I recently encountered the research of Phil Attard and others, in which the contact problem is solved, relaxing the restrictions of the traditional contact models (Hertz, JKR, DMT) and solving based on a formulation where the governing equations are derived using finite-range surface forces and calculated numerically, self-consistently.

Hello all,

I have created a 3-d dynamic model in ABAQUS using shell elements.  When I run the analysis I get several warning messages indicating that I have zero pivot nodes.  When I locate where these nodes are, I find that they are in the middle of my beam (modeled with shell elements) away from any boundary conditions.  Does anyone know why ABAQUS is indicating these inconsistent overconstraints in the middle of my model???  The analysis fails to converge when NLGEOM=yes but has no problems converging when NLGEOM is removed.

Thanks in advance

I am trying, quite unsuccessfully, to model a composite steel frame under dynamic loads.  The problem is nonconvergence brought upon by the concrete tensile strains (i think).  Apparently ABAQUS kills the analysis once cracks form in the concrete.  Has anyone had any success using the "Concrete damaged plasticity model" under cyclic loads and large strains.  I have found that researchers use many different concrete properties to get convergence, but I am more interested in a better concrete representation.

Any help on this would be greatly appreciated.