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help for applying the cohesive model to predict the fatigue lift for bimaterial system with perfect interfaces
Dear fellows,
We will predict the fatigue life for the metal-ceramic multilyer devices subjected to cyclic load in service . Residual stresses are induced during high- temperature process in the devices, which were known in the previous work. Considering the bimaterial interface as a weak plane, no geometric discontinuity are taken into account, i.e., perfect interfaces are considered.
How to construct the cohesive interface model (no initial crack)?
appreciate your advice in advance.
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Cohesive elements for fatigue
You may need to define a damage parameter associating with your cohesive elements. The damage may depend on dissipation in a element durng cyclic loading or maximum stress if you like. I get the impression that Ortiz's group at Caltech has done something like this before but I am not certain about it.
Anyway, you may fit the simulation results to your experiments but can not PREDICT the lifetime of the interface subjected to specific loading. You probably can abstract numbers from one boundary value problem and use them to 'predict' another BVP.
Have a look at this paper
Robinson P, Galvanetto U, Tumino D, Belluci G and Violeau D, Numerical simulation of fatigue-driven delamination using interface elements, International Journal for Numerical Methods in Engineering 63(13), 1824-1848, 2005.
It might be useful.
--
Yuval