Integrated Durability Analysis Using ANSYS, ADAMS, and Finite Element Fatigue

In the competitive economic environment that now exists in practically every segment of mechanical design, the value of assessing the durability of mechanical components as early in the design cycle as possible is obvious. This paper describes an example of an integrated durability analysis process performed on a rotary cutter developed by John Deere, Welland Works using CAE tools exclusively. The Pro/Engineer solid geometry of the cutter was used to generate both a basic ADAMS model (using the embedded product MECHANISM/Pro) and finite element meshes for the flexible components (using Pro/MECHANICA). The flexible bodies were generated using the finite element program ANSYS and then imported into the ADAMS model and their flexibility accounted for in the dynamic simulation of the cutter. The simulation mimicked a rotating drum test that is used in the development of new cutter systems. Embedding finite element representations of critical components within the ADAMS model, offers the advantage of being able to recover the stress/time histories at every node in the finite element model for the entire simulation. This would be analogous to having a virtual strain gauge at every node in the finite element model during the simulation. With the stress/time histories available, FE-Fatigue can be used to perform the durability analysis and the resulting damage and life predictions imported into ANSYS for post processing. This approach successfully predicts crack locations in a physical prototype, thereby validating the analysis procedure.

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