Impacts of principal stress rotation on the nonlinearity of strain-hardening cementitious composites with fibers

An experimental program was conducted to investigate the effects of simultaneous opening-sliding of multiple cracks on the behaviour of strain-hardening cementitious composite plates. Newly proposed testing method was developed to reproduce possible rotating principal axis during the material strain-hardening. The experimental results showed he change in principal stress direction has a substantial impact on the macroscopic plate behaviours including multi-directional cracking pattern, and reductions in strength, ductility, and initial stiffness. A space-averaged constitutive model for this type of material was developed and further incorporated into FE analysis program. The model simulated reasonably various responses observed in the experiment and demonstrated the reductions observed were attributed to the lack of shear transfer across the multiple cracks. Further analyses of shear-critical R/SHCC panels and beams were carried out and confirmed the applicability of the model to simulate the behaviours at structural levels. Finally, this paper briefly presents our recent attempt to improve the structural performance with robust SHCC material under stress field rotation.