FE investigations of the effect of fluctuating local tensile strength on coupled energetic–statistical size effect in concrete beams

• We model a deterministic and statistical size effect in concrete beams using FEM.
• We examine the correlation length of the random field of tensile strength.
• The effect of the coefficient of variation of local tensile strength is studied.
• The FE analyses are carried out for four different beam sizes.

The effect of fluctuating local tensile strength on a coupled energetic–statistical size effect in plain concrete beams under bending was numerically investigated. First, the influence of varying autocorrelation length of the random field describing a spatial variation of local tensile strength was studied. Next, the influence of the coefficient of variation of local tensile strength was analyzed. The numerical FE investigations were performed for unnotched concrete beams of similar geometry under quasi-static three point bending within elasto-plastic model assumptions, accounting for non-local softening. The FE analyses were carried out for four different beam sizes. In the calculations, the tensile strength took the form of spatially correlated random field described by a Gaussian distribution.

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