Simulation von Risswiderstandskurven mit dem Kohaesivmodell: Large scale yielding

Fracture resistance curves (R curves) for describing ductile material behaviour play an important rule for integrity assessment analyses. The determination of R curves is widely expressed by experimentally based standardized procedures. But the considered standard test specimens are usually small sized and the problem of resistance transferability from small laboratory specimens under large scale yielding to large sized structures under contained yielding emerges. It will be presented in the following a new strategy based on a cohesive type model in combination with the conventionally finite element method. It allows numerical simulations of stable (ductile) tearing uniquely for small scale yielding (presented formerly in this journal) as well up to fully plastic deformation states only by two constant material parameters. With the respective choise of cohesive parameters it is possible to generate synthetical resistance curves which allows a new systematic understanding of the driving influences and their margins, especially the geometry (loading) induced variations. By changing the two cohesive parameters an arbitrary material can be introduced where the correlation between material and resistance behaviour can be answered. Furthermore, the inhomogeneous behaviour of compounds, made of different material phases, can be investigated straightforward and opens new perspectives in the fields of engineering testing and characterization. Conventional methods as used for homogeneous cases are no more sufficient for many aspects of new composed materials and structures. (orig.)Also published in 'Mat.-wiss. u. Werkstofftech. 29, 652-661 (1998)'Available from TIB Hannover: RA 3251(98/E/49) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman