Effect of Geometric Nonlinearity on the Life of a Herringbone Lock Joint in Creep

The effect of geometrically nonlinear deformation on the design life of a herringbone blade joint in creep is examined. The design life is evaluated by the moment scheme of the finite element method. The algorithm for solving the systems of nonlinear equations is based on differentiation with respect to the parameter λ, which consists of the replacement of the system of nonlinear equations with the Cauchy problem for the system of ordinary differential equations with respect to the parameter, which can be the intensity of external mechanical loading or forced displacement. The material deformation in creep is described on the basis of the Kachanov–Rabotnov theory. Geometrically nonlinear deformation is simulated with reference and actual object configurations. The Cauchy of actual stress tensor as an objective derivative is used to describe the stress state, the Aldroid derivative is used to determine strain and stress increments. The design life is evaluated to attain the critical damage parameter of the material. Quantitative and qualitative damage parameter variations with time are followed, and the quantitative estimation of the design life change in view of geometrically nonlinear deformation is carried out.