ISO 22074-8 pdf download Railway infrastructure — Rail fastening systems — Part 8: Test method for vertical stiffness
The calibration of displacement-measuring instruments shall be in accordance with ISO 9513.
6Test procedures for pads
6.1Static test procedure for pads6.1.1 Principle
A force is applied normal to the test pad and the displacement is measured.6.1.2Apparatus
22.214.171.124 Controlled temperature test area, area of the laboratory where the test is conducted,maintained at ([25±5)°C.
Where pads are to be used at other ambient temperatures, additional tests shall be performed in atemperature-controlled chamber，if required by the purchaser, at one or more of the followingtemperatures: (-30± 3)°C,(-20± 3)c, (-10 ±3) R℃,(0 ±3) Cand (50± 3) C.
Additional test temperatures may be agreed between the manufacturer and the purchaser.126.96.36.199 Metal plate,rigid, larger than the load distribution plate.
188.8.131.52 Load distribution plate，rectangular upper load distribution,made from metal 10 mmminimum thickness, with smooth, rounded edges,such that the load distribution plate does not damagethe pad under test.The dimensions of the plate depend on the type of pad being tested as follows:
Rail pads: the same width as the foot of the rail used for the repeated loading test (see IS0 22074-4)and a length of 210 mm.Alternatively, a short length of rail, at least 210 mm long,may be usedinstead of the upper load distribution plate and upper metal plate.
Baseplate pads: the same width and length as the maximum rectangular area within the part of thebaseplate transmitting the load to the pad in the fastening assembly.
When the pad is supported in use over a limited area, a lower load distribution plate, of the samedimensions as the part of the pad which would be actively supported in the fastening assembly, is alsorequired.
NOTE1 For tests on continuous pads used in slab track a length of pad of 150 mm is used.
NOTE2 lf the metal plate described in 184.108.40.206 matches the size of the upper load distribution plate, the loaddistribution plate can be omitted.
220.127.116.11 Abrasive cloth, with grit size P120 to P400(ISO 6344-1)in unworn condition,the dimensionsof each sheet being not less than the full area of the pad to be tested.
18.104.22.168 Actuator capable of applying a force of (FsPmax+10 %)kN through a spherical seating.NOTE Typically,the maximum force is 120 kN.
22.214.171.124 Displacement-measuring instruments
a) lf contacting displacement-measuring instruments are used, they shall conform with lS0 9513.b)lf non-contacting displacement-measuring instruments are used, they shall be calibrated to ensure
that they can measure the displacement of the metal plate relative to the base as required in 6.1.3.
The instruments shall be capable of measuring displacements as follows:
— for pads with a declared stiffness s 100 MN/m, displacement measurement within ±0,02 mm;— for pads with a declared stiffness > 100 MN/m, displacement measurement within ±0,01 mm.126.96.36.199 Force measuring instruments conforming with ISO 7500-1:2018,Class 1 over the requiredrange of force.
188.8.131.52 Recording equipment, to make a digital recording and print out of the displacement andapplied force.
All components and equipment used shall be kept at a temperature of (25 ± 5) °C or another testtemperature (see 184.108.40.206) for at least 16 h prior to starting the test. Place the test set-up on a flat, rigid,horizontal base, which supports the whole area of the pad, in the following sequence: base, lower loaddistribution plate (if necessary), abrasive cloth (abrasive side up), pad, abrasive cloth (abrasive sidedown), upper load distribution plate, metal plate as shown in Figure i.
Ensure the load distribution plates are located on the active area of the pad. Locate at least threeindependent instruments to measure the displacement of the metal plate at equal intervals around theperimeter of the plate.
Apply a force,FsPmax， with a rate of application (120 ± 10) kN/min as specified in the performancerequirements for the type of track for which the pad is intended.
NOTEPerformance requirements are set out in other standards.
Reduce the force to the minimum value, FSp;, and repeat this cycle of loading and unloading twice more.Increase the applied force from Fsp1 to Fspmax, recording the displacement while increasing the force inthis final cycle.