Publica
Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Variable amplitude fatigue of highstrength cast iron alloys for automotive applications
 International journal of fatigue 91 (2016), Pt.2, S.445458 ISSN: 01421123 

 Englisch 
 Zeitschriftenaufsatz 
 Fraunhofer LBF () 
Abstract
In the automotive sector, the cumulative damage calculation method generally applied is the Palmgren–MinerHypothesis with its modification according to Haibach (steeper slope of the SNline after the kneepoint) as a means of also including the damage by stress amplitudes below the kneepoint. This approach results in the total damage sum of the spectrum Dspec. However, the resulting question is the value of the allowable damage sum Dal for the evaluation of Dspec ⩽ Dal. The only design code that considers the assessment of cast iron components under spectrum loading is the FKMGuideline of the Cooperative Research Association for Mechanical Engineering (FKM, Frankfurt/Germany) for designing machine components. Here, the theoretical Palmgren–Minerdamage sum Dth = 1.0 is still suggested as the allowable damage sum Dal despite the fact that this damage sum renders unsafe calculated fatigue lives in about 90% of all published results.
The results obtained with componentlike notched specimens of modern highstrength cast iron alloys (Rm = 650–800 MPa) such as ENGJS5007, SiboDur 70010 and MADI (Machinable Austempered Ductile Iron), which were investigated under a standard Gaussian spectrum for chassis applications and also for a fuller injection pump spectrum, suggest the allowable damage sum Dal = 0.3 for fatigue life estimations of components manufactured with these materials can be proposed; i.e. the allowable fatigue life is about one third compared to calculations with the theoretical damage sum Dth = 1.0 that is still used.