Thermoelastic analysis of a bearing-cage weld seam

Abstract

This manuscript discusses the implementation of a thermo-elastic setup and analysis, to monitor and record the stress levels at the weld-seam of a bearing-cage, under different loadings. The setup includes a high speed, ultra sensitive infrared focal plane array and in-house developed pre and post-processing codes. The pre-processing neutralizes the emittance variation with the cage geometry using new mapping scheme, while the post-processor creates spatial neighbourhoods to average the stress signal and reduce the detector and the environment noise; also the algorithm checks for the adiabatic conditions through the synchronicity between the load cyclic frequency and that of the temperature differentials. The thermo-elastic investigation is done at different loadings from 20 - 140 Lbf at a frequency of 10 Hz, in two modes: a calibration mode with the weld-seam located at 9 o'clock position and a detailed mode with the weld-seam at 6 o'clock location. A Finite Element FE simulation is used to adjust the thermo-elastic constant using the calibration trials (weld at 9 o'clock). The detailed trials (weld at 6 o'clock) are then compared with the FE simulation, showing good agreement in predicting the stress values and maps. The proposed hardware and software map the stresses 3 dimensionally for the weld region with a 25 MPa resolution, in real-time and is found to resolve stress changes for each 20 Lbf loading.