new method and basic data for the overall rapid detection of
the crawler crane truss beam.
44.2 Study of AE Attenuation and Source Location
in Truss Beam
44.2.1 AE Attenuation Characteristics of Truss Structure
In order to collect effective AE signals in the AE testing of crane truss beam, it
is necessary to arrange sensors reasonably. Usually, there are four main chords in
the truss beam, and the main chords are tubular structures. We test the attenuation
Z. Wu et al.
Truss structure is a common type of crane boom structure. It is often used in
crawler crane, wheel crane, tower crane, portal crane and other cranes. The truss
structure is complex, and composed of upper chord, lower chord and web rod. And
the web rod is divided into oblique web rod and straight web rod. As the truss boom
is mostly welded by K-type, T-type and other types of pipe joints, there are a large
number of welds. Also, due to its large slenderness of the member itself and its large
structure, it is difficult to detect its defects or may be missing by using the normal
method.
The nondestructive testing techniques used in cranes ordinary are visual inspection, ultrasonic flaw detection, stress testing, etc., which will be conducted for
sampling parts of steel structure. But this method only can detect in a small range
with low speed and low efficiency, also do not have the ability to discover early
damage. It is easy to cause missed inspection, and the inspection cost is higher. The
cracks are one of the familiar faults in crane structures. The acoustic emission (AE)
is a supplemental technique for the testing. The activity defects in the whole structure can be found in once loading test, and also can be supervised on line, which
will reduce the inspecting cycle, cost and has potential of early damage forecasting
[1–5]. Therefore, the purpose of this study was to explore the feasibility of applying
acoustic emission technology to detect and evaluate the structural integrity of the
crawler crane truss beam.
At present, the research and application of acoustic emission of crane steel beam
is mainly box beam, and the study on truss beam structure is rarely reported. In order
to achieve the purpose of acoustic emission technology in crane field inspection, it is
necessary to study the acoustic emission characteristics of defects on the crane truss
beam.
In this paper, the acoustic emission attenuation characteristics and source location
characteristics of truss beam are studied firstly. And then, the three-point bending test
is carried out on the crane truss beam, and the acoustic emission signal is collected
by the acoustic emission instruments during the test. Through the test, the AE characteristics of the destructive test process of the truss beam are obtained, including
the characteristics of AE parameters, frequency spectrum and location. The results
of this study provide a new method and basic data for the overall rapid detection of
the crawler crane truss beam.
44.2 Study of AE Attenuation and Source Location
in Truss Beam
44.2.1 AE Attenuation Characteristics of Truss Structure
In order to collect effective AE signals in the AE testing of crane truss beam, it
is necessary to arrange sensors reasonably. Usually, there are four main chords in
the truss beam, and the main chords are tubular structures. We test the attenuation