Delamination Analysis of Multilayered Functionally Graded ‎Beams which Exhibit Non-linear Creep Behavior

General solution of the time-dependent strain energy release rate for delamination cracks in multilayered functionally graded load-bearing beam structures which exhibit non-linear creep is derived. The material is functionally graded along the length of layers. The Ramberg-Osgood stress-strain relation is used by assuming that the material in each layer behaves differently in tension and compression. The second term in the Ramberg-Osgood relation includes time dependence to treat the non-linear creep. The solution derived holds for multilayered functionally graded beams with arbitrary number of layers which have different width and material properties. The solution is applied for a delamination in a multilayered beam with a built-in end. An analysis is performed also by considering the balance of the energy in the multilayered beam configuration for the sake of verification. The effect of time is also studied. It is found that the strain energy release rate grows with the time. The results obtained here are useful for understanding the time-dependent delamination in multilayered functionally graded structural components subjected to non-linear creep.