engleski

On the applicability of cyclic and fatigue parameters estimation methods to high strength steels

Due to very favourable combination of properties, high strength steels are of great importance for numerous industrial applications where lightweight designs are of interest, such as automotive/mobility industry. Material modelling and simulation are an integral part of fast and integrated product development in these areas, so that detailed knowledge of materials’ cyclic stress-strain and fatigue behavior and corresponding properties/parameters, as early in the product design process as possible, becomes ever more important. Consequently, various existing methods for estimation of cyclic/fatigue parameters from monotonic properties are used, and new ones are developed. With rare exceptions such as method of variable slopes and modified uniform material law where high strength steels and sheet steels are treated separately, most estimation methods have been developed and evaluated using data on wide range of metallic materials or on rather general groups such as unalloyed, low-alloy and high-alloy steels. As previous evaluation of estimation methods performed on a representative HSLA steel has shown, this may result in significant results averaging and estimation errors. In this work, several methods for estimation of cyclic and fatigue parameters have been analyzed and evaluated with regard to their applicability to high strength steels. Using error criterion i.e. fraction of data points falling within a predefined scatter bands, performance of individual methods has been evaluated in low-cycle and high-cycle fatigue regime separately. Comparison is provided based on estimation results obtained for more general groups of steels (all steels, unalloyed, low-alloy, high-alloy steels). Notable differences could be observed and are reported regarding the applicability of analyzed methods for low- and high-cycle fatigue regimes and for selected subgroup of high strength steels.

cyclic parameters ; fatigue parameters ; estimation methods ; high strength steels

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