Аннотация:Delayed fracture of bended rectangular plate is researched under creep condition in unsteady complex stress state with consideration for the effect of an ambient medium. Using Rabotnov’s kinetic theory, time to fracture of such plate was determined during sequential bending in different planes. Piecewise constant dependences of bending moments levels on time are considered. The time to fracture of the plate is determined using a fractional linear creep model. The effect of the ambient medium on the creep and the creep rupture of the plate is attributed to diffusive penetration of ambient medium elements into the material of the plate. Ambient medium effect is taken into consideration by introducing a function of cumulative average concentration into constitutive and kinetic fractional linear equations. The times to fracture while using scalar and vector damage parameters are compared.