Developing and experimental verification of a mathematical model fordetermination of service life of cardan shaft

The cardan shaft which transmits the power from the engine to the differantial in the motor vehicles is one of the vital elements in the driveline. Cardan shafts compensate the angular and axial differences between the components in which the torque is transmitted, during transmitting power and rotation movement. The axial compensation is provided by a group of splined components which are mutual and called as slip assembly involves a group of opposing sliding components while angular compensation is provided by the universal joints. Cardan shafts designed to meet customer requirements are first verified by finite element analysis; prototypes produced for frozen designs are taken to laboratory and then vehicle tests and evaluated in terms of suitability. Laboratory tests are carried out by using special test machines developed for drive shafts. The inputs and success criteria in the tests are determined by the vehicle manufacturers (OEM). Long test times also increase the cost of the verification process. In this study, two different new mathematical models have been developed, which have been verified by tests to determine the number of safe cycles of the propeller shaft. These two new developed mathematical models are named as Sen-Atik-I and Sen-Atik-II by using an abbreviation. Here, the numbers I and II indicate that the model is the first or second model. The safe cycle times calculated with the new developed models were compared with the laboratory test results. After the comparison, it was determined that Sen-Atik- II, one of the new developed mathematical models, gave the results to be close to the test results within an deviation of 4,84% for the worst case. Thus, with this obtained convergence, it was determined that the new developed mathematical model Sen-Atik-II could be used instead of laboratory tests.