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GB/T 36668.2-2018 PDF in English

GB/T 36668.2-2018 (GB/T36668.2-2018, GBT 36668.2-2018, GBT36668.2-2018)
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GB/T 36668.2-2018: PDF in English (GBT 36668.2-2018)

GB/T 36668.2-2018
ICS 97.200.40
Y 57
Condition monitoring and fault diagnostics of amusement
device - Part 2. Acoustic emission monitoring method
Issued by. State Administration for Market Regulation;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Method overview ... 5 
5 Safety requirements ... 8 
6 Personnel requirements ... 8 
7 Equipment and apparatus requirements ... 9 
8 Monitoring process specification ... 10 
9 Monitoring methods ... 11 
10 Evaluation and grading of monitoring results ... 15 
11 Fault diagnostics ... 16 
12 Maintenance strategies ... 17 
13 Records and reports ... 17 
Appendix A (Normative) Acoustic emission system performance requirements
... 19 
Condition monitoring and fault diagnostics of amusement
device - Part 2. Acoustic emission monitoring method
1 Scope
This Part of GB/T 36668 specifies the method of operating condition monitoring
and diagnostics of rotating components of amusement device using acoustic
emission technique and the evaluation and grading of the results.
This Part applies to condition monitoring and fault diagnostics of rotating
components of newly-manufactured and in-use amusement device.
2 Normative references
The following documents are indispensable for the application of this document.
For the dated references, only the editions with the dates indicated are
applicable to this document. For the undated references, the latest edition
(including all the amendments) are applicable to this document.
GB/T 9445 Non-destructive testing - Qualification and certification of NDT
GB/T 12604.4 Non-destructive testing - Terminology - Terms used in acoustic
emission testing
GB/T 19800 Non-destructive testing - Acoustic emission inspection - Primary
calibration of transducers
GB/T 19801 Non-destructive testing - Acoustic emission inspection -
Secondary calibration of acoustic emission sensors
GB/T 20737 Non-destructive testing - General terms and definitions
GB/T 20921 Condition monitoring and diagnostics of machines - Vocabulary
GB/T 34370.1 Nondestructive testing of amusement equipments - Part 1.
General requirement
GB/T 34370.2 Nondestructive testing of amusement equipments - Part 2.
Visual examination
GB/T 34370.3 Nondestructive testing of amusement equipments - Part 3.
a) vulnerable to attenuation;
b) vulnerable to high operating background noise;
c) failure to correlate monitored acoustic emission defect characteristics with
accurate fault mechanism.
4.4 Interference factors
Before performing acoustic emission monitoring, it shall be aware of potential
sources of noise, such as electronic noise (electromagnetic and radio frequency
interference), airborne noise (air leakage or impact of grains of sand in a windy
environment), operating background noise (fluid flow in the tube), and
mechanical background noise. Their presence may affect the acoustic emission
monitoring results.
5 Safety requirements
This Clause does not list all of the safety requirements for implementation.
Users using this Part shall, before implementation, establish safety criterion.
Safety requirements during implementation are at least as follows.
a) The monitoring personnel shall abide by the safety requirements for the
on-site operation of amusement device. The personnel at the monitoring
location are required to wear protective overalls and wear relevant
protective equipment;
b) It shall pay attention to the temperature condition of the device being
monitored, to avoid scalds;
c) During the monitoring, attention shall be paid to the movement of car
during the start and operation of amusement device, to prevent personnel
from colliding and obstructing the connection of cable;
d) When operating at high altitude, factors such as the fall of personnel,
monitoring equipment and apparatus shall be considered. Necessary
protective measures shall be taken.
