UPPER BOUND THEOREM FOR RIGID/PLASTIC SOLIDS GENERALIZED TO INCLUDE COULOMB FRICTION

The usual definition of a kinematically admissible velocity field is unnecessarily restrictive for the validity of the upper bound inequality of limit analysis. In consequence, it is shown that this inequality can be used to derive overestimates of quantities of interest in metal-forming processes which have not been considered hitherto. In particular, upper bounds can be obtained for the total load in the presence of Coulomb friction on the tool/workpiece interface. In illustration, the technique is applied to problems of compression and extrusion. © 1969.