Influence Of Contact Configuration On Fretting Fatigue Behavior Of Medium Carbon Steel

The fretting fatigue failure widely exists in the mechanical, especially nuclear industry and aviation industry. To compare with the ordinary fatigue, freeing may cause the frictional wear and accelerate the crack initiation and expansion, then make the mechanical part failure earlier than the expected life, leading to the major accident and economic loss at last.Medium carbon steel45-carbon steel was selected to study the influence of the surface contact and line contact on behavior of fretting fatigue, including three aspects:fretting fatigue test, microscopic observation of the fretting surface, the finite element analysis of contact mechanics. The main work and results are as follows:1. The fretting bridge with plane, radius40mm,70mm cylindrical foot surface, and the experiment samples by two parallel planes were designed. Combined with shimadzu fatigue tester, the fretting fatigue test with different contact configuration was processed successfully.2. To establish the corresponding finite element model and verify the accuracy and feasibility. Through the results of the finite element calculation, find the base for comparing, it is cyclic stress amplitude.3. The fretting fatigue Sa-N curves of45-carbon under different contact configuration has been obtained by fretting fatigue test, the result of comparative analysis indicate that different contact configuration may bring greater influence to fretting fatigue life.4. Contrast with the microscopic appearance of contacting surface, the process and mechanism of fretting wear were discussed, compared with surface contact, the fretting wearing surface of line contact was more bright and clean.5. With the same cyclic stress amplitude, the stress intensity and stress intensity amplitude on contacting surface under different contact configuration were given analysis, and it was found that stress amplitude play an important role in the crack initiation and expansion.The paper studies the influence of different contact configuration on the behavior of fretting fatigue from macroscopic to microscopic, and obtains some conclusion. Combining with ordinary fatigue life theory and fracture mechanics, further research on quantification and the relation between the stress distribution on contact surface and fatigue life can be carried out.