ISO 22074-8:2022 pdf – Railway infrastructure — Rail fastening systems — Part 8: Test method for vertical stiffness

ISO 22074-8:2022 pdf – Railway infrastructure — Rail fastening systems — Part 8: Test method for vertical stiffness.
1 Scope This document specifies laboratory test procedures to determine the static and low-frequency dynamic stiffness of rail pads, baseplate pads and complete rail fastening assemblies. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 7500-1:2018, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Calibration and verification of the force-measuring system ISO 9513:2012, Metallic materials — Calibration of extensometer systems used in uniaxial testing ISO 22074-1, Railway infrastructure — Rail fastening systems — Part 1: Vocabulary 3? Terms? and? definitions For the purposes of this document, the terms and definitions given in ISO 22074-1 and the following apply. ISO and IEC maintain terminology databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https:// www .iso .org/ obp — IEC Electropedia: available at https:// www .electropedia .org/ 3.1 static stiffness force required to cause a unit displacement of a pad or a rail fastening assembly with the load applied slowly enough to avoid all significant loading rate effects 3.2 low-frequency dynamic stiffness force required to cause a unit displacement of a pad or a rail fastening assembly with a cyclic load applied at a frequency and force amplitude representative of the loading in railway track associated with passing wheels or bogies
6 Test procedures for pads 6.1 Static test procedure for pads 6.1.1 Principle A force is applied normal to the test pad and the displacement is measured. 6.1.2 Apparatus 6.1.2.1 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 a temperature-controlled chamber, if required by the purchaser, at one or more of the following temperatures: (−30 ± 3) °C, (−20 ± 3) °C, (−10 ± 3) °C, (0 ± 3) °C and (50 ± 3) °C. Additional test temperatures may be agreed between the manufacturer and the purchaser. 6.1.2.2 Metal plate, rigid, larger than the load distribution plate. 6.1.2.3 Load distribution plate, rectangular upper load distribution, made from metal 10 mm minimum thickness, with smooth, rounded edges, such that the load distribution plate does not damage the 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 ISO 22074-4) and a length of 210 mm. Alternatively, a short length of rail, at least 210 mm long, may be used instead 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 the baseplate 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 same dimensions as the part of the pad which would be actively supported in the fastening assembly, is also required. NOTE 1 For tests on continuous pads used in slab track a length of pad of 150 mm is used. NOTE 2 If the metal plate described in 6.1.2.2 matches the size of the upper load distribution plate, the load distribution plate can be omitted. 6.1.2.4 Abrasive cloth, with grit size P120 to P400 (ISO 6344-1) in unworn condition, the dimensions of each sheet being not less than the full area of the pad to be tested. 6.1.2.5 Actuator capable of applying a force of (F SPmax + 10 %) kN through a spherical seating. NOTE Typically, the maximum force is 120 kN.