摘要

In the safety assessment of existing structures made of old mild steel and for the decision on necessary repair and reinforcement measures, the verification of sufficient material toughness is essential. The assessment methods to avoid brittle failure in DIN EN 1993-1-10 [1] were developed based on extensive fracture mechanics investigations. The determination of permissible element thickness for certain steel grades was derived and tabulated for welding constructions made of steels according to DIN EN 10025 with generally high toughness. This method is not suitable for mild steel structures with holes for riveted or bolted joints (see [40]). In this article, experimental, analytical and numerical studies of the brittle fracture behavior of structures with holes made of old mild steels are presented. The results were carried out through various research projects at the Institute for Steel and Timber Construction of the TU Dresden and its cooperation partners (see, e.g. [2]). Part 2 describes mechanical and metallographic investigations in the area of punched holes and sheared edges of structural elements, the results of which are important for the cracking behavior of quasi-statically stressed components. After a brief introduction in the basics of fracture mechanics, analytical models for the determination of the stress intensity factor K-I on cracks are given and adapted to the special requirements of connections with load application via rivets and bolts. On the basis of extensive parameter studies by FEM calculations on angle profiles with different cross-sections and connection configurations, the K-factor solutions are adapted. Finally, examples for the assessment of the brittle fracture with the material toughness from Part 1 of the article [40] are presented.

  • 出版日期2017-8

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