SKnn exceed ft value

The program uses two yield surfaces, i.e. crack detection surface for tension and compression yield surface for compression. The yielding (tension or compression) is determined based on the effective pressure stress (p) and Mises equivalent deviatoric stress(q ), instead of principal tensile stress and principal compressive stress.

In the figure below, the two yield surfaces are plotted on the p-q plane. The blue line represents crack detection surface and the red line compression yield surface. The high stresses in your model are produced at the point where the blue line and the red line intersects each other. The high stress larger than tensile strength can occur because of the effect of compression.