Robust Model for Behavior of Complex Materials during Spin Testing

The objective of this project is to develop a practical finite element-based simulation of spin-pit tests of disks. The performance of disks in spin-pit tests critically depends on localized effects, such as residual stresses, dislocations, and microstructure gradients. Therefore, a two-scale modeling approach is adopted. At the global-scale, the disk is represented by means of finite elements with embedded internal discontinuities. Local-scale models are employed to account for localized effects, such as the influence of microstructure on inelastic properties (e.g., creep and plastic hardening). An important feature of the proposed approach is that it enables the simulation of arbitrarily oriented localized “softening” effects (relative to the geometry of the finite element mesh). This feature is critical because it enables the simulation of the propagation of oriented localized effects, such as fatigue cracks, independent of the mesh geometry. This project will also result in novel two-scale material models, and procedures to obtain the associated material properties. Numerical simulations of spin-pit tests of dual-heat treated disks will be used to validate the proposed development. Both two- and three-dimensional simulations will be performed. These simulations will include both steady-state disk spinning, as well as transient states (i.e., acceleration and deceleration). BENEFIT: The outcome of this project is simulation software to predict the performance of advanced turbine disks in spin pit tests. In particular, it will permit the analysis of the influence of imperfections and residual stresses, introduced during the manufacturing process, on the performance of turbine dicks. This software will enable improved optimization of disk design, leading to increased fatigue life, and reduced maintenance. In particular, it will enable reliable analyses of advanced disks such as dual-heat treated disks, which are used in the high-pressure section of jet engines for both civil and military applications. The demand for higher fuel efficiency mandates that engines operate at higher temperatures. As a result, the need for advanced disks (i.e., dual-heat treated and hybrid disks) is increasing. In fact, future advancements in jet engine technology hinges on the availability of such disks. The tool that Symplectic Engineering is proposing, therefore, is aimed at meeting a clear demand identified by jet engine manufacturers (e.g., GE, Pratt & Whitney, and Rolls-Royce), as well as by the Air Force and Navy. For this reason, Symplectic Engineering expects to successfully commercialize its technology.