6 Personnel requirements
Personnel who use this Part for monitoring shall, in accordance with the
requirements of GB/T 9445 or the regulations of the relevant competent
department, obtain the grade qualification certificate of acoustic emission
testing and monitoring issued or recognized by the corresponding agency for
8 Monitoring process specification
8.1 General monitoring process specification
Organizations engaged in acoustic emission monitoring shall, in accordance
with the requirements of this Part, develop general acoustic emission
monitoring process specification. Its contents shall include at least the following
a) scope of application;
b) referenced standards and regulations;
c) qualifications of implementers;
d) monitoring instruments and equipment. coupling agent, sensor, sensor
fixture, signal line, preamplifier, cable, instrument host, monitoring data
acquisition and analysis software, etc.;
e) information about the device and components being monitored. name,
type, number, structural style, dimensions, installation location, design
and operating parameters;
f) installation position and installation mode of sensor;
g) operating conditions and timing of monitoring;
h) sensitivity measurement;
i) monitoring process and data analysis and interpretation;
j) evaluation of monitoring results;
k) monitoring records, reports, and data archiving;
l) personnel of development, review, and approval;
m) date of development.
8.2 Monitoring work instruction or process card
For each monitored component or each set of monitored devices, in
accordance with the requirements of 8.1, acoustic emission monitoring work
instruction or process card shall be developed.
monitoring process specification, the acoustic emission monitoring work
instruction or process card shall be developed, to determine the location and
surface conditions of the installation of acoustic emission sensor. At the same
time, the monitored device is surveyed; the monitored positions are numbered;
and the structural schematic diagram of the monitored device is drawn. Without
affecting the monitoring, the sensor shall be installed as close as possible to
the rotating component.
9.2 Baseline setting
Baseline data are mainly used to compare against subsequent measured
values, to find changes in the monitored object. The determination of baseline
data shall accurately specify the initial stable working conditions of amusement
device. Baseline data shall be obtained under normal operating condition of the
device. For the device with multiple operating conditions, a baseline shall be
established for each condition.
For new and overhauled devices, changes in measured values during the first
few days or weeks of operation are usually observed. Therefore, before
baseline data are collected, run-in time shall be specified.
For device which has been running for a long time and is monitored for the first
time, its baseline can be used as a reference point for device stabilizing.
9.3 Installation of sensor
The installation of sensor shall meet the following requirements.
a) According to the sensor installation position determined by the schematic
diagram, install the sensor;
b) The installation position of sensor is surface-treated, to make the surface
flat and expose the metallic luster. If the surface has a smooth and dense
protective layer, it can be retained; but the attenuation of acoustic
emission signal by the protective layer shall be measured;
c) Coupling agent is applied to the installation position of sensor. The
coupling agent shall be made of materials with good acoustic coupling
performance. It is recommended to use vacuum grease, vaseline, butter,
and other materials. The use temperature class of the selected coupling
agent shall be matched with the surface temperature of the piece under
d) PRESS the sensor at a certain installation position, so that the contact
surface of the sensor and the installation position achieves a good
acoustic coupling condition;
9.5 Monitoring implementation
9.5.1 Loading of monitored device
Under no-load conditions, the monitored device shall operate normally
according to its operating mode. The operating time shall ensure that sufficient
acoustic emission data is obtained.
Acoustic emission monitoring shall begin after the start-up operating speed of
the device reaches the normal operating speed. Continuously MARK at least
10 operating cycles; and it shall ensure that the device is continuously operated
for one week. If the device has different speeds, different steering, and other
working conditions, it shall be tested separately under each working condition
of the actual operation of the device.
9.5.2 Monitoring environment
Monitoring shall be carried out when environmental conditions permit. If there
are factors affecting the monitoring results, they shall be excluded before
During the monitoring process, it shall be noted that the following factors may
generate noises which affect the monitoring results.
a) External mechanical vibration;
b) Movement or collision of components;
c) Electromagnetic interference;
d) Interference from wind, rain, hail, etc.;
e) Leakage of pneumatic and hydraulic components.
During the monitoring process, if strong noise interference occurs, it shall stop
the operation and suspend monitoring; and then monitor after eliminating the
strong noise interference.
9.5.3 Monitoring data acquisition and process observation
The monitoring data shall at least collect the parameters specified in Appendix
A; and be able to acquire the acoustic emission signal waveform.
During monitoring, the change trend of acoustic emission RMS voltage and (or)
energy over time shall be observed.
9.5.4 Monitoring data analysis
10.2 Result verification
If the monitoring result is rated at Grade I, no verification is required. If the
monitoring results are all Grade I for several consecutive times, the monitoring
cycle can be extended appropriately.
