Description: The algorithm to compute nodal values of contact pressure and contact shear stress associated with output variable CSTRESS to the output database (.odb) file has been improved, such that contour plots of these variables will more accurately reflect the extent of regions with elevated contact stress for surfaces based on second-order element types. Previously, the extent of regions of high contact pressure was often exaggerated, and small, nonphysical “islands” of elevated contact pressure surrounded regions with physical peaks. Another effect of this change is that the peak contact pressure reported for local contact stress concentrations will tend to increase somewhat for surfaces based on second-order elements (for example, increases of 5% are typical). Modifications were made in the algorithm that computes nodal contact stress components based on contact stresses associated with individual contact constraints; the modifications do not affect contact stresses associated with individual contact constraints, so contact constraint stresses reported to the data (.dat) and results (.fil) files are not affected by this change.

Figure 11–4 shows contact pressure contours on a solid sphere meshed with C3D10 elements and pinched between two rigid plates. The contact pressure contours on the right represent the extent of the contact regions more accurately, and nonphysical contact pressure outside the contact region is avoided.