Browsing by Author "Petrangeli, Mario"

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Open Access
Nonlocal fracture analysis - identification of material model parameters
(1994) Ozbolt, Josko; Petrangeli, Mario; Eligehausen, Rolf
In the present paper a short description of the nonlocal microcrack interaction approach is presented. The physical meaning of this approach when used in the smeared finite element code is discussed. The present nonlocal "averaging" consists of a long-range interaction (crack interaction function) and local averaging. The first controls the crack propagation and the second is responsible for the correct energy consumption due to cracking. It is demonstrated that the nonlocal material model parameters may be identified by usual concrete fracture properties such as tensile strength, concrete fracture energy and maximum aggregate size. The nonlocal microcrack interaction approach is compared with the nonlocal strain approach and a possible simplification is considered.
Open Access
The size effect in concrete structures
(1994) Ozbolt, Josko; Eligehausen, Rolf; Petrangeli, Mario
In the present paper the results of a size effect study on plain concrete unnotched and notched beams loaded in three-point bending are shown and compared with experimental results and Bazant's size effect law. The numerical results, obtained using the nonlocal microplane finite element code, confirm a strong size effect for smaller beam sizes. However, for larger unnotched beams the nominal strength tends to a constant value related to the uniaxial tensile strength. These results are in good agreement with what has been observed in experiments. The reason why the nominal strength of large unnotched beams should approach a limit value different from zero is investigated and the range of applicability of the size effect law is discussed. It has been concluded that the applicability of the size effect law is dependent on the problem type i.e. if the crack propagation before peak load is very stable the size effect law may be used in a rather broad size range. However, if this is not the case, the validity of the size effect law is limited to a smaller size range. Therefore, before extrapolating the size effect from tests with a small size range to a very large size range experimental data from a large size range should be available.