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General Information on the Computer-Aided Fatigue Analysis with Endurance Strength

With the aid of Endurance Strength, the behaviour of components under dynamic load can be analysed and an important aim is to obtain a fatigue life prognosis. Along with the often very time consuming experimental way, the computer-aided fatigue life analysis is becoming more and more important since it enables a fast and reasonably priced analysis. It is also possible, using parameter studies, to identify the important factors so that any additional experiments which might still be required can be carried out more precisely and less extensively. The Endurance Strength analysis demands extensive knowledge on the operating loads which occur, the production process, material etc, so that companies, which only occasionally need to concern themselves with such problems, willingly fall back on our services for the Endurance Strength Analysis.

When carrying out an Endurance Strength Analysis is the Fatigue Evaluation.needs to be treated in a special way. The characteristic bending point of the S-N curve (fatigue evaluation) is an important parameter which is often used for the dimensioning. The relationship of the maximum operational load to the fatigue evaluation is provided in the form of the performance ratio. For this it is not necessary to know detailed load-time functions but just the maximum value of the loads and their form (alternating, tumescent, constant). The performance ratio is then calculated, presuming a worst-case scenario. If there is only a low performance ratio in the Fatigue Evaluation, then it is often possible to omit the comparatively time consuming Endurance Strength Analysis.

There are several rules and regulations which make the process easier and help to find a state of the art dimensioning. Here we would like to mention the FKM Guidelines, the rules and regulations stipulated by German Lloyd (for ship building and wind energy plants) and the IIW-Guidelines (International Institute of Welding).

The results of the endurance limit process is - along with a deeper understanding of one‘s own product - a more efficient structure of the component, less weight and often also a cost saving.. As well as the technical aspects, the question of product liability also plays an important part in the motivation for using this process.

Our software winLIFE has been developed to use the established methods in a way which is as simple as possible to use. For winLIFE to be successful it is essential that the user has good basic knowledge in mechanical engineering. In our seminars (two days, three times a year) we cover the basics for a more detailed introduction to the theories of Endurance Strength and the use of our software. If required, we can assist the winLIFE user with his first projects. This gives the user a faster introduction to the methods and more confidence to correctly interpret his results. The publications and winLIFE video examples give an impression of the possibilities available.