ONERA’s Multiaxial and Anisothermal Lifetime Assessment for Engine Components

This paper presents the calculation methods developed at ONERA to assess the lifetime of aeroengine structures subjected to multiaxial thermo-mechanical loadings. The complexity of the steps required in this process has grown over the past years, in order to take advantage of extremely accurate observations in materials and more precise experimental results. The research activities in the field of fatigue are presented within a framework that covers microstructural observations, mechanical testing, the development of constitutive equations and fatigue damage models associated with numerical calculations. All of these steps are today closely interrelated in the complex analysis of lifetime predictions. A fundamental aspect is highlighted: the simultaneous consideration of multiaxial and anisothermal loadings, which requires specific developments. These points are detailed, illustrated by many examples of applications and positioned with respect to research works in the literature.