Locking and Zero energy Mode
Locking and Zero energy Mode
(OP)
In using 4 noded non conforming element forplate bending it is said that it "Locks". How is locking associated with energies. Will adaptive refinement help me inpreventing Locking? Will adpative refinement reduce zero energy modes?
In computing the energy of the system should i leave out the shear terms?
In computing the energy of the system should i leave out the shear terms?
Raj





RE: Locking and Zero energy Mode
Zero energy modes (or hourglassing) is associated with lower order elements with (say) single point integration schemes. These elements are unable to capture the strain energy under certain modes of deformation (the lozenge effect, for example). To control hourglass modes in lower-order elements, an hourglass stiffness is sometimes added, which provides a stiffness to resist the zero energy modes. Although the default hourglass stiffness value is usually sufficient, you can usually override this if necessary. Again, consider using a different element formulation if possible (higher order element with midsided nodes should do the trick).
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