If the monitoring result is rated at Grade II, according to the use of the
component under inspection, the monitoring cycle can be shortened.
If the monitoring result is rated at Grade III, the monitoring cycle shall be
significantly shortened. According to actual conditions, the need for verification
shall be determined.
If the monitoring result is rated at Grade IV, the operation of the device shall be
stopped immediately; the rotating components shall be disassembled. Other
testing methods shall be used for verification.
The verification of monitoring result grading shall, according to the testing
methods specified in GB/T 34370.1~GB/T 34370.6, be carried out for surface
and (or) internal defect testing.
11 Fault diagnostics
11.1 Measurement interval
According to the age, operating condition, and the last monitoring results of
device, the next monitoring time interval shall be determined. After the first
monitoring, generally no more than 12 months, it shall be monitored again. The
adjustment of measurement interval is used to grasp the signs of the
occurrence of a fault and the deterioration speed and behavior of the expected
fault, with the aim of accurately predicting the fault.
11.2 Acoustic emission signal interpretation
The primary purpose of data analysis is to correlate acoustic emission
measurement results with operating condition, and to measure or monitor any
deviations from the baseline, to help identify the condition of the device.
The criteria used to evaluate the operating condition of the device by acoustic
emission include at least.
a) The strength of acoustic emission signal continues to increase over time;
b) Abnormal acoustic emission signal during steady operation;
c) At the fault repetition frequency, an amplitude modulated signal appears.
b) Name, type, installation location, and installation date of the monitored
c) Type, model, and speed of the monitored rotating component;
d) Monitoring cycles and defects;
e) Executed standards and (or) reference standards;
f) Monitoring method, instrument model, coupling agent, sensor model, and
fixing method;
g) Test results for sensitivity of each channel;
h) The setting value of each channel threshold and system gain;
i) Measured value of background noise;
j) Schematic diagram of sensor installation position;
k) Monitoring software name and data file name;
l) The history plot for sound emission signal of the device running for one
week (including the current and previous monitoring results);
m) Waveform of typical acoustic emission signal;
n) Analysis of monitoring results, grading and data graph;
o) Fault diagnostics conclusion;
p) The signature of monitoring personnel, report writer and reviewer and the
qualification certificate number;
q) Date of monitoring and issuance of report.
preamplifier uses a differential circuit, its common-mode noise suppression
shall be no less than 40 dB.
A.6 Filter
The frequency response of the filter placed in the preamplifier and system host
processor shall match the frequency response of sensor.
A.7 System host
A.7.1 The acoustic emission system host shall have sufficient number of
channels covering the inspection area. It shall at least display and store
parameters of acoustic emission signal in real time (including arrival time,
threshold, amplitude, ring-down count, energy, rise time, duration, number of
impacts, RMS voltage). It shall have at least one channel for the acquisition of
waveform. It shall have the function of receiving and recording external
electrical signals such as load and temperature.
A.7.2 The independent sampling frequency of each channel shall not be lower
than 10 times the frequency of the center point of sensor response frequency.
A.7.3 The threshold accuracy shall be controlled within ±1 dB.
A.7.4 The accuracy of count measured values of acoustic emission signal shall
be within ±5%.
A.7.5 Within 10 s from the start of signal impact, the acoustic emission system,
in the process of collecting, processing, recording, and displaying each channel,
shall have the ability to process no less than 10 acoustic emission impact
signals per second. When there is a large amount of data and a blockage
occurs, the system shall be able to signal an alarm.
A.7.6 The accuracy of peak amplitude measured value shall be within ±2 dB.
At the same time, the dynamic range of the signal undistorted shall not be less
than 65 dB.
A.7.7 The accuracy of the RMS voltage and energy measured values shall be
within ±5%.
A.7.8 For the time difference positioning acoustic emission monitoring system,
the resolution of rise time, duration, and arrival time of each channel shall be
no more than 0.25 μs. The accuracy shall be within ±1 μs. The error between
each channel shall be no more than ±3 μs of the average.
A.7.9 The accuracy of the voltage value of external parameters measured by
the system shall not be less than 2% of the full scale.
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.