P 1279 – Design recommendations for the materialefficient use of high strength steel hollow sections in agricultural soil-working machines
The demands on the performance of modern agricultural machinery and equipment are constantly increasing and the accompanying development faces enormous challenges. In view of these development trends, a conflict of objectives arises between the required performance, the permissible machine weights and the economically available cost framework.
This problem is addressed in the project and investigated on the basis of agricultural tillage machines, which include, for example, tillers, cultivators, harrows and plows. These tillage machines offer great potential for the lightweight and material-efficient use of higher-strength steels, as they are profile-intensive structures in which standard materials (e.g. S355) are traditionally used. The structural design is usually based on experience without knowledge of the exact loads, which makes it difficult to achieve an optimal and appropriate design. Within the scope of the research project, an equivalent load spectra for soil cultivation equipment is created. Therefore realistic test runs with a soil tillage implement are performed. The developed load sprectra forms the basis for the operationally stable design of agricultural soil cultivation equipment.
In parallel to the determination of the load spectra, fatigue tests are carried out on three constructional details that frequently occur in agricultural engineering, as well as on a sample component. On the basis of the experimental results, a fatigue class recommendation is developed for these details. Using numerical parametric studies, a variation of geometric parameters is carried out so that, as a result of the numerical analyses, corresponding formulas are provided which enable the determination of the stress concentration factors for the underlying constructional details.
Prof. Dr.-Ing. T. Ummenhofer, Prof. Dr.-Ing. Ch. Schäfers