Use of the experimental modal analysis for analytical lifetime estimation of a bogie frame

¹ SC Softronic SRL, Calibration and Mechanical Testing Laboratory, Craiova, No.40, Dolj, Romania
² Polytechnic University of Bucharest, Sector 6, Splaiul Independentei, No. 313, Romania
³ INMA Bucharest, Sector 1, Blv. Ion Ionescu de la Brad, No. 6, Romania

^* Corresponding author: ion.manea@softronic.ro

Abstract

The fatigue strength validation by tests of the railway bogie frames requires existence of an expensive laboratory and a long time for testing of about 6 to 10 months. Considering these aspects, the European norms admit that fatigue tests can be replaced by finite elements analysis (FEA), with the condition that analytical model to be correctly realized and validated by tests. Experimental modal analysis (EMA) provides a powerful tool for validation of the FEA model by experimental data. The article presents an application for assessment of the fatigue strength of a three-axle locomotive bogie frame. Using Ansys, was carried out the structural analysis of the bogie frame, resulting the modal model characterized by the modal parameters: Eigen frequencies and Eigen shapes. The analytical model was validated by an EMA application carried out on the bogie frame and correlation analysis of the EMA and FEA models. Using a special measuring wheel set, were determined the wheelrail interaction forces for various locomotive running conditions. The analytical structural model, validated through experimental data, and the data files containing the wheel-rail interaction forces, constitutes the input data for the nCode program that evaluates the bogie frame lifetime using appropriate stress curves and a recognized accumulation of damage hypothesis, e.g. the Palmgren-Miner.