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Y. Yuan et al.
when the cracks propagate, thin neck deformation can be seen on the sample surface.
From a microscopic point of view, the microcrystalline macromolecular structure
begins to undergo orientation changes, and the degree of order changes from small
to large, and then to decline.
24.4.2 Analysis and Discussion of the Characteristics
of Acoustic Emission Signals
1. During the tensile process, the acoustic emission signals are detected in all three
samples. The samples without pre-defects are mainly plastic deformation. The
amount of deformation is large. The number of hits of the acoustic emission
signal is large. The preset round notch sample is mainly a small amount of
plastic deformation and fracture at the notch part, the amount of deformation
is small, and the hits of acoustic emission signal is small. The preset V-shaped
notch sample is mainly the fracture of the notch, accompanied by a very small
amount of plastic deformation, the amount of deformation is smallest, and the
hits of acoustic emission signal is least.
The positive correlation between the hits and the amount of deformation shows
that the signal detected by the acoustic emission signal is a plastic deformation
signal.
2. A high amplitude signal appears in the preset V-shaped notch sample, indicating that the amplitude of the acoustic emission signal generated by the fracture is higher, and the amplitude of the acoustic emission signal generated by
plastic deformation is lower; Compared with the sample without pre-defects, the
high-energy signal appeared in the sample with the preset V-shaped notch, indicating that the energy of the acoustic emission signal generated by the fracture
is relatively high.
It can be concluded that the fracture signal has the characteristics of high amplitude and high energy compared with the plastic deformation acoustic emission
signal.
3. By analyzing the acoustic emission waveform and spectrum, it is found that
the frequency of the acoustic emission signal is mainly distributed between 70–
260 kHz, the peak of the spectrum is around 140 kHz, and the frequency when
broken is around 150 kHz.
Therefore, the selection of resonance sensor VS150-M can meet the requirements
of detecting and monitoring the acoustic emission signal of HDPE material.
Y. Yuan et al.
when the cracks propagate, thin neck deformation can be seen on the sample surface.
From a microscopic point of view, the microcrystalline macromolecular structure
begins to undergo orientation changes, and the degree of order changes from small
to large, and then to decline.
24.4.2 Analysis and Discussion of the Characteristics
of Acoustic Emission Signals
1. During the tensile process, the acoustic emission signals are detected in all three
samples. The samples without pre-defects are mainly plastic deformation. The
amount of deformation is large. The number of hits of the acoustic emission
signal is large. The preset round notch sample is mainly a small amount of
plastic deformation and fracture at the notch part, the amount of deformation
is small, and the hits of acoustic emission signal is small. The preset V-shaped
notch sample is mainly the fracture of the notch, accompanied by a very small
amount of plastic deformation, the amount of deformation is smallest, and the
hits of acoustic emission signal is least.
The positive correlation between the hits and the amount of deformation shows
that the signal detected by the acoustic emission signal is a plastic deformation
signal.
2. A high amplitude signal appears in the preset V-shaped notch sample, indicating that the amplitude of the acoustic emission signal generated by the fracture is higher, and the amplitude of the acoustic emission signal generated by
plastic deformation is lower; Compared with the sample without pre-defects, the
high-energy signal appeared in the sample with the preset V-shaped notch, indicating that the energy of the acoustic emission signal generated by the fracture
is relatively high.
It can be concluded that the fracture signal has the characteristics of high amplitude and high energy compared with the plastic deformation acoustic emission
signal.
3. By analyzing the acoustic emission waveform and spectrum, it is found that
the frequency of the acoustic emission signal is mainly distributed between 70–
260 kHz, the peak of the spectrum is around 140 kHz, and the frequency when
broken is around 150 kHz.
Therefore, the selection of resonance sensor VS150-M can meet the requirements
of detecting and monitoring the acoustic emission signal of HDPE material.