EN 13146-9-2020 pdf download.Railway applications – Track – Test methods for fastening systems – Part 9: Determination of stiffness.
6.1.3 Procedure
All components and equipment used shall be kept in a temperature of (23 ± 5) °C or other test temperature (see J.L1) for at least 16 h prior to starting the test. Place the test set-up on a flat, rigid, horizontal base, which will support the whole area of the pad, in the following sequence: base, lower load distribution plate (if necessary), abrasive cloth (abrasive side up), pad. abrasive cloth (abrasive side down), upper load distribution plate, metal plate as shown In Figure 1.
Ensure the load distribution plates are located on the active area of the pad. Locate at least three independent instruments to measure the displacement of the metal plate at equal intervals around the perimeter of the plate.
Apply a force, Fspmax, through a spherical seating in the actuator as specified In the performance requirements for the type of track for which the pad is Intended.
NOTE Performance requirements are set out In other standards including the EN 13481 series.
Then reduce the force to the notional fastening assembly clamping force (F5p1) and repeat this cycle of loading and unloading twice more with a rate of force application (120 ± 10) kN/min. Maintain the applied force F5p1, then record the displacement whilst increasing the applied force to FSp2, which is 0,8 Fspmax
If the displacement measured by any of the instruments differs from the average displacement by z 20 % of the maximum displacement, repeat the loading cycle ensuring that the force is applied centrally to the pad. Calculate the static stiffness from Formula (1) where d5p is the average displacement when the applied force is increased from F5p1 kN to F5p2 kN:
1) intended use of the pads tested;
g) configuration of the load distribution plates used in the test;
h) temperature at which the test was performed;
i) load deflection curve or curves;
j) values of Fpj and Fsp2; source of loading information (e.g. reference to EN U.±W1 or other standard)
k) static stiffness of the pads tested.
If the test is made at more than one temperature a separate report should be prepared for each test
temperature.
6.2 Dynamic low-frequency test procedure for pads
6.2.1 General
This method is valid for frequencies in the range (3 to 30) Hz.
6.2.2 PrincIple
A cyclic force is applied, normal to the test pad, through an actuator at a single specified frequency or, if a general value of low-frequency dynamic stiffness is required, at three constant frequencies. The resulting maximum and minimum displacements of the surface of the pad are measured at the maximum and minimum forces.
6.2.3 Apparatus
The following equipment used for the static test is also used in this test:
a) controlled temperature test area 6.1.2J);
b) metal plate (6.1.2.2) and load distribution plate (6.1.2.3)
c) abrasive cloth (6LL4).
6.2.3.1 Actuator
Actuator capable of applying a force of up to (FLFPmaX + 10 %) kN at the required test frequencies.
6.2.3.2 Displacement-measuring instruments
Displacement-measuring instruments shall be in accordance with 6.1.2.6.
6.2.3.3 Force-measuring Instruments
Instruments conforming to EN ISO 7500-1:2018. Class 1 over the required range of force and capable of
measurement at a minimum of 20 samples per cycle.
6.2.3.4 Recording equipment
Equipment to make a digital recording and print-out of the displacement and applied force at the required test frequencies with a sampling frequency of at least 20 times the loading frequency.
6.2.4 Procedure
All components and equipment used shall be kept in a temperature of (23 ± 5) °C or other test temperature (see .1.2L1) for at least 16 h prior to starting the test. Place the test set-up on a flat, rigid, horizontal base, which will support the whole area of the pad, in the following sequence: base, lower load distribution plate (if necessary), abrasive cloth (abrasive side up), pad, abrasive cloth (abrasive side down), upper load distribution plate, metal plate as shown in Figure 1.
Ensure the load distribution plates are located on the active area of the pad. Locate at least three independent instruments to measure the displacement of the metal plate at equal intervals around the perimeter of the plate.
Obtain the specified value of FLFpmax, from the performance requirements for the type of track for which the pad is intended.
NOTE Performance requirements are set out In other standards Including the EN 13481 series.
Apply a cyclic force of FLFP1 kN to FLFP2 kN, where FLFP2 = 0,8 FLFPmaX for 10 s at the required test frequency ± 1 Hz. If no test frequency is defined, the test shall be carried out at the following frequencies:
a) (5±1)Hz;
b) (10 ± 1) Hz;
c) (20 ± 1) Hz.
After 10 s, at each frequency, record the applied load and the metal plate displacement at a minimum of 20 samples per cycle for at least 10 cycles and calculate the average displacement dLFP at each frequency. If the displacement measured by any of the three instruments differs from the average displacement by  20 % repeat the loading cycle ensuring that the force is applied centrally to the pad. Calculate the dynamic stiffness at each frequency using Formula (2):EN 13146-9-2020 pdf download.