A general formulation of hypoplasticity

A general formulation of the theory of hypoplasticity is given, under the assumption that Cauchy stress is the only state variable. Such a formulation allows to discuss the relation between the so-called out-of-axis and in-axis moduli. It is proved that, in general, the out-of-axis moduli are independent from the in-axis moduli, which allows the former to be calibrated making use of experimental shear band data, as it is done in CLoE-hypoplasticity. The implicit assumptions made in K-hypoplasticity are detailed for two particular models of this family. Copyright © 2004 John Wiley & Sons, Ltd.