Determining the stress-strain state of the elastic clip of rail fastening W30

Introduction. The article provides performance evaluation of the elastic clip of intermediate rail fastening during their strength characteristics assessment. In modern conditions this issue is solved by modelling using the finite element method. In order to obtain reliable calculation results, the authors carry out verification of the finite element model. The purpose of the article is to model Skl 14 elastic clip of W30 intermediate rail fastening, as well as to verify the obtained results of the clip under static loading on the test bench by strain-gauging method.

Materials and methods. For stress-strain modelling the researchers developed a finite element model of the elastic clip, which includes 450,000 elements of the tetrahedron type of size 1 mm and 90,000 nodes. In order to verify the developed model and the calculation results, laboratory tests of full-scale terminal were carried out while determining tangentional and bending stresses by strain-gauging method of a full-scale clip were performed while determining torsional and bending stresses by the strain-gauging method. Sensors with base of l = 5 mm for recording tangential stresses due to torsion were glued at 45º on diametrically opposite sections of the bar on the outer and inner radii in the zones of technological bends of the elastic clip. Sensors were glued on the upper part of the outer transverse sections of the elastic clip to register bending stresses.

Results. Virtual and experimental calibration of the elastic clip was performed. Calculation tests were conducted to determine tangential, bending and equivalent stresses. They showed that the highest level of equivalent stresses is observed in the zones of technological bends. A comparative analysis of calculated and experimental values of stresses at measuring points was performed.

Discussion and conclusion. The average value of discrepancies for 13 test points was 10.1%, which allows to conclude that the developed finite element model of Skl 14 elastic clip with a sufficient accuracy for practical application could be used to determine its stress-strain state, and the stress levels may become standards for the development of new clip designs. It is advisable to continue studies of the stress-strain state of elastic clips under operating conditions with the determination of speed influence, axial load, undercarriage design, condition of wheel pairs and tread of rails, as well as to use the applied analysis methodology.