AGMA 93FTM10-1993 pdf free.High Speed, Heavily Loaded and Precision Aircraft Type Epicyclic Gear System Dynamic Analysis by Using AGMA Gear Design Guidelines Enhanced by Exact Definition of Dynamic Loads.
Achieving gear system quality-characteristic goals for operability, reliability, and power density will require an accurate design system focused on the right issues. For example, adequate operability margin will require accurate predictions for both system and component natural frequencies and modes as well as for system response to transient events. Achievement of reliability and power density goals will require accurate predictions for steady-state and transient dynamic loads and relative velocities.
The ideal simulation, then, would provide accurate predictions for dynamic loads and relative velocities, based on specification of certain configuration parameters. The utility of such a system depends on the ability of the simulation to not only make accurate predictions, but to make them with respect to those issues of greatest significance.
In the quest toward accurate simulation, the guideline must be to create the simplest model that retains the essential features of the physical system. After a certain model complexity has been reached, it is likely that improvcments in accuracy come in ever smaller increments while solution time increases disproportionally.
Although excitation frequencies are much higher than the lowest natural frequency, they are not so high that the duration of loading is in the order of wave traversal times. The problem, therefore, is a structural dynamics problem rather than a wave propagation problem.
The simulation requirements can be met by developing two distinct capabilities: (1) a natural frequency/mode shape analysis, and (2) a direct integration time history analysis. The first capability provides means of comparing natural frequencies to excitation frequencies to ensure adequate margin, but yields relative displacements. The second capability provides predictions for instantaneous positions, velocities, accelerations, forces and moments acting on all bodies in the system as a result of the application of given forces and moments. The predictions, however, are a function of the mass distribution, stiffnesses, and damping assumed in creating both the analysis and the representation of the physical system being modeled. In addition, the integration process must be stable and accurate. For these reasons, it is extremely important that the simulation model be carefully correlated to verify the validity of the predictions.AGMA 93FTM10 pdf free download.