In this paper, a delaminated beam made of functionally graded materials subjected to general edge conditions is studied The mechanical properties vary as a general function of thickness coordinate and can be changed abruptly at the interface of two connected beams. The procedure is based on a technical engineering theory for calculation of strain energy release rate and its separation into modes I and II of fracture. By choosing a suitable displacement field based on second-order shear-thickness deformation theory and using the principle of minimum total potential energy, the equilibrium equations are obtained. The total strain energy release rate is obtained by using the J integral for the delaminated beam. The separation of J integral into modes I and II is carried out by decomposition of stress and strain fields from point symmetric to the crack plane. Double cantilever beam (DCB) problem is a special case of this general problem in which loading is in mode I of fracture. The results are compared with the results of finite element method. This comparison shows good agreement between the results.

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