Using acoustic emission to study fretting induced damage mechanisms
Kasurinen, Taavi (2025)
2025
Konetekniikan DI-ohjelma - Master's Programme in Mechanical Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2025-06-30
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202506307463
https://urn.fi/URN:NBN:fi:tuni-202506307463
Tiivistelmä
Fretting is defined as a low amplitude, reciprocating sliding movement between contacting and loaded surfaces. It occurs in seemingly stationary contacts, such as interference fits, loaded with cyclic loads, being present in almost all machinery. Fretting results in material damage through fretting wear and fretting fatigue. In fretting wear, relative motion between interacting bodies causes debris formation and loss of matter. In fretting fatigue, the surface subjected to fretting is also loaded with alternating bulk stresses. Fretting fatigue may result in a severe reduction in fatigue life due to fretting induced crack nucleation and propagation.
Fretting damage often remains hidden within the contact interface, thus making the detection of the damage challenging without nondestructive testing methods. One of these methods is called acoustic emission. In acoustic emission, transient stress waves are generated due to the rapid release of energy from localized sources within a material. Some of the common sources of acoustic emission in metals include crack growth, plastic deformation and surfaces rubbing against each other. These acoustic emission waves can be detected with an acoustic emission measurement system.
This thesis investigated the use of acoustic emission as a tool to analyze the fretting-induced damage in dry self-mated quenched and tempered steel. The research was conducted using a previously designed annular flat-on-flat fretting device, which was equipped with an acoustic emission measurement system. The research focused on the relationship between acoustic emission parameters and the underlying damage mechanisms in fretting. 26 tests were conducted in total, of which 19 were performed with gross slip and 7 with partial slip conditions.
Based on the test results, it could be suggested that acoustic emission parameters of amplitudes, energies, cumulative energies, cumulative RMS and dominant frequencies can be used in the analysis of fretting damage. Acoustic emission amplitudes and energies could help in differentiating when the damage mode is adhesive and when the change to more abrasive damage happens. Dominant frequencies could assist in this analysis since distinct high frequencies at initial cycles of the testing could be related to adhesive wear and cracking, and a wider range of frequencies to abrasive wear prevailing after a sufficient amount of wear particles are generated. Sudden increases in cumulative energy could also be used in estimating when changes in these conditions happen. Values of total cumulative energy and total cumulative RMS also seem to be higher when the magnitude of damage increases in gross slip tests. In addition, cumulative RMS values seem to be a promising tool for evaluating the generated wear mass.
Overall, the findings support the feasibility of using acoustic emission as an evaluation and diagnostic tool in fretting damage on flat-on-flat contact configuration of self-mated quenched and tempered steel.
Fretting damage often remains hidden within the contact interface, thus making the detection of the damage challenging without nondestructive testing methods. One of these methods is called acoustic emission. In acoustic emission, transient stress waves are generated due to the rapid release of energy from localized sources within a material. Some of the common sources of acoustic emission in metals include crack growth, plastic deformation and surfaces rubbing against each other. These acoustic emission waves can be detected with an acoustic emission measurement system.
This thesis investigated the use of acoustic emission as a tool to analyze the fretting-induced damage in dry self-mated quenched and tempered steel. The research was conducted using a previously designed annular flat-on-flat fretting device, which was equipped with an acoustic emission measurement system. The research focused on the relationship between acoustic emission parameters and the underlying damage mechanisms in fretting. 26 tests were conducted in total, of which 19 were performed with gross slip and 7 with partial slip conditions.
Based on the test results, it could be suggested that acoustic emission parameters of amplitudes, energies, cumulative energies, cumulative RMS and dominant frequencies can be used in the analysis of fretting damage. Acoustic emission amplitudes and energies could help in differentiating when the damage mode is adhesive and when the change to more abrasive damage happens. Dominant frequencies could assist in this analysis since distinct high frequencies at initial cycles of the testing could be related to adhesive wear and cracking, and a wider range of frequencies to abrasive wear prevailing after a sufficient amount of wear particles are generated. Sudden increases in cumulative energy could also be used in estimating when changes in these conditions happen. Values of total cumulative energy and total cumulative RMS also seem to be higher when the magnitude of damage increases in gross slip tests. In addition, cumulative RMS values seem to be a promising tool for evaluating the generated wear mass.
Overall, the findings support the feasibility of using acoustic emission as an evaluation and diagnostic tool in fretting damage on flat-on-flat contact configuration of self-mated quenched and tempered steel.