Abstract: A limit surface for engineering materials in terms of three invariants of stress is proposed in which the shape of the surface in the deviatoric plane is described as a function of mean pressure. The shape is triangular ...

Abstract: The relationship between material softening and structural softening is investigated through the use of a model problem in one dimension. If the size of the softening zone is large the structural ...

Abstract: A theory of viscoplasticity for frictional materials is developed in which first and third invariants of stress and strain are used instead of the more conventional second invariants. Rate effects are incorporated directly ...

Abstract: A theory of plasticity for frictional materials is developed in which first and third invariants of stress and strain are used instead of the more conventional second invariants. The usual concepts of strain‐hardening ...

Abstract: Failure modes of polycrystalline alumina in compact-tension specimens were studied using the scanning electron microscope. Microcrack propagation was monitored under large magnification. Starting with a preexisting chevron ...

Abstract: Certain materials exhibit a capability to heal with time. Healing implies that microcracks and microvoids reduce in size, with a corresponding increase in stiffness and strength, features that are exactly the opposite of ...