Is the von Mises criterion generally applicable to soft solids?

Area of Science:

• Materials Science
• Solid Mechanics
• Rheology

Background:

• The purely viscoplastic model shapes current understanding of yield stress materials.
• Common assumptions about yielding, including a scalar yield condition and the von Mises criterion, are oversimplifications for general yield stress materials.

Purpose of the Study:

• To investigate the yielding behavior of seven materials under extensional loading (traction and compression).
• To evaluate the performance of the von Mises criterion for these materials.
• To propose and assess a new yield criterion accounting for differences in traction and compression.

Main Methods:

• Experimental investigation of material yielding under distinct loading conditions.
• Comparative analysis of the von Mises criterion against experimental data.
• Development and validation of a novel yield criterion incorporating the third invariant of the deviatoric yield stress tensor.

Main Results:

• The von Mises criterion demonstrated poor performance in predicting the yielding of the tested materials.
• A new proposed criterion, considering the third invariant, improved predictions for traction and compression but failed for shear loading.
• Significant discrepancies were observed between traction and compression yielding points.

Conclusions:

• The von Mises criterion is not universally applicable to all yield stress materials.
• A new criterion offers improvements but does not fully capture yielding behavior across all loading types.
• The existence of a universal yield criterion for all yield stress materials is unlikely.