An energetic view on the limit analysis of normal bodies

This note presents a limit analysis for normal materials based on energy minimization. The class of normal materials includes some of those used to model masonry structures, namely no-tension materials and materials with bounded compressive strength; it also includes Hencky plastic materials. Considering loads that depend affinely on a loading multiplier, we examine the infimum of the potential energy over the set of all admissible displacements; we prove that the set of all loading multipliers where this infimum is finite is an interval and call its endpoints collapse multipliers. We then examine the validity of the static and kinematic theorem of limit analysis under the present definition.