441 likes | 1.08k Views
Elastic-Plastic Deformation. Simple Constitutive Relations. And Their Graphs. Flow Rule. Anisotropy. Yield Surfaces. Drucker postulate. Kinematic hardening. Kinematic hardening is a monotonically growing & saturating function of strain and is a complex function of temperature.
E N D
Kinematic hardening Kinematic hardening is a monotonically growing & saturating function of strain and is a complex function of temperature
Isotropic Hardening Latent hardening is a monotonically growing and saturating function of strain and is a complex function of temperature
Example on the simple Beams • Let us consider the simple problem or two, which should give us general feeling what is the plasticity is about • We look at 1D problem • We look at non-hardening problem • We look at isothermal problem • Nothing is more illustrative as beam examples
Simple Beam • Given: E, l1, l2, P N1 P N2
Yield of Each Part Limiting or critical Force is: Compare
Displacements ASSUME NOW THAT APPLIED LOAD IS THEN UNLOAD IT
Elements of Shake Down Method Ec=E; Es=2E; P
Shake Down Limiting Load: Elastic solution: Let us apply the Force P1 to the system: Let us now unload the system: Let us apply the Force -P2 to the system:
Limiting Cycle OHGF – Elastic Regime ABGH and FGDE – system adjusts after first cycle; P1+P2<5Ny BCD- cyclic plastic deformations P2 B C A Out of Big-square- Failure G H D O F E P1