A series of ram extrusion tests was carried out on a short-fiber-reinforced, semisolid,
fresh cementitious composite. An elastoviscoplastic constitutive model is proposed for
the extrudable fresh cementitious composite. It features the associative flow rule, a
nonlinear strain rate-hardening law, and the von Mises yield criterion. The
model is then implemented in ANSYS/LS-DYNA explicit finite element
code.
Various ram extrusion processes of the fresh cementitious composite were
simulated. It has been found that the extrusion load versus imposed displacement
predictions agree well with the experimental results. The fresh paste flow, through
the die entry and the die-land, is then interpreted in light of the evolution of the
deformation and distribution of state variables, mainly based on numerical results
and the ram extrusion mechanism.
The effects of extrusion ratio and extrusion velocity on extrusion load are also
investigated, based on the mechanical properties of the fresh cementitious composite.
The study indicates that the numerical procedure established, together with the
constitutive model proposed, is applicable for describing ram extrusion of
short-fiber-reinforced fresh cementitious composites, which might provide a numerical
rheometric tool from which ram extrusion of elastoviscoplastic paste-like materials
can be examined and quantified.