Damage Mechanics

Zebulon offers the largest variety of damage mechanics related options of any commercial FEA software. Features include crack integrals (J, delta J, etc), crack growth boundary conditions and debonding interfaces with contact activation, continuum damage mechanics, and new developments arriving for non-local solutions.

This is a calculation of crack growth using a maximum crack tip strain criterion. notice the change in crack opening angle as the growth accelerates towards failure. Implicit dynamic solutions can be helpful for this type of analysis to prevent numerically related instability creating run away growth.

This is a weld fracture using the Gurson porous plastic behavior. The failure was calculated to completion in 290 loading increments. This is a plot of the cumulated plastic strain using Gauss point plots (exact values). The loading was vertical tension and horizontal to the right side.

This is a simulation of void coalescence in a ductile material (Gurson model). Again, damage is calculated to total failure. Note the interesting symmetry MPC which was imposed. The mesh for this calculation is extremely fine, so the calculation was run on an IBM SP2 supercomputer.

New cutting edge anisotropic damage models with anisotropic viscoplasticity are under development. This figure shows several different stages. The first non-linearity is the onset of damage, followed by a distinct yielding. Load reversal shows a reduced modulus, and reversed yielding with kinematic hardening. As the stress becomes more negative a "fiber-closure" mechanism is reached (stiffining the material), but the damage still exists so another reversal has a point above which the modulus is still reduced.