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Die Schwingfestigkeit von Kerbstaben kann durch Oberflachendriikken betrachtlich erhciht werden, wenn die Kenntnis der Werkstoffbeanspruchung im Wtilzkontakt zur Optimierung der Driickkraftbedingungen vorliegt. Es wurde deshalb ein Rechenprogramm erstellt, das eine hertragung von optimierten Driickkraften auf beliebige Probengeornetrien gestattet. Die Ergebnisse der Schwingfestigkeitsuntersuchungen zeigen, daS oberfllchenverfestigte Kerbproben unabhingig von ihrer Formzahl Dauerfestigkeitswerte erreichcn, die oberhalb der Grenzwerte von glatten schiuSgerollten Proben liegen. Die dabei erzieibaren Steigerungsraten gekerbter Proben mit Anrissen im Kerbgrund, die nicht zum Bruch &en, werden auf die Wirkung stabiler Druckeigenspannungssysteme 1. Art zuriickgefiihrt .Optlmlsatlon of Fatigue Properties by Surface-Rolling of Notched Specimens of Dlfbrent SizeThe fatigue properties of notched specimens can be largely improved by surface-rolling, It is important to know the material strengthening in the rolling contact to improve the conditions of the surface-rolling process. A computer program is presented, which allows a determination of rolling pressures to any geometries of specimens.As a result of the fatigue investigations it is shown that surface-rolled notched specimens improve the fatigue limit above the fatigue strength of smooth specimens independed on the stress concentration. The improvement of endurance limit of notched specimens with non propagated cracks is based on the effect of constant compressive residual stresses.

Material Stressing in a Hertzian Contact – Influence of Load and Internal Stresses For the analysis of the material stressing in a Hertzian Contact due to elliptically distributed normal load it is sufficient to calculate the stresses at z ≥ 0, × = y = 0. At this point the maximum stress occurs in the contact surface as well as in the stressed volume. From the center to the rim of the contact the stress decreases. In the case of residual stresses in the material it is necessary to calculate the resulting stresses in the entire contact area. The superposition of stresses due to load and internal stresses can cause stressings of the material with a maximum in the region of the rim of the contact area. The calculation of the conditions in the center alone can lead to misinterpretations.

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