DETERMINING THE STRESS-CRACK OPENING RELATIONSHIP OF SFRM BY INVERSE ANALYSIS

The stress-crack opening relationship is a basic material input in fracture mechanics-based design methodology and numerical simulation for fiber reinforced cementitious composites. In the present study, the tensile stress-crack opening relationship of steel fiber reinforced mortar (SFRM) is determined by inverse analysis using load versus crack mouth opening displacement (CMOD) curve from notched beam tests. Five series of SFRM with different steel fiber volume fractions (from 0.5% to 2.5%) were tested. Direct tension tests were performed to obtain the tensile strength of SFRM. Behavior of the SFRM is classified into two types: CMOD-softening and CMOD-hardening. The results show that the tri-linear model can be used to model the stress-crack opening relationship of SFRM with CMOD-softening behavior, and the drop-constant model can be used to simulate the stress-crack opening relationship of SFRM with CMOD-hardening behavior.