Numerical simulation and experimental validation of normal strain distribution and pitting phenomenon in industrial gears

In this paper, the normal strain distribution and pitting phenomenon on gears are investigated by means of numerical finite element analyses and experimental activities. In the first part of the paper, results of experimental tests for the investigation of the pitting phenomenon on gears are reported. These durability tests are made at a specific nominal load and far from the resonance. The experimental data are collected periodically from two tri-axial accelerometers placed on the gear shafts. After a short time, a visible pitting phenomenon arises on the gear teeth, where the contact pattern is perfectly centered (due to the high lead crown imposed on the teeth) and the wear pattern is consistent with FE simulations. In the second part of the paper, numerical finite element studies on the normal strain distribution at the base of the gear teeth during the contact are reported. These analyses are made at the same nominal load of the previous pitting analyses and at very low rotational speed (static analyses). A peak of normal strain at the base of the contact tooth is found around the contact time, preceded and followed by a low constant value of normal strain. The numerical results are validated by comparisons with experimental tests carried out in the same operating conditions and placing strain gauges at the tooth base of the gears.