Some standard content:
TC: 62-27 : 534. 832
National Standard of the People's Republic of China
GB/T 15168
Vibration and shock isolators measuringmethod for its characleristics1994-06-30Issued
Implementation on1995-05-01
Issued by the State Bureau of Technical Supervision
W.National Standard of the People's Republic of China
Vibration and shock isolators measuringmethod fur ils characleristics1Subject content and scope of application
This standard specifies the test method for the static and dynamic performance of isolators and the shock isolation energy injection. This standard is applicable to the performance test of linear and nonlinear isolators of various materials, types and uses. 2 Reference standards GB2298 Mechanical vibration and shock terminology Environmental test equipment for electrical and electronic products Basic parameter verification methods GB5170 General provisions for electronic measuring instrument errors GB6592 GH8510 Guide to the determination of characteristics of vibration and shock isolators GJB 150.18 Environmental test methods for military equipment 3 Test conditions Shock test GB/T 15168-94 3.1 Isolators made entirely or partially of rubber should be placed in an ambient temperature of 25.15°C for 46 hours and the performance test should be carried out at this ambient temperature: 3.2 The rubber isolator must be parked for more than 24 hours after vulcanization before performance testing can be carried out. 3-3 Test equipment and instruments, only the table should comply with the requirements of GB5170, 4 Static performance test
4.1 Static performance parameters
The static performance of the isolator includes:
a. Static deformation under rated load;
1. Static stiffness under rated load;
Static load and static deformation relationship curve.
4.2 Test equipment and instruments
4. A device that can load uniformly or a calibrated gauge to measure quality: b. Force measuring device - the minimum position of the force indication should not be less than 10 of the rated load of the isolator, and the measurement display error should not be greater than 1 head: e. Displacement measuring instrument - the measurement error should not be less than 1%. 4.3 Test procedure
4.3.1 Repeat the preloading and unloading tests in the load-bearing direction of the isolator. The load range is from up to 1.25 times of the rated load. The deformation of the isolator should be 4.3.2 After loading gradually from zero to 1.25 times the rated load for the first time, keep loading for 3 seconds and then gradually unload to the top. At the same time, the deformation values of the loading and unloading points (including 0.9 times, 1.1 times and 1.25 times the rated load) should be recorded. The average deformation value (i.e. the average deformation value) should be taken when loading and unloading. Approved by the State Administration of Technical Supervision on June 30, 1994 and implemented on May 1, 1995 |W.bzsoso:com The average of the deformation position after unloading load) is the static deformation. 4.4 Test result calculation wwW.bzxz.Net
GB/T15168—94
4.4-1 The rated load value K of the isolator is calculated by (1). K.
Where: P--rated static load value of the isolator, N; AP static load increment, N;
AX-static deformation increment, I
AP1-1P,-0. 9P
The static deformation value of the isolator at 1.1 times the rated load, m; The static deformation value of the isolator at 0.9 times the rated load, 1m. (—)
4.4.2 According to 4. 3.2 The measured static load P at each point of the isolator and the average static deformation value X when loading and unloading. Draw the static load-static deformation curve.
5 Dynamic performance test
5.1 Dynamic performance parameters
The dynamic performance of the isolator includes:
The natural frequency of the main bearing direction under the rated load; a-
damping ratio;
Transmission rate or amplitude-frequency characteristics:
d. Linear isolator dynamics:
For nonlinear isolation processes, the relationship between static load and natural frequency and the relationship between excitation displacement amplitude and solid frequency and damping ratio should be drawn separately.
5.2 Dynamic performance test method
The test of the dynamic performance parameters of the isolator is based on the theory of the balance of inertial force, damping force, elastic force and external force in a single-pass elastic system, assuming that the elastic system is viscoelastic structure damping and the input is simple harmonic signal and condition. The test methods specified in this standard include five methods: fixed load excitation method, variable load excitation method, foundation excitation method, hammer method and ellipse method. 5.3 Test equipment and instruments
5.3.1 The test equipment should be able to generate sinusoidal excitation within a wide frequency range, and the lower limit frequency and load should be able to meet the test requirements. 5.3.2 The basic parameter error requirements of the amplitude waveform distortion, frequency and displacement indication of the sinusoidal excitation equipment should comply with the provisions of Appendix B or Appendix C of GB5170.13~5170.15. 5.3.3 The measuring instrument should include sensors, amplifiers, oscilloscopes and frequency meters. There should be recorders in the saw-down method and scanning method tests. 5.3.4 The frequency range, frequency response and linearity requirements of the measuring instrument should comply with the provisions of GB6592. 5.4 Test system equipment and test requirements
5.4.1 The test system consists of the mass applied to the isolator and the isolator. 5.4.2 The rated load shall be applied in the load bearing direction of the isolator. The excitation force shall be applied in the main axis direction of the stiffness to be measured of the isolator. 5.4.3 The connections of all parts of the system shall be firm during the test to avoid loosening during vibration. 5.4.4 When multiple isolators are tested at the same time, in order to make the static load and excitation force act evenly on each isolator, the system stiffness center, mass energy center and excitation force action center shall be in the same straight line. The eccentricity shall not exceed 10 of the maximum span of the support. 5.4.5 When the desired direction is 90° with the support, the distance between the mass center and the stiffness center shall be minimized to reduce the combination of axial vibration and swing vibration.
5.4.6 The mounting frame or transition pole shall have sufficient test performance, and its local inherent frequency shall be at least four times the natural frequency of the tested system or 60Hz.
5.4.7 The vibration sensor should be fixed close to the mass centerline of the test system and the centerline of the platform. 2
W.GB/T 15168— 94
5.4.8 If the sinusoidal excitation device or the test system is suspended, the ratio of the natural frequency of the test system and the suspended system should be at least large enough to stabilize the vibration of the test system.
5.4.9 When using an exciter for excitation, the excitation should be applied to the centerline of the mass or base through a flexible rod. 5.5 Test procedure and calculation of test results
5.5.1 Micro-vibration scanning test procedure
The scanning procedure for constant load excitation, variable load excitation and foundation excitation (vibration table excitation) is as follows: 5.5.1.1 Apply the rated static load sheet to the isolator bearing space, install and fix the system, and check the test system according to the relevant requirements of 5.1.
5.5.1.2 Perform excitation. In a linear system, the displacement value should be adjusted to: a. When the constant load and variable load excitation are performed, the amplitude value is 1+0.2mm; b. When the foundation is excited, the foundation displacement phase value is 0.2±0.05mm. 5.5.1.3 Scan the frequency from low to high to find the resonance point. When the constant load is used for excitation, the lower limit frequency of the scan should be one fifth of the natural frequency of the system or the lowest stable frequency of the system. When the variable load is used for excitation, the ratio of the upper limit frequency of the scan to the natural frequency of the system should be greater than 4 or the highest frequency of the actuator.
5.5-1.4 Select 6 to 8 points in the scanning frequency range, including the vibration point and the half-power point, and record the system mass base displacement, the base input displacement and the corresponding frequency during the foundation vibration. 5.5.1.5 For the nonlinear isolation vibration, the amplitude and static load are scanned. The amplitude is changed to static load: H. Change the excitation amplitude, starting from 60% of the displacement amplitude in 5.5.1.21, and excite at different amplitudes of 20% to 160%. Repeat the procedures of 5.5.1.3 and 5.5.1.4. At this time, the static load is still the rated value. b. Change the static load, starting from 60% of the rated load. Then, conduct excitation with different static loads of 20% increment rate and 140%. Repeat the procedures of 5.5.1.1~5.5.1.4. At this time, the excitation amplitude remains unchanged. 5.5.2 Calculation of excitation test results
5.5.2.1 The natural frequency
of the isolator under the rated load.Use formula (2) to calculate jk
minus: K.
dynamic stiffness of the isolator N/m:
when 0.25
K.—m(2fm)—K
when>0.25,
a) variable load vibration,
K,=ml 21/. Y1-/2] -K.
b) fixed load and basic excitation,
K.-m2nf.//1--7/2)\-K. \
In the formula,: consumption factor-K
-mass of the isolator's rated load, kE;
m-mass of the excitation system, kg.
f-resonance frequency of the excitation system, Hz
The sum of the dynamic stiffness of other elastic elements in the excitation system except the isolator under test, K.
If there are no other elastic elements, then K.-0.
5. 5- 2. 2Yinni ratio
Let: In the constant load excitation method, the damping ratio is calculated according to formula (4) or formula (5): (2)
(3a)
(3h)
W. In the formula: TAmm=Xm./Xnl
T-- Xmr/X. :
System resonance displacement amplitude.m:
CB/T 15168—94
Xm-XDisplacement amplitude at the lowest stable frequency of the system, mX. ——Displacement response amplitude under any load, m; w. System excitation frequency, ad/.
System resonance frequency, rad/s
b In the variable load excitation method, the damping ratio is obtained by formula (6) or formula (7): Special
Where: Tk
The stable displacement response value that no longer changes with the frequency after exceeding the resonance frequency, mc In the foundation excitation method, the damping ratio is calculated according to formula (8)1
Where: T.--X./u.
Displacement amplitude of foundation or vibration platform, m
5.5. 2. 3 Transmissibility
（6）
a. In the constant load excitation method, if the stable displacement response amplitude X is measured, it is equal to the displacement response value X under the intended frequency. The ratio of the transmission rate T at this frequency can be calculated according to formula (9), and the relationship curve between T and /m is plotted, which is the transmission rate curve: If the system does not have Xp, it is not appropriate to use this method to obtain the performance parameters of the isolator. TA=
bIn the variable load excitation method, the stable displacement response value X is measured: According to formula (1(), the cabinet transmission rate Tk is calculated, and the relationship curve between T and o/ is plotted. It is the relative transmission curve. If the system does not have Xe value, it is not appropriate to use this method to obtain the quasi-energy parameters of the isolator. TR-
(10)
In the foundation excitation method, the displacement response amplitude X at each frequency is measured, and the foundation excitation displacement amplitude ratio is used to calculate the transmission rate TA. The relationship curve between T and m/as is plotted, which is the transmission rate curve. TA
(11)
W.bzsoso:comGB/T 1516B-94
5.5.3 Test procedure and result calculation of hammer impact method 5.5.3.1 Check the receiving system according to the relevant requirements in 5.4. 5.5.3.2 Apply a transient force through the center of mass. 5.5.3.3 Record the self-vibration attenuation displacement waveform of the mass and the reference positive waveform. 5.5.3.4 Calculation of test result of hammer impact method
Direct: Damping ratio
When the number of free vibration waveforms is 4, the damping ratio is calculated according to formula (12), otherwise the hammer impact method cannot be used. Ax
24 element +
single waveform logarithmic attenuation rate, -
Where, —
free vibration Number of moving waveforms;
the peak amplitude of the i+nth wave, m;
the (i+n)th peak amplitude of the wave, m
h. Natural frequency
When there are no other operating components in the free-moving system except the isolator under test, the natural frequency is calculated according to formula (13). f,
Where: 1.
Reference waveform wavelength, m;
Reference waveform frequency, Hz 1
L—Measured waveform wavelength, I.
c. Vibration hysteresis
Calculated according to formula (3).
5.5.4 Ellipse method test procedure and result calculation.
5. 5. 4. 1 According to 5. 4 Check the test system according to the relevant requirements in 1
5.5.4.2 Install the force sensor between the isolator and the output terminal of the transmitted force. 5.5.4.3 Scan to determine its resonance point, and the total reported displacement amplitude should be kept within the range of 1±0.2mmm. 5.5.4.4 Record the displacement and transmitted force signal of the resonance point on the XY recorder, draw a circular graph, (12
5.5.4.5 Calibrate the force and displacement, and determine the force and displacement values represented by the unit length on the graph based on the sensor sensitivity and the amplifier output sensitivity.
5.5.4.6 Calculate the test results using the ellipse method
Damping ratio Calculate using formula (14)
-is_1
Displacement =Transmission force when the displacement reaches the maximum value (equal to the strain force), N: Transmission force when the displacement reaches zero is the double-width length of the hysteresis loop, mm! Transmission force corresponding to the maximum displacement is the double-width length of the hysteresis loop, n1m. Dynamic stiffness is calculated according to formula (15):
FI_·8
-maximum displacement on the hysteresis loop.1: effective amplitude length.mm: In the formula; A—
-displacement represented by unit length of the horizontal axis on the hysteresis diagram, m/trint (14)
(15)
W.GB/T15168-94
8——Tree diagram 1: force represented by unit length of the vertical axis, N/mm. c. Natural frequency is calculated according to formula (2).
6 Impact isolation performance test
6.1 Impact isolation performance parameters
Isolator impact isolation performance includes:
a. Impact acceleration transmission rate;
b. Isolator impact deformation.
6-2 Test equipment and instruments
6-2.1 The test equipment should be able to meet the requirements for impact pulse shape, peak acceleration, duration and effective load, or according to the application of the isolator. Determine the impact test equipment and requirements according to the relevant provisions of GJI150.18. 6.2.2 Requirements for measuring instruments are in accordance with 5.3.4. 6.2.3: The impact measuring instrument should include a measuring system or mechanical design for measuring the impact deformation of the isolator. 6.2.4 The indicator should have the function of holding the maximum value of the transient signal. 6.2.5 The lateral sensitivity ratio of the impact platform acceleration sensor shall not exceed 5%. 6.3 Requirements for installation and testing of the test system
6.3.1 The installation and testing of the test system shall meet the requirements of 5.4.1 to 5.1.7. 6.3.2 The distance between the mass center and the system stiffness center of the test system located in the impact machine shall not be less than half of the minimum spacing of the isolator.
6.3.3 The sensor for measuring the impact hoop shall be connected to the input table through a mechanical device with matching transfer characteristics. 6.3.4 The root of the input wire connected to the sensor shall be close to the measured object. 6.4 Test procedures and result calculation
6.4.1 The impact test shall be carried out in the directions of the main axes of the isolator perpendicular to each other. Impact shall be carried out at three heights (or angles) in each direction.
6.4.2 Each impact shall record the impact deformation of two isolators on any diagonal line in the direction of the force, the impact response acceleration of the mass and the impact input acceleration of the table.
6.4.3 Before each impact, all connecting screws of the sensor, system and table must be checked and tightened. 6.4.4 After the isolator is impacted once, the changes in the components and the relationship between them shall be checked. After the impact test, the changes in the isolator performance shall be checked and recorded in the test report. 6.4.5 Calculation of test results
The average impact deformation of the isolator and the calculation according to formula (16) are as follows:
The deformation value of each isolator for each impact, III; the number of displacement measurement points.
b Shock acceleration transmission rate T, calculated according to formula (17): x
Tah(dE)-20ig
Where: x
-shock acceleration response value.g
Shock acceleration input value: g.
（17）
W.GH/T 15168-94
Appendix A
Test principle
(Test piece)
A1 Dynamic performance test principle
The dynamic performance parameters of the isolator are determined based on the principle of balance among inertia force, elastic force, Grinding force and external force in a single degree of freedom elastic system. When the system is assumed to be viscoelastic structure damping and the input is a simple harmonic signal, regardless of the excitation method, its mechanical model is shown in Figure A1, and the motion equation is determined by equation (A),
MX+K(X--u)(I+jn)--F,c
Where: M-
-the quantity of the moving object in the system, kz+
K--the dynamic stiffness of the elastic element in the system. N/m; -—the loss factor caused by the viscoelastic structure, its value is twice the damping ratio·7-2X the absolute displacement of the moving object, m;
X·-the absolute acceleration of the moving object n/s*, t\the absolute displacement of the base or table, m
F-. Exciting force value, N;
exciting frequency, rad/s.
Constant load vibration
Figure AI Single-layer H-degree system mechanical model
（Al）
A1.1 Constant load excitation method
When the value in equation (A1) is 0, it is constant load micro-vibration, and the mechanical model is shown in Figure A1(a). Solving the motion equation (AI) yields: a. Displacement response amplitude
The displacement response value at any frequency is ×, and the displacement response amplitude at the resonant frequency is X, respectively.
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