Willam's test is a quick numerical benchmark in tension-shear regime, which can be used to verify inelastic (quasi-brittle) material models at the point level. Its sequence consists of two separate steps: uniaxial tension accompanied with contraction-until the tensile strength is attained; and next for softening (cracking) of the material-tension in two directions together with shear. A rotation of axes of principal strains and principal stresses is provoked in the second stage. That kind of process occurs during the analysis of real concrete structures, so a correct response of the material model at the point level is needed. Some familiar concrete models are selected to perform Willam's test in the paper: concrete damaged plasticity and concrete smeared cracking-distributed in the commercial ABAQUS software, scalar damage with coupling to plasticity and isotropic damage-both implemented in the FEAP package. After a brief review of the theory, computations for each model are discussed. Passing or failing Willam's test by the above models is concluded based on their results, indicating restrictions of their use for finite element computations of concrete structures with predominant mixed-mode fracture.
Keywords: FEM; Willam’s test; concrete models; damage; nonlinear analysis; plasticity; smeared cracking.