Description: The enhanced hourglass control method is now used by default for all first-order reduced-integration elements modeled with finite-strain elastic materials: hyperelastic and hyperfoam materials in both ABAQUS/Standard and ABAQUS/Explicit and hysteresis materials in ABAQUS/Standard. This method provides increased resistance to hourglassing for nonlinear materials and better coarse mesh accuracy in displacement solutions for linear elastic materials than other hourglass control methods. The enhanced hourglass control approach is compatible between ABAQUS/Standard and ABAQUS/Explicit and is the recommended method for all import analyses.

In ABAQUS/Explicit the enhanced hourglass method cannot be used for elements modeled with finite-strain elastic materials that are included in an adaptive mesh domain. Thus, if you decide to use hyperelastic or hyperfoam materials in an adaptive mesh domain, you must choose a different hourglass control approach. The use of adaptive meshing in domains modeled with finite-strain elastic materials is not recommended since better results are generally predicted using the enhanced hourglass control method. Therefore, for these materials it is recommended that the analysis be run without adaptive meshing but with enhanced hourglass control.

To recover the default hourglass control behavior from previous versions (the total stiffness approach in ABAQUS/Standard and the integral viscoelastic approach in ABAQUS/Explicit), you can use the abaqus upgrade utility with the previousdefaults